VNS Message Board

VNS DISCUSSIONS => Legislative Activism In Regards to VNS => Topic started by: dennis100 on May 11, 2011, 11:08:56 AM



Title: Electrodes
Post by: dennis100 on May 11, 2011, 11:08:56 AM
Event Date 09/11/2000
Event Type Injury
Patient Outcome Hospitalization; Required Intervention
Event Description
Reporter indicated that device was explanted due to infection and protrusion through skin. In 2000 wound opened up due to infection and generator was explanted. In 2001, lead began protruding through incision and was explanted (electrodes left on nerve). About 8 weeks later patient presented with red and granulated tissue around the neck area. Physician noticed a small piece of wire sticking up through the skin. During surgery to remove remainder of lead, physician reported that what was remaining of the lead and electrodes was floating in the neck. Physician reported that the electrode had slipped off the nerve and had started comming through the skin.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=326155


Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 11:10:13 AM
Model Number 300-20
Event Date 12/03/2001
Event Type Malfunction
Event Description
Reporter indicated that at a follow up visit during the week in 2002, the patient's physician ordered x-rays to check the connection of the lead since the patient does not display any side effects of stimulation and has reported continued lack of benefit from the vns implant. It was reported that the x-ray suggests that one part of the connection to the nerve is "disconnected" but that the x-ray was inconclusive. The physician increased the programmed parameters and as the device was tested with the magnet the patient went into a seizure during magnet mode stimulation. It was reported that the patient continues to have seizures in which their left side completely goes numb, rendering the patient helpless and severely limiting the patient and the patient's parents' activities. It was reported that this is a relatively new phenomena (past year) and that the patient has had two or three bad episodes of this since the stimulator was activated (12/2001). It was reported that the physician planned only to observe the patient over the next three months. It is suspected that user error may have caused or contributed to a lead discontinuity, improper lead placement on the nerve, or improper lead connection to the generator, resulting in lack of therapy for the patient.

Manufacturer Narrative
Reporter indicated that during the revision surgery on 3/27/2002 it was verified that the lead was nowhere near the nerve. It was also reported that no tie downs were used in the initial implant. The neurosurgeon was going to reattach the lead to the nerve but during the surgery he noticed that the lead was damaged. The initial lead was explanted and a new lead was re-implanted. Lead test at re-implant surgery resulted in an ok impedance.

Manufacturer Narrative
Physician indicated that the pt's lead was not placed correctly on the nerves. Pt's parent reported that the pt is scheduled to have revisional surgery performed on his neck to properly connect the wire to the nerve on 3/27/02.

Manufacturer Narrative
Device programming history was reviewed. X-rays were reviewed. Manufacturing records were reviewed. Review of device programming history did not reveal any anomalies or abnormalities. X-ray review revealed that the electrodes and adjacent lead appear to be in a non-recommended routing. No tie-downs are present. The electrodes do not appear to be properly aligned (not parallel). The lead appears to be fully intact; however, the electrodes appear to be low on the nerve if on the nerve at all. Review of manufacturing records did not reveal any anomalies or abnormalities that would have an adverse effect on device performance.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=379476


Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 11:10:47 AM
Event Date 07/01/2002
Event Type Malfunction
Event Description
Reporter indicated that device diagnostic testing at office visit in 07/02 resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The patient underwent generator replacement surgery in 2002 due to end of service. Device diagnostic testing in 06/2002 resulted in high lead impedance reading (dc-dc code 4, ok and high), indicating that the ncp system was functioning properly, but that the generator was working harder to deliver the programmed therapy. X-rays did not reveal any obvious discontinuities in the ncp system, but it did appear that the negative electrode may not be properly attached to the nerve. Further follow-up revealed that the lead was replaced in 2002. The patient reportedly had an excessive amount of scar tissue around the lead coils on the nerve. The physician indicated that the excess scar tissue may have contributed to the high lead impedance readings by preventing a good connection of the lead to the nerve. In addition, the nurse reported that they believed that the patient was still feeling stimulation prior to lead replacement surgery because the patient would grab at their neck. It was also reported that the patient was not as alert and was hallucinating before lead replacement surgery because of heavy medication changes. The patient stated that they were not aware of any injury that they may have experienced that could have caused damage to the ncp system. The patient has reportedly had fewer seizures with the vns implant.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=412996



Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 11:11:21 AM
Event Date 01/01/2001
Event Type Injury
Patient Outcome Life Threatening; Hospitalization Required Intervention
Event Description
Reporter indicated that the patient developed an infection and the ncp system was replaced. The original electrodes were left in place on the nerve. The patient developed cyst-like lumps over the incision sites and the second ncp system was removed. Reporter indicated that the patient has gone through 10 surgeries to resolve the infection. Reporter indicated that in december 2001, the patient developed another lump in the scar on their neck which made the scar open, exposing the coil from the nerve. It was reported that the patient's family member pulled the coil out with their fingernails. An attempt to obtain additional information was made. No response to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=406405


Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 11:12:15 AM
Event Date 05/25/2001
Event Type Malfunction
Manufacturer Narrative
Review of x-ray was unable to determine whether the electrodes were properly placed on the vagus nerve. No tie-downs were evident on the x-ray film. Revision surgery is scheduled for 2001.

Event Description
Reporter indicated that it was believed that the electrode may have slipped off of the nerve because the pt was having pain in neck.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=339415


Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 11:12:48 AM
Event Date 02/01/2003
Event Type Malfunction
Event Description
Reporter indicated that for the past couple of weeks, the patient has had an increase in seizure activity. Device diagnostic testing at office visit in 2003 resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The elective replacement indicator was no, indicating that the generator was not at end of service. X-rays reviewed by physician did not reveal any obvious discontinuities in the ncp system. Exploratory surgery was performed the following month at which time the patient's original lead was connected to a new generator. Device diagnostic testing repeatedly resulted in high lead impedance readings, indicating a potential break in the patient's original lead. The patient's ncp system (both lead and generator) was replaced. The patient indicated to neurosurgeon's nurse that the original lead electrodes had come off of the nerve, causing the high impedance readings; however, investigation to date has been unable to confirm.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=452602


Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 12:06:25 PM
Event Date 05/22/2003
Event Type Other Patient Outcome Other;
Event Description
Pt undergoing removal of a vagal nerve stimulator implant that was placed in 2003. The surgeon was removing it due to an infection. He couldn't remove all of it since the lead was wrapped around carotid and vagal nerves. The device did not malfunction.

Event Description
Add'l info rec'd from mfr 7/31/03: cyberonics reported this event to the fda on 06/20/2003 (reference 1644487-2003-00345). Further follow-up revealed that the infection was present at both the pulse generator pocket and the lead cervical incision sites. Swab cultures were performed in 2003 at the pulse generator pocket area and resulted in staph aureus. The pulse generator was explanted and the lead was cut, leaving the electrodes attached to the vagus nerve. The infection was treated with antibiotics. A re-implant is planned; however, it has not been scheduled. The physician indicated that the infection has been resolved. Additionally, it was reported that the pt had surgery on their left shoulder within three months of having the vns implant. The voluntary medwatch form (mw1028672) indicates that the lead was wrapped around carotid and vagal nerves. This is incorrect. Cyberonics obtained the operative notes from the explant. The operative notes do not state that the lead was wrapped around the carotid nerve. The surgeon stated ". It was so heavily infested with scar tissue there was no way to see any of the plane between the vagus and the carotid" due to this, the surgeon elected to cut the lead and leave the electrodes on the vagus nerve rather than risk damaging the vagal nerve or carotid artery. The expiration date on the initial mdr was incorrectly entered. The expiration date is 09/30/2004 and the device was implanted prior to this date. This correction was included in an mdr supplement submitted to the fda on 07/22/2003. The manufacturing records were reviewed for both the pulse generator and the lead. Sterilization was confirmed. Cyberonics does not believe that the infection was attributable to the devices. Cyberonics believes that the infection was attributable to the implant surgery.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=465978




Title: Re: Electrodes
Post by: dennis100 on May 11, 2011, 11:23:38 PM
Event Type Malfunction
Event Description
Reporter indicated that device diagnostic testing resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The patient had reportedly undergone generator replacement surgery for end of service approximately one year prior. Shortly after generator replacement surgery, the original lead came off of the nerve. Revision surgery was performed and the lead was reconnected to the nerve. Approximately one year later, device diagnostic testing resulted in high lead impedance reading. The elective replacement indicator was no, indicating that the generator was not at end of service. Lead break or disconnect is suspected. Revision surgery is planned.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=479190



Title: Re: Electrodes
Post by: dennis100 on May 12, 2011, 12:33:58 AM
Event Date 01/01/2003
Event Type Malfunction
Event Description
Reporter indicated that device diagnostic testing at office visit resulted in high lead impedance reading (dc-dc code 7), indicating possible device malfunction. The patient reportedly felt the device was not working at times and occasionally did not feel stimulation. The patient had not suffered any injury or trauma that may have damaged the vns therapy system. Further follow-up revealed that the patient underwent revision surgery during which the lead was noted to be disconnected from the generator. Generator malfunction was ruled-out as pre-implant test on the device was within normal limits. The lead connector pins were cleaned and reconnected to the generator, after which device diagnostic testing again resulted in high lead impedance reading. The surgeon then opened the neck incision and noted excessive amounts of scar tissue. After 3 hours of dissecting through the scar tissue, the surgeon had not still been able to locate the vagus nerve. Both the lead and generator were explanted and the patient was not reimplanted.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=470181



Title: Re: Electrodes
Post by: dennis100 on May 12, 2011, 07:49:54 AM
Event Date 01/01/2003
Event Type Malfunction
Event Description
Reporter indicated that the lead electrodes had come completely off of the pt's nerve. The pt had experienced nearly 100% efficacy with the vns therapy, but treating neurologist ordered x-rays due to a recent seizure. Upon review of the x-rays, it appeared that there was no strain relief loop present in the lead wires. Revision surgery was performed during which it was noted that the lead electrodes were completely off of the nerve. The lead was replaced and the explanted lead was discarded. It was reported that the pt manipulates the generator through the skin. Treating neurologist believed that this was the cause of the lead being off of the nerve and that there was no malfunction or anomaly with the lead itself.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=512136



Title: Re: Electrodes
Post by: dennis100 on May 13, 2011, 01:31:51 AM
Event Date 01/01/2004
Event Type Malfunction
Event Description
Device diagnostic testing at office visit resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The elective replacement indicator was no, indicating that the generator had not reached end of service. Pt was seen for follow-up neurologist because the pt felt as if their device was no longer working. The pt also reports pain in the neck area. X-rays were performed and reviewed. It was reported that there are no visible lead fractures on the x-rays. It was also reported that the pt's jugular vein was "pasted" onto the vagus nerve and scar tissue has built up, therefore, revision surgery may not be performed. Review of the programming history concluded that within the last two months the device impedance increased to a dc dc code of 7 and limit indicating a possible device malfunction.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=612038


Title: Re: Electrodes
Post by: dennis100 on May 13, 2011, 01:32:26 AM
Event Date 05/19/2004
Event Type Injury
Patient Outcome Required Intervention;
Event Description
Reporter indicated that during device diagnostic testing at initial implant surgery, surgeon noted that the pt experienced neck spasms. Subsequent device diagnostic testing during initial implant surgery also resulted in the pt experiencing neck spasms. Further follow-up revealed that the surgeon initially placed the lead electrodes around the hypoglossal nerve. Surgeon then re-identified the vagus nerve and placed the lead electrodes without further incident.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=530557



Title: Re: Electrodes
Post by: dennis100 on May 13, 2011, 04:05:45 AM
Model Number 302-30
Event Type Malfunction
Event Description
Reporter indicated that device diagnostic testing at office visit resulted in high lead impedance (dc-dc code unk), indicating possible device malfunction. It was also reported that the pt experienced an increase in seizures. It is unk if the increase in seizures is above the pt's pre-vns baseline frequency. Revision surgery was performed. During revision surgery, neurosurgeon noted that the generator setscrew was stripped. Both the pulse generator and bipolar lead were then replaced, it is likely that the high lead impedance reading was a result of the negative electrode not being attached to the pt's vagus nerve.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=612165



Title: Re: Electrodes
Post by: dennis100 on May 14, 2011, 09:57:09 AM
Event Date 05/01/2003
Event Type Malfunction
Event Description
The device had been turned off approx one month prior to the surgery. It was also reported that only the lead was replaced during surgery. The surgeon reported that during the revision surgery, he observed a lot of fibrosis around the old lead/nerve interface and so he clipped the electrodes and implanted a new lead. The surgeon also stated that during the procedure he did not find any gross anamalies with the old lead and that the lead did not come off the nerve as the pt initially alleged. The surgeon further commented that he believes the fibrosis had kept the lead helicals firmly in place. The pt had complained of twitch with his sternocleidomastoid muscle during vns stimulation; this was the reasons for the revision surgery. The device was turned on after the surgery. Post-surgery, the pt complained of headaches, which reportedly resolved.

Event Description
Reporter indicated his lead came off the vagus nerve approx 3 months after the implant. The pt began experiencing muscle twitching in his neck. The pulse generator was reportedly inactivated 32 months after the implant and the pt no longer felt the muscle twitching. The pt recently underwent lead revision surgery. However, it is unk at this time if the lead was explanted, replaced with a new lead, or re-attached to the vagus nerve. The cause of this event is unk; the event is currently being investigated.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=662891



Title: Re: Electrodes
Post by: dennis100 on May 14, 2011, 09:58:02 AM
Event Date 04/01/2005
Event Type Malfunction
Event Description
The patient underwent revision surgery, at which time it was discovered that the lead electrodes were not attrached to the vagus nerve. Both the lead and generator were replaced. The burning sensation has resolved with the device replacement. The lead assembly was returned to manufacturer for analysis. The reported events of burning or heat sensations are not duplicate in the laboratory environment. Visual examination of the lead assembly identified incisions, punctures in the silicone tubing, and exposed sections of the lead coils; however, it is unknown whether these conditions existed during the implant life. The condition of the returned portion of the lead, in general, is consistent with conditions that typically exist following an explant procedure. The lead pin showed evidence of a proper mechanical and electrical connection as expected. The pulse generator was also returned to manufacturer for analysis. Device diagnostic testing was within normal limits, indicating proper device function. The elective replacement indicator was no, ruling out generator battery end of life. Visual examination performed prior to decontamination showed that the septum was cored and contained dried blood in the septum cavity. There were no performance anomalies or any condition found with the pulse generator that would have contributed to the reported events; however, if the septum was cored during the implant life, this may have been a contributing factor to the paresthesia. The likely cause of the patient's symptoms is the fact that the lead electrodes were not attached to the vagus nerve. The reason that the electrodes were not attached has been ascertained.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=652946




Title: Re: Electrodes
Post by: dennis100 on May 14, 2011, 01:22:59 PM
Event Date 04/20/2007
Event Type Malfunction
Event Description
Reporter indicated that a vns patient was not sensing normal stimulation upon the initial activation of the device. A systems diagnostics test was performed and the results were reported to be within normal limits. The output current was increased incrementally up to 3ma output current and the patient still did not sense the stimulation. X-rays were reviewed by manufacturer and it appeared that the anchor tether may not be attached to the vagus nerve. Additionally, the caudal (positive) electrode did not appear to be placed around the vagus nerve in the typical helical orientation, which is not what is typically seen unless it is due to the patient's anatomy. The patient had a surgical consult regarding the event. It is unknown if or when the patient scheduled for revision surgery. Attempts to obtain additional information from the surgeon and have been unsuccessful.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=852324


Title: Re: Electrodes
Post by: dennis100 on May 15, 2011, 12:22:21 PM
Event Date 01/01/2005
Event Type Malfunction
Event Description
Device diagnostic testing at office visit resulted in lead impedance reading, indicating possible device malfunction. The elective replacement indicator was no, ruling out generator battery end of life as a likely cause of the high lead impedance test result. It was reported that device diagnostic testing performed approx nine months prior was within normal limits, indicating proper device function at that time. The pt no longer feels device stimulation and reported that one of his children had recently fallen on him, possibly causing damage the ncp system. Treating physician suspects a lead discontinuity and revision surgery is planned; however, the physician indicated that the pt may not have room left on his left vagus nerve since he had several leads already.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=664208


Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 06:12:52 AM
Event Date 01/01/2003
Event Type Injury
Patient Outcome Required Intervention;
Event Description
Reporter provided an op report that stated a patient was experiencing an "erosion of the electrodes through the area of his lower neck" that "probably represented acne infection with abcess, which communicated with the wire and because of the retained "foreign body," this lesion could not heal. The only way to control this was to remove the device. " follow-up with the physician's office indicated that the pt had developed small pimples around different parts of the body including the neck site around the lead area. The doctor stated that the pt's body was most likely rejecting the lead which was the suspected cause of the pimples around the pt's body. The infection was caused when the lead eroded through the surface of the skin. No pt manipulation is suspected.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=861038


Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 06:13:44 AM
Event Date 04/30/2007
Event Type Injury
Patient Outcome Hospitalization; Required Intervention
Event Description
Reporter indicated that the patient began experiencing hoarseness 48 hours following implantation surgery. The patient's vns was not programmed on yet. The physician indicated that turning the vns device on made the patient's hoarseness worse. The patient was diagnosed with left vocal cord paralysis by an ent physician. Further information received indicated that "post-implantation of a 2mm lead the patient presented with the significant hoarseness and vocal cord paralysis, prior to initiation of stimulation. " revision surgery was performed in 2007. It was reported the doctor noticed "swelling in the electrode region causing pressure on the nerve. " the surgeon elected to remove the 2. 0 mm lead and plans to re-implant the patient with a 3. 0 mm lead in the future. It was indicated that the patient's hoarseness has improved about 80% since removal of lead.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=862295


Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 06:14:34 AM
Event Date 01/01/2007
Event Type Malfunction
Patient Outcome Hospitalization;
Manufacturer Narrative
Device malfunction is suspected.

Event Description
Reporter indicated that the 'pt's electrodes were coming off the vagus nerve. " physician notes received by manufacturer indicated that the pt started to "have problems with seizure management" and was experiencing "pain over the left side of face, about the left eye, problems swallowing, problems speaking, and pain with tingling and burning referred into the arms, hands, and now sometimes legs. " "it appears that the lead attached to the left vagal nerve is not well attached and may actually be totally displaced. " the pt was admitted to the hospital, her settings were planned on being changed, and revision surgery planned in an attempt to resolve the pt's issues. Follow-up with the physician indicated that he looked at the pt's x-rays and did not see anything. He also explained that the normal mode diagnostics obtained were ok. Additionally, it was reported that the pt was experiencing headaches and jaw pain. The physician thinks tha it may have something to do with the pt's anatomy that causes the lead to come off. He explained that the pt was extremely psychotic prior to the vns and is now a "completely different person. " revision surgery was performed in 2007. Diagnostics were performed prior to surgery and obtained all normal results with a dcdc code of 3 and eri=no. It was reported that the surgeon found that there was inadequate strain relief "due to improper positioning of the tie downs, the lead was in the shape of a figure 8, and there was a great deal of scar tissue which was never removed from previous surgery that contributed to the pt's events. " the surgeon removed the lead implanted in 2006 and almost all of the scar tissue that was present on the vagus nerve of the pt. There was part of the scar tissue that he did not remove to avoid damage to the vagus nerve. The replacement lead's electrodes were positioned right below the original site of the scar tissue. Diagnostics performed after the surgery obtained normal results.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=861962


Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 08:38:55 AM
Event Date 01/01/2006
Event Type Malfunction .
Event Description
Reporter indicated a pt had high impedance readings at an office visit, indicating a possible lead break. The pt was also experiencing an increase in seizures. The seizure increase was not greater than pre-vns baseline levels. Review of x-rays by the manufacturer revealed a suspicious area at the negative electrode that appears to be a break. Revision surgery is planned.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=885326



Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 12:44:18 PM
Event Date 03/15/2006
Event Type Malfunction
Event Description
Reporter indicated that high lead impedance was obtained via intraoperative diagnostic testing during a new implant procedure, indicating a possible lead malfunction. Lead was subsequently replaced during same procedure and was returned to manufacturer for product analysis. During analysis, it was noted that the "furthest electrode from the bifurcation has what appears to be silicone adhesive/elastomer coverage over the electrode area, which exceeds specification. Based on the product analysis findings, there is evidence to suggest that the condition of the furthest electrode ribbon surface would have contributed to the high impedance complaint. ".

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=889844




Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 12:47:58 PM
Model Number 302-30
Event Date 08/10/2005
Event Type Malfunction
Event Description
Reporter indicated that he received high lead impedance during multiple system diagnostics tests during a patient implant procedure. Troubleshooting did not resolve the issue. Reporter additionally indicated that "the positive electrode appeared to be abnormal" because "the electrode size appeared larger than the other electrodes when he removed the lead from the sterile packaging. " he then reported that it looked as if the positive electrode was not making a good connection with the nerve compared to the other two electrodes. " lead was then replaced during same procedure and returned to manufacturer for analysis. During analysis, measurements of the inner diameters performed on the electrodes showed that the diameters of both of electrodes did not meet manufacturer specification of approximately 50-60% of the circumference. It was additionally determined that due to the actual condition of the lead, it is unknown whether this condition was present prior to manipulation of the lead by the physician.

Manufacturer Narrative
Device malfunction occurred, but did not cause or contribute to a death or serious injury.

Event Description
Operative notes for the (b)(6) 2005 vns implant surgery were received to the manufacturer. After diagnostics testing noted high lead impedance, it was decided 'this lead is not a good lead' and it was not implanted. The surgeon also noted 'it had been apparent from the onset the coils were not in contact with the nerve and that this may have been a defective lead. ' a new lead was used without issues.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=889846


Title: Re: Electrodes
Post by: dennis100 on May 16, 2011, 12:48:30 PM
Event Date 07/01/2007
Event Type Injury
Patient Outcome Required Intervention;
Event Description
Reporter indicated that the vns electrodes had been "pulled out" by the patient and that there was an infection at the site of extraction. The ncp generator and lead were explanted as a result of the events. Attempts to obtain additional information from the physician have been unsuccessful to date. Product analysis was completed on the ncp generator and lead, although the electrode portion of the lead was not returned for analysis. No anomalies were identified with the generator or portion of the lead returned.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=902907


Title: Re: Electrodes
Post by: dennis100 on May 17, 2011, 04:00:59 AM
Event Date 08/22/2007
Event Type Malfunction
Event Description
Reporter indicated that during an initial vns therapy system implant surgery, the surgeon had trouble implanting the lead because the electrodes were not staying on the nerve. The surgeon also reported that he had manipulated the lead too much and chose to implant a new lead. The lead was returned to manufacturer for analysis. Product analysis on the returned lead portions revealed the closest electrode bifurcation was damaged showing bends in the electrode ribbon and partial detachment from the silicone helix. The likely cause of the damaged electrode is the force exerted during manipulation of the helix.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=915355


Title: Re: Electrodes
Post by: dennis100 on May 17, 2011, 04:02:14 AM
Event Date 08/01/2007
Event Type Malfunction
Event Description
Initial reporter indicated that, the patient had been to surgery for a generator replacement for end of battery life and would be rescheduled for a total revision related to "malfunction of electrodes" at a later date. Physicians office reported that, the patient was unable to feel the adjustments being made to her device and was also experiencing pain in the neck region "which leads me to believe she a defective electrode". Further follow-up with the physician's office, it was reported the patient's vns was at complete end of battery life and no diagnostics could be performed preoperatively. In the or, it was discovered after replacing the patients generator and connecting it to the indwelling lead that the patient had high lead impedance. The patient was then scheduled for a full revision at a later date. The patient had their full revision surgery and good faith attempts are being made for product return for analysis.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=914286


Title: Re: Electrodes
Post by: dennis100 on May 17, 2011, 04:03:46 AM
Event Date 09/20/2007
Event Type Malfunction
Patient Outcome Hospitalization;
Manufacturer Narrative
X-rays were reviewed by the manufacturer. X-ray review showed the electrode placement was not what is typically seen. Although it can not be stated conclusively, the electrodes placement is consistent with other instances where the electrodes have become detached from the vagus nerve, or where the electrodes are attached, but the pt anatomy is a-typical. Device malfunction is suspected, but did not cause pt death.

Event Description
Reporter indicated the pt presented with high lead impedance on a system diagnostics test, indicating a possible lead malfunction. No trauma, pt manipulation or any other condition was reported that could have caused or contributed to the high lead impedance. The pt's generator was programmed off. X-rays were viewed by the manufacturer, and it appeared the electrode placement was not consistent with what is typically seen. Although it can not be stated conclusively, the electrodes placement is consistent with other instances where the electrodes have become detached from the vagus nerve, or where the electrodes are attached, but the pt anatomy is a-typical. The pt underwent vns therapy system replacement surgery. In the operative report the surgeon reported the "electrodes had shifted in their position. They had actually projected the vagus nerve anteriorly and were in a more horizontal position than expected. " it was also noted "the upper most electrode had partially eroded into the vagus nerve. Fortunately, there was no transection. The electrodes were then carefully removed intact. " the generator was replaced prophylactically. The generator was returned to the manufacturer, but the lead was discarded by the hospital staff. Therefore a product analysis can not be performed.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=929776


Title: Re: Electrodes
Post by: dennis100 on May 17, 2011, 04:05:35 AM
Event Date 08/20/2007
Event Type Malfunction
Event Description
Reporter indicated that high lead impedance was discovered during a generator revision surgery. Pre-operative diagnostic testing was not possible as the generator was at eos and unable to communicate. Follow up with the treating physician revealed that there was no apparent cause for the high impedance. The lead and generator were repplaced and returned for analysis. The lead was found to have a coil fracture near the electrode bifurcation.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=914949



Title: Re: Electrodes
Post by: dennis100 on May 17, 2011, 04:06:20 AM
Event Date 09/07/2007
Event Type Malfunction
Patient Outcome Other;
Event Description
It was reported to mfr that a sys diagnostic test performed at the vns pts follow up visit due to a recent increase in seizure activity, revealed high lead impedance. The increase in seizures was reported by the caregiver to be above the pre-vns baseline. The treating physician believes that a possible cause for the high lead impedance could be due to the pt repetitively reaching over a "half door" located at the pt's residence, which may have resulted in damaging the lead. X-rays were taken of the left chest and neck to assess the continuity of the system. The x-rays were reviewed by the mfr and no obvious discontinuities or anomalies were observed that could be contributing to the high lead impedance. The pt's device was programmed off at the time the high lead impedance was noted. The believed cause for the increase in seizures was due to lack of vns therapy. The pt had surgery to replace the problematic lead. During surgery, a lead break was discovered in the lead in the neck area and the positive helical was described by the surgeon as not being on the nerve. The explanted lead has been returned to mfr and is pending the completion of product analysis.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=925128


Title: Re: Electrodes
Post by: dennis100 on May 18, 2011, 02:40:06 AM
Event Date 01/01/2007
Event Type Malfunction
Event Description
Initial reporter indicated the pt was having worsening seizure activity over the last 6-9 months. The seizures reported were at the pt's preimplantation seizure rate. The device was interrogated and high lead impedance was discovered indicating a possible lead malfunction. X-rays were reviewed by the pt's treating physician "who thought there may be an indication of one of the coils come off the vagus nerve. " the pt had not been seen in the clinic for at least 15 months, there was no report of any falls as the child cannot walk and is in a chair continuously. It was additionally reported "he has grown a great deal since implantation. " the pt underwent full revision surgery. Cyberonics is pending receipt of the explanted products for analysis. It was reported the "surgeon could not see exactly where the problem had occurred but thought the 'loop' had disappeared. ".

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=959506



Title: Re: Electrodes
Post by: dennis100 on May 18, 2011, 06:52:02 AM
Event Date 12/01/2007
Event Type Malfunction
Patient Outcome Other;
Event Description
Initial reporter indicated that the patient had not been seen for over a year. It was reported that the patient had an increase in seizures in last six months or more. No pain with stimulation reported in neck area. Diagnostics were performed that showed high lead impedance indicating a possible lead malfunction. Patient x-rays reviewed by physician "showed possible problem with electrodes, pin seemed in place. Opinion of surgeon, is child has grown a lot and he is considering what he could do to address the problem reloops in the neck". The patient may be scheduled for lead revision

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=973217


Title: Re: Electrodes
Post by: dennis100 on May 18, 2011, 12:52:59 PM
Event Date 01/01/2008
Event Type Injury
Patient Outcome Other;
Event Description
Reporter indicated that pt was undergoing exploratory surgery, because pt was having "problems" with vns therapy. During the procedure the lead was accidentally cut by the surgeon. Additionally, one of the electrodes was found to be off of the nerve. During the same procedure, the pt's lead and generator were replaced, and the explanted products were returned to mfr for analysis. To date that analysis is not yet complete. Good faith attempts for further info are currently being made.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1021317


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 02:49:12 AM
Event Date 01/18/2008
Event Type Malfunction
Event Description
It was reported that the vns pt had surgery where the generator was replaced due to end of service, and the lead was replaced due to an unk reason. Attempts to obtain the reason for lead replacement have been made, but have been unsuccessful to date. The lead and generator were returned to mfr for analysis. Analysis of the generator revealed that the generator was not found to be at end of service (eri flag set to no) and there were no performance anomalies observed during testing. Analysis of the lead was completed and a lead discontinuity was confirmed on the quadfilar coil of the closest (white) helical electrode (positive to the pulse generator). Scanning electron microscopy was performed on the quadfilar coil break and identified the area as having evidence of a stress-induced fracture (fatigue appearance) with mechanical damage with fine pitting on the surface of the coil. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. An abraded opening was observed, found on the outer silicone tubing, and most likely provided a leakage path for what appeared to be remnants of dried body fluid found inside the outer silicone tubing. The condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. There were no performance anomalies or discontinuities noted on the remaining portion of the lead.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1028710


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 02:49:56 AM
Event Date 04/23/2008
Event Type Injury
Patient Outcome Other;
Event Description
Reporter indicated a vns patient's "electrodes have slipped into the sternocleidomastoid muscle. " the event was reportedly confirmed via x-rays reviewed by the medical professional. Normal and system diagnostics are within normal limits. There was no trauma or patient manipulation of the device. Revision surgery is likely. Good faith attempts to obtain additional information have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1051739


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 02:50:45 AM
Event


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 05:16:30 AM
Event Date 05/20/2008
Event Type Injury
Patient Outcome Required Intervention;
Event Description
Reporter indicated a pt underwent generator replacement surgery due normal end of svc. X-rays and ct taken prior to surgery indicated that the pt's leads were not attached to the vagus nerve. The pt stated she was never able to perceive stimulation. During the surgery, the surgeon noted the old lead was attached to the sternocleidomastoid and not the vagus nerve. The pt underwent a complete revision. Good faith attempts to obtain add'l info have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1063419


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 06:22:55 AM
Event Date 05/12/2008
Event Type Injury
Patient Outcome Required Intervention;
Event Description
Reporter indicated a vns patient underwent generator replacement surgery due to normal end of service. Pre-operative x-rays noted the leads were not attached to the nerve. Diagnostic testing was within normal limits. During surgery, the surgeon noted the negative lead and anchor tether were attached to the nerve but the positive electrode was not. The surgeon cleaned up some scar tissue and then re-attached the negative electrode to the vagus nerve. The generator was replaced as scheduled, and diagnostics confirmed proper device function. Good faith attempts to obtain additional information have been successful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1059653


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 06:23:34 AM
Event Date 05/08/2008
Event Type Injury
Patient Outcome Other;
Event Description
Reporter indicated a patient will have lead revision surgery due to pain at the electrode site. The patient has stated "the lead fell off the nerve". Attempts for more information from the reporter and product information are pending.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1057679


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 10:16:20 AM
Event Date 06/13/2008
Event Type Injury
Patient Outcome Required Intervention;
Event Description
Reporter indicated a vns pt has pain in her neck and the lead seems to be moving. The pt is very skinny so lead can be seen protruding out of the patient's neck. Diagnostic test were all normal. The manufacturer reviewed x-rays and no strain relief bend or loop were visualized. Additionally, the negative electrode does not appear to be in vertical alignment with the positive electrode as typically seen. Good faith attempts to obtain additional info have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1080752


Title: Re: Electrodes
Post by: dennis100 on May 19, 2011, 10:17:18 AM
Event Date 06/27/2008
Event Type Malfunction
Event Description
Reporter indicated vns was opened, but was not utilized because it was defective. F/u with the surgeon revealed the lead was placed in the pt's vagus nerve, but the electrode keep falling off of the nerve. A second lead was used and everything worked well. The handheld has been returned to the mfr and is pending product analysis.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1081542



Title: Re: Electrodes
Post by: dennis100 on May 20, 2011, 03:07:48 AM
Event Date 01/01/2008
Event Type Injury
Patient Outcome Other;
Event Description
Reporter indicated a vns pt's "electrodes have slipped into the sternocleidomastoid muscle. " the pt's name was not provided. Good faith attempts to obtain additional info have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1102472


Title: Re: Electrodes
Post by: dennis100 on May 21, 2011, 12:50:48 AM
Event Date 08/01/2008
Event Type Malfunction
Event Description
It was reported that patient's last diagnostics test showed a high lead impedance. It was also indicated that the patient stopped feeling stimulation about three months ago and a mild intensification of seizures occurred. X-rays were reviewed by the physician and he indicated that one electrode (distal to head) is partially uncoiled and displaced. The line containing electrodes does not lie parallel to the normal location of vagus nerve. The patient's device is programmed off and electrode replacement is planned in case of further worsening of epilepsy. Follow up with nurse stated that no trauma occured and x-rays have been sent to manufacturer for further review. No additional information is available.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1350383



Title: Re: Electrodes
Post by: dennis100 on May 21, 2011, 12:51:27 AM
Event Date 09/18/2008
Event Type Injury
Patient Outcome Required Intervention;
Event Description
It was reported that the pt had her vns device turned off for three weeks, and when the device was turned back on, she began experiencing pain/burning sensations at the chest site. She also experienced extreme shortness of breath during system diagnostics test and magnet use. Diagnostic tests showed vns to be functioning properly. The pt's device was programmed off. X-rays were sent to the mfr for review. The negative electrode did not appear to be in the typical helical orientation. Additionally, the electrodes were not aligned vertically. The strain relief of the lead body at the neck did not appear to be adequate. No tie-downs were visualized. No obvious lead discontinuities were observed. The pt has currently been referred for a surgical consult. Good faith attempts to obtain additional info have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1212658


Title: Re: Electrodes
Post by: dennis100 on May 23, 2011, 05:50:50 AM
Event Date 03/24/2009
Event Type Malfunction
Event Description
Reporter indicated a vns therapy patient underwent generator replacement surgery. During the surgery, the surgeon noted the lead was "all balled up" and off the nerve. The surgeon elected to explant the entire vns therapy system. At a later date, the patient underwent vns therapy implant surgery. The explanted products were returned to the manufacturer and are pending analysis. Good faith attempts to obtain additional information have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1421314




Title: Re: Electrodes
Post by: dennis100 on May 23, 2011, 05:51:17 AM
Event Date 01/01/2009
Event Type Malfunction
Patient Outcome Hospitalization; Required Intervention
Event Description
Reporter indicated that the pt was in the hosp due to a fluid build-up around his generator. The pt had both the generator and lead removed. During the procedure, what appeared to be pus was found inside of the lead, and the negative electrode had "disintegrated" as per the company representative's account. During the procedure, cultures of the site were taken and were negative for an infection, but the surgeon still believed that the fluid build-up could be due to an infection that started during the pt's previous prophylactic generator replacement surgery, as the pt had been on multiple antibiotics since the beginning of the hospitalization. During the removal procedure, it was noted that there were metallic bits within the fluid that was surrounding the generator. Attempts for more info were unsuccessful. The lead has been returned to the manufacturer, along with the metallic bits found in the fluid surrounding the generator, for analysis, but analysis has not yet been completed.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1426599


Title: Re: Electrodes
Post by: dennis100 on May 23, 2011, 05:51:45 AM
Event Date 01/01/2009
Event Type Malfunction
Event Description
Reporter indicated that the pt underwent full revision surgery, after having a generator revision surgery approx a month earlier. At the follow-up visit following the initial surgery, high impedance was noted, which prompted the full revision surgery. Once the lead was removed during the full revision surgery, it was noted that there was an abraded opening in the silicone sheath surrounding the lead coils. The surgeon was unsure if this occurred due to pulling when removing the lead or not. A portion of the lead was returned to the manufacturer for analysis. Analysis found a lead fracture in the returned lead portion. Pitting and electro etching were found at the site of the fracture which is evidence that the fracture occurred outside of surgery and that stimulation was present for a period of time while the coils were fractured. The reported abrasion in the silicone sheath was also found in the returned lead portion.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1424784


Title: Re: Electrodes
Post by: dennis100 on May 24, 2011, 01:01:42 AM
Event Date 01/01/2008
Event Type Malfunction
Event Description
It was initially reported that the vns pt had their lead and generator replaced due to an unk reason. Further follow up with the surgeon revealed that the pt had the lead replaced due to a lead fracture that was visualized on x-rays, and the generator was replaced at that time as well. Further follow up with the referring neurologist revealed that the pt was a new pt to the physician and when the device was initially interrogated and tested, high lead impedance resulted. The physician disabled the device at that time, and referred the pt for x-rays and to the surgeon to replace the device. The radiologists x-ray assessment indicated that there was "a disconnect of the electrodes in the neck". There was no report of manipulation of the device or trauma. The explanted lead and generator were discarded following surgery, and the devices are therefore not available to be returned to manufacturer for analysis.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1467996


Title: Re: Electrodes
Post by: dennis100 on May 31, 2011, 11:04:05 AM
Event Date 01/01/2010
Event Type Malfunction
Event Description
During generator replacement surgery due to generator battery depletion, when the new generator was connected to the existing lead, high lead impedance resulted. The surgeon opened the neck incision to explore the cause of the high lead impedance, and it was noted by the surgeon that "one of the electrodes was detached from the nerve and there was also a lead fracture. " the lead was subsequently explanted and a new lead was implanted. The explanted lead and generator were discarded after the surgery, and are therefore not available to be returned to manufacturer for additional analysis. Further follow up with the treating physician revealed that the last diagnostic test was done in (b) (6)2009, which revealed normal device function. The device was not able to be interrogated at subsequent follow up visits that took place in (b) (6)2009, and again in (b) (6)2010 prior to surgery, which was believed to be due to battery depletion. There were no x-rays taken prior to surgery to assess the continuity of the device.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1619798


Title: Re: Electrodes
Post by: dennis100 on May 31, 2011, 11:04:34 AM
Event Date 01/20/2010
Event Type Malfunction
Event Description
It was reported that high lead impedance was read in system diagnostics during a follow up visit with the treating neurologist. The patient had reported an assault and trauma to the neck area in (b) (6) 2009. System diagnostics were fine (ok/ok/1/no) in (b) (6) 2009 after the incident and the high lead impedance (7/limit/high/no) was encountered on (b) (6) 2010 after performing both a system and normal mode diagnostic test. The device was programmed off by the neurologist and the patient was recommended for x-rays. X-ray review from the manufacturer revealed the generator was placed in the left chest in normal orientation. The filter feed-thrus appeared to be intact. The lead wires appeared to be intact at the connector pin and the lead connector pin appeared to be fully inserted into the generator connector block. Furthermore, no acute angles or discontinuities were observed in the visualized portion of the device, though a small portion of the lead behind the generator could not be visualized or assessed. The patient's positive electrode appeared to be misaligned with the negative electrode, which may be due to electrode/nerve detachment. A clinic note was received from the office of the treating neurologist at the time of the incident which indicated the patient was grabbed by the throat and after he was released, he felt the lead was moved and was hoarse due to the trauma. Follow up with the treating neurologist revealed the patient was doing well with no adverse events and revision surgery had been scheduled and was likely to occur.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1613594



Title: Re: Electrodes
Post by: dennis100 on May 31, 2011, 11:05:00 AM
Event Date 03/01/2010
Event Type Malfunction
Event Description
It was initially reported by the physician that the pt was at their office and when she performed system diagnostics, she got high lead impedance. This was only the second time he had seen the pt in his office. Last time he saw him was in july but did not perform any diagnostics at that time. Pt's device was turned off at that time. Physician did not know if any pt manipulation or trauma had occurred. He stated pt had shown no change in seizure frequency. X-rays were sent to manufacturer for further review. Review of the x-rays showed that the electrodes appeared to be off the nerve which could be contributing to the high lead impedance; however, a lead discontinuity cannot be ruled out in the part of the lead that could not be assessed. Pt's last good diagnostics were obtained in (b)(6) 2007. Additional information received stated that the pt had a full revision surgery. Good faith attempts to obtain explanted products for analysis have been unsuccessful.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1674177


Title: Re: Electrodes
Post by: dennis100 on June 01, 2011, 11:22:07 AM
Event Date 01/01/2009
Event Type Malfunction
Event Description
It was initially reported by the site that the pt was taken into surgery for implanting a nerve stimulator. Pt is implanted with vns and after the implant of nerve stimulator, the surgeon noticed high lead impedance on system diagnostics. X-rays were taken and sent to mfr for review. The improper connector pin insertion is most likely contributing to the high lead impedance. However, a lead discontinuity on the portions of the lead body that could not be assessed cannot be ruled out. The electrodes were also placed inverted on the vagus nerve. No manipulation or trauma was reported and pt showed increase in seizures in the past week or so. Good faith attempts to obtain additional info have been unsuccessful till date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1658414


Title: Re: Electrodes
Post by: dennis100 on June 01, 2011, 11:24:25 AM
Event Date 01/01/2003
Event Type Malfunction
Patient Outcome Required Intervention;
Event Description
It was reported to the mfr that the vns pt has been experiencing an increase in seizure activity. It is unk if the increase is above pre-vns baseline. The pt's generator (102r) was believed to be at the end of service, therefore, the pt was sent for generator replacement surgery. During surgery, the new generator was attached to the existing lead body and diagnostic tests were performed that resulted in high lead impedance. Troubleshooting did not resolve the event; therefore, a full revision was performed. During the explant of the existing lead body, it was found that the negative electrode was off the nerve and encapsulated in scar tissue. The positive electrode and the anchor tether remained on the nerve. X-rays were not taken prior to surgery to assess the integrity of the device as an issue with the lead was not suspected. Review of programming history revealed that the pt's previous generator (100c) showed high lead impedance with the same lead body in 2003. Diagnostic tests following that date or test results from generator revision surgery are not available to confirm the resolution of the high lead impedance event. Therefore, the cause of the increase in seizure activity is unk at this time. Good faith attempts to obtain the explanted products back for analysis and add'l info regarding the reported event are underway.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1659943


Title: Re: Electrodes
Post by: dennis100 on June 01, 2011, 11:26:03 AM
Event Date 04/01/2010
Event Type Malfunction
Event Description
It was initially reported by the physician that the pt showed high lead impedance on system mode diagnostics. Pt's device was turned off and pt was referred to the surgeon for a full revision surgery. Additional info received stated that the pt had a full revision surgery. While replacing the lead, the surgeon noticed that one of the electrodes was off the vagus nerve. Surgeon did not visualize any breaks. Pt was implanted with a new lead and diagnostics on the new device showed everything working within normal limits. Good faith attempts to obtain explanted products for analysis has been unsuccessful till date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1701618


Title: Re: Electrodes
Post by: dennis100 on June 03, 2011, 03:45:49 AM
Event Date 04/13/2010
Event Type Malfunction
Event Description
Reporter indicated a patient's vns electrodes were displaced. The vns was disabled, and the reporter indicated the patient would be sent for a surgical eval. X-ray films were requested, but ct scans were sent to the mfr which were unable to be interpreted. All further attempts to the reporter for add'l info and the plan of care have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1733184



Title: Re: Electrodes
Post by: dennis100 on June 04, 2011, 03:19:02 AM
Event Date 01/01/2007
Event Type Injury
Patient Outcome Required Intervention;
Event Description
It was reported by pt that while she was driving, she jerked her neck and the leads were protruding from her neck. She had to undergo an exploratory surgery to identify the cause of protruding. Pt also stated that during the surgery, the surgeon told her that the leads had migrated and they were off the nerve. Good faith attempts to obtain additional info have been made, but no response has been received to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1889149


Title: Re: Electrodes
Post by: dennis100 on June 06, 2011, 11:46:00 PM
Event Date 01/01/2002
Event Type Injury
Patient Outcome Life Threatening; Hospitalization Required Intervention
Event Description
Reporter indicated that vns patient was scheduled for explant for unknown reason after less than one year of service. Further follow-up revealed that the patient had experienced an increase in seizures "by 20 times" after vns implant and has subsequently required 22 emergency room visits for seizure activity. The patient also reported constant worsening of asthma, shortness of breath, and burning in the throat. The patient's device was programmed to off five days prior to explant. Device diagnostic testing on day of explant was within normal limits, indicating proper device function. The elective replacement indicator was no, indicating that the generator was not at end of service. X-rays on day of explant surgery revealed that the location of the lead was inconsistent with normal vns lead placement. There were no tie-downs used, the lead was in disarray, not aligned in the normal parallel orientation, and was located lower than normal. It was reported that the lead electrodes were not wrapped around the vagus nerve. Poor implant technique at time of initial implant is suspected.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=461860


Title: Re: Electrodes
Post by: dennis100 on June 07, 2011, 04:00:19 AM
Event Date 01/01/2003
Event Type Malfunction
Event Description
Reporter indicated that vns pt underwent lead replacement surgery approx 5 months post-implant due to lead break. The pt could no longer feel stimulation just 3 months post-implant and that the neck site in the area of the lead was "raised and ridgey". Both device diagnostic testing and evoked potential monitoring was within normal limits, indicating proper device function. The raised area at the neck site had reportedly gone away prior to revision surgery. The pt's caregiver indicated that the pt did not have full range of motion after vns implant and that the pt kept their head down and could not look up due to something in their neck. X-rays reviewed by physician revealed a discontinuity in the ncp system. During lead replacement surgery, the lead electrode was noted to be twisted eight or ten times near the generator and it was believed that the generator had been manipulated through the skin by the pt. There was tension in the neck, but the strain relief was still present. The lead was clearly broken, though the pt denies manipulating the device through the skin.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=478617


Title: Re: Electrodes
Post by: dennis100 on June 08, 2011, 12:12:50 PM
Event Date 06/03/2003
Event Type Malfunction
Event Description
Vns pt was scheduled for reimplant because treating neurologist believes that the lead electrodes may not be on the vagus nerve. It was reported that the pt has never felt stimulation. Device diagnostic testing was within normal limits, indicating proper device function. Device settings were increased, after which the pt felt stimulation. Device settings were then decreased back to prescribed levels.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=612015


Title: Re: Electrodes
Post by: dennis100 on June 09, 2011, 12:17:03 AM
Model Number 300-20
Event Type Malfunction
Event Description
Reporter indicated that patient's neurologist suspects that one of the lead electrodes is no longer on the vagus nerve. The patient reports a recent increase in seizure activity as well as a feeling of neck tightness with stimulation. The patient's device was subsequently programmed to off, resulting in loss of therapy. It was reported that prior to the incident, the patient was receiving efficacy from the vns therapy. The patient was referred to surgeon for evaluation.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=611886


Title: Re: Electrodes
Post by: dennis100 on June 13, 2011, 12:14:59 PM
Event Date 01/01/2006
Event Type Malfunction
Patient Outcome Required Intervention;
Event Description
Reporter indicated that the patient experienced periods of constant jaw pain. The pain was later reported to be only during stimulation and radiating from her throat and neck to her chest. Diagnostic test results were within normal limits and review of x-rays did not reveal any lead discontinuities, although inadequate strain relief was observed. The patient underwent revision surgery, where both the generator and the lead were replaced. The explanting surgeon indicated that the original lead electrodes were not attached to the vagus nerve and were instead encapsulated in scar tissue. It is unk whether the electrodes were ever properly attached to the vagus nerve or whether they slipped off the nerve after implant. Product analysis did not reveal any device failure of the lead, although the electrode portion of the lead was not returned for analysis.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=948543


Title: Re: Electrodes
Post by: dennis100 on June 14, 2011, 12:36:55 AM
Model Number 300-30
Event Type Malfunction
Event Description
Further follow-up revealed that the pt underwent ncp system replacement. Both the pulse generator and bipolar lead were replaced.

Manufacturer Narrative
H. 6. The safety and efficacy of the vns therapy system treatment have not been established for stimulation of the right vagus nerve or of any other nerve, muscle, or tissue. Additionally, the vns therapy system is indicated for use as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents with partial onset seizures that are refractory to antiepileptic medications. In the united states, the vns therapy system is approved for use in adults and adolescents with partial onset seizures that are refractory to antiepileptic medications.

Event Description
Reporter indicated that patient's device diagnostic testing at office visit resulted in high lead impedance indicating possible device function. X-rays were taken and revealed that the lead electrodes may be off the nerve which can cause the high impedance results. The patient reportedly has not experienced any change in seizure level and has not exprienced any pain related to the electrodes coming off the nerve. Revision surgery is planned. The implanting surgeon is interested in replacing the ncp system and placing the new system on the right vagus nerve. In addition, the patient had a previous ncp system which was replaced in 2000 because of a reported similar lead issue. The implanting surgeon indicated that the reason for replacement was that the lead had "slipped off the nerve". Review of manufacturing records for both the pulse generator and the bipolar lead revealed no anomalies that would adversely effect device performance. Investigation to date has been unable to determine why the lead electrodes are off the nerve. This event is currently under investigation.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=627565


Title: Re: Electrodes
Post by: dennis100 on June 14, 2011, 11:50:19 AM
Model Number 302-20
Event Type Malfunction
Event Description
The patient underwent revision surgery, during which the lead was replaced. During the procedure, the surgeon noted that the original lead connector pin appeared to be seated adequately in the generator header. The original lead was disconnected from the generator and then reconnected, after which device is diagnostic testing outside the pocket was reportedly within normal limits. At this point, the neck incision was opened. The vagus nerve was back into the pocket yielded high lead impedance results. At this point, the neck incision was opened. The vagus nerve was noted to be extremely scarred. The electrodes, which were densely scarred to the vagus nerve, were removed. Scar tissue was cut away from the nerve which was reportedly left intact and preserved. The entire lead was explanted and a replacement lead was then implanted. Intraoperative device diagnostic testing of the replacement lead connected to the original generator was within normal limits, indicating proper device function. Attempts to obtain the explanted lead for the purpose of product analysis have been unsuccessful to date. Lead break is suspected; however, the scar tissue build-up in the area of the lead electrodes could have been a casual/contributing factor to the high lead impedance condition.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=654396


Title: Re: Electrodes
Post by: dennis100 on June 14, 2011, 11:53:44 AM
Model Number 300-20
Event Type Malfunction
Event Description
Replacement surgery due to lead discontinuity. Both the lead and generator were replaced. Treating neurologist indicated that prior to replacement surgery, the patient reported an increase in seizure activity and not feeling device stimulation anymore. Device diagnostic testing at office visit resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The elective replacement indicator was no, ruling out generator battery end of life as a likely cause of the high lead impedance test result. A high impedance test result was also obtained at previous office visit approximately six months prior, but physician chose to only monitor the patient at that time, because the patient had not experienced an increase in seizure activity. X-rays reviewed by treating physician did not reveal any obvious discontinuities in the ncp system. At the time of replacement surgery, the lead reportedly appeared to be intact, but had come loose from the nerve and was in soft tissue. The explanted products were returned to maufacturer for analysis. Approx 43. 5 cm of the lead assembly was returned for analysis in four pieces. Visual inspection revealed a break in both the positive and negative coils at the electrode bifurcation. It is believed that stimulation was present for some period of time after the fracture occurred as evidenced by the presence of pitting on the broken coil wire surfaces. Due to metal dissolution and mechanical distortion (smoothed surfaces), the fracture mechanism cannot be determined. Analysis of the concomitant device (pulse generator) revealed no anomalies that would adversely affect device performance. The pulse generator met visual and electrical specifications.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=651362


Title: Re: Electrodes
Post by: dennis100 on June 14, 2011, 10:29:02 PM
Event Date 10/11/2005
Event Type Malfunction
Event Description
Reporter indicated that he was not able to feel the device stimulate. The reporter also stated that he had many (38) petit grand mal seizures the evening of the day he noticed that he could no longer feel the device stimulation. Diagnostic testing was performed and was found to be within normal limits indicating proper device function. X-rays were performed and they did not show any lead anomalies that may result in no stimulation. The patient subsequently had surgery to replace the lead. The cause of the patient not being able to perceive stimulation was likely due to the previous vns replacement surgery that the patient recently undergone. During the patient's previous surgery to replace the vns system, the surgeon noted extensive fibrous tissue growth around the leads on the vagus nerve. The surgeon then made a decision to place the electrodes in the same area of the vagus nerve as the previous electrodes were placed. In order to do this, the surgeon determined that larger electrodes (3mm) were needed. The 3mm electrodes were placed over the fibrous growth on the vagus nerve. Additional fibrous growth following the surgery likely developed between the larger electrodes and the vagus nerve causing a current barrier between the electrodes and the vagus nerve. Therefore, the patient was not receiving the vns stimulation. A new lead (2mm electrode) has now been placed on a different area of the vagus nerve where there is no fibrous growth and the issue has resolved. The patient can now feel stimulation and has regained seizure control (efficacy).

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=663114


Title: Re: Electrodes
Post by: dennis100 on June 18, 2011, 02:17:17 AM
Model Number 300
Event Type Malfunction
Event Description
Reporter indicated that patient needs a complete ncp system replacement because of damage to electrode insulation. Revision surgery is planned.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=774550


Title: Re: Electrodes
Post by: dennis100 on June 18, 2011, 02:17:42 AM
Event Date 04/01/2006
Event Type Injury
Patient Outcome Hospitalization; Required Intervention
Event Description
Reporter indicated that a vns pt experienced difficulty breathing and left vocal cord paralysis, during device stimulation cycles. It was reported that adjustments to programmed device settings did not alleviate the pt's symptoms. Fluoroscopy revealed left hemidiaphragmatic tetany, during device stimulation cycles. Evaluation with a fiberoptic camera revealed left vocal cord tetany and paralysis, with partial involvement of the right vocal cord, during device stimulation cycles. It was reported that the pt was unable to breath during these episodes. Revision surgery was performed, during which the surgeon noted that "the silicone around the electrode was severed and the metal electrode was making direct contact with the nerve", the lead was explanted and replaced. Stimulation was initiated immediately after lead replacement surgery, after which all adverse events have reportedly resolved.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=757095


Title: Re: Electrodes
Post by: dennis100 on June 18, 2011, 07:08:33 AM
Event Date 08/01/2006
Event Type Malfunction
Event Description
Reporter indicated that system diagnostic testing resulted in high lead impedance reading, indicating a possible device malfunction. It was also reported that the pt was diagnosed with left vocal cord paralysis during the same month. X-rays were reviewed by the manufacturer. A gross lead discontinuity was observed at the negative electrode, which is the most likely root cause for the high impedance event. The treating physician indicated that the vocal cord paralysis was not likely related to the implantation procedure as the patient had already been implanted with vns for over a year. Revision surgery is likely.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=854613


Title: Re: Electrodes
Post by: dennis100 on June 22, 2011, 06:31:53 PM
Model Number 302-30
Event Date 09/25/2006
Event Type Malfunction
Manufacturer Narrative
Device failure suspected but did not cause or contribute to a serious death or injury.

Event Description
Reporter indicated that a patient underwent vns replacement surgery. When the new system was implanted, a system diagnostics test in the operating room resulted in high lead impedance. The reporter indicated that "the vagal nerve was so scarred in and somewhat swollen, that the readout from the vns generator read high impedance. " the physician did not feel "that there is something wrong with electrodes. " the surgeon completed the implant surgery with vns system indicating high lead impedance. Review of x-rays indicated that the lead pin may not be fully inserted into the connector block and the electrodes do not appear to be placed on the vagus nerve. The explanted system is reported separately.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=938387


Title: Re: Electrodes
Post by: dennis100 on June 25, 2011, 01:57:58 AM
Event Date 05/19/2003
Event Type Injury
Patient Outcome Hospitalization; Required Intervention
Event Description
Reporter indicated that vns pt underwent revision surgery due to protrusion of the lead electrodes under the skin. It was reported that the protrusion occurred because the implanting surgeon used dissolvable stitches. It is believed that the dissolvable stitches were used both to anchor the lead and to close the incision site. Investigation to date has been unable to determine whether the lead electrodes came off the nerve as a result of the use of dissolvable stitches to anchor the device.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=479683


Title: Re: Electrodes
Post by: dennis100 on November 04, 2011, 02:42:20 PM
Model Number 303-20
Event Date 08/29/2011
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized.

Event Description
Additional information was received that the patient went for a lead revision but it was unable to be completed due to adhesions. The office was unsure if the lead was left connected or not. It is unknown what the plan forward will be.

Manufacturer Narrative
Analysis of programming history.

Event Description
It was initially reported that the patient had high impedance on a recent systems diagnostics. It is unknown want interventions will be taken but surgery is likely but has not occurred to date. There was not known trauma or manipulation that would have contributed to the patient's high impedance. X-rays were taken and provided to the manufacturer. X-rays did not show any discontinuities in the lead. There was a suspect issue that one of the electrodes may not be on the nerve as the electrodes did not appear to be aligned with each other. This has not been confirmed and may be due to the patient's anatomy. It was also unable to be confirmed that the pin was fully inserted based on the available images and the image quality of the x-rays. Good faith attempts for more information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2260627


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 07:29:56 AM
Model Number 300-20
Event Date 06/01/2001
Event Type Malfunction
Manufacturer Narrative
Method: manufacturing records reviewed. Results: review of manufacturing records did not reveal any anomalies nor abnormalities that would have an adverse effect on device performance.

Event Description
Reporter indicated that revision surgery was performed due to patient inability to perceive stimulation after parameters increased. During revision surgery, it was noted that the lead was not on the nerve. The lead was explanted and a new lead was implanted.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=342827


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 07:33:57 AM
Model Number 300-20
Event Date 08/01/2001
Event Type Malfunction
Manufacturer Narrative
Method: a continuity check using a multimeter was performed on the portions of the lead returned. Results: continuity check did not identify any discontinuities in the portions of the lead assembly returned.

Event Description
Rptr indicated that a high lead impedance reading was obtained during lead test (dc-dc code 7). The pt could not feel stimulation nor would their voice become hoarse upon magnet stimulation. Pt went in for a revision surgery in 2001. Before the surgery, an x-ray was taken which did not show anything abnormal. During the revision surgery, the physician noticed that the positive electrode was exposed and broken through the insulation. A new lead was implanted and lead test results were acceptable.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=353974


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 07:36:57 AM
Model Number 300-20
Event Date 03/07/2001
Event Type Malfunction
Patient Outcome Hospitalization; Required Intervention
Manufacturer Narrative
The following dates are estimated. Only the month/year is known: d. 8, explant date.

Event Description
Possible lead discontinuity. Reporter indicated that device has been implanted for approximately two years, but was turned off after one year of service because family did not feel that device was helping. New physician tried to re-program the device to on resulting in high lead impedance. Upon surgical revision, electrodes reported to be knotted. Both lead and generator were replaced.

Manufacturer Narrative
The pt is doing "fantastic" following the procedure, according to the physician's nurse. Results: the physician stated the pt broke the lead by "playing" with it.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=326913


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 07:40:56 AM
Model Number 300-30
Event Date 07/01/2000
Event Type Injury
Patient Outcome Life Threatening;
Manufacturer Narrative
Method: device manufacturing records were reviewed. X-rays were reviewed. Results: review of manufacturing records did not reveal any anomalies nor abnormalities that would have an adverse effect on device performance. Review of x-rays revealed that no strain relief loop was seen and that one of the lead bodies appeared to be off of the nerve. The electrodes did not appear properly aligned or parallel.

Event Description
Reporter indicated that the patient experienced pain in their shoulder after implant. The patient reportedly had good seizure control initially, but has experienced an increase in seizures over the past few months. Device diagnostic testing (date unknown) resulted in high lead impedance reading (dc-dc code 7), indicating possible device malfunction. The patient reports that they no longer consistently feel stimulation. A discontinuity in the ncp system is suspected. Review of x-rays did not reveal any obvious fracture or discontinuity, however, one of the electrodes appears to be off of the nerve. The electrodes do not appear to be properly aligned. Further follow-up revealed that the patient fell on their forehead in late 2001 or early 2002. The patient began to experience an increase in seizures after they fell. Physician is unsure whether or not the increase in seizure is similar to the patient's pre-vns baseline. The patient reportedly suffered a grand mal seizure in march 2002. It was also reported that the patient underwent some type of physical therapy for the pain in their shoulder. It is possible that if the patient's physical therapy included deep massaging or treatment to the neck or shoulder area, that there might be a possibility that the leads were pulled, causing the apparent displacement of the electrode. Attempts to obtain additional information have been unsuccessful to date. The patient is scheduled for a consultation with a neurosurgeon on 07/2002.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=403717


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 07:51:12 AM
Model Number 300-20
Event Date 09/10/2001
Event Type Malfunction
Manufacturer Narrative
Ncp system labeling states that the helical electrodes and anchor tether should be coiled around the nerve, beginning with the electrode that is farthest from the lead bifurcation (with green suture embedded in the helical material). This electrode should be nearest (proximal to) the patient's head. To maximize system performance and minimize possible mechanical damage to the nerve or lead, pay careful attention to electrode placement. The vns therapy system is indicated for use as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents over 12 years of age with partial onset seizures that are refractory to antiepileptic medications. In the united states, the vns therapy system is approved for use in adults and adolescents over 12 years of age with partial onset seizures that are refractory to antiepileptic medications.

Event Description
Patient was not experiencing efficacy with the vns therapy and it was believed that the lack of efficacy was due to incorrect lead placement. The patient had reportedly received a letter form previous neurologist indicating that the lead electrodes were implanted upside-down. Incorrect lead placement was reportedly confirmed via x-ray. Device diagnostic testing was within normal limits. Revision surgery is planned.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=499525


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 07:59:15 AM
Event Type Injury
Patient Outcome Disability;
Manufacturer Narrative
H. 6. Vns therapy labeling cautions that magnetic resonance imaging (mri) should not be performed with a magnetic resonance body coil in the transmit mode. The heat induced in the lead by an mri body scan can cause injury. If an mri should be done, use only a transmit and receive type of head coil. Magnetic and rf fields produced by mri may change the pulse generator settings (change to reset parameters) or activate the device. Mri compatibility was demonstrated using a 1. 5t general electric signa imager with a model 100 only. The model 102 is functionally equivalent to the model 100. Testing on the imager as performed on a phantom indicated that the following pulse generator and mri procedures can be used safely without adverse events. Pulse generator output programmed to 0 ma for the mri procedure, and afterward, retested by performing the lead test diagnostics and reporgrammed to the original settings. Head coil type: transmit and receive only. Time-varying intensity: < 10 tesla/sec. Use caution when other mri systems are used, since adverse events may occur because of different magnetic field distributions.

Event Description
Reporter indicated that vns pt's lead electrodes were "fired" as a result of the pt undergoing a siemens mri.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=534841


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:05:41 AM
Model Number 302-20
Event Date 01/01/2004
Event Type Malfunction
Event Description
Clinic notes were received and reviewed. There was no mention of the pt's loss of stamina following the revision surgery. The neurologist indicated that the pt was on a lifting restriction, but it was routinely reported that the pt felt well and was tolerating the vns therapy. The event was not confirmed to be related to the vns therapy, and the cause is unknown. Potential causes include: aed side effects, unknown vns interaction, or complication from revision surgery. The headache complaint was not addressed in the clinic notes or a request from the manufacturer. The possible causes include: intolerable vns settings, and other causes not related to the vns therapy. The pt's increased seizures were apparently resolved with the lead replacement. The pt's current seizure rate appears to be at or below the seizure frequency prior to the device malfunction; therefore, the new system resolved this event.

Manufacturer Narrative
H. 6. : vns therapy system labeling states that the helical electrodes and anchor tether should be coiled around the nerve, beginning with the electrode that is farthest from the lead bifurcation (with green suture embedded in the helical material). This electrode should be nearest (proximal to) the pt's head. To maximize system performance and minimize possible mechanical damage to the nerve or lead, pay carefull attention to electrode placement.

Event Description
Reporter indicated that device diagnostic testing at office visit resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. Device diagnostic testing performed eight months prior was within normal limits, indicating proper device function at that time. The pt denied any recent injury or trauma that may have damaged the vns therapy system. Review of x-rays did not reveal any obvious discontinuities in the vns therapy system, but did reveal that the lead electrodes were implanted in an inverted confirguration and were placed farther down on the vagus nerve than is recommended in device labeling.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=612016



Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:09:37 AM
Model Number 300-20
Event Date 01/01/2004
Event Type Malfunction
Manufacturer Narrative
H. 6. Vns therapy system labeling states to always use the tie-downs and to loosely attach the 3-cm strain relief bend to the adjacent fascia with tie-downs before routing the lead over the muscle. The lead wire has a potential for fracture if the recommended 3-cm strain relief bend is not provided as described. Additionally, device labeling lists improper surgical implantation of the vns therapy system, including (but not limited to) providing an inadequate strain relief loop, placing sutures directly on the lead body, not using the tie-downs, and suturing to muscle as events that can shorten the life expectancy of the lead.

Event Description
Vns pt was scheduled for ncp system replacement surgery due to "lead migration resulting in stimulation of surrounding neck muscles". When the device stimulates, the pt's neck muscles "pull back to their ears". Device diagnostic testing was within normal limits, indicating proper device function. The elective replacement indicator was no, indicating that the generator had not reached end of service. Adjustments to device settings did not alleviate the pt's symptoms. During ncp system replacement surgery, surgeon noted that the lead wire strain relief was medial instead of lateral. He also noticed that there were no tie-downs securing the strain relief loop. While attempting to dissect to the vagus nerve for removal of electrodes, the surgeon nicked the jugular vein. The pt reportedly lost close to 400cc of blood. After the bleeding was stoppeed, the surgeon noticed a very sharp bend in the lead wire near the bifurcation. The lead was explanted, leaving the original electrodes in place and an new lead was implanted with new electrodes placed below old electrodes on the vagus nerve. The generator was also replaced. Review of mfg records for both the pulse generator and the bilpolar lead revealed no anomalies that would adversely effect device performance. Lead break is suspected.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=612181


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:13:37 AM
Model Number 302-20
Event Date 01/11/2005
Event Type Injury
Patient Outcome Disability;
Manufacturer Narrative
H. 6. Vns therapy system labeling lists voice alteration (hoarseness), increased coughing, aspiration and left vocal cord paralysis as potential adverse events possibly associated with surgery or stimulation. Vns therapy system labeling states that the safety and efficacy of this therapy have not been systematically established for use in pt's with history of previous therapeutic brain surgery.

Event Description
Reporter indicated that pt's voice was very hoarse two weeks post-implant and that the pt coughs a lot while talking to the point that pt becomes breathless. Stimulation had not yet been initiated. It was reported that implanting surgeon may have taken a little longer than usual to attach the lead electrodes to the vagus nerve during initial implant surgery. Further follow-up with treating neurologist revealed that the pt's condition had not improved almost one month post-implant and that pt continued to cough excessively with possible aspiration. Additionally, the pt was diagnosed with dense left vocal cord paralysis by an ent. The pt has reported started speech therapy to strengthen the vocal cord.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=575744


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:17:11 AM
Model Number 302-20
Event Type Malfunction
Manufacturer Narrative
The vns therapy system is indicated for use as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents with partial onset seizures that are refractory to antiepileptic medications. In the united states, the vns therapy system is approved for use in adults and adolescents with partial onset seiuzres that are refractory to antiepileptic medications. Vns therapy system labeling indicates that the safety and efficiacy of this therapy have not been systematically established for use in pt's with history of previous therapeutic brain surgery.

Event Description
The explanted lead assembly was returned to manufacturer for analysis. Two lead coil wire fractures were identified via visual inspection. Electron microscopy performed in the area where the breaks were identified revealed pitting on the broken coil wire surfaces, indicating that stimulation was present for some period of time after the fracture occurred. The fracture mechanism could not be determined due to the metal dissolution on the ends of the broken coil wires. Continuity checks did not reveal any other discontinuities in the lead wire. The remaining conditions of the lead portion returned were consistent with conditions that typically exist following an explant procedure.

Event Description
Device diagnostic testing at office visit resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The elective replacement indicator was no, indicating that the generator had not reached end of service. Additionaly, it was not reported that the lead is protruding through the pt's neck. Neurologist indicated that the pt has not suffered any recent injury or trauma that may have damaged the vns therapy system. Review of x-rays were inconclusive in determining whether a lead break was present; however, the lead is at an acute angle, which could be a kink. No strain relief loop was seen and the negative electrode is not aligned parallel with the positive electrode. It is possible that the negative electrode may not have been properly placed on the pt's vagus nerve or that the abnormal alignment of the electrodes could be due to the anatomy of the pt's vagus nerve. If the negative electrode is not in its proper position and not coiled around the nerve, this could result in both the high lead impedance reading and protrusion events. Investigation to date has been unable to determine the cause of the high lead impedance reading. Review of manufacturing records for both the pulse generator and the bipolar lead revealed no anomalies that would adversely effect device performance.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=576032


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:21:01 AM
Event Type Injury
Patient Outcome Life Threatening; Hospitalization Required Intervention
Manufacturer Narrative
H. 6. Vns therapy system labeling states that the helical electrodes and anchor tether should be coiled around the nerve, beginning with the electrode that is farthest from the lead bifurcation (with green suture embedded in the helical material). This electrode should be nearest (proximal to) the pt's head. To maximize system performance and minimize possible mechanical damage to the nerve or lead, pay careful attention to electrode placement.

Event Description
Reporter indicated that vns pt experienced an increase in blood pressure during stimulation, resulting in an emergency room visit. It was reported determined that the lead electrodes were implanted in an inverted configuration. Revision surgery was performed to reposition the lead electrodes as recommended in device labeling, after which the pt reportedly did not experience further episodes of elevated blood pressure.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=563546


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:28:30 AM
Model Number 302-20
Event Date 11/23/2004
Event Type Injury
Patient Outcome Hospitalization; Required Intervention
Event Description
Reporter indicated that vns pt could not tolerate a normal mode output current setting >0. 25ma. It was reported that when normal mode output current was increased from 0. 50ma to 0. 50ma, the pt experienced excessive choking sensation with significant throat pain and extreme coughing. A reduction in the pulse width setting did not alleviate the pt's symptoms. Review of x-rays revealed that the lead electrodes were placed directly above the clavicle, which is lower than the recommended placement in device labeling. Revision surgery is planned.

Event Description
Further follow-up revealed that the pt underwent revision surgery to change the position of the lead electrodes. Treating physician indicated that the pt still complains of pain with device stimulation and that the pt is experiencing an increase in anxiety concerning the event. Treating physician believes that the vns therapy system and surgery are related to the reported event.

Manufacturer Narrative
H. 6. Vns therapy system labeling lists increased coughing, pharyngitis and dysphagia as potential adverse events possibly associated with surgery or stimulation. H. 6. Vns therapy system labeling states that the recommended stimulation site is a 3-cm section of the vagus nerve, approximately half-way up between the clavicle and the mastoid process, where it is clear of branches (below where the superior and inferior cervical cardiac branches separate from the vagus nerve.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=596436


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:32:41 AM
Model Number 302-20
Event Type Malfunction
Event Description
Product analysis summary: the lead assembly was returned for analysis in pieces visual inspection of the lead assembly identified a suspected break at approximately 2cm past the electrode bifurcation. Scanning electron microscopy was performed at the area where the suspected break was identified. Scanning electron microscopy identified that the appearance of the coil ends show that pitting or electro-plating conditions have occurred. Due to mechanical distortion and metal dissolution the fracture mechanism cannot be ascertained. Other conditions of the lead, in general, were consistent with conditions than exist following the explant proceduce. The concomitant device (pulse generator) was also returned and analyzed. The pulse generator met electrical test specifications. There were no visual anomalies identified. The pulse generator did not not show any condition that would have contributed to the reported events.

Event Description
Device diagnostic testing at office visit resulted in high lead impedance reading (dd-dc code 7 and limit), indicating possible device malfunction. It was reported that the patient's generator was implanted high on their chest (almost to their neck). There is a "bump" or "hard spot" present on the patient's neck, in the area where the lead electrodes would be, giving the appearance that the electrodes may have come off of the vagus nerve. Review of ex-rays revealed a complete break in both lead wires. The patient was seen by neurosurgeon for consult, but is not yet scheduled for lead replacement surgery. Review of manufacturing records for both the pulse generator and the bipolar lead revealed no anomalies that would adversely effect device performance. Investigation to date has been unable to determine the cause of the apparent lead fracture.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=580426


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:50:41 AM
Model Number 302-30
Event Date 01/01/2006
Event Type Malfunction
Event Description
Reporter indicated that a system diagnostics test resulted in high lead impedance indicating a suspected devices malfunction. It was later reported that after viewing the x-rays, the surgeon " concluded without any objection that the positive electrode was 'opened' and not properly connected anymore to the vagus nerve" , and that " this is why the system diagnostics gave high impedance, limited output current status, and dcdc code 7. " good faith attempts to obtain further information have been made.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=952928


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 08:56:21 AM
Event Date 06/23/2010
Event Type Injury
Patient Outcome Required Intervention;
Event Description
The pt recently had surgery for routine generator replacement, and during surgery, the surgeon cut the lead in error and therefore had to implant a new lead as well. The surgeon uses a single incision implant technique. The pt was seen by the neurologist for the first follow up appointment since surgery, and when the device was programmed on to "the lowest setting", the pt experienced intolerable coughing and painful stimulation in the neck and was not able to tolerate any stimulation. The surgeon was notified of the events, and it was noted by the surgeon that it is possible that based on these side effects, that the lead may be implanted on the wrong structure, possibly the phrenic nerve, rather than the vagus nerve. The pt is scheduled for surgery to have the lead replaced by a new surgeon, which is scheduled to occur on (b)(6)2010. Per the neurologist, diagnostic testing was performed which revealed normal device function; however, the specific results were not provided. In addition,the neurologist noted the device has been programmed off at this time.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1801204


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 09:05:37 AM
Event Date 11/13/2007
Event Type Malfunction
Event Description
Initial reporter indicated that the pt would be having full revision surgery. It was suspected by the treating physician that the pt had a lead break. No x-rays were taken preoperatively. The neck site was opened and it was visualized that the lead electrodes were found to be off the nerve and at least 1/2 inch away from the nerve. It was also reported that the lead was very taught and there was no strain relief of tie downs found as well. The pt's generator and lead were both replaced and adequate strain relief was used.

Manufacturer Narrative
Device malfunction suspected, but did not cause or contribute to a death or serious injury.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=962689


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 09:09:53 AM
Model Number 302-20
Event Date 02/15/2008
Event Type Malfunction
Event Description
Reporter indicated that the patient was scheduled for surgery consultation due to high impedance on system diagnostic test. X-rays were reviewed by the manufacturer; the lead body was visible and no gross lead fracture was found. The entire lead could not be assessed because there was a portion of the lead that was behind the generator. There were two tie downs present; one was no longer attached to the leads but appeared to be free floating. The lead electrodes were not aligned in the typically observed vertical fashion. This may be due to patient's anatomy or may be due to the electrodes not being properly connected to the vagus nerve. This anomaly may possibly contribute to the high impedance readings. Further follow up indicated that surgery had taken place. The manufacturer was informed that, "the negative electrode was not attached to the vagus nerve. Only the positive electrode and anchor tether were attached. ".

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1014329


Title: Re: Electrodes
Post by: dennis100 on March 09, 2012, 09:22:03 AM
Model Number 302-20
Event Date 01/01/2008
Event Type Malfunction
Event Description
It was reported that vns pt had generator replacement due to normal end of service. When the new generator was attached to the lead during surgery, they received high impedance. Surgeon tried re-inserting the pin three times and they were sure the pin was fully inserted, but they still received high impedance. Surgeon then decided to replace the lead. When he opened the neck site to expose the vagus nerve he reported, "the electrodes were broken and looked like they had been snapped off of the nerve. " they ran system diagnostics with the new lead and everything was within normal limits. Attempts for further info are in progress. Product analysis is pending on the generator and lead.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1096205


Title: Re: Electrodes
Post by: dennis100 on March 12, 2012, 01:13:55 PM
Model Number 304-20
Event Date 07/29/2014
Event Type Malfunction
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records of the lead confirmed all quality tests were passed prior to distribution.

Event Description
The ent surgeon reported that during implant surgery the surgeon noticed that the negative and positive electrodes were stuck together. It was reported that it appeared as though the electrodeshad melted together. The surgeon was able to pull the electrodes apart and reported that there did not seem to be any visible damage to the lead. Device diagnostics once implanted were within normal limits. This event was previously investigated and concluded to likely be due to a manufacturing operator error and was missed during inspection. Attempts to obtain additional relevant information have been unsuccessful to date.

Manufacturer Narrative

Manufacturer Narrative
Describe event or problem, corrected data: previously submitted mdr incorrectly stated that the event was previously investigated and concluded to likely be due to a manufacturing operator error and was missed during inspection. The cause for the event remains unknown, and the device is still implanted in the patient.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4038355



Title: Re: Electrodes
Post by: dennis100 on March 12, 2012, 01:16:33 PM
Event Date 01/01/2004
Event Type Malfunction
Event Description
It was reported in an article that during initial vns placement, a preliminary lead test showed hight lead impedance. Corrective measures were taken, including repositioning of the electrodes, and a standard lead test was performed. Good faith attempts to obtain additional information have been unsuccessful to date.

Manufacturer Narrative
"complete heart block with ventricular asystole during left vagus nerve stimulation for epilepsy. " epilepsy & behavior 5 (2004) 768-771. Conclusions: device failure is suspected.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1123809


Title: Re: Electrodes
Post by: dennis100 on March 12, 2012, 01:19:22 PM
Event Date 07/15/2008
Event Type Injury
Patient Outcome Disability;
Event Description
It was reported to manufacturer that the vns pt had an mri scheduled to "check on the status of the patient's hearing. " the pt reportedly has been having some problems hearing in the left ear and the doctor wants to rule out that the electrodes that might be causing hearing problems. Attempts to obtain add'l info are underway.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1120671


Title: Re: Electrodes
Post by: dennis100 on March 16, 2012, 02:03:30 PM
Model Number 300-20
Event Date 10/01/2008
Event Type Malfunction
Event Description
It was reported that the pt's system mode diagnostics showed high lead impedance. The pt also had a small increase in seizures. Follow up with the nurse revealed that pt was sick and was recently toxic on lamictal. The nurse indicated that these could have attributed to her seizures and cannot really tell if it is because of vns therapy. The nurse also stated that the pt had fell previously and injured her neck and head. The level of seizures is same as pre-vns baseline. X-rays were reviewed by the mfr and it was observed that the negative electrode was off the vagus nerve, no obvious lead discontinuities were observed.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the mfr, no gross lead discontinuities visualized. Negative electrode was observed to be off the vagus nerve.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1249827



Title: Re: Electrodes
Post by: dennis100 on March 26, 2012, 12:26:37 PM
Model Number 300-20
Event Date 07/04/2009
Event Type Malfunction
Event Description
It was reported that high lead impedance readings were obtained during a routine office visit. The patient was in a pillow fight a few weeks prior to the high impedance readings being obtained. The end of service indicator was 10 years and the lead impedance was greater than 10,000 ohms. The patient's device was programmed off and lead revision will be discussed if there is an increase in seizure frequency. X-rays were sent to the manufacturer for review and it was found that the electrode may not be fully on the vagus nerve which could contribute to the high lead impedance event; however, the exact placement of the electrodes in relationship to the vagus nerve could not be determined from the x-ray view provided. No other obvious anomalies were observed that could be contributing to the report of high impedance. Good faith attempts to obtain additional information from the patient's physician have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1496319


Title: Re: Electrodes
Post by: dennis100 on March 26, 2012, 12:29:49 PM
Model Number 302-20
Device Problem Failure to align
Event Date 06/23/2009
Event Type Malfunction
Event Description
Reporter indicated high lead impedance readings were obtained for a vns pt. The pt's seizures were also increased. The vns was disabled. The pt will be observed clinically with the vns disabled for now, and no vns revision surgery is currently planned. X-rays were reviewed by the manufacturer and no lead discontinuities were noted. However, it was identified that the vns electrodes are not in alignment; this is suggestive of one of the electrodes possibly not being secured to the vagus nerve. All attempts to the reporter for additional information have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Results - x-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Conclusions - device failure is suspected.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1483313


Title: Re: Electrodes
Post by: dennis100 on March 26, 2012, 12:34:38 PM
Model Number 302-20
Event Date 03/18/2009
Event Type Injury
Patient Outcome Required Intervention;
Event Description
It was reported that the electrodes of a vns patient's lead had begun to extrude through the skin of her right neck. Follow up with the patient's explanting surgeon revealed that the event was believed to be related to the patient being allergic to the material on the electrode. Though the patient has undergone several lead replacement surgeries due to patient manipulation, the patient's surgeon and treating vns therapy physician indicated that there had been no admissions of manipulation for this recent event.

Manufacturer Narrative
Patient physiology caused or contributed to the event.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1397148


Title: Re: Electrodes
Post by: dennis100 on March 26, 2012, 12:38:02 PM
Model Number 302-20
Event Date 01/29/2009
Event Type Injury
Patient Outcome Hospitalization; Required Intervention
Event Description
It was reported that the vns pt experienced swelling, wound dehiscence and allergic reaction at the electrode site. The pt was reportedly hospitalized and the events were resolved surgically. Diagnostics tests revealed proper device function. It was indicated that there was no pt manipulation that led to the events. It was also indicated that the pt did not have a medical history of allergies prior to vns. The events were determined to be due to wound dehiscence and definitely related to implantation.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1356631


Title: Re: Electrodes
Post by: dennis100 on March 26, 2012, 03:13:39 PM
Model Number 102
Event Date 03/01/2010
Event Type Injury
Event Description
It was reported to the manufacturer that the vns pt's generator and part of the lead body were explanted due to an infection at the electrode site. It is unk if there was any pt manipulation or trauma at the device site that may have caused or contributed to the reported event. It is unk if cultures were taken to confirm the event. It is unk if there is infection also at the generator site. Good faith attempts to obtain add'l info regarding the reported event are currently underway.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator an lead prior to distribution.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1656292



Title: Re: Electrodes
Post by: dennis100 on June 08, 2012, 06:48:00 AM
Event Date 04/06/2012
Event Type  Malfunction  
Event Description
Patient came to the or for a scheduled placement of a vagal nerve stimulator. Upon interrogating a new vns demipulse duo generator, it was discovered that the patient's existing vns electrode had failed as well as the vns generator.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=2591379


Title: Re: Electrodes
Post by: dennis100 on April 10, 2013, 03:18:01 AM
Type of device: stimulator, vagal nerve, lead stimulator, vagal nerve
Device brand name:
Device manufacturer's name: Cyberonics, Inc.
Date of this report:(mm/dd/yyyy)    
05/23/2012
Describe the event or problem:    
Patient came to the OR for a scheduled placement of a Vagal Nerve Stimulator. Upon interrogating a new VNS Demipulse Duo Generator, it was discovered that the patient's existing VNS electrode had failed as well as the VNS generator.

The device(s) may have caused or contributed to: Potential for patient harm

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/medsun/medsun_details.cfm?ID=91287


Title: Re: Electrodes
Post by: dennis100 on April 10, 2013, 07:04:06 AM
Type of device: stimulator, autonomic nerve, implanted for epilepsy
Device brand name: vns lead
Device manufacturer's name: Cyberonics, Inc
Date of this report:(mm/dd/yyyy)    
11/23/2011
Describe the event or problem:    
Pt had a vagus nerve stimulator placed in approximately 2005 or 2006. Pt has a seizure disorder & hydrocephalus; traumatic birth. Pt recently had an increase in his frequency and type of seizures. Battery was interrogated by Dr. and found to be completely depleted of voltage. Pt presented here recently for generator replacement but we found that the lead was completely disconnected from the wires up in the neck. It appeared that there was fluid that filled the channel indicating that this was longstanding. The wound had been closed and the patient sent home for a week while we arranged for a time to bring him back to do the longer surgery were we need to explore the vagus nerve and scar tissue and remove his broken lead and place a new one. Surgery recently completed for this procedure: dissection made down to the scar to the platysma, which we freed up and undermined. Worked way through scar just medial to the sternocleidomastoid muscle and identified the broken wires protruding upward. There was one anchor that was holding this electrode, which is the reason that this fractured at this point. There was no strain release loop left in the neck. We released the anchor, divided the lead, and then followed the lead down towards the vagus nerve. The jugular vein was identified and freed up as was the carotid artery. We worked our way on the more proximal and where there was not as much scar tissue and came down to the vagus nerve. We then worked our way cranially up the vagus nerve and then along the wire with a 15 blade until we came to the junction of the wire in the vagus nerve. Under loupe magnification, able to release the scar over the lead and then unwind the lead from around the nerve. There was quite a bit of scar tissue around the nerve and we were not sure how well a new electrode would work so we made sure we had a long segment of nerve, especially with some on the more proximal end to accept the local lead. The wound was irrigated, new lead wrapped around the vagus nerve carefully so as not to touch the wires and as well as its anchor. Slight strain releasee inferiorly and then looped the thick end of the electrode upward and secured it in 2 places with anchors under the paracervical musculature. We made a pocket for upward loop of the electrode. Tunneler to pass electrode. Tested lead; impedances were all good. Generator was zeroed out and will have to be set by Dr. some time in future. Wounds irrigated, sutured. Pt to recovery in stable condition.

The device(s) may have caused or contributed to: Potential for patient harm

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/medsun/medsun_details.cfm?ID=83904



Title: Re: Electrodes
Post by: dennis100 on April 10, 2013, 07:05:13 AM
Type of device: STIMULATOR, AUTONOMIC NERVE, IMPLANTED FOR EPILEPSY
Device brand name: VNS Demipulse
Device manufacturer's name: CYBERONICS, INC.
Date of this report:(mm/dd/yyyy)    
05/19/2010
Describe the event or problem:    
Patient has intractable epilepsy and an oligodendroglioma in the frontal lobe. Approximately 10 or 11 months ago, a Vagus Nerve Stimulator (VNS) was placed into position for her because her seizures have been poorly controlled with medical therapy. At the time of surgery, the impedance test of the electrode yielded a somewhat high impedance of 45. At the time the system was inspected very carefully because this value was somewhat unusual, and did not notice any excessive tissue affecting the nerve. After discussions with Cyberonics at the time, they recommended to continue with the implantation process, as the impedance was below the maximum threshold allowed. Patient did appear to have a response from the device. However, a while after implantation the impedance rose from values that had initially been postoperatively in the 7000 range to greater than 100,000. Subsequently, later on last year, the lead impedance was high enough that the device indicated it was not transmitting current properly. Despite this, patient has had what her family describes as a response to the device. It is, however, not entirely clear that is working for her, and in addition, the potential failure of the device has made it very difficult to obtain a MRI for her. Specifically, there is a concern that the electrode lead is broken.

The device(s) may have caused or contributed to: Potential for patient harm

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/medsun/medsun_details.cfm?ID=60522


Title: Re: Electrodes
Post by: dennis100 on April 10, 2013, 07:06:20 AM
Type of device: lead, stimulator, vagus nerve stimulator, vagus nerve
Device brand name: VNS Therapy
Device manufacturer's name: Cyberonics, Inc.
Date of this report:(mm/dd/yyyy)    
07/29/2008
Describe the event or problem:    
Surgical Procedure for nerve stimulator battery failure. Pt presenting with chronic intractable seizures. The leads tested during the procedure were associated with high impedance and it was elected to replace the generator and the electrode stimulation system. The bipolar unit and lead were replaced.

The device(s) may have caused or contributed to: Not known

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/medsun/medsun_details.cfm?ID=42264


Title: Re: Electrodes
Post by: dennis100 on April 10, 2013, 07:07:15 AM
Type of device: Stimulator, Neurological, Vagus
Device brand name: VNS Therapy
Device manufacturer's name: Cyberonics, Inc
Date of this report:(mm/dd/yyyy)    
07/24/2008
Describe the event or problem:    
The 102 model generator seems to be fine. There was a high impedance reading which implies a break somewhere in the electrode lead, so this component had failed.

The device(s) may have caused or contributed to: Potential for patient harm

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/medsun/medsun_details.cfm?ID=42090


Title: Re: Electrodes
Post by: dennis100 on April 10, 2013, 07:08:02 AM
Type of device: Stimulator, Vagus Nerve
Device brand name: Cyberonics
Device manufacturer's name: Cyberonics, Inc.
Date of this report:(mm/dd/yyyy)    
03/02/2007
Describe the event or problem:    
Approximately nine months ago, the stimulator was reported to be malfunctioning after patient had a bad fall due to a seizure. After the fall, test results did not show any lead fracture, so a surgical revision of the stimulator itself was done. The stimulator was twisted about 360 degrees as was the electrode, which was also twisted and under tension. The positions were corrected and the electrode tested fine, so the system was left implanted in the patient. About three month later, the stimulator was again malfunctioning and could not be interrogated. A second surgical intervention was done and at this time it was noted that the top screw of the stimulator was totally loose although it had been secured during the previous intervention. At this time, the stimulator was removed and another device was implanted.

The device(s) may have caused or contributed to: Serious injury

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/medsun/medsun_details.cfm?ID=30180


Title: Re: Electrodes
Post by: dennis100 on April 04, 2014, 07:05:31 AM
Event Date 01/20/2014
Event Type  Injury  
Patient Outcome  Required Intervention,Hospitalization
Event Description
It was reported that the patient presented with an infection at the electrode site. The patient was admitted for explant of the vns system. The patient was prescribed antibiotics. It was reported that the infection was a result of vns implantation.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for the generator prior to distribution.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3672262


Title: Re: Electrodes
Post by: dennis100 on April 04, 2014, 07:36:31 AM
Model Number 105
Event Date 01/25/2014
Event Type  Injury  
Patient Outcome  Required Intervention
Event Description
It was reported that the vns patient began experiencing pain at the electrode site on the left side of her face and neck on (b)(6) 2014. Additionally, the patient had difficulty chewing during stimulation. According to the neurologist, the relationship between the reported pain and vns is increased sensitivity to vns stimulation due to unknown etiology. The pain appeared to occur with stimulation. To preclude a serious injury, the neurologist lowered the patient¿s programmed settings. Product information is not available due to hospital policy. The available programming history did include any diagnostic results.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3677841


Title: Re: Electrodes
Post by: dennis100 on June 06, 2014, 12:54:55 PM
Model Number 302-20
Event Date 04/11/2014
Event Type Malfunction
Event Description
It was reported that the vns patient¿s device was tested on (b)(6) 2014 and diagnostic results revealed high lead impedance (impedance value >= 10,000 ohms). The patient¿s device was subsequently programmed off. There was no change in the patient¿s seizure activity. Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2012. X-rays dated (b)(6) 2014 were provided to the manufacturer for further review. The generator appears in the upper left chest in a normal placement. The filter feed-through wires appeared to be intact. The lead connector pin was fully inserted into the generator connector block. The electrodes appeared to be placed in normal arrangement. Part of the lead was behind the generator. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. Based on the x-rays images, the cause high lead impedance could not be determined. The patient underwent generator and lead replacement surgery on (b)(6) 2014 due to lead discontinuity. During the procedure, it was noted that the electrode had visible damage right beyond the anchor tether. The explanting facility discarded the explanted products; therefore, no analysis can be performed.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Device manufacturing records and available programming and diagnostic history were reviewed. X-rays reviewed by manufacturer, no gross lead discontinuities visualized. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure occurred, but did not cause or contribute to death or serious injury.

Manufacturer Narrative
The initial manufacturer report incorrectly stated that the x-rays showed normal placement of the generator in the upper left chest. The x-rays showed abnormal placement of the generator in the left abdominal area.

Event Description
The generator appears in the left abdominal area in an abnormal placement.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3796059


Title: Re: Electrodes
Post by: dennis100 on June 06, 2014, 01:19:57 PM
Model Number 302-20
Event Date 04/14/2014
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that prior to prophylactic generator replacement surgery, the vns patient¿s device showed high lead impedance. High impedance was not previously observed so no x-rays were taken and the device was not programmed off. The patient¿s generator and lead were replaced during the procedure. The surgeon noted that the electrodes were detached from the nerve. When replacing the generator, the surgeon was able to explant the generator and lead prior to opening the neck incision site. The explanted lead was fully intact and no other issues were noted. No patient manipulation or trauma was reported. The explanting facility discarded the explanted products; therefore, no analysis can be performed.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3802074


Title: Re: Electrodes
Post by: dennis100 on June 23, 2014, 05:29:49 AM
Model Number 302-20
Device Problems High impedance; Malposition of device
Event Date 12/14/2009
Event Type Malfunction
Patient Outcome Required Intervention
Event Description
It was reported that system diagnostics resulted in high lead impedance at f/u appointment. Add'l info provided through a company representative from the treating physician revealed no trauma or manipulation was reported that could have contributed to the event. X-rays were taken and further reviewed by the manufacturer which revealed the lead connector pin appeared to be fully inserted into the generator connector block and the filter feed-thrus appeared to be intact. Moreover, there was no lead behind the generator and no acute angles or discontinuities were observed in the visualized portion of the device. Add'l info was provided from the surgeon through a company representative as the pt was scheduled to have lead revision surgery due to the reported event. Info from the company representative revealed that during the surgery, the surgeon tried to explant the lead but there was a build up of fibrosis around the nerve and noted that the negative electrode was not around the vagus nerve. The surgeon informed the representative that the vagus nerve was partially sectioned and decided to explant both generator and lead as there was no possibility to re-implant a new lead due to the issue with the vagus nerve. At the moment, good faith attempts to obtain add'l info have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-ray reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1585532


Title: Re: Electrodes
Post by: dennis100 on July 04, 2014, 01:41:46 AM
Model Number 303-20
Event Date 05/09/2014
Event Type Injury
Patient Outcome Required Intervention
Event Description
It was reported that the vns patient would at times experience numbness under her chin and hot flushes in her left arm after her device was programmed on during an office visit on (b)(6) 2014. The patient¿s device showed lead impedance within normal limits (impedance value ¿ 2304 ohms) at the time. The patient was seen on (b)(6) 2014 and reported having some pain in her left arm after her device settings were increased. The patient¿s device showed increased lead impedance but still within normal limits (impedance value ¿ 4649, 4622 and 4701 ohms). X-rays dated (b)(6) 2014 were provided to the manufacturer for further review. The generator appears in the left chest in a normal placement. The filter feed-through wires appear to be intact. The lead connector pin appears fully inserted into the generator connector block. The electrodes appeared to be placed in an abnormal arrangement as they do not align with the spine but rather perpendicular to the spine. Part of the lead was behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. Based on the images provided, the cause of the reported events may be due to the abnormal placement of the electrodes. However, no definitive conclusions can be made. The patient was referred for surgery but no known surgical interventions have occurred to date. Attempts for additional relevant information have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by manufacturer, no gross lead discontinuities visualized but identified abnormal placement of electrodes.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3899453


Title: Re: Electrodes
Post by: dennis100 on July 30, 2014, 12:24:49 AM
Device brand name: VNS Lead   
Device manufacturer's name: Cyberonics   
Date of this report:
(mm/dd/yyyy)
07/03/2011   
Describe the event or problem:
Patient underwent implantation of her Vagus Nerve Stimulator (VNS) ~3 years ago. Initially, it worked well to reduce the frequency and severity of patient seizures. Patient was able to use the device to help abort her seizures. Patient is now having events 1-2 times a week. She has begun to experience auras again. Interrogation of her VNS indicates high impedance, suggesting a malfunction. Chest XRay performed and suspect the lower contact on the nerve may be fractured. The contact is sitting at an odd angle on the nerve, and does not seem to be winding around the nerve the way it should.   

The device(s) may have
caused or contributed to: Potential for patient harm   

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/Medsun/medsun_details.cfm?ID=77103


Title: Re: Electrodes
Post by: dennis100 on August 08, 2014, 02:18:49 AM
Model Number 302-20
Event Date 06/11/2014
Event Type Malfunction
Event Description
It was reported that during generator replacement surgery due to end of service, the vns patient's device showed high impedence after the new generator was connected to the existing lead. Pin reinsertion was performed. The patient's lead was also replaced during the procedure. It was reported "surgeon said it looked like one of electrodes was off and possible broke wire". The explanted lead has been received for analysis. Analysis is underway, but has not been completed to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
Analysis of the lead was completed on 07/31/2014. The lead was returned in its entirety in three segments. Two lead fractures in the positive coil were identified just past the lead bifurcation. Pitting of the coil was identified near the fraction locations. Three abraded openings were identified (with fluid ingress) near the same area on both the positive and negative coil tubings. Note that compression of the tubing was identified near the bifurcation from what is likely sutures that were directly applied to the lead body.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3921584


Title: Re: Electrodes
Post by: dennis100 on August 08, 2014, 02:19:13 AM
Model Number 304-20
Event Date 06/10/2014
Event Type Injury
Patient Outcome Required Intervention
Event Description
It was reported that the surgeon thinks that he inverted the lead electrodes during implant surgery on the patient the day prior. The surgeon indicated that he planned to fix the placement since the patient was still hospitalized. Additional information was received that the patient underwent lead revision where the position of the electrodes was corrected and the patient is fine. It was reported that x-rays confirmed the electrodes were initially placed incorrectly.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3922681


Title: Re: Electrodes
Post by: dennis100 on October 10, 2014, 06:35:22 AM
Event Date 08/19/2014
Event Type Malfunction
Event Description
It was reported that during initial vns implant surgery on (b)(6) 2014, the patient¿s lead electrodes were observed to be not in contact with the patient¿s vagus nerve. As result, diagnostic results showed high impedance. It was noted that the patient¿s vagus nerve was very thin. No known surgical interventions for the reported high impedance and electrode placement have occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4096581


Title: Re: Electrodes
Post by: dennis100 on November 07, 2014, 12:47:20 AM
Model Number 102
Event Date 01/01/2014
Event Type Injury
Event Description
It was reported that the vns patient had been experiencing an increase in seizures for several months. The patient stated that he was also having pain at his lead electrode site. Attempts for additional relevant information have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4210557


Title: Re: Electrodes
Post by: dennis100 on November 07, 2014, 12:47:59 AM
Model Number 303-20
Event Date 08/03/2014
Event Type Injury
Event Description
It was reported that the vns patient went to the er on (b)(6) 2014 due to painful stimulation in her neck which was occurring every 10 minutes for the past month. During the patient¿s last office visit in (b)(6) 2014, the device output current was increased from 2. 75ma to 3. 25ma. The patient¿s device was tested during the visit and diagnostic results showed normal device function. The patient underwent surgery on (b)(6) 2014 to explant her generator and lead due to electrode failure and pain. The explanting facility discarded the explanted devices; therefore, no analysis can be performed. The patient has not been re-implanted to date to allow sufficient time to let her vagus nerve heal.

Manufacturer Narrative

Manufacturer Narrative
This information was inadvertently left off of initial mfr. Report.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4210450


Title: Re: Electrodes
Post by: dennis100 on November 07, 2014, 09:27:14 AM
Model Number 105
Event Date 07/22/2014
Event Type Injury
Event Description
It was reported that the recently implanted vns patient underwent surgery on (b)(6) 2014 to explant his generator and lead. The patient had been scratching at his cervical wound site which subsequently led to extrusion of the electrode. It was noted that the patient had a history of combativeness, aggressiveness, and self-mutilating behavior. The patient went to the er where approximately 6cm of the patient¿s lead was found to be visibly extruding from the approximate 6mm opening of the patient¿s wound. There was no purulence but the patient was sent for surgery due to risk of infection. During explant, granulation tissue was found at the area of dehiscence and a significant amount of scarring was noted within the patient¿s neck. The extruding portion of the patient¿s lead was cut and discarded. Samples were taken for cultures and the patient¿s wound was cleaned and irrigated. The patient has not been re-implanted to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4131361


Title: Re: Electrodes
Post by: dennis100 on December 05, 2014, 03:23:51 AM
Model Number 302-20
Event Date 01/01/2005
Event Type Injury
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. However, lead electrodes were noted to be inverted on the nerve.

Event Description
It was reported that the patient had vns explant in 2006 due to cardiac episodes and painful stimulation. The patient had previously had generator replacement on (b)(6) 2006. Review of the generator programming history revealed that the device was programed off on (b)(6) 2007. The explant therefore occurred sometime after that time. The patient had vns re-implant surgery on (b)(6) 2014. During surgery, the surgeon noted that the old lead electrodes were inverted on the vagus nerve (with the positive and negative electrodes inverted). It was reported that in 2005, the patient had a cardiac episode and was hospitalized for bradycardia. Additionally, the patient had painful stimulation. As a result, the device was turned off, and the generator and a portion of the lead in the chest area was explanted. Review of programming history in-house reveals the device was programmed off on (b)(6) 2007. Follow-up with the patient's treating neurologist revealed that there is only limited information regarding the events, as the patient was treated by a different physician at the practice at the time of the events and that physician no longer works at the practice. The currently treating physician's recollection is that there were "big problems" with getting the patient regulated which would be explained by the inverted electrodes, per the physician. The explanted portion of the lead from surgery on (b)(6) 2014 was received by the manufacturer for analysis. Note that a large portion of the lead assembly (body); including the connector pin / boot section with model and serial number tag and the electrodes was not returned; therefore it was not possible to verify the model and serial number during this analysis and a complete evaluation could not be performed on the entire lead product. The condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. Continuity checks of the returned lead portions were performed, during the visual analysis, and no discontinuities were identified. Based on the findings in the product analysis lab, there is no evidence to suggest discontinuity in the returned portion of the device which may have contributed to the stated allegations. Additionally for the explanted generator on (b)(6) 2006, analysis was completed. Based on the battery life analysis, the pulse generator approached a normal end of life condition. In addition, the pulse generator was operating at an increased duty cycle (71%) and, as defined in the physician¿s manual, this will deplete the battery faster than a low duty cycle; this may have been a contributing factor. The reported condition of erratic stimulation at that time was not verified in the laboratory. Delivered generator output across an electrical load confirmed a steady output voltage consistent with programmed parameter settings. There were no signs of variation in the output signal. The pulse generator would not interrogate, therefore was opened. The measured battery voltage was below the low battery operation level specified for the pulse generator, which indicates that the pulse generator had reached the end of life. These measurement in the lab demonstrate appropriate current consumption for the device, resulting in normal battery depletion. No performance anomalies were noted.

Event Description
The surgeon's office reported that the patient had explant surgery on (b)(6) 2008. It was also reported that the explanted generator and portion of the lead explanted at that time were discarded.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4233217


Title: Re: Electrodes
Post by: dennis100 on February 06, 2015, 07:31:13 AM
Model Number 302-20
Event Date 12/01/2014
Event Type Injury
Event Description
It was reported that the physician underwent explant of the vns and it was noted that the lead electrodes had been "scorched" on the patient's nerve. Attempts to obtain additional relevant information have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4394209


Title: Re: Electrodes
Post by: dennis100 on March 06, 2015, 03:20:14 AM
Model Number 304-20
Event Date 12/01/2014
Event Type Injury
Event Description
It was reported that the patient had his vns removed due to the vns electrode breaking through the skin on his left shoulder and subsequent infection. The physician reported that it was interesting that he noticed several weeks prior that the patient was not using his left arm and they could not figure out why, but orthopaedics found no issues with his shoulder. The generator and lead were explanted on (b)(6) 2015 due to infection at both devices sites. It was unknown if there were any external factors that may have contributed to the events.

Manufacturer Narrative
Manufacturer device history records were reviewed. Review of the manufacturer device history records confirmed sterilization was performed for both the generator and lead prior to distribution.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4504658


Title: Re: Electrodes
Post by: dennis100 on March 06, 2015, 03:20:50 AM
Model Number 300-20
Event Date 12/31/2014
Event Type Injury
Event Description
Hospital procedure notes dated (b)(6) 2014 note that during generator and lead replacement surgery (mfr. Report # 1644487-2014-03136), during dissection of the electrodes from the patient's vagus nerve the surgeon experienced brisk venous bleeding from the jugular vein. The surgeon identified a small hole in the vein and controlled the bleeding with direct pressure and then closed the hole with a 5-0 prolen interrupted suture. The surgeon then placed surgicel over this. It was noted that the patient tolerated the procedure well and was transferred to pacu in stable condition. The physician assistant indicated that the bleeding is a known complication when removing old lead and that the risk was discussed prior to surgery. It was reported that the vns caused this in the fact of it's presence and the leads scared down to the surrounding anatomy.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4476773


Title: Re: Electrodes
Post by: dennis100 on September 18, 2015, 05:50:21 AM
Model Number 304-20
Event Date 07/02/2015
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that during elective removal of a patient's generator and partial removal of the patient's lead the provider stated that he observed the electrodes to be in a very superficial position. His visual assessment was that the electrodes were not as deep as the carotid sheath. Although the electrodes were lined up as they would be if they were on the vagus nerve, the physician questioned whether they had come off the nerve. The physician did not dissect into the neck to remove the electrodes. A small portion of the lead (<1. 5cm), including the electrode portion, was left implanted. Operative notes from the original implant of the lead were obtained and reviewed. The operative notes revealed a routine lead and generator implant procedure with no mention of superficial electrode placement or any unusual patient anatomy. The explanted generator and partial lead segment were discarded and are not available to be sent to the manufacturer for product analysis. Attempts for additional relevant information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5022795


Title: Re: Electrodes
Post by: dennis100 on September 18, 2015, 05:51:30 AM
Model Number 302-20
Event Date 07/27/2015
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that device diagnostics resulted in high impedance (dc dc code - 7). It was reported that the physician last saw the patient in (b)(6) 2013 at which time device diagnostics were within normal limits. The patient did not want the device programmed off since her seizure frequency has remained stable for over a year. The patient was referred for x-rays. X-rays were reviewed by the manufacturer. It was noted that the lead electrodes were implanted on the nerve inverted. There was a suspect lead fracture identified in the review. It was reported that the patient would undergo lead and generator replacement. No known surgical interventions have occurred to date. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5022041


Title: Re: Electrodes
Post by: dennis100 on September 22, 2015, 02:38:51 AM
Model Number 304-20
Event Date 11/06/2012
Event Type  Malfunction   
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed no non-conformances or other adverse conditions were noted in the lead's dhr.
 
Event Description
It was initially reported that it is believed that the lead electrode detached from the patient's nerve. Soon after being implanted that patient was in an altercation which resulted in the patient being kicked in her neck and resulted in the electrodes coming off the nerve per the patient as this has not been confirmed by a physician. The patient had not been turned on following surgery. Additional information was received that the patient incisions were healing well around the generator and lead. The physician was aware of the trauma but did not see any external evidence of it externally. The physician ordered x-rays but is unclear when the patient will be having them taken. The plan is if nothing seen on x-rays than the patient will be turned on and had diagnostics run. The device history record (dhr) for the lead was reviewed and no non-conformances or other adverse conditions were noted in the lead's dhr. Good faith attempts for additional information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2920462


Title: Re: Electrodes
Post by: dennis100 on September 30, 2015, 03:02:15 AM
Model Number 300-20
Event Date 10/10/2013
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Manufacturer Narrative

Event Description
It was reported that the patient is doing fine. It was reported that the insolation over the lead had degenerated over an approximately 6 cm in length in the portion underneath the generator. It was reported that the lead was destroyed during removal.

Event Description
An implant card was received that noted that the patient underwent generator and lead replacement due to battery depletion and "old electrode disolved, no isolation". Attempts to obtain additional information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3487604


Title: Re: Electrodes
Post by: dennis100 on October 05, 2015, 11:04:27 AM
Model Number 302-20
Event Date 06/13/2013
Event Type Malfunction
Manufacturer Narrative
Analysis of programming history. Device failure occurred but did not cause or contribute to a death or serious injury.

Event Description
On (b)(6) 2013, it was reported that there was a high impedance situation. The device output current was disabled, and the patient was referred for surgery. X-rays were taken but have not been provided. There was no patient manipulation or trauma that was believed to have caused or contributed to the high impedance. The patient underwent full revision on (b)(6) 2013. Upon opening the neck incision, the surgeon found that an electrode was broken. The explanted devices have not been returned. Review of programming history shows that previous diagnostics from (b)(6) 2011 were within normal limits. The device was disabled on (b)(6) 2013 and then programed back on to 0. 25 ma.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3208533


Title: Re: Electrodes
Post by: dennis100 on October 06, 2015, 12:20:35 AM
Model Number 302-20
Event Date 05/30/2013
Event Type Malfunction
Event Description
It was initially reported that the patient had high impedance. Diagnostics were run and resulted in an impedance value of 5208 ohms which did not trigger the impedance ¿ high. When diagnostics were run again high impedance was seen and the impedance value was 5352 ohms. High impedance triggers at 5300 ohms. There was no reported trauma or manipulation. Diagnostics were within normal limits on (b)(6) 2012 with an impedance value of 2460 ohms. Follow-up indicated that x-rays were taken and per the physician it did not appear that the lead pin was fully inserted as it could not be seen past the connector block. X-rays were not provided to the manufacturer for review. Surgery is likely but has not occurred. No further information was provided. Review of manufacturing records confirmed there were no unresolved non conformances found with the generator and lead prior to distribution.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that the patient underwent surgery on (b)(6) 2013. It was reported that the lead pin was fully inserted into the generator header and was not the cause of the lead impedance. It was reported that the lead impedance was resolved with lead replacement and the generator was not replaced. The explanted lead was returned to manufacturer for analysis. Analysis is underway, but has not been completed to date.

Manufacturer Narrative
New information changes the suspect device.

Event Description
Analysis of the lead was completed on 04/17/2014. Scanning electron microscopy was performed on the connector end of the (+) connector ring quadfilar coil break (found at 63mm) and identified the area on three of the broken coil strands as being mechanically damaged with fine pitting which prevented identification of the coil fracture type and residual material. Pitting was observed on the coil surface. The remaining broken coil strand was identified as having the appearance of being melted, with re-solidified material (evidence of being melted at one time). Scanning electron microscopy was performed on the electrode (mating) end of the (+) connector ring quadfilar coil break (found at 63mm) and identified the area on two of the broken coil strands as being mechanically damaged with fine pitting which prevented identification of the coil fracture type. Pitting was observed on the coil surface. The remaining broken coil strands were identified as having the appearance of being melted, with re-solidified material (evidence of being melted at one time). Pitting was observed on one of the coil melt areas. What appeared to be spatter was found on the quadfilar coil strand. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. The abraded openings found on the outer and (+) connector ring inner silicone tubes most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids found inside the outer and (+) inner silicone tubes. For the observed (-) connector pin inner tubing dried remnants of what appeared to have once been body fluids found inside, there was no obvious path for fluid ingress other than the cut ends that were made during the explanted process. What appeared to be white deposits were observed in various locations. Eds (energy dispersion spectroscopy ¿ provides chemical or element identity/composition analysis) was performed and identified the deposit as containing silicon, phosphorus, sodium, magnesium, aluminum, sulphur and calcium. Refer to attached eds sheet for additional information. The melted appearance on some of the quadfilar coil strands appears to be related to the explant procedure. With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed there were no unresolved non conformances found with the generator and lead prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3188480


Title: Re: Electrodes
Post by: dennis100 on October 06, 2015, 12:21:54 AM
Event


Title: Re: Electrodes
Post by: dennis100 on October 07, 2015, 01:15:36 AM
Model Number 302-20
Event Date 03/04/2013
Event Type Malfunction
Manufacturer Narrative

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was initially reported that the patient was referred to surgery due to ¿lead impedance¿. Additional clarification was received that the patient had low impedance. This event is reported in mdr # 1644487-2013-01184. Product analysis was completed and there were no anomalies found with the pulse generator. Abraded openings were identified in the outer and the inner silicone tubing of both lead coils of the vns lead. Additionally, remnants of dry body fluids were found inside the inner and outer silicone tubing with no obvious point of entry other than the aforementioned tube openings and ends of the returned lead portion. No other anomalies were identified in the returned lead portion other than typical wear and explant related observation.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3157022


Title: Re: Electrodes
Post by: dennis100 on October 07, 2015, 01:16:49 AM
Model Number 102
Event Date 05/03/2013
Event Type Injury
Event Description
In the pa lab, the device output signal was monitored for more than 24-hrs, while the generator was placed in a simulated body temperature environment. Results showed no signs of variation in the pulse generator¿s output signal and demonstrated that the device provided the expected level of output current for the entire monitoring period. The pulse generator diagnostics were as expected for the programmed parameters. In addition, a comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. There were no performance or any other type of adverse conditions found with the pulse generator.

Manufacturer Narrative

Event Description
Clinic notes dated (b)(6) 2013 were received for the patient¿s referral for surgery which indicated the patient presented to the neurologist with complaints of vns discomfort. The patient reported that she did not feel the vns was working, and at the same time, she felt that the vns is causing pain that goes from the area of the generator to the neck. The discomfort was constant. The episode started in the prior 7 days. The altered mental status developed gradually. The problem is unchanged. There was left-sided focality noted with associated symptoms including neck pain. Past treatments included acetaminophen, but the treatment did not provide relief. The neurologist reported in the notes that he personally reviewed the csr x-ray, and the study showed normal lead placement with the generator ¿very low in the breast. ¿ the chest pa and lateral x-ray reported indicated the reason for review was ¿nerve stimulator malfunction¿ with portable chest comparison from (b)(6) 2013. The lead appeared unchanged since the comparison examination, and the lead appeared intact. The vns was interrogated, and the impedance was normal. The vns was working properly per the notes. The vns was turned off, and the patient continued to complain of discomfort. The patient also complained of breakthrough seizures. The patient¿s anti-seizure medication was increased and the patient was prescribed medication for the patient. She was also referred to neurosurgery follow-up. Clinic notes dated (b)(6) 2013 from the surgeon¿s office revealed that the patient was experiencing increased shocking in her left breast around the generator implant, but she was still getting control of her seizures. This progressed until it became severe enough that she went back to the neurologist, and he did an x-ray that showed the generator had ¿migrated deep into the breast and appeared to be stretching on the electrode. The electrode remained in good position. ¿ the neurologist turned the device off, and the pain resolved but since then, she has had increasing seizure frequency and severity indicating the efficacy of the device. Therefore, the surgeon indicated that the patient would require electrode revision. The surgeon reported that the shocking indicates that there is ¿probably damage to the electrode lead and we will interrogate this at the time of surgery. ¿ the patient was referred for generator replacement surgery with possible lead replacement if warranted. Follow up with the neurologist¿s office revealed that the device was turned off on (b)(6) 2013. The believed cause for the pain in the chest and neck was due to the generator being misplaced. The patient believes a child pushed on the generator making it move. The patient therefore had surgery to move the generator. Attempts to the surgeon to determine if a non-absorbable suture to secure the generator to the fascia have been unsuccessful to date. The patient had generator replacement surgery on (b)(6) 2013. Good faith attempts for product return are underway but have been unsuccessful to date.

Manufacturer Narrative

Event Description
The surgeon reported that a non-absorbable suture used to secure the generator to fascia during implantation of the device during implant surgery on (b)(6) 2011. The company representative reported that the product disposition is unclear at this time.

Event Description
The company representative reported that the explanted device was available for return. The generator was received by the manufacturer on (b)(4) 2013. However, product analysis has not been completed to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3161364


Title: Re: Electrodes
Post by: dennis100 on October 09, 2015, 01:27:32 AM
Model Number 304-20
Event Date 01/01/2015
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that the patient's device has high impedance and that one of the electrode coils appeared to be stretched to the physician in the x-rays. Based on the x-ray image received of the electrode site, the electrode coils did not appear to be stretched. However a complete evaluation of the lead was not possible with the image received. Attempts for additional relevant information were unsuccessful.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5111878


Title: Re: Electrodes
Post by: dennis100 on October 09, 2015, 04:11:50 AM
Model Number 304-30
Event Date 08/25/2015
Event Type Malfunction
Manufacturer Narrative

Event Description
During an implant surgery, the surgeon reported that the electrodes seemed to be "straighter" and that the electrode coils didn't have the normal turns so it was more difficult to wrap around the nerve. Diagnostics performed with this lead were recorded the impedance to be 748 ohms and 800 ohms. Due to the lower impedance value, the surgeon opted to replace the lead. The explanted lead was received on (b)(6) 2015. Analysis is underway but has not been completed to date. An impedance value greater than 600 ohms and less than 5300 ohms is considered to be within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5085587


Title: Re: Electrodes
Post by: dennis100 on October 29, 2015, 12:19:50 PM
Model Number 302-20
Event Date 10/04/2010
Event Type  Malfunction   
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
Reporter indicated high lead impedance was noted at a vns pt's office visit. No trauma or device manipulation had occurred. The pt later had vns lead and generator replacement surgery. No anomalies were noted with the lead during surgery. Fibrosis was noted at the lead electrodes. The explanted lead and generator have been returned and are currently in product analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1893347


Title: Re: Electrodes
Post by: dennis100 on October 30, 2015, 03:00:13 AM
Model Number 302-20
Event Date 11/01/2010
Event Type Malfunction
Event Description
Reporter indicated that system diagnostic tests resulted in high lead impedance during an office visit. The reporter stated that there is no known trauma that may have caused the high lead impedance. The pt's generation has been turned off and x-rays were taken. X-rays were received and evaluated by the mfr. Review of x-rays indicated the generator was placed in the left chest in a normal orientation. The connector pin appeared to be fully inserted. The lead appeared to be intact at the connector pin and some lead was present behind the generator. The filter feed-thru wires appeared to be intact at the connector pin. The alignment of the positive and negative electrodes appeared to be normal. However, a suspect lead discontinuity was seen on the positive electrode in the neck area. The pt will most likely be referred for revision surgery. However, no surgery has been planned yet.

Manufacturer Narrative
Device failure is suspected, but did not cause or contributed to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1943924


Title: Re: Electrodes
Post by: dennis100 on November 03, 2015, 01:52:23 AM
Event Date 02/13/2015
Event Type  Malfunction   
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
It was reported that the patient underwent explant surgery following an infection reported in the mfr. Report # 1644487-2015-04630.
 
Event Description
It was reported that the recently implanted vns patient¿s device was tested two days following implant on (b)(6) 2015 and system diagnostic results revealed high impedance (impedance value >= 10,000 ohms). The patient¿s device was tested again at the second follow-up visit on (b)(6) 2015 and lead impedance was found to be within normal limits. X-rays were received by the manufacturer for review. The generator appears in the upper left chest in a normal placement. The filter feed-through wires appeared to be intact. The lead connector pin was fully inserted into the generator connector block. The electrodes appeared to be placed in normal arrangement but not aligned, though this is likely due to the position of the patient¿s head while taking the x-rays. Part of the lead was behind the generator and could not be reviewed. No clear lead breaks or sharp angles were visible. No known interventions have occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4631956


Title: Re: Electrodes
Post by: dennis100 on November 03, 2015, 01:21:26 PM
Event Date 09/01/2009
Event Type Injury
Event Description
It was reported to the manufacturer that the vns patient's electrodes moved and has been experiencing discomfort in the neck region. It is unknown at this time how the migration condition was detected. The patient is scheduled for a full revision of the device for the reported event. Good faith attempts to obtain additional information regarding the reported event have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1491033


Title: Re: Electrodes
Post by: dennis100 on November 14, 2015, 03:16:12 AM
Model Number 302-20
Event Date 06/01/2007
Event Type Injury
Event Description
Reporter indicated that a vns patient was experiencing painful stimulation and muscle spasms near the electrode site. X-rays were reviewed by the manufacturer and no cause for the reported complaint was identified; however, it was observed that strain relief was inadequate. A full revision of the lead and generator was planned due to the painful stimulation and muscle spasms. The treating psychiatrist reported that he believed there may have been "faulty implantation". During the surgery, the surgeon identified that one of the electrodes was detached from the vagus nerve. The lead and generator were replaced.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=922749


Title: Re: Electrodes
Post by: dennis100 on November 14, 2015, 06:36:13 AM
Model Number 302-20
Event Date 07/01/2007
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Review of x-rays by the manufacturer revealed a gross lead break. Device failure occurred but did not cause or contribute to a death.

Event Description
Additional information was attained from the patient's mother that she had noticed a lump on her childs neck a couple of nights ago and when she tried to touch it they became upset and wouldn't let her touch it. She then took them to see their neurologist and x-rays were taken. The device is still off at this time (turned off (b)(6) 2007) and family will be deciding whether or not they will have a revision or have the system explanted. X-rays were received for review. The generator is visualized in the left upper chest in a normal orientation. Filter feedthru wires appear to be intact, and the lead pin does appear to be fully inserted into the header of the generator based on the views available. The lead body is intact at the lead pin. The lead body and electrode site were able to be visualized. The electrodes appear to be implanted at c5 level. The electrodes appeared to not be in alignment. The negative electrode is not in alignment with the positive electrode based on one lateral view. It is unable to be assessed if it has detached from nerve or related to body positioning. In the other lateral view with the shoulders forward, the electrodes do not appear to be detached from the nerve. Of significance, there appears to be a lead break in the area distal to the tie-down that is visible in the lateral neck image. A strain relief bend is present, but a strain relief loop is not present. One tie-down is present securing the bend. A large subcutaneous loop should also be formed and secured with a tie-down. The strain relief should be adequate to allow for full neck movement to its maximum stretched positions. Most of the lead was visible. Some lead is behind the generator, and therefore, this portion cannot be assessed. Based on the x-ray review, there is likely a lead break distal to the one tie- down that caused their high lead impedance. The negative electrode being detached from the nerve cannot be ruled out and could be related to body position in the x-ray.

Event Description
Additional information was received that the patient's device was disabled on (b)(6) 2007 and set at 0/30/500/30/5/0/60/500. Since that time it was reported that the patient's mother noted that she had been able to see the patient's lead visibly taut and reported that is because the patient has grown since her initial implant. The patient is now having an increase in seizures that is why the parents are looking for a replacement of their device. At this time no surgery has been planned.

Event Description
Additional information was received stating that the vns patient was referred for surgery to explant her device. No known surgical interventions have occurred to date.

Event Description
It was reported that the patient underwent lead and generator explant surgery on (b)(6) 2014. It was reported that the patient was not implanted with replacement devices because the generator had been disabled for a long time and the patient's mother indicated that the seizure rate was acceptable. The explanted devices have not been returned to date.

Manufacturer Narrative
Xray reviewed by manufacturer yielded no lead discontinuities. Device malfunction is suspected, but did not cause or contribute to a serious injury or death.

Event Description
Initial reporter indicated that they performed a system diagnostics test in their office that resulted in high impedance, indicating a possible lead malfunction. The physician reported he had performed a system diagnostic test a month earlier with the same results. The physician reviewed x-rays and did not visualize any lead discontinuities. X-rays review by manufacturer did not identify any anomalies. Revision surgery is likely.

Event Description
Additional information was received stating that one of the helices from the vns patient¿s lead had previously detached from the patient¿s nerve. The patient was referred for surgery to explant her device but no known surgical interventions have occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=908041


Title: Re: Electrodes
Post by: dennis100 on November 14, 2015, 06:36:56 AM
Model Number 302-20
Event Date 11/01/2006
Event Type Injury
Event Description
Reporter indicated that a pt was undergoing revision surgery to correct the original placement of his vns therapy lead, as it was too high and was causing his neck muscles to twitch with stimulation. Mfr review of x-rays showed electrode placement at c2 to c3. Explanted lead was returned to mfr for product analysis, however, that analysis is not yet complete. Good faith attempts for further info are currently being made.

Manufacturer Narrative
X-rays reviewed by mfr. Mfr review of x-rays showed electrode placement at c2 to c3.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=905654


Title: Re: Electrodes
Post by: dennis100 on November 14, 2015, 06:37:45 AM
Model Number 302-20
Event Date 01/01/2006
Event Type Injury
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the lead and generator prior to distribution. Device failure confirmed by surgeon during revision surgery.

Event Description
Reporter indicated that a pt was undergoing full revision surgery due to a seroma and foreign body reaction located under the neck incision site. Further investigation revealed that the pt was also experiencing an increase in seizures. It is unk if the seizure level was above pre-vns levels. Pt was no longer having voice alteration with device stimulation. The surgeon indicated that the pt had experienced a traumatic event which dislodged the electrodes from the nerve and fractured the leads. Preoperative x-rays reviewed by the surgeon confirmed that the electrodes had migrated off the vagus nerve. An ent determined the pt had left vocal paralysis believed to have been as a result of the scarring of the vagus nerve from the trauma which dislodged the electrodes from the nerve. Postoperatively, the surgeon indicated that there was fluid surrounding the lead and the generator. Surgeon also noted an area of inflammation around the anchor together which had a "greenish reaction to the plastic. " samples were sent to pathology and the gram stains for bacteria were negative. The surgeon confirmed that the leads had fractured and that the electrodes were no longer attached to the vagus nerve. The detached electrodes were surrounded by a fluid which "appeared purulent". These samples were also sent to pathology which showed that the gram stains for bacteria were negative but an increase level of white blood cells was noted. It was also observed that there was scarring of the vagus nerve which is believed to be caused by the migration of the electrodes. The site has discarded the explanted products. Due to this possibility of the future infection, the surgeon decided to not immediately re-implant the pt. The pt is currently scheduled to be re-implanted.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=917666


Title: Re: Electrodes
Post by: dennis100 on November 16, 2015, 02:54:44 AM
Model Number 300-20
Event Date 01/01/2007
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected.

Event Description
Patient underwent vns therapy system revision surgery due to high lead impedance noted on a system diagnostics test. During revision surgery, the surgeon noted that "the electrode was found to have fluid in it, and there was a brownish-yellowish discoloration inside the electrode". The lead and generator were replaced. Further follow up with the physician revealed that the patient experienced an increase in seizures and a change in behavior. It is unknown, if seizures are above pre-vns seizure level. X-rays were performed prior to surgery, and there was no documentation of a lead discontinuity. A lead break is suspected. The lead and generator were returned to manufacturer, product analysis is pending.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=852322


Title: Re: Electrodes
Post by: dennis100 on November 16, 2015, 09:28:39 AM
Model Number 302-20
Device Problems Break; Kinked; Cut in material
Event Date 03/02/2007
Event Type Malfunction
Manufacturer Narrative
Device malfunction occurred but did not cause or contribute to a death or serious injury.

Event Description
Rptr indicated that physician noticed that the "second electrode coil was broken" on the lead while performing an implant. Product analysis identified a slice mark on the connector ring inner silicone tubing and kinked quadfilar coil. No other obvious anomalies were noted.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2304502


Title: Re: Electrodes
Post by: dennis100 on November 16, 2015, 09:29:09 AM
Model Number 302-20
Event Date 01/01/2007
Event Type Malfunction
Event Description
Reporter indicated that patient presented for office visit where high lead impedance was obtained on a system diagnostics test indicated a suspected device malfunction. A gross lead discontinuity was noted directly caudal to the negative electrode in an x-ray review performed by manufacturer. Patient's lead was subsequently replaced. To date lead in question has not been received into product analysis.

Manufacturer Narrative
X-rays reviewed by manufacturer. Manufacturer noted gross lead discontinuity directly caudal to the negative electrode. Device malfunction occurred, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=957064


Title: Re: Electrodes
Post by: dennis100 on November 16, 2015, 09:29:40 AM
Model Number 300-20
Event Date 10/24/2006
Event Type Malfunction
Event Description
Reporter indicated that patient developed an abcess at the lead electrode site that was "causing lead impedance". Patient underwent surgery to drain abcess and the generator was removed. Attempts to gather additional information from surgeon have been unsuccessful.

Manufacturer Narrative
A device malfunction is suspected but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=953499


Title: Re: Electrodes
Post by: dennis100 on November 17, 2015, 01:46:07 AM
Model Number 302-20
Event Date 02/01/2007
Event Type Malfunction
Event Description
Reporter indicated that the pt had a recent increase in seizures below pre-vns baseline, dysphagia, and was not sensing stimulation. The reporter indicated the pt experienced trauma in the neck area immediately preceding the events. Systems, normal mode, and magnet mode diagnostics were performed and all resulted in normal device function (see b6). No serious injury was reported. X-rays were reviewed by manufacturer and the following was observed. The electrodes appeared to be at an angle indicating that there may not be adequate connection between the nerve and electrodes. It is possible that the orientation of the electrodes is related to the events, but it is not conclusive. Additionally, the entire lead body is not visible and there is no way to rule out a lead fracture through visible inspection. The pt is scheduled for a surgical consult.

Manufacturer Narrative
Review of pa and lateral x-rays by mfr revealed that the electrodes appeared to be at an angle indicating that there may not be adequate connection between the nerve and electrodes. Device failure suspected, but did not cause or contribute to death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=937144


Title: Re: Electrodes
Post by: dennis100 on November 17, 2015, 11:30:29 AM
Model Number 302-20
Event Date 02/12/2007
Event Type Injury
Manufacturer Narrative
Vns therapy system labeling lists heart rate/rhythm changes as a potential adverse event possibly associated with surgery or stimulation. Conclusion: device failure suspected and possibly caused or contributed to a serious injury.

Event Description
Reporter indicated that a system diagnostics test was performed during an initial implant surgery which resulted in high lead impedance. Multiple attempts were made to reposition the electrodes and several system diagnostics tests were performed. The surgeon reported that the electrode was irregularly shaped out of the packaging which resulted in the electrode not making good contact with nerve. One of the system diagnostics test resulted in ok lead impedance; however, the patient experienced bradycardia for 6 to 12 seconds. Glycopyrrolate was administered to the patient for the bradycardia, but the patient was still experiencing bradycardia when another system diagnostic test was performed. The physician chose to remove the initial lead and implant another lead. A system diagnostics test was performed with the new lead and the high lead impedance resolved. The patient still experienced some mild bradycardia during the system diagnostics test. The surgeon completed the implant with the new lead. The patient's generator has not yet been turned on by their physician.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=828407


Title: Re: Electrodes
Post by: dennis100 on November 18, 2015, 02:28:53 AM
Model Number 302-20
Event Date 01/01/2006
Event Type Malfunction
Manufacturer Narrative
H. 6: pa and lateral of chest and neck x-rays were reviewed. Results - pa and lateral of chest and neck x-rays: no indication of lead discontinuities within the system. Revealed inverted electrodes on the vagus nerve. Device failure is suspected but did not cause or contribute to a death or serious injury.

Event Description
Reporter indicated that a system diagnostics test at an office visit yielded high lead impedance reading indicating a possible lead break. The patient has not felt stimulation for about three to four months prior to the reported event. Review of x-ray by manufacturer did not identify any obviouis lead discontinuities; however, the electrodes were found to be inverted on the vagus nerve. Revision surgery is likely. No serious injury was reported.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=779132


Title: Re: Electrodes
Post by: dennis100 on November 19, 2015, 08:19:57 AM
Model Number 302-20
Event Type Malfunction
Event Description
Reporter indicated that device diagnostic testing at office visit resulted in high lead impedance reading (dc-dc code 7 and limit), indicating possible device malfunction. The elective replacement indicator was no, ruling out generator battery end of life as a likely cause of the high lead impedance test result. The device was programmed to off pending revision surgery due to suspected lead discontinuity. The pt underwent revision surgery approximately one month after the high lead impedance condition was discovered. Both the lead and generator was explanted. At the time of explant surgery, the surgeon indicated that the pt's vagus nerve was dilated and expanded and that there was an encapsulated abscess around the vagus nerve with signs of infection. It was reported that the surgeon observed a discontinuity at the lead electrode upon explant of the lead. The pt reportedly experienced hoarseness and upper respiratory illness approximately one month before the high imepdance condition was discovered; however, device diagnostic testing at that time was within normal limits, indicating proper device function. Treating physician believes that the abscess may have been caused by an allergy to the device. Visual inspection and electrical testing of the concomitant device (pulse generator) did not reveal any anomalies that would adversely affect device performance.

Manufacturer Narrative
Vns therapy system labeling lists foreign body reaction to implants, including possible tumor formation, as a potential adverse event possible associated with surgery or stimulation. A majority of the explanted lead assembly was not returned for analysis. Only the electrodes, electrode bifurcation area, and a small portion of the lead body were returned. A discontinuity of the electrode, as was reported by the surgeon, was not observed; however, visual inspection vealed that a portion of the quadfilar coil between the detached negative electrode and the electrode bifurcation had dissolved within the inner silicone tubing. The end of the inner silicone tubing appears to be torn in the area of the dissolved coil wire, which may have resulted in the coil wire coming into contact with body fluids and subsequently dissolving in the presence of current flow. The cause of the apparent insulation tubing failure and subsequent coil wire failure has not been ascertained. The coil wire breakdown was the cause of the high lead impedance test results.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=726444


Title: Re: Electrodes
Post by: dennis100 on November 19, 2015, 08:20:30 AM
Model Number 300-20
Event Type Malfunction
Manufacturer Narrative
Device malfunction is suspected, but did not cause or contribute to a death or serious injury.

Event Description
Manufacturer received device tracking information indicating that patient underwent ncp system replacement due to an electrode malfunction. Patient was having revision surgery to replace a generator that was reported to be at end of service. System diagnostic testing during replacement surgery resulted in a high lead impedance reading, indicating a possible lead break. The surgeon then implanted a new generator and lead. No serious injury was reported.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=772315


Title: Re: Electrodes
Post by: dennis100 on November 20, 2015, 10:24:28 AM
Model Number 302-20
Event Date 01/01/2006
Event Type Injury
Event Description
The reporter indicated that the lead electrodes were too small for the nerve, causing the patient to experience constant hoarseness. It was also reported that the vns system had not yet been turned on. Revision surgery was performed to replace the lead (2. 0mm) with a larger one (3. 0mm). During the revision surgery, fibroses was observed and the vagus nerve was found to be visibly inflamed. Following the replacement surgery, the patient's voice was better within two to three days. The hoarseness has reportedly resolved completely. No further complications have been reported to the manufacturer. The lead was returned and analyzed. Product analysis summary: continuity checks of the various lead sections were perfromed with no discontinuities identified. The condition of the lead portions returned is consistent with conditions that typically exist following an explant procedure. No coil breaks were found. No other obvious anomalies were noted. Based on the product analysis findings, there is no evidence to suggest an anomaly with returned portions of the lead which may have contributed to the reported event.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=672742


Title: Re: Electrodes
Post by: dennis100 on November 29, 2015, 03:25:55 AM
Model Number 302-20
Device Problem High impedance
Event Date 06/25/2015
Event Type Malfunction
Event Description
Further information was received indicating that the patient's epilepsy is well controlled without vns and that a surgical revision is not planned. X-rays of the patient dated on were reviewed by the manufacturer. The generator is placed in a normal position in the upper left chest. The filter feed-through wires appeared to be intact. The lead connector pin is fully inserted. The lead wires at the connector pin appeared to be intact. The electrodes at the vagus nerve implant site are not aligned, and the negative one appeared to be detached from the nerve. A strain relief loop was present, but not a bend. One tie-down was visible, securing the loop. Portions of the lead appeared to be behind the generator and could not be fully assessed. No acute angles, no breaks were found in the parts of the lead that could be assessed.

Manufacturer Narrative
Device manufacturing records and available programming and diagnostic history were reviewed. Review of manufacturing records confirmed that both the lead and the generator passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that the patient铠vns system was tested on (b)(6) 2015 and system diagnostics returned a high impedance result with >=10000 ohms, current delivered=0. 5ma, ifi=no. The programmed output current was reduced to 1ma and the pulse width was reduced to 250usec. It was reported that the patient was implanted with vns in (b)(6) 2011 and became seizure-free in (b)(6) 2011. It was reported that the cessation of seizures was thought to be a result of natural progression of the disease as opposed to the effect of vns. X-rays were taken and they were reported to be unremarkable by the healthcare professional. Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2012. Review of manufacturing records confirmed that the lead and the generator passed all functional tests prior to distribution. No known surgical interventions have occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4924659


Title: Re: Electrodes
Post by: dennis100 on November 29, 2015, 03:57:25 PM
Model Number 302-20
Event Date 05/22/2009
Event Type Injury
Manufacturer Narrative

Event Description
It was reported that the patient has been experiencing pain from her neck to her hand that began approximately one month following generator and lead replacement six years prior. The pain began with swelling in the patient's neck, shoulder, and arm, and the patient believes that a nerve was pinched at that time. The patient has been on pain medications and has undergone physical therapy and nerve blocks due to the pain. The patient believes that the vns lead electrodes may have been placed incorrectly and that the placement may be putting pressure on another nerve. The patient indicated that the pain occurs with device stimulation because the pain was exacerbated when the device settings were increased in (b)(6) 2014. The patient reported that the device was programmed off for a while and that the pain subsided a great deal. The device was programmed back on in (b)(6) 2015 and the pain began again in (b)(6) 2015. The physician's office reported that the patient has been seen recently and has not reported these events. The physician's office indicated that the patient would be contacted regarding the reported pain. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4909657


Title: Re: Electrodes
Post by: dennis100 on November 29, 2015, 03:58:07 PM
Model Number 304-20
Device Problems Fracture; High impedance
Event Date 06/05/2015
Event Type Malfunction
Event Description
The lead was received by the manufacturer for analysis on 07/21/2015. Product analysis is underway, but has not been completed to date.

Event Description
It was reported that the patient was referred for surgery due to high lead impedance and believed fractured lead. The patient had lead replacement on (b)(6) 2015. It was reported that the generator was not replaced. The explanted lead has not been received by the manufacturer to date for analysis.

Manufacturer Narrative

Event Description
Product analysis was completed and during analysis, discontinuities were noted on both the negative and positive electrodes. The discontinuities were caused by fatigue fractures. It was noted that set screw marks were observed on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Based on this product analysis, it can be concluded that there is evidence to suggest there were discontinuities in the returned portions of the device which may have contributed to the allegation of fractured leads.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4881567


Title: Re: Electrodes
Post by: dennis100 on November 29, 2015, 03:58:48 PM
Model Number 302-20
Event Date 12/15/2010
Event Type Malfunction
Manufacturer Narrative
Device manufacturing records and available programming and diagnostic history were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
During review of the patient's programming history available in the manufacturer's database, it was identified that low impedance was observed for patient's device. Patient's vns was finally disabled on (b)(6) 2012. Patient underwent full explant of lead and generator on (b)(6) 2013. Surgical notes indicate that the patient was not receiving benefit from vns due to low impedance and that the patient experienced pain in the chest. During the surgery, the surgeon observed that there was a fracture in the electrodes which were coiled up around the generator. The cervical incision was also opened but there were no electrodes remaining there. The explanted products are suspected to be discarded by the explant facility after 30 days from explant.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4922893


Title: Re: Electrodes
Post by: dennis100 on December 08, 2015, 02:45:31 AM
Model Number 304-20
Event Date 01/21/2015
Event Type Malfunction
Event Description
It was reported that during initial vns implant surgery, the lead electrode broke when the surgeon attempted to place it on the patient¿s nerve. It was noted that the surgeon may have caused the damage to the lead. The damaged lead has been returned to the manufacturer where analysis is currently underway.

Event Description
Analysis of the explanted lead was completed. The lead was returned intact. The (+) white electrode ribbon appeared to be stretched with what appeared to be remnants of dried body fluids on the surface. The helical appeared to be misshaped with what appeared to be specs of dried body fluids on the surface and the suture appeared to be partially detached. The (-) green electrode quadfilar coil appeared to be kinked. The (-) green electrode ribbon appeared to be stretched and mangled with what appeared to be remnants of dried body fluids on the surface. The (-) green electrode helical appeared to be misshaped, partially cut with what appeared to be specs of dried body fluids on the surface and the suture appeared to be partially detached. This most likely occurred due to manipulation of the lead during the attempted implant procedure while attempting to place the electrodes on the vagus nerve. Setscrew marks were not observed on the connector pin. The condition of the lead assembly returned is consistent with conditions that typically exist following an attempted implant procedure; therefore the absence of setscrew marks on the connector pin and abrasions on the connector boot and outer silicone tubing is evidence that the lead assembly was not fully implanted. No other obvious anomalies were noted. Continuity checks of the returned lead assembly were performed with no discontinuities identified. Overall length and resistance measurements of the complete returned lead were determined to be in compliance with those defined in the manufacturing specifications.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4521161


Title: Re: Electrodes
Post by: dennis100 on December 08, 2015, 02:46:16 AM
Model Number 302-20
Event Date 01/01/2015
Event Type Malfunction
Event Description
It was reported that during generator replacement surgery on (b)(6) 2015, the vns patient¿s device also showed high impedance so the lead was also replaced during the procedure. X-rays had been previously taken which showed a bend in the lead approximately 4cm from the anchor tether. Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2014. The explanted devices have not been returned to date.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to death or serious injury.

Manufacturer Narrative
Review of the available programming and diagnostic history. Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
The explanted lead and generator were received on (b)(6) 2015 and they are currently undergoing analysis.

Event Description
Analysis of the lead was completed on (b)(4) 2015 and it identified a break in the negative coil, 2mm from the proximal end of the anchor tether. Evidence of a stress-induced fracture was found at the break area, with mechanical damage and pitting. During the visual analysis the (+) white electrode ribbon appeared to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the (-) white electrode ribbon from coming in contact with the vagus nerve. No other discontinuities were identified. The positive electrode ribbon presented remnants of dried body tissue. Findings consistent with an explant procedure were also identified. Analysis of the returned generator was completed on (b)(4) 2015. The battery voltage was 2. 975 volts, which indicates an ifi=no condition. No adverse conditions were found on the generator. The generator performed according to specifications.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4528383


Title: Re: Electrodes
Post by: dennis100 on December 08, 2015, 02:47:01 AM
Model Number 302-20
Event Date 01/19/2015
Event Type Malfunction
Event Description
The explanted generator and lead were returned to the manufacturer for analysis. There were no performance or any other type of adverse conditions found with the pulse generator. A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. Analysis of the returned lead confirmed discontinuity of negative quadfilar coil in the electrode region. Extensive pitting and evidence of electro-etching were observed on the coil surface. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that the vns patient was experiencing neck pain. The patient¿s device was tested and diagnostic results revealed high impedance (impedance value ¿ 7012 ohms). The patient¿s device settings were subsequently decreased. An implant card was received indicating that the patient underwent generator and lead replacement surgery on (b)(6) 2015. It was noted that the patient¿s lead appeared to be ¿falling apart¿ at the nerve. The explanted devices have not been returned to date.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4516900


Title: Re: Electrodes
Post by: dennis100 on December 08, 2015, 10:25:08 AM
Model Number 302-20
Event Date 12/10/2014
Event Type Malfunction
Event Description
It was reported that device diagnostics resulted in high impedance. The patient was scheduled for follow-up with the physician and a company representative present. The patient was seen again with the company representative present and high impedance was confirmed (>= 10,000 ohms). It was reported that there has not been any increase in seizures. The patient was referred to surgeon for consult. No known surgical interventions have been performed to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
The patient underwent full revision on (b)(6) 2015. The surgeon noted that the electrode placement of the lead prior to explant was inverted. Two tie-downs were used and both were sutured to the sternocleidomastoid muscle for the old lead. He also noted that the lead was coiled on top of the generator rather than underneath or to the side prior to explant. Once the new system was fully implanted, three intra-operative diagnostics were run (one out of pocket, one in pocket skin open, and one in pocket skin closed) and all were within normal limits. The explanted products were reported to have been discarded.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4392697


Title: Re: Electrodes
Post by: dennis100 on December 12, 2015, 12:54:34 AM
Model Number 302-20
Event Date 10/14/2014
Event Type Malfunction
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to death.

Event Description
Further information was received indicating that no x-rays had been taken. A lead fracture was observed during explant surgery. Explant surgery was completed due to patient's infection. Analysis of the returned device found fracture and pitting of both coils approximately 28mm from the electrode bifurcation.

Event Description
It was reported that device diagnostics resulted in high impedance following generator replacement on (b)(6) 2014. X-rays were taken and reportedly did not identify any obvious discontinuities. The patient suffered an infection and once resolved the patient went back to surgery and a lead break was identified. It was reported that the patient did not have efficacy with vns and the devices were explanted. Attempts to obtain additional relevant information have been unsuccessful to date.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death.

Event Description
Additional information was received indicating that the distal end of the lead electrode showed a break by means of x-ray imaging. The explanted lead was received for analysis. It was reported that the explanted generator was discarded by the explanting facility. Analysis of the lead is underway, but has not been completed to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4337754


Title: Re: Electrodes
Post by: dennis100 on December 12, 2015, 12:55:29 AM
Model Number 302-20
Event Date 11/12/2014
Event Type Malfunction
Event Description
It was reported that the patient underwent generator and lead replacement due to high impedance. The physician observed the high impedance two weeks prior to the surgery and the device was programmed off. The generator was replaced prophylactically. The explanted devices have been returned for analysis, but have not been received to date. No additional relevant information has been received to date.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
Analysis of the returned lead portion was completed. A fracture was identified in the negative and positive coils. Corrosion of both broken coil ends were observed.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records of the lead confirmed all quality tests were passed prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
The explanted generator and lead were returned to the manufacturer for analysis. The generator performed according to functional specifications. There were no anomalies found with the pulse generator. Analysis of the returned lead is currently underway.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4338178


Title: Re: Electrodes
Post by: dennis100 on December 14, 2015, 03:51:39 AM
Model Number 302-20
Device Problem Insufficient Information
Event Date 06/18/2015
Event Type  Malfunction   
Event Description
The patient reached out to a company representative explaining that she requested help with implant removal for the vns. It appears the patient is looking for a physician to "take out the damaged coils and leads". The patient later explained that she would like to find somebody who can help her deal with her damaged vagus nerve. The patient also stated she now has tachycardia and that she had a mild transient ischemic attack/stroke. Attempts for additional relevant information have been unsuccessful to date.
 
Event Description
It was reported by the patient that she has nerve damage due to the surgeon who explanted her vns on (b)(6) 2015. The patient also noted that she has experienced vocal cord paralysis, a hematoma in her neck, and gastroparysis ever since. The patient also explained that she can't walk any more because she gets out of breath. The patient later spoke to a company representative and explained that she has no complaints about vns. Attempts for additional relevant information have been unsuccessful to date.
 
Manufacturer Narrative
Date of event, corrected data: the initial report inadvertently reported the incorrect event date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5061282


Title: Re: Electrodes
Post by: dennis100 on December 14, 2015, 11:46:44 PM
Model Number 302-20
Event Date 09/29/2014
Event Type Malfunction
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that device diagnostics resulted in high impedance (dc dc code - 7). The patient was referred to neurosurgery. No additional relevant information has been received to date.

Event Description
It was reported that during surgery device diagnostics showed high impedance with the new generator attached to the existing lead. The generator was tested with the test resister which showed the generator was within normal limits. The surgeon then dissected the lead coils off of the nerve and placed a new lead. An implant card was received confirming that both the generator and lead were replaced and that lead impedance with the new system was within normal limits. The explanted lead was received for analysis. Analysis of the lead was completed on (b)(4) 2014. A break was identified in the positive coil. Scanning electron microscopy images of the positive coil broken ends show that pitting or electro-etching conditions have occurred at the break location. However, due to metal dissolution and surface contamination the fracture mechanism cannot be determined. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead portion.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4201101


Title: Re: Electrodes
Post by: dennis100 on December 16, 2015, 10:53:46 AM
Model Number 102
Event Date 08/22/2014
Event Type Malfunction
Event Description
It was reported that the patient's surgery was cancelled because device diagnostics were within normal limits. The generator was programmed back on.

Event Description
It was reported that the vns patient was experiencing pain in his neck and arms. Diagnostic results showed lead impedance within normal limits (dc dc ¿ 2). Follow-up revealed that the patient had recently experienced a drop seizure which may have affected the patient¿s device. Following the drop seizure, the patient began experiencing an increase in seizures. During stimulation on-times, the patient experienced epiglottis contractions, itching around the neck, spasms of the left arm and pain the left arm. The patient stated that he was able to feel the electrical pulse from his device travel through the lead. X-rays were taken and no lead breaks were found; however, the physician stated that the electrodes appeared misaligned on the patient¿s nerve and suspected a partial detachment or shift of the electrodes. X-rays were provided to the manufacturer for further review. The generator appears in the left chest in a normal placement. The filter feed-through wires appear to be intact. The lead connector pin appears fully inserted into the generator connector block. The electrodes appeared to be placed in normal arrangement. Part of the lead was behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. It was noted that the electrode alignment on the vagus nerve did not follow a straight line. Based on the images provided, the cause of the reported events cannot be determined. No known interventions have occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4113291


Title: Re: Electrodes
Post by: dennis100 on December 17, 2015, 06:28:05 AM
Model Number 300-20
Event Date 06/10/2014
Event Type Malfunction
Event Description
It was reported that the patient underwent generator and lead replacement. The surgeon indicated that the lead appeared to be on a similar nerve close by the vagus nerve. It was later reported that the surgeon believes he may have damaged a nerve during electrode removal that may be causing the patient's eye to droop. It was reported that the explanting facility does not return explanted devices without patient consent. Attempts to obtain additional relevant information have been unsuccessful to date.

Manufacturer Narrative
Device failure suspected, but did not cause or contribute to a death.

Event Description
It was reported that the patient would be referred for generator replacement. Clinic notes dated (b)(6) 2014 note that the patient has not reported any adverse effects with continuing device stimulation and that the patient's seizures remain in good control. It was noted that continuing device stimulation is important as long as the patient does not experience any adverse effects and that generator replacement will be expedited. No known surgical intervention has been performed to date.

Event Description
Clinic notes dated (b)(6) 2014 note that the patient has noticed an increase in micro-seizures since using a bone stimulator to help with bone fusion following neck surgery. The neurologist advised the patient to discontinue use of the bone stimulator to see if the seizures decrease. Clinic notes dated (b)(6) 2014 note that when the patient discontinued use of the bone stimulator, the patient's seizures abruptly stopped about 7-10 days later. It was noted that device diagnostics resulted in low impedance (<600 ohms). No surgical intervention has been performed to date.

Event Description
It was reported by the physician that the vns electrodes appeared to have been attached to the sympathetic nerve instead of the vagus nerve. He believes that the electrode had been on the nerve at some point in time and that it may have become detached. The patient has developed horner¿s syndrome, which was due to the surgery. The syndrome was reported to be permanent, but mild, no additional interventions were taken.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3985372


Title: Re: Electrodes
Post by: dennis100 on December 19, 2015, 10:01:28 AM
Model Number 302-20
Event Date 08/25/2009
Event Type Injury
Event Description
On (b)(6) 2015 the patient reported that his vns has been turned off for about 5. 5 months because of ¿several problems¿. It was later reported that the patient has had his device for a while due to painful stimulation. The patient will be proceeding with explant of the vns device. Although surgery is likely, it has not occurred to date.

Manufacturer Narrative
Device manufacture date; corrected data: additional information was received that changes the product from the generator to the lead.

Event Description
Follow-up revealed that the vns patient¿s device was disabled on (b)(6) 2014. The patient underwent surgery on (b)(6) 2015 to explant his device due to pain and to pursue an alternative treatment option. During the procedure, the surgeon noted that the electrodes were not in proper alignment and had been implanted upside-down. Additionally, a tie-down had been placed on the electrode coil on the nerve. No other tie downs were observed. The explanting facility discarded the explanted devices; therefore, no analysis can be performed.

Event Description
Initially, it was reported that the patient has experienced pain in the left jaw and teeth. The patient was evaluated by a dentist, but nothing was found wrong with the patient's mouth or teeth. The patient disabled the device with the magnet and the pain went away; however, when the magnet was removed the patient began choking and gagging. The patient reported that there appears to be muscles twitching in his neck area. The patient indicated that he is no currently followed by a treating physician and the patient was provided with vns treating physicians. It was later reported that the patient would be referred to surgeon for full vns revision surgery. Clinic notes dated (b)(6) 2014 note that the patient is having trouble with vns and the device was disabled and will likely require a full revision. No additional relevant information has been received to date. No surgical intervention has been performed to date.

Event Description
It was reported that the patient was turned up that day from 1. 0ma to 1. 25ma. Everything was fine while he was at the physician¿s office but when he got home he experienced pain in his jaw again. It only lasted a little bit. The physician stated that the patient is having the same pain in the jaw with the new generator. The patient used to be set at 1. 75ma, but now when they turn the current up to 1. 25ma the patient experiences instant pain when the device turns on. He also states that after a few hours of normal operation the pain gets worse. Settings are output=1-1. 25ma/frequency=30hz/pulse width=500usec/on time=30sec/off time=5omin. Diagnostics are ok; impedance=2213ohms. The physician stated that they would try adjusting the pulse width and decreasing the duty cycle.

Event Description
It was reported that the patient underwent generator replacement. The lead was not replaced. Device diagnostics prior to and during surgery were within normal limits. It was reported that the explanting facility does not returned explanted devices for analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3845774


Title: Re: Electrodes
Post by: dennis100 on December 19, 2015, 10:02:11 AM
Model Number 102
Event Date 02/17/2012
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported by the patient's mother on (b)(6) 2012, through an online forum, that the patient was losing epilepsy control. The mother indicated that diagnostics were performed and had normal results; however specifics were not provided. The mother also mentioned that the patient may have scar tissue around her lead. The cause of the loss of epilepsy control is currently unknown, and attempts for additional information are underway.

Manufacturer Narrative
Corrected data: the previously submitted mdr provided information not related to this patient or event.

Event Description
Follow-up revealed that the information provided on the previous manufacturer report did not involve this patient and was reported in manufacturer report # 1644487-2015-04342.

Event Description
Additional information was received that the patient underwent explant around (b)(6) 2013. Attempts for the explanted devices have been unsuccessful. The patient repeatedly complained of ¿shocking¿ in her neck, despite the device being switched off for more than 2 or 3 years (output current and magnet current set to 0. 0 ma) when it was initially programmed on, all system diagnostic tests were within normal limits. The patient has an intellectual impairment, and the mother doesn¿t know that the patient can always communicate her experience clearly, so the ¿shocking¿ feeling she had was not certain. The patient¿s mother was convinced the stimulator made the patient¿s epilepsy worse, whether it was on or off, as it was irritating the patient; therefore, removal was requested. The coils of the lead were left in place during explant. The surgeon said there was some tension on the electrode, which is what the patient may have been experiencing as the ¿shocking. ¿ it may have been this sensation of tension as she grew and there wasn¿t enough tension relief on the lead. The patient's device was explanted on (b)(6) 2013 and not replaced. The device was disabled approximately two years prior; however, the exact date is unknown.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2493978


Title: Re: Electrodes
Post by: dennis100 on December 22, 2015, 09:41:45 AM
Model Number 302-20
Device Problem High impedance
Event Date 01/23/2014
Event Type Malfunction
Event Description
Additional information was received stating that the vns patient underwent surgery to explant the generator and lead due to high impedance on (b)(6) 2014. Pre-operative diagnostic results showed high impedance (impedance value ¿ 7641 ohms). The patient¿s generator was replaced and diagnostic results with the replacement generator and existing lead also showed high impedance. When the surgeon went to replace the lead, it was noted that the patient may have manipulated the device as one electrode had broken/slipped off the nerve and was slightly corroded. The surgeon observed significant scar tissue and fibrosis when explanting the lead. The patient was not re-implanted as the surgeon was unable to find adequate space on the nerve to place the new lead. Attempts to have the product returned for analysis were made but the product has not been received to date.

Event Description
Patient underwent surgery on (b)(6) 2015 and was implanted with vns generator and lead.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of programming history. Review of manufacturing records for the lead confirmed all quality tests were passed prior to distribution. Device failure is suspected but did not cause or contribute to a death.

Event Description
It was reported by the neurologist that diagnostic results of the vns patient¿s generator revealed high impedance (6433 ohms) but was not programmed off. The patient was referred for x-rays and surgery. Surgery is likely but has not taken place. Clinic notes were received for the vns patient¿s office visit involving increasing lead impedance values on (b)(6) 2014. The notes indicate that the patient experienced an increase in breakthrough seizures so the surgeon increased the patient¿s settings on (b)(6) 2014. The patient has autism and his aggressiveness is believed to have contributed to the reported lead impedance. Review of the available programming and diagnostic history showed normal diagnostic results through 2011. Attempts for additional information have been unsuccessful.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3667615


Title: Re: Electrodes
Post by: dennis100 on December 23, 2015, 06:16:37 AM
Model Number 302-20
Event Date 05/01/2004
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that the vns patient was re-implanted with a generator and lead on (b)(6) 2014. The patient was initially implanted with a generator and lead in 2004; however, the devices were explanted three months post-implant due to infection at an implant site (infection reported on medwatch report # 1644487-2014-00552) and a broken electrode on the lead. A review of programming and diagnostic history for the device revealed no diagnostic test results. Attempts for additional information are in progress.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3651753


Title: Re: Electrodes
Post by: dennis100 on December 23, 2015, 06:17:15 AM
Model Number 304-20
Event Date 01/14/2014
Event Type Malfunction
Event Description
Analysis of the returned lead was completed. Review of the as-received photograph showed one end of the anchor tether silicone helix in the vicinity of the center portion of the helix. Also, the closest electrode to the bifurcation was damaged showing bends on the electrode ribbon and partial detachment of the electrode ribbon and suture from the silicone helix. The furthest electrode to the bifurcation had creases/bends on the electrode ribbon partially losing its helical shape. The lead electrodes including the anchor tether were installed in a training fixture and it was verified that placement of the electrodes and anchor tether was possible. Based on the inspection results it can be concluded that the most likely cause for the observed damage to the closest and furthest electrode to the bifurcation was manipulation of the lead not consistent with our labeling. However, a conclusive determination of whether one of the lead electrodes was tangled prior manipulation of the lead cannot be made.

Event Description
It was reported that a vns lead was being implanted into the patient in the initial implant surgery, but upon opening the lead from the packaging, it was noted that the electrode helical was entangled. The surgeon attempted to attach the helical to the nerve; however, "it did not fit". The helical was described as mis-shaped. Another lead was implanted into the patient and this lead was returned to the manufacturer. The returned product is pending product analysis. No other information has been provided.

Manufacturer Narrative
Device manufacturing records and programming history were reviewed. Review of manufacturing records confirmed the device met all final testing specifications prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3627271


Title: Re: Electrodes
Post by: dennis100 on December 24, 2015, 12:47:21 AM
Model Number 300-20
Event Date 11/29/2013
Event Type Malfunction
Manufacturer Narrative
Device manufacturing records and programming history were reviewed. Review of manufacturing records confirmed the device met all final testing specifications prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
On (b)(6) 2013, it was reported that the patient stated she did not receive the stimulation anymore. System diagnostics were performed which showed high impedance. X-rays showed the implanted electrodes were implanted the wrong way, per the reporter, and the electro-voltage potentiometer measured a typical lead break. The patient refers from an accident one year ago, after she takes a osteosynthetic implant. Follow up with the physician found that the patient cannot remember when she first noticed the stimulation did not work anymore. The magnet activation still helps her, as of (b)(6) 2013. The generator was disabled on (b)(6) 2013. It is unknown if causal or contributory programming or medication changes preceded the onset of the stimulation not perceived event. The manufacturer's review of x-rays confirmed that the electrode placement on the vagus nerve appears to be abnormal, as the electrodes were inverted upon implant. No strain relief was observed. No clear sharp angles or lead breaks were found on the visible part of the lead. X-rays of the generator were not provided, so the generator and that portion of the lead could not be assessed. No other information has been provided.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3557310


Title: Re: Electrodes
Post by: dennis100 on December 25, 2015, 02:38:28 AM
Model Number 102
Event Date 01/01/2005
Event Type Injury
Event Description
The nurse reported that the patient was initially implanted with vns in 2004. About a year or less later, the patient began having "some sore of neck swelling or possible infection", so the vns device was disabled. The device was disabled for years until about a year ago (around 2012). No other information was provided.

Event Description
Additional information was received stating that the vns patient began having issues with her device since implant. The patient¿s device was disabled because the patient would experience neck pain and swelling during stimulation on-times. The patient was unable to tolerate a device output current above 0. 5ma. The patient underwent surgery on (b)(6) 2014. Pre-operative system diagnostic results showed normal device function at the time. During the procedure, the surgeon noted that the lead electrodes were tightly wrapped around the vagus nerve and another unknown branch which was surrounded by a large amount of scar tissue. The surgeon attributed the patient¿s issues to the incorrect placement of the electrodes around both the vagus nerve and the unknown branch. The patient¿s lead and generator were replaced during the procedure. The patient¿s generator and lead were replaced during the procedure. The generator and lead replacement was reported in manufacturer report #1644487-2013-03847.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3528935


Title: Re: Electrodes
Post by: dennis100 on December 25, 2015, 02:39:10 AM
Model Number 304-20
Event Date 11/14/2013
Event Type Malfunction
Event Description
On (b)(6) 2013, high impedance was reported on the patient's vns device. It was first observed during a clinic visit on (b)(6) 2013. The patient's device was disabled that day and x-ray images were sent to the manufacturer for review. The lead was replaced due to a lead discontinuity. The manufacturer reviewed x-rays. The generator was seen in a normal position in the left chest. The filter feedthru wires appear to be intact. The lead pin appears to be fully inserted into the head. The lead wire appears intact at the connector pin; however, there is a portion of the lead located behind the generator that could not be assessed. There does not appear to be any lead discontinuities in the portion of the lead that could be visualized. The electrode appears not to be placed on the vagus nerve, but rather appears to be attached on or to a nearby bodily structure or unknown object. There are two tie downs present, but they do not appear to be placed as per labeling. There does not appear to be a proper strain relief bend or loop placed as per labeling. The portion of the lead behind the generator cannot be assessed, therefore a lead fracture in that portion of the lead cannot be ruled out. The presence of a micro-fracture in the lead also cannot be ruled out.

Manufacturer Narrative
Manufacturer reviewed x-rays. Device manufacturing records and programming history were reviewed. Review of manufacturing records confirmed the device met all final testing specifications prior to distribution. Manufacturer's review of x-rays found no gross lead discontinuities. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3520201


Title: Re: Electrodes
Post by: dennis100 on December 26, 2015, 01:20:54 AM
Model Number 302-20
Event Date 06/30/2010
Event Type  Malfunction   
Event Description
It was reported through an implant card that a vns patient underwent lead replacement surgery due to lead discontinuity. Info was previously received from the treating nurse indicating the pt was to undergo lead replacement surgery as the pt's lead was found to be inverted during the review of x-rays. Further information was received indicating the pt underwent lead replacement surgery as scheduled and the neurosurgeon reported that when he went into the neck the coils were not on the nerve and he described the nerve as "pristine" as though no scar tissue was present. The surgeon felt like the coils may have never been on the nerve. Follow-up was made with the treating nurse who indicated that the surgeon could not tell for sure if a lead discontinuity was present at the time. (b)(4) attempts to obtain the explanted lead have been unsuccessful to date.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1959055


Title: Re: Electrodes
Post by: dennis100 on December 27, 2015, 11:16:57 PM
Event Date 11/05/2010
Event Type Malfunction
Event Description
Reporter indicated that the recently implanted vns patient was seen for a follow up appointment, and when a diagnostic test was performed, high lead impedance had resulted. The patient was referred back to the implanting surgeon for follow up. The surgeon opted to explore the cause of high impedance surgically. During the exploratory surgery, the surgeon first re-inserted the vns lead pin inside the generator, however, this subsequent diagnostic testing revealed that this did not correct the high impedance. The surgeon then opted to explore the electrode placement on the nerve. The surgeon had noted in the operative report that the electrode helices and anchor tether did appear to be in good contact with the vagus nerve; however based on the high lead impedance the electrodes were then readjusted on the nerve. Subsequent diagnostic testing has been within normal limits. No adverse events have been reported. Attempts for further patient and product information have been unsuccessful to date.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1948987


Title: Re: Electrodes
Post by: dennis100 on December 31, 2015, 01:50:07 AM
Model Number 302-20
Event Date 02/20/2013
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death.

Event Description
On (b)(6) 2013 it was reported that the vns patient underwent a lead revision surgery on (b)(6) 2013 due to a ¿lead discontinuity¿. Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. It was later reported that the patient was seen on (b)(6) 2013 with increased seizures. The patient reported trauma to her neck from her boyfriend trying to choke her. The lead impedance was high and x-rays were done. It was stated that the x-rays appeared to show that one of the electrodes was off the nerve and possibly broken. The explanted lead has not been returned to the manufacturer to date.

Event Description
On (b)(6) 2013 it was reported that the explanted lead could not be returned for product analysis as it was taken off in pieces and discarded by the hospital.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3201678


Title: Re: Electrodes
Post by: dennis100 on January 02, 2016, 12:06:35 AM
Event Date 01/01/2013
Event Type Malfunction
Event Description
I was initially reported on a call the physician office needed a company representative to come to their site and they needed their contact information. I was inquired as to if there was a problem or issue that they needed assistance with but it was repeatedly said there was no issue they just wanted the company representative to come to the site as they had not seen him in a while. Shortly before getting off the phone the caller did mention there was a patient whose lead came off the nerve. Attempts were made to determine the identity of the patient but it was unknown. The caller what made them think the electrodes were off the nerve and if there was high impedance seen and the response was ¿i guess so. ¿. All attempts to get any additional information about the patient and the high impedance have been unsuccessful to date. The call was ended before the name of the physician or the facility was able to be attained. The company representative whose contact information was given to the call has not heard from the office.

Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3129442


Title: Re: Electrodes
Post by: dennis100 on January 02, 2016, 11:17:30 AM
Model Number 102
Event Date 04/01/2013
Event Type Malfunction
Event Description
It was reported that this vns patient apparently lost the effect of vns rather brutally while the stimulator was working. X-rays were received and reviewed. The generator appears in the upper left chest in a normal placement. The filter feed-through wires and the lead connector pin¿s insertion into the generator connector block could not be fully assessed due to the quality of the images. The electrodes arrangement did not appear to be normal, as the positive electrode seems to be separated from the vagus nerve. Part of the lead was behind the generator. No acute angles or clear breaks were found in the parts of the lead that were visible and could be assessed. Attempts for additional information have been unsuccessful.

Event Description
Additional information was received that the device was disabled in (b)(6) 2013. Attempts for additional information have been unsuccessful.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3119881


Title: Re: Electrodes
Post by: dennis100 on January 07, 2016, 05:15:16 AM
Model Number 302-20
Event Date 12/01/2012
Event Type Malfunction
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed that all quality tests were passed prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Manufacturer Narrative
Device failure is suspected and may have contributed to an increase in seizures.

Event Description
It was reported that during a scheduled prophylactic generator replacement on (b)(6) 2013 that high lead impedance was observed in the operating room, so the lead was replaced as well. Follow-up with the surgeon's office that per the operative notes, the surgeon observed a defect found in the coating of the electrode during surgery. Details were not provided. Attempts for additional information have been unsuccessful to date. The explant facility does not return explanted products to the manufacturer for analysis, so the explanted products have not been received to date.

Event Description
Information was received from the surgeon reporting that the scarring around the electrode and vagus nerve as due to normal presence of the device. The patient began experiencing increased seizures below pre-vns baseline about what appears to be about two months prior. The patient was therefore referred for revision. No causal or contributory programming changes, medication changes, or other external factors precede the onset of the increased seizures. Only one seizure type increased.

Event Description
Additional information was received from the surgeon reporting that the patient was not receiving stimulation for some time due to the lead break. The operative notes indicate that a "defect was seen in the plastic coating of the vns electrode within the chest cavity. " the pre-operative diagnosis states "malfunction device. " additionally, "inspection of the fluid within the insulation of the electrode and upon closer inspection, a small defect or laceration of the plastic sheath was observed. Based on this, decision was to open up the cervical wound and replace the electrode. " during the surgery, the previous vns electrode was dissected from the surface of the vagus nerve and scar tissue was dissected "rostrally and caudally form the nerve surface to provide for adequate exposure for a new electrode placement. " the generator and lead were replaced and good lead impedance resulted upon diagnostics. The high lead impedance was not observed prior to surgery, and dcdc=7 was not observed upon diagnostics in the operating room. The device was not turned off prior to surgery. There an outer tubing defect per the surgeon where there was blood tracking inside the tubing. The patient exhibited decreasing efficacy of stimulation associated with the high impedance. It is unknown if there was patient manipulation or trauma that may have contributed to the event. Indications listed in the operative note state that the patient was experiencing increasing seizure frequency with grand mal seizures 3 to 4 per night, and she was referred for surgery for generator replacement. Attempts for additional information have been unsuccessful to date.

Event Description
The neurologist reported that the patient has been stabilized. No further information will be shared at this time.

Manufacturer Narrative
Describe event or problem, corrected data: the data in supplemental #3 was inadvertently not included in supplemental report #2, as the information was attained on (b)(6) 2013 prior to supplemental report #2 being submitted. Date received by manufacturer, corrected data: the supplemental reports #2 and #3 inadvertently had the incorrect the information was received by the manufacturer. The dates for report #2 and #3 should have read as (b)(6) 2013, respectively.

Manufacturer Narrative
The supplemental report #4 inadvertently did not change the patient's age at the time of the increased seizures first began. The supplemental report #4 inadvertently did not change the approximate onset of the increased seizures first began per the surgeon.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3001446


Title: Re: Electrodes
Post by: dennis100 on January 08, 2016, 03:41:05 AM
Model Number 302-20
Device Problem High impedance
Event Date 11/10/2015
Event Type Malfunction

Event Description
It was reported on (b)(6) 2015 that the patient had an appointment that day and system diagnostics were run with results of high impedance. The device was programmed off the day the high impedance was observed. No x-rays are scheduled at this time. They do not suspect that there was any trauma or manipulation. The patient had a full replacement on (b)(6) 2015. It was reported that the negative electrode was detached from the lead. Attempts for product return have been made, but the explanted device has not been received to date.

Manufacturer Narrative

Manufacturer Narrative

Event Description
Information received on 12/01/2015 indicated that the explanted device was discarded after surgery and is therefore unavailable for analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5263683


Title: Re: Electrodes
Post by: dennis100 on January 11, 2016, 03:56:11 AM
Model Number 304-20
Event Date 01/16/2013
Event Type Injury
Event Description
The patient has left vocal cord paralysis. He was seen on (b)(6) 2013 for a followup visit. It was reported that his voice was somewhat better. His vns is currently programmed on and no setting changes made.

Manufacturer Narrative

Event Description
This patient was recently implanted with their vns system. During surgery there was difficulty implanting related to helicals popping off nerve. Ultimately the electrodes stayed on the nerve and diagnostics performed were within normal limits. It was reported (b)(6) 2013 that the patient now has lost his voice. It was reported the event was noticed by their neurologist on (b)(6) 2013. The patient reports voice change right after surgery that has not gotten worse and stayed the same with continuous voice loss. The patient was evaluated by and ear nose and throat physician on (b)(6) 2013. A scope was performed according to the patient and they were diagnosed with paralysis of their left vocal cords. They will be seen for follow up in two months. Their device is currently programmed on.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2992303


Title: Re: Electrodes
Post by: dennis100 on January 13, 2016, 03:04:45 AM
Model Number 302-20
Event Date 10/24/2008
Event Type Injury
Event Description
Reporter indicated the patient's pain was not related to the vns, but the cause was not specified. It was felt to possibly be due to vns stimulation. It was unknown if any contributory programming or medication changes preceded the onset of the pain. It is possible there was patient trauma and manipulation of the vns. The lead repositioning surgery was not performed to preclude a serious injury. The lead tie-downs were secured with non-absorbable suture.

Manufacturer Narrative

Event Description
It was reported by a physician's office that the patient had repositioning surgery for the lead in (b)(6) 2008 due to migration of the electrodes. It was indicated that the patient was experiencing painful stimulation in the neck so the revision was performed. It was indicated that absorbable sutures were used during the initial implant. Attempts for additional information are in progress.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2882636


Title: Re: Electrodes
Post by: dennis100 on January 15, 2016, 11:01:48 AM
Model Number 300-20
Event Date 08/29/2002
Event Type Malfunction
Event Description
On (b)(4), 2012 it was reported that the patient had a full revision in (b)(4) 2002 due to 'loose electrodes. ' the physician did not have any further information as the patient was under someone else's care at that time. Good faith attempts were made for further information from the physician the patient was seeing in 2002 but no additional information was received. Good faith attempts were also made to the implanting hospital for the patient's implanted product information but were unsuccessful. Attempts are underway for the return of the explanted products but they have not been received to date.

Event Description
Additional information was received on (b)(6) 2013 when the implanting hospital provided the patient's product information.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2856755


Title: Re: Electrodes
Post by: dennis100 on January 16, 2016, 04:26:21 AM
Model Number 302-20
Event Date 04/01/2011
Event Type Injury
Manufacturer Narrative

Event Description
Additional information was received that the patient did not have any trauma. Their dcdc code still remains at a 2. The patient will be seen for followup again.

Event Description
A vns surgeon reported to our country manager in (b)(6) that their patient presented in clinic with a complaint of the electrode site being painful upon stimulation, the device was switched off approx 9 months ago, their physician believes the issue maybe the electrode placement. One screen shot was received for review which is inconclusive. One tie down was noted. At least an ap and lateral view is needed to determine if an electrode is detached or misplaced if it is not obvious. Good faith attempts were made for further details about the reported event.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2850763


Title: Re: Electrodes
Post by: dennis100 on January 19, 2016, 02:05:25 AM
Model Number 302-20
Event Date 10/15/2012
Event Type Malfunction
Event Description
Product analysis was approved on (b)(6) 2013. A break was identified in the positive coil. Scanning electron microscopy images of the positive coil show that pitting or electro-etching conditions have occurred at the break location. In addition abrasions in the inner and outer tubing were found. Note that since the electrode array portion was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead portion.

Event Description
On (b)(6) 2012, this vns patient underwent lead revision. Pre-implant diagnostics indicated high impedance. The patient's generator was left at the settings he came in to the operating room with. (these settings are indicative of a faulted system diagnostic test. This event is captured in mfr report # 1644487-2013-00002. ) post-implant diagnostics showed proper device function. According to the doctors, the top two electrodes of the old lead were off the nerve. The lead was received on (b)(4) 2012 and is currently undergoing product analysis.

Manufacturer Narrative

Event Description
On (b)(6) 2012, it was reported that this vns patient underwent generator revision. The generator was explanted and a new generator was implanted; however, high impedance was seen. Generator diagnostics on both the new and old generator with the test resistor were performed with normal results. Attempts to re-insert the pin were three times with the new generator. Diagnostics were not run on the old generator connected to the lead. X-rays were taken in the operating room and it was verified that something was wrong with the lead; however, the x-rays images were not saved and would not be provided for review. The new generator was placed, the device was left programmed off, and the lead was not replaced at the time of surgery. Surgery is likely but has not taken place.

Manufacturer Narrative
Device failure occurred but did not cause or contribute to a serious injury or death.

Manufacturer Narrative
Device failure is suspected but did not cause or contribute to a death.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2830719


Title: Re: Electrodes
Post by: dennis100 on January 19, 2016, 12:44:45 PM
Model Number 302-20
Event Date 05/01/2012
Event Type Malfunction
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed there were no unresolved non conformances found with the generator and lead prior to distribution. Describe event or problem: corrected data: follow-up report #1 inadvertently did not include the information that the lead and generator were replaced and that the generator was returned to the manufacturer for evaluation. If explanted, give date (mo/day/yr): corrected data: follow-up report #1 inadvertently did not include the explant date of the lead.

Event Description
Additional information was received that the patient had a generator and lead replacement. Only the generator was returned to the manufacturer for evaluation. Review of manufacturing records confirmed there were no unresolved non conformances found with the generator and lead prior to distribution.

Event Description
It was reported that the patient's vns was now indicating high lead impedance. Follow-up with the site found the high impedance is believed to be related to the electrode no longer being on the nerve based on ct scans taken in may of 2012. No trauma or manipulation is believed to have caused or contributed to the high lead impedance. The patient was noted as having an "exponential" decrease in seizures with vns however they suspected an issue when the seizures began to return. The increased seizures are back at the pre-vns baseline. The patient was noted as now "playing" with the lead in his neck which is in a ball that can be felt by the patient. The magnet has been used to temporarily disable the patient's vns however the site has not had a chance to turn off the patient's vns. The patient was noted as experiencing voice alteration following vns implant which went away but has now returned with the high impedance. Last known diagnostics were not available upon request. Surgery to replace the lead and generator is likely.

Event Description
Review of decoder data shows that the device impedance went from 4137 ohms to 3039 ohms on (b)(6) 2011. The as-received decoder does not indicate that high impedance was ever seen. Of note, the generator was returned programmed to 1 hz. It is unknown when this was programmed.

Manufacturer Narrative
Device failure is suspected.

Event Description
Additional information was received that product analysis was completed on the generator. Results of diagnostic testing indicated the device was operating properly. Electrical test showed that the pulse generator was operating within specification. There were no adverse functional, mechanical, or visual issues identified with the returned generator.

Event Description
On (b)(6) 2013 the physician¿s nurse stated that per the operative note from surgery, the old generator was removed from the pocket, and a replacement device was connected to a lead and the lead was found to be functioning normally. The battery was put back into the pocket and tested again with normal impedance and proper lead function found. She said that it does not appear from the notes that any other actions were taken except replacing the generator which reportedly resolved the high impedance. However, per the implant card, the patient's lead was indeed replaced. They have not heard from the patient since the surgery so assume everything is okay. It was not dictated in the notes if the electrode was off of the nerve. No additional information or clarification could be provided.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2825195


Title: Re: Electrodes
Post by: dennis100 on January 22, 2016, 09:04:14 AM
Event Date 09/27/2012
Event Type Malfunction
Event Description
On (b)(6) 2012, a nurse reported that the vns patient has high impedance, impedance value=7424ohms. The patient had a new vns generator implanted in (b)(6) 2012. The nurse has disabled the device and had the patient take a chest x-ray. The patient's mother reported that his seizures are much better recently. It was later reported that the x-rays would not be provided. The patient has a severe learning disability and does not talk so the nurse doesn't think there was any trauma. No diagnostics were performed during the patient's surgery in (b)(6) 2012. It was unknown if any diagnostics were performed prior to the diagnostics indicating high impedance.

Event Description
On (b)(6) 2012, it was reported that the x-rays of the patient would be reviewed. The x-rays were reviewed by the manufacturer's regional manager; however, it was reported that there wasn't anything clear. The surgeon queried if the lead pin might not be fully inserted; however, whether the lead pin was fully inserted into the header of the generator could not be assessed on the x-rays due to the angle of the x-rays. It was noted that a tie down over the left clavicle looks as if the lead has been dragged out of place and the lower electrode appears to be stretched. It was also reported that there looks to be a broken portion of lead adjacent to where the anchor tether is; however, another view was not provided to confirm this assessment. The x-rays were not provided to the manufacturer. No diagnostics were performed during surgery; the patient was just programmed on during surgery and the first diagnostics were performed after surgery which indicated high impedance. Although surgery is likely, it has not occurred to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported on (b)(6) 2012 that no further information was received from the physician. It was later reported that no more x-rays were being taken. Although surgery is likely, it has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2799141


Title: Re: Electrodes
Post by: dennis100 on January 27, 2016, 12:50:34 PM
Model Number 302-20
Event Date 08/08/2012
Event Type Malfunction
Event Description
Reporter indicated a patient had high lead impedance >8,000 ohms with vns diagnostics testing, and also was experiencing constant hoarseness. The vns generator was also felt to have migrated in the chest. The vns was disabled. The reporter later stated the patient was confirmed to have left vocal cord paralysis, and was experiencing choking and coughing. X-rays did not note any obvious lead anomalies per the reporter, but the generator was noted to be low in the chest. The patient had no known trauma. Surgery to replace the vns lead and generator is planned, but has not occurred to date. Attempts for further information are in progress.

Event Description
The explanted vns generator and lead were returned on (b)(6) 2013. Analysis of the generator did not identify any anomalies, and the generator performed per specifications. Analysis of the lead is still pending.

Manufacturer Narrative
Device malfunction is suspected.

Event Description
Vns generator product information was obtained from the explanting hospital on (b)(6) 2013. Manufacturer review of available programing history noted high lead impedance of 8635 ohms was noted with normal mode diagnostics on (b)(6) 2012 with an output current of 2. 75ma. Diagnostics were last within normal limits on (b)(6) 2012 with 1668 ohms.

Event Description
Product analysis of the lead was completed. During the visual analysis discoloration was observed on the (-) connector pin quadfilar coil and the coil appeared to have broken coil strands, in some areas. Determination could not be made as to whether the end of the coil was cut or broken. Scanning electron microscopy was performed and identified the broken coil strand areas and the ends of the quadfilar coil as having a twisted appearance with evidence of a stress induced fracture (torsional appearance) with mechanical damage and no pitting. Evidence of pitting and electro-etching was observed on the coil surface. The condition of the quadfilar coil end suggests the fractures are a result of the explant procedure. A definite cause for the pitting and electro-etching observed on the coil surface could not be determined based on the lead portion returned. The abraded openings; slice marks and cut out holes found on the outer silicone tubing, most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the outer silicone tubing. With the exception of the pitting and electro-etching observed on the (-) connector pin quadfilar coil, the condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, and no discontinuities were identified. The electrode array was not returned.

Event Description
The caregiver reported to the manufacturer that the patient's vocal cord paralysis began after generator replacement on (b)(6) 2011. Diagnostics were last within normal limits in (b)(6) 2012. Hoarseness was not noted until (b)(6) 2012 by the treating neurologist, and at that time high lead impedance was also noted. The patient has had no trauma. The patient received injections to the vocal cord as an intervention, but the vocal cord is still permanently paralyzed. The patient had vns lead and generator replacement performed on (b)(6) 2012. During the surgery, it was noted one of the electrodes was "incompletely wrapped" and "the superior electrode had severe inflammation around the nerve". The generator was also noted to be "loose in the pocket". A lead break was not seen. The vocal cord paralysis is felt to be due to the vns stimulation per the surgeon. No medication change or vns programming change preceded the vocal cord paralysis. The new vns system was activated on (b)(6) 2012. Attempts for return of the explanted devices have been unsuccessful to date.

Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2734831


Title: Re: Electrodes
Post by: dennis100 on January 28, 2016, 02:00:56 PM
Model Number 303-20
Event Date 07/11/2012
Event Type Malfunction
Manufacturer Narrative

Event Description
A portion of the positive helical was missing (appeared to be torn) leaving only the electrode ribbon without the helical support. The suture was also missing. A cause could not be identified, although it does appear to be related to manipulation associated with the attempted implantation. With the exception of the positive helical, the condition of the returned lead assembly is consistent with conditions that typically exist following an attempted implant procedure. No other obvious anomalies were noted except for the void / indentation mark that was observed on the inside of the remaining portion of white (+) electrode helical. Setscrew marks were not observed on the connector pin. Continuity checks of the returned lead assembly were performed with no discontinuities identified. No coil breaks were found. Overall length and resistance measurements of the complete returned lead were determined to be in compliance with those defined in the manufacturing specifications. Based on the findings in the product analysis lab, there is no evidence to suggest a discontinuity in the returned portion. However, the positive helical was received with a portion torn and the suture missing. A cause for this observed condition is not known, but may be related to manipulation from the attempted implant procedure.

Event Description
It was initially reported by a company representative that a vns implanting md reported to them that the electrode off a vns lead had detached from the lead body during initial implant. The lead was removed and replaced with a new one during the same implant operation. The lead reported as broken was returned to the manufacturer and is currently undergoing product analysis.

Manufacturer Narrative
A portion of the positive helical was missing (appeared to be torn) leaving only the electrode ribbon without the helical support. Manufacturing records were reviewed and confirmed the electrode was in place prior to distribution of the lead. A cause for this observed condition is not known, but may be related to manipulation from the attempted implant procedure.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2685121


Title: Re: Electrodes
Post by: dennis100 on January 30, 2016, 02:27:49 AM
Model Number 302-20
Event Date 06/13/2012
Event Type Malfunction
Event Description
It was reported by a company representative that high impedance was received at a follow-up appointment upon system diagnostics. No patient manipulation or trauma is suspected and patient was referred for x-rays along with the recommendation to program the device off. The last known good diagnostics were from (b)(6) 2011 and were within normal limits. Additional information from the area representative indicated the x-rays revealed a lead discontinuity in accordance to the treating physician. At the moment revision surgery is being planned and the device was programmed off as recommended. X-rays were provided to the manufacturer for review. Review of x-rays indicated the placement of the generator, the filter feed-trough wires and the lead wires at the connector pin could not be fully assessed due to lack of a full chest images. The generator was partially visible in one of the available views. The electrodes appeared to be in a normal arrangement although the negative electrode seemed to be detached from the vagal nerve. Part of the lead was behind the generator. An acute angle is visible at the lead bifurcation. A lead break is visible at the distal part of the neck area.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2648176


Title: Re: Electrodes
Post by: dennis100 on January 30, 2016, 11:49:52 AM
Model Number 303-20
Event Date 06/11/2012
Event Type Injury
Event Description
It was reported that a vns patient was going to have their lead replaced related to neck pain and migration of their electrodes. The patient had been complaining, for almost 1 month, of increasing neck pain and obvious increasing prominence of the lead anchors under her skin. There didn't seem to be an effect of stimulation on the pain and there was no increase in seizure frequency. There was no history of trauma that preceded the lead migration or pain. X-rays confirmed the leads being almost horizontal in the neck, suggesting that some/all leads were not on the vagal nerve. X-rays were not provided to the manufacture for review. In the operating room, the generator was inconsistent on interrogation - sometimes the surgeon could get a baseline read on the settings, and other times would get an eos warning, or no response. Based upon this, the generator was replaced with a new m103. During surgery, the anchors in the neck were still in position with non-dissolvable sutures still in place. The anchors appeared to have been anchored to the surface of the sternocleidomastoid muscle, explaining their obvious prominence. The leads were still wrapped on a nerve, but the incision was very low, and the nerve was not the main trunk of the vagus, likely a distal branch. The jugular vein was not present lower in the neck and was a tiny vein higher up. The lead was removed and the anchor and the surgeon was able to follow the carotid upwards and isolate a length of vagal nerve above the previous surgery site. He then hooked up the leads to generator and reprogrammed the new generator to the last known settings. The physician felt it was possible the vns leads were implanted too low in the neck on a distal branch of the vagus, and anchored just under the skin. He also wondered if the jugular vein was injured or sacrificed during that surgery. The patient will be monitored following surgery to see if their pain resolves. Good faith attempts were made for the explanted product and it was not returned for analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2643048


Title: Re: Electrodes
Post by: dennis100 on February 01, 2016, 01:49:37 AM
Model Number 302-20
Event Date 05/15/2012
Event Type Malfunction
Manufacturer Narrative
Type of report, corrected data: inadvertently did not check "30-day" on initial report.

Event Description
Additional information was received on (b)(6) 2012, when product analysis was completed on the explanted generator. The generator performed according to functional specifications. During the product analysis there were no anomalies found with the pulse generator. Product analysis on the lead was completed on (b)(6) 2012. Pa on lead completed on (b)(6). A portion of the lead assembly was not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis the white positive electrode quadfilar coil appeared to be broken approximately 1. 5mm and 2. 5mm from the distal end of the anchor tether. The coil segment in between the coil break areas appeared to have dissolved. Scanning electron microscopy was performed on the white positive electrode quadfilar coil break (found at 1. 5mm) and identified the area as having extensive pitting which prevented identification of the coil fracture type. Scanning electron microscopy was performed on the white positive electrode quadfilar coil break (found at 2. 5mm) and identified the area as having evidence of a stress induced fracture with mechanical damage and fine pitting. Determination could not conclusively be made on the fracture mechanism. One of the coil strands had evidence of a stress induced fracture (torsional appearance) which most likely completed the fracture. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. What appeared to be remnants of dried body fluids were observed inside the outer and inner silicone tubes, in some areas. What appeared to be remnants of dried body tissue were observed wrapped around two areas of the green negative electrode inner silicone tubing. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.

Event Description
Additional information was received on august 3, 2012 when the generator and lead were returned to the manufacturer for product analysis. Product analysis is still underway and has not yet been completed.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was reported by a nurse that high impedance was received during normal and system diagnostics at a follow-up appointment. The last known good diagnostics were from (b)(6) 2011. The patient was referred for x-rays and reviewed by the nurse. Review of views indicated the lead appeared to be intact. No patient manipulation or trauma was believed to have occurred. The nurse was advised to program the device off. Additional information was received from the treating nurse indicating the patient had undergone exploratory surgery after being implanted with vns in 2008. The surgery was done to remove a tie-down that was seen to be protruding through the skin. The nurse believed this could have had an effect on the lead. X-rays were sent to the manufacturer and evaluated. Review of x-rays indicated the generator was visualized in the left upper chest. The filter feed-through wires appeared to be intact. The lead connector pin seemed to be fully inserted into the generator connector block. There was part of the lead placed behind the generator and could therefore not be assessed. Electrodes seemed correctly aligned on the vagus nerve. No strain relief bend is present. There was a clear discontinuity on the positive electrode. A sharp angle is visible on the ap neck view, close to the electrodes which could not be confirmed on the lateral view. At the moment revision surgery is likely.

Event Description
Additional information was received on (b)(6) 2012, when it was discovered that the patient underwent a full revision surgery that day due to a lead discontinuity and prophylactic generator replacement. The implant card was received indicating the patient's product information and that lead impedance after the full revision was within normal limits. The explanted generator and lead are in route to the manufacturer for product analysis.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Review of x-rays by the manufacturer revealed a gross lead discontinuity. Device failure occurred, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2604616


Title: Re: Electrodes
Post by: dennis100 on February 01, 2016, 05:47:02 AM
Model Number 302-20
Event Date 05/10/2012
Event Type Malfunction
Event Description
Additional information was received from the area representative indicating there was no manipulation or trauma involved that could have had contributed to the report of high lead impedance. At the moment no interventions have been planned for the patient.

Event Description
It was reported by a physician that high impedance was read at a follow-up appointment upon performing system diagnostics. The patient was referred for x-rays and the generator was programmed off. The last known good system diagnostics were noted to be from (b)(6) 2011. X-rays were received and evaluated by the manufacturer. The generator was placed in the lower left chest, in the left side of it, a few centimeters below the axilla. The filter feed-through wires appeared to be intact. The lead connector pins appeared to be fully inserted into the generator connector block. The lead wires at the connector pin appeared to be intact. The negative and positive electrode appeared not be aligned, and the negative electrode seems to be detached from the vagal nerve. Portions of the lead appeared to be behind the generator and could not be fully assessed. An acute angle appears to be present right below the positive electrode. At the moment, good faith attempts to obtain further information have been unsuccessful to date.

Event Description
Additional information was received that the patient did not have any trauma or manipulation of their device reported prior to the event. At this time no surgery is scheduled. The patient may in the future have either replacement or explant of their lead. The patient is reported to be doing well and a decision will be made in (b)(6) when they see a surgeon.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Review of x-rays by the manufacturer revealed a gross lead discontinuity. Device failure occurred, but did not cause or contribute to a death or serious injury.

Manufacturer Narrative
Type of report, corrected data: initial report inadvertently did not indicate type of report. Report should have read 30-day.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2592703


Title: Re: Electrodes
Post by: dennis100 on February 02, 2016, 06:58:27 AM
Model Number 302-20
Event Date 04/20/2012
Event Type Malfunction
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury. Age at time of event: corrected data: the patient's age was incorrectly reported on the initial mdr. The patient was (b)(6) at the time of the event.

Event Description
It was reported, that during a replacement procedure for generator end of service, high impedance, greater than 10,000 ohms, was observed. Prior to the replacement, the generator could not be interrogated so device diagnostics were not available. When the new generator was attached to the lead, the high impedance was observed. Pin re-insertion was attempted a couple of times, and the lead pin was wiped to remove any extraneous material and the set screw was backed out to clear any obstruction. The surgeon also performed a generator diagnostic test to rule out the generator as the cause and the results revealed proper device function. None of this resolved the high lead impedance so the lead was also replaced. The surgeon noted during the procedure that the top most electrode was off of the nerve and embedded in scar tissue. Following lead revision, system diagnostics test was performed and results revealed proper device function with an impedance value of 1489 ohms. The explanted generator and lead were returned on (b)(4) 2012; however product analysis is not yet complete.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
Product analysis on the lead was completed on (b)(6) 2012. A section of the lead assembly was returned for analysis in one piece. The lead's electrodes were not returned for evaluation. The reported high impedance allegation was not verified within the returned lead portion. Three sets of setscrew marks were seen on the connector pin providing evidence that proper contact between the setscrew and the connector pin existed at least once. A single setscrew mark was seen at the end tip of the connector pin indicating that the lead connector was not inserted completely at one point in time. The exact point in time of when this occurred is unknown. Though it is difficult to state conclusively, the identified single setscrew mark at the end tip of the connector pin does have the potential for being a contributing factor for the reported "high impedance" allegation the silicone tubing has what appears to be a puncture at approximately 3. 5 cm from the end of the connector boot. No damage to the inner tubing or the lead coils was identified at this location. The lead assembly also has remnants of what appears to be dry body fluids inside the inner and the outer silicone tubing but there was no obvious point of entrance noted other than the end of the returned lead portion. Note that since the electrode array portion was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than the above mentioned observations and typical wear and explant related observations, no product anomalies were identified in the returned lead portion. Pa on the generator was completed on (b)(6) 2012. The reported end of service, was duplicated in the pa laboratory and determined to be the result of normal expected battery depletion, based on the battery life analysis and electrical test results. The pulse generator module performed according to functional specifications. There were no performance or any other type of adverse conditions found with the pulse generator. Follow up with the patient's treating neurologist revealed that there was no suspected manipulation or trauma to the device, however they could tell prior to surgery that the vns was not working as the patient was no longer "aware" of stimulation. It is unclear at this time if this was due to the end or service or the lead break as no diagnostic or programming history for the patient was provided. No other information was provided.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2578454


Title: Re: Electrodes
Post by: dennis100 on February 03, 2016, 05:49:57 AM
Model Number 302-20
Event Date 02/01/2012
Event Type Malfunction
Event Description
The implant card was received and confirmed the generator and lead replacement surgery on (b)(6) 2012. The generator was replaced prophylactically, and the lead was replaced due to the electrode being off the nerve and therefore causing the high impedance. Lead impedance following replacement was okay. Product analysis for the explanted products has not been completed to date.

Manufacturer Narrative
Date of event, corrected data: the initial report inadvertently reported the incorrect date. The clinic notes received on (b)(4) 2012, indicated that the patient blacked out in (b)(6) 2012, fell, and landed on his left shoulder. The patient feels like he pulled the lead at that time which likely contributed to the high impedance.

Event Description
The patient had generator and lead replacement surgery on (b)(6) 2012 due to the high impedance. The explanted products were received by the manufacturer for analysis, however it has not occurred to date. The return product form reported that the generator was replaced prophylactically and the lead was replaced due to the electrode being off of the nerve.

Event Description
Clinic notes were received dated (b)(6) 2012, which again reported that the patient blacked out in (b)(6) 2012, fell, and landed on his left shoulder. The patient feels like he pulled the lead at that time. It was also noted that the battery is low. The patient felt that the vns was helping him prior to the device being disabled when the high impedance was first observed at (b)(6). The notes also reported that the x-rays revealed that the lead appears to be off the vagal nerve, which was reported by the manufacturer. The physician is referring the patient for generator and lead replacement surgery. Although surgery is likely, it has not occurred to date.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was reported normal mode and systems diagnostic tests revealed high impedance. The physician's office planned on disabling the device on this day and was referring the patient for x-rays. The patient had a blackout in (b)(6) and feel on his left shoulder. He has had shoulder pain ever since, but has not felt a difference in vns stimulation. This fall may have contributed to the high impedance, per the physician. The last time diagnostics were performed on the patient's device was reportedly a year ago. The patient is likely being referred for generator and lead replacement surgery, but it has not occurred to date. Attempts for additional information have been unsuccessful to date. Film and computer a/p and lateral x-rays images of the neck and chest were reviewed by the manufacturer. It appears that one (or both) electrodes is detached from the nerve, as the positive electrode is angled at approximately a 120 degree angle from the negative electrode. It is unlikely that the patient's nerve curves in such a fashion. It appears that the positive electrode may be detached from the nerve. There were no acute angles or lead discontinuities seen in the visible portion of the lead body. Based on the x-ray images provided, the cause for the reported high impedance is most likely related to the electrode being detached from the nerve. The presence of a microfracture in the lead or a lead discontinuity in the portion of the lead that was behind the generator cannot be ruled out.

Event Description
Product analysis was completed on the generator and lead. A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. There were no performance or any other type of adverse conditions found with the generator. Note that the electrodes were not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis of the returned 96mm portion the quadfilar coils appeared to be stretched and kinked approximately 72mm and 92mm past the end of the electrode bifurcation. The end of quadfilar coil 1 appeared to be broken approximately 72mm from the end of the electrode bifurcation. Scanning electron microscopy was performed and identified the area as having extensive pitting which prevented identification of the coil fracture type. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The resistance measurement taken during decontamination verified an electrical and mechanical contact between the generator and connector pin at one point in time. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2543658


Title: Re: Electrodes
Post by: dennis100 on February 03, 2016, 10:21:36 AM
Model Number 102
Event Date 03/30/2012
Event Type Injury
Event Description
It was reported that a patient was experiencing more seizures which the physician stated could be due to end of service of the generator. Interrogation of the device did not show end of service; however, the patient was referred for generator revision surgery. Attempts for additional information will be made.

Event Description
Additional information was received on (b)(6) 2012 when the neurologist's reported that the patient had not informed them of an increase in seizure activity so they would not be able to provide an assessment. The nurse for the neurologist stated that they had not seen the patient for a few months until recently and at this time, there is not an increase in seizure activity.

Manufacturer Narrative

Event Description
Reporter indicated that during vns generator replacement surgery for the patient on (b)(6) 2012, the vns lead was accidentally broken. The reporter then noted the vns lead electrodes were not on the vagus nerve, but a different structure. A new vns lead was implanted on the left vagus nerve, in addition to the new generator being implanted. The plan of care is to wait until (b)(6) 2012, to begin vns stimulation. Vns diagnostics immediately prior to the surgery were within normal limits. Attempts for return of the explanted devices have been unsuccessful to date.

Event Description
Reporter stated that the patient had generator replacement surgery only initially on (b)(6) 2012, but when the patient was waking up from the anesthesia, she had a seizure. The seizure was not unusual for this patient. Diagnostics with the new generator and resident lead were within normal limits. The patient was then brought to the post-anesthesia care unit and the surgeon decided to replace the vns lead at that time to control her seizures. The patient was then brought back to the operating room for a second procedure. During surgical dissection of the vns lead, the surgical resident accidentally broke the lead. A new lead was implanted. Diagnostics were within normal limits per the implant card received to the manufacturer.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2539141


Title: Re: Electrodes
Post by: dennis100 on February 13, 2016, 04:54:25 AM
Event Date 02/07/2012
Event Type Malfunction
Event Description
It was reported that, during a generator replacement procedure, high impedance was observed when a system diagnostics test was performed with the new generator. Pin re-insertion was tried and generator diagnostics were performed with normal results. The high impedance did not resolve. The new generator was left implanted, and a full revision at a later date is likely; however it has yet to occur. X-rays were taken, however per hospital policy, they will not be returned. A manufacturer's representative present at the replacement procedure reviewed the x-rays and indicated that it appeared as if one electrode was "disconnected from the nerve", however this allegation cannot be confirmed. Trauma and manipulation were not suspected, and recent diagnostic history was not available. Diagnostics with the new generator were provided. Attempts for lead product information have been unsuccessful to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2481643


Title: Re: Electrodes
Post by: dennis100 on February 13, 2016, 04:55:04 AM
Model Number 302-20
Event Date 01/20/2012
Event Type Malfunction
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
Analysis was completed on the returned portion of the lead. Analysis of the returned lead indicated a break was identified in the positive coil. Scanning electron microscopy images of the positive coil show that pitting or electro-etching conditions have occurred at the break location. However, due to pitting and mechanical distortion (smoothed surfaces) the fracture mechanism cannot be determined. Other than the above mentioned observations, and typical wear and explant related observations, no other anomalies were identified in the returned lead portion.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was initially reported by a surgeon that high impedance was found in the or. The surgeon indicated the electrode in the part proximal was partially loose; however repositioning the electrode still showed high lead impedance. Additional information was received from the area representative indicating that on office visit on (b)(6), 2012 system diagnostics showed high impedance; output status = limit. Patient was sent to revision on (b)(6). Anchor tether was partially out of the nerve. After reconnecting, for a short moment, system diagnostic showed ok, but right after again showed high impedance. The generator was programmed to 0 ma. X-rays were received and reviewed by the manufacturer. Review of x-rays indicated the generator was in a normal orientation in the left chest. Based on image quality, the full insertion of the connector pin inside the connector could not be assessed. The generator feed through wires appeared to be intact. The electrodes seemed to be aligned properly. The presence of lead behind the generator could not be assessed due to poor image quality. No gross lead discontinuities or sharp angles could be visualized. Additional information was received from the area representative indicating the patient underwent lead replacement surgery. The explanted lead was returned to the manufacturer and currently undergoing analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2474687


Title: Re: Electrodes
Post by: dennis100 on February 13, 2016, 04:55:47 AM
Model Number 304-20
Event Date 01/30/2012
Event Type Malfunction
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests, and quality and manufacturing inspections. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that the patient is scheduled for generator replacement for end of service and that a lead revision will be done at the same time since the lead was implanted after the surgeon pulled the silicone off of the positive electrode during the initial implant procedure. Surgical intervention has not been performed to date.

Event Description
It was reported that during an initial implant procedure, one of the electrodes was detached from the silicon. The surgeon elected to proceed with implantation as diagnostics were said to be normal. At the patient's follow up appointment on (b)(6) 2012, the patient was programmed on and diagnostics were again run and found to be within normal limits. The device history record for the implanted lead was reviewed. The lead passed all quality and manufacturing inspections prior to shipment.

Event Description
It was reported that the patient underwent replacement surgery. The old lead was not explanted and was left intact in the pocket. Diagnostics with the new vns system were within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2470225


Title: Re: Electrodes
Post by: dennis100 on February 18, 2016, 04:42:02 AM
Model Number 300-20
Event Date 12/21/2011
Event Type Malfunction
Event Description
Reporter indicated that during a vns generator replacement surgery due to end of service, it was noted the vns lead was fractured on the positive electrode. The generator was unable to be interrogated due to end of service. The lead and generator were both replaced. The patient has had no recent trauma, but had not been seen by a neurologist in four years. The explanted vns lead and generator were discarded after the surgery.

Manufacturer Narrative
Device failure occurred but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2419701


Title: Re: Electrodes
Post by: dennis100 on February 18, 2016, 04:42:47 AM
Model Number 302-20
Event Date 12/22/2011
Event Type Malfunction
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned.

Event Description
Additional information was received on (b)(4) 2012, where it was reported that there were no x-rays available to send to the manufacturer for review. There were no reports of trauma or manipulation. The relationship of the seizures to vns is unknown as well as the relationship of the seizures to vns as they did not detect any high lead impedance until the date of surgery. The patient was hospitalized due to the seizures and her medication was adjusted. The patient does have multiple types of seizures and all increased. It was difficult to assess whether any causal or contributory programming/medication changes or other external factors preceded the onset of the seizures. Product analysis of the explanted generator and lead was completed. There was no condition noted during the product analysis evaluation that would suggest any anomaly with the device. The condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. The resistance measurement taken during decontamination verified an electrical and mechanical contact between the generator and connector pins at one point in time. Continuity checks of the returned lead portion were performed, during the visual analysis, with no discontinuities identified. Note that since a portion of the lead assembly (body) including the electrode array section was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.

Event Description
It was initially reported that during prophylactic generator revision surgery on (b)(6) 2011, high lead impedance was obtained with the old generator and new generator therefore the lead was replaced. A company representative called back later and stated that originally, they thought the high lead impedance was due to the patient's output current being high (3. 5 ma) however with the new generator attached to the existing leads, high lead impedance was obtained therefore it was decided to replace the lead. The surgeon noticed that some of the helices did not appear to be attached to the nerve and were embedded. This portion of the lead was not removed as the surgeon did not feel it was safe to do so. Once the new lead and generator were implanted, the impedance value was 1350 ohms. Per the patient's mother, the patient started having more seizures (below baseline levels) and about a month ago, the patient had two grand mal seizures which had not occurred previously. The magnet also appeared to be less effective in aborting seizures. The explanted lead and generator were returned on 12/27/2011 and are currently undergoing device evaluation. Good faith attempts to obtain additional information have been unsuccessful to date. The patient¿s programming and device diagnostic history available in the in-house database were reviewed and no records of high lead impedance were found however the data was only available up to 12/07/2010.

Manufacturer Narrative
Analysis of programming and device diagnostic history performed. Device failure is suspected but cannot be confirmed.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2420397


Title: Re: Electrodes
Post by: dennis100 on February 22, 2016, 03:50:23 AM
Event Date 11/03/2011
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized.

Event Description
It was reported by a company representative that a patient's electrode appeared to be detached from the vagus nerve as high lead impedance was received. The patient also reported the lack of perception of stimulation from the device. X-rays were received and evaluated by the manufacturer. Review of x-rays indicated the generator was visualized in the upper chest, but it is not possible to determine whether it is in the left or the right side of the chest. The filter feed-through wires appeared to be intact. The lead wires at the connector pin appeared to be intact. The lead connector pin appears to be fully inserted into the generator connector block. The electrodes appeared to be placed in normal arrangement, but in an unusual location, in the lower neck. It is not possible to determine whether it is the left or the right side of the chest. There is part of the lead behind the generator and could not be fully assessed. No obvious lead breaks or acute angle were observed in the assessed portions. Additional information was received from a company representative indicating the patient had an increase in seizures after no longer perceiving stimulation from the generator. The patient underwent generator and lead replacement surgery due to the reported high lead impedance and now patient is able to perceive stimulation. Good faith attempts to obtain further information remain underway.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2386853


Title: Re: Electrodes
Post by: dennis100 on February 24, 2016, 02:37:11 AM
Model Number 302-20
Event Date 12/07/2012
Event Type  Malfunction   
Event Description
Reporter indicated the high lead impedance was due to an electrode fracture. The electrode array was not explanted. The generator was replaced due to end of service.
 
Event Description
Reporter indicated via the manufacturer¿s implant card that the patient had vns lead and generator replacement surgery on (b)(6) 2013 due to a lead break. The explanted devices were given to the patient.
 
Event Description
Reporter indicated vns high lead impedance readings were noted for a patient at an office visit. The patient also no longer felt vns stimulation; the settings were previously decreased in (b)(6) 2012 from 1. 25ma to 0. 75ma due to unspecified side effects. The patient was also having increased depression. The vns was disabled. The patient is currently in the hospital due to an unknown reason. The patient had no known trauma and has been scheduled for x-rays. Attempts for additional information are in progress.
 
Manufacturer Narrative
Device failure is suspected.
 
Event Description
On (b)(6) /2013, it was reported that this vns patient was seen on (b)(6) 2013, and the device was interrogated. No additional information was provided and attempts for additional information have been unsuccessful. Surgery is likely but has not taken place.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2897491


Title: Re: Electrodes
Post by: dennis100 on February 25, 2016, 07:01:47 AM
Model


Title: Re: Electrodes
Post by: dennis100 on February 27, 2016, 06:40:12 AM
Model Number ASKU
Event Date 10/17/2011
Event Type Malfunction
Event Description
Further information was received from the area representative indicating that the patient's device was disabled and intervention had been planned for the patient. An implant card was received and it indicated that the patient underwent generator and lead replacement surgery due to lead discontinuity.

Event Description
Information from the area representative indicated the explanted devices will not be returning for analysis. Good faith attempts to obtain product information were unsuccessful to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported by a company representative that high lead impedance was found on vns patient at a follow-up appointment. The last known diagnostics were from (b)(6) 2011 and were within normal limits (no specifics). There was no reported manipulation or trauma to have contributed to the reported high lead impedance; however the patient does tend to have falls. The patient was referred for x-rays, the device was programmed off and surgical interventions are still pending. X-rays were sent and reviewed by the manufacturer. Review of x-rays indicated the generator appeared in the upper left chest in a normal placement. The filter feed-through wires appeared to be intact. The lead connector pin appeared to be fully inserted into the generator connector block. The electrodes did not appear to be placed in normal arrangement as the anchor tether appeared to be detached from the vagal nerve. No acute angles or lead breaks were observed in the assessed portions of the lead. Good faith attempts to obtain additional information remains underway.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2328467


Title: Re: Electrodes
Post by: dennis100 on February 27, 2016, 06:41:18 AM
Model Number 302-20
Event Date 10/10/2011
Event Type Malfunction
Event Description
It was reported by a neurologist through a company rep that high impedance was rec'd at a f/u appointment. The physician believes the event to be due to fibrosis caused by an injury that occurred a yr and a half ago. X-rays were taken and examined by the physician who indicated the vns system was fine as well as normal and system diagnostics after the injury was reported. The physician was instructed to program the pt to 0 ma and at the moment good faith attempts to obtain further info on the reported high lead impedance have been unsuccessful to date.

Event Description
Further information was received from the area representative indicating that the electrode was removed as there was excessive fibrosis and the electrode was disconnected. Good faith attempts to obtain further information have been unsuccessful to date.

Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
The explanted generator and lead were returned to the manufacturer for analysis. The generator performed according to functional specifications. No anomalies found with the pulse generator. Analysis of the returned lead portion observed abraded openings on the outer silicone tubing, which most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids inside the outer silicone tubing. For the observed inner tubing fluid remnants, there was no obvious path for fluid ingress other than the cut ends that were made during the explanted process. The condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, and no discontinuities were identified. Note that since a portion of the lead assembly including the electrode array section was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.

Event Description
Further information was received, indicating that the remaining portion of the lead was explanted during a full revision surgery performed on the patient. The explanted devices are expected to be returned for analysis, but have not been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2359833


Title: Re: Electrodes
Post by: dennis100 on February 27, 2016, 06:42:05 AM
Model Number 304-20
Event Date 10/13/2011
Event Type Malfunction
Event Description
It was reported that during an initial vns implant, the surgeon was having problems with the negative coil of the lead. Per reporter, "it is curling weird and difficult getting around the nerve. " manufacturer representative was at the surgery and verified the coil looked different than other coils. Per reporter, the surgeon was eventually able to get the coil around the nerve and product was implanted successfully. Per reporter, the surgeon did not use excessive force of manipulate the coil. Review of manufacturing records reveals that the device met specifications prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2382223


Title: Re: Electrodes
Post by: dennis100 on February 29, 2016, 06:41:57 AM
Model Number 302-20
Event Date 02/01/2011
Event Type Malfunction
Event Description
It was reported by the co rep that following an acute psychogenic seizures, pt had high impedance (dcdc code 7). X-ray has been performed, no obvious lead discontinuity or issue was found. Pt refused to undergo to lead replacement and asked vns complete explantation. During the surgery, the surgeon noticed that the electrode was broken. The hospital won't be returning the explanted devices for mfg analysis. Good faith attempts have been unsuccessful for add'l info.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2321498


Title: Re: Electrodes
Post by: dennis100 on March 01, 2016, 04:57:10 AM
Model Number 302-30
Event Date 08/31/2011
Event Type Malfunction
Event Description
Although surgery is likely, it has not occurred to date.

Event Description
It was reported by the physician that the pt had been referred for replacement as he was unable to interrogate the pt's generator. End-of-service (eos) was suspected as the cause. However, during the pt's replacement surgery the pt was found to have a "broken lead". As the pt did not consent for a lead replacement, the pt only had the generator changed at that time. There was no known trauma prior to the event, and last known diagnostics showed the device to be properly functioning. A revision surgery in the future is likely.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Review of x-rays by the manufacturer revealed a gross lead discontinuity. Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
Additional information was received on (b)(4) 2012, when it was discovered that the patient decided to seek a second opinion regarding the lead revision. The patient's device was checked and it is still reading high impedance. The device was disabled and the patient was sent for x-rays. The x-rays were received and reviewed by the manufacturer on (b)(6) 2012. An ap view of the chest and a lateral view of the neck dated (b)(6) 2012, were received. The filter feedthru wires were intact and the lead pin could be seen past the second connector block indicating that it is fully inserted into the generator. There was a portion of the lead located behind the generator that could not be assessed. A break was observed in the lead body near the electrode bifurcation. The electrodes were observed in the neck and the first electrode (negative) appears to be on the nerve but the second electrode (positive) does not appear to be in alignment with the first electrode. Also, based on the location of the lead body the anchor tether does not appear to be on the nerve either. Based on the x-ray images provided, the cause of the high impedance is likely the observed break identified in the lead body. Also, the second electrode (positive) did not appear to be on the nerve as it did not appear to be in alignment with the first electrode (negative) and therefore could be the cause of the high impedance. The presence of a fracture in the lead portion located behind the generator could not be assessed, also additional micro-fractures in the lead cannot be ruled out.

Event Description
Additional information was received on (b)(4) 2012, when it was discovered that the vns patient had attended a consult for lead replacement with a surgeon but has not contacted the surgeon to schedule the lead replacement. The patient voiced concern about possible loss of voice if lead is replaced. A second neurology opinion was arranged but there were issues with that appointment due to patient compliance and transportation. It is unknown at this point whether the patient will consent to a lead replacement. Although surgery is likely, it has not yet occurred.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
On 04/02/2015 product analysis was completed on the leads which confirmed discontinuity of negative quadfilar coil in the electrode region of the returned lead portions; also observed abraded opening of inner tubing near break area. The electrodes were not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis the (-) connector pin quadfilar coil appeared to be broken approximately 6mm, 6. 5mm, 10mm and 11mm from the end of the electrode bifurcation. Scanning electron microscopy was performed on the connector end of the (-) connector pin quadfilar coil break found at 6mm and identified the area as having extensive pitting which prevented identification of the coil fracture type. Pitting was observed on the coil surface. During the cleaning process the electrode (mating) end of the (-) connector pin quadfilar coil break found at 6mm and the coil break found at 6. 5mm 11m (from the end of the electrode bifurcation) became separated; therefore determination could not be made between the two coil breaks. Scanning electron microscopy was performed and identified the areas as being mechanically damaged which prevented identification of the coil fracture type with pitting and residual material. Pitting was observed on the coil surface. After the cleaning process determination could not be made between the (-) connector pin quadfilar coil breaks found at 10mm and at 11mm (connector end) from the end of the electrode bifurcation. Scanning electron microscopy was performed and identified the areas as being mechanically damaged which prevented identification of the coil fracture type with pitting. Pitting was observed on the coil surface. Scanning electron microscopy was performed on the electrode (mating) end of the (-) connector pin quadfilar coil break found at 11mm and identified the area as being mechanically damaged which prevented identification of the coil fracture type with pitting. Pitting and flat spots were observed on the coil surface. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. With the exception of the observed discontinuities the condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. Continuity checks of the returned lead portion were performed, during the visual analysis, and no other discontinuities were identified. An abraded opening was observed on the (-) connector pin inner silicone tubing approximately 6mm-11mm from the end of the electrode bifurcation. Product analysis was completed on the generator on 04/02/2015. The generator performed according to functional specifications; there were no anomalies found with the pulse generator.

Event Description
On (b)(6) 2015 it was reported that the patient underwent a full revision surgery that day. A lead fracture was not visualized in the or, but the electrode had come off the nerve. It was also noted that there was no tie-downs on the lead. The explanted generator and lead were returned for product analysis on (b)(6) 2015. Product analysis is still underway and has not yet been completed.

Event Description
On (b)(4) 2012, additional information was received when it was discovered that the explanted generator had been discarded after surgery on (b)(6) 2011.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2278717


Title: Re: Electrodes
Post by: dennis100 on March 02, 2016, 03:13:32 AM
Model Number 302-20
Event Date 07/27/2011
Event Type Malfunction
Manufacturer Narrative
Mfr reviewed x-rays of implanted device. Review of x-rays by the mfr revealed a gross lead discontinuity. Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was reported by the pt's physician that the pt's generator placement appeared to be different in orientation than when studied on (b)(6) 2008. However, the pt had undergone a battery replacement surgery on (b)(6) 2011, which could have caused this finding. Later info showed that the pt had high impedance measurements for his past two f/u appointments. The pt's x-rays were sent into the mfr for review. They showed a gross lead fracture and lead disconnection from the negative electrode. The physician stated that the impedance values had been within normal limits on (b)(6) 2011 at the end of the implant surgery. A revision surgery in the future is likely. Attempts for further info have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2260284


Title: Re: Electrodes
Post by: dennis100 on March 04, 2016, 08:41:45 AM
Model Number 304-20
Event Date 08/04/2015
Event Type Injury
Event Description
A patient developed a postoperative anterior cervical wound infection (stitch abscess) following vns implant surgery which occurred on (b)(6) 2015. On (b)(6) 2015 the patient's physician treated the infection via drainage and antibiotics and cultures were taken. A second stitch abscess involving the superior aspect of the cervical incision was observed on (b)(6) 2015 and drained on that date. On (b)(6) 2015 purulent fluid was noted at the pocket and cervical wound site with associated extrusion of one of the lead tie-downs. On that date pulse generator and partial lead removal was then undertaken and was initially deemed to have been successful at resolving the infection, however the infection recurred again at a later date. Due to the recurring infection the physician elected to remove all remaining portions of the lead on (b)(6) 2015. During the subsequent removal procedure the anchor tether and negative electrode were observed to be detached from the vagus nerve and this observation was attributed to the prior partial lead removal procedure. Scar tissue was observed in the nerve area. Patient drooling is believed to have contributed to the infection and it stated that the patient is very susceptible to infections. Manufacturing records were reviewed for the patient's pulse generator and lead and proper sterilization was confirmed prior to device shipment. The explanted devices were discarded by the explanting facility.

Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5431179


Title: Re: Electrodes
Post by: dennis100 on March 05, 2016, 09:43:09 AM
Model Number 302-20
Event Date 07/14/2011
Event Type Malfunction
Event Description
On (b)(6) 2011, a vns treating physician reported that the vns patient had recently undergone a battery replacement surgery on (b)(6) 2011 due to the battery being at end of service. The patient then had complete seizure control until about a month ago when she started having an increase in seizures, same as pre-vns baseline levels. The patient experienced 11 seizures in 4 weeks. The patient was seen last week and the physician performed diagnostics which revealed high impedance with an impedance value greater than 8000 ohms. The physician did not disable the generator despite the high impedance. The physician sent the patient for x-rays and he reported that there was no indication of a lead fracture. The physician also reported that the patient was in the operating room on (b)(6) 2011 and the surgeon noticed a fluid build-up around the electrode helices. A culture was taken and at this time there was no sign of infection. The physician reported that he thinks the lead failed which caused the build up of lymphatic fluid. A break in the lead with the device still stimulating could cause a foreign body response. No trauma or manipulation to the device was reported and there was no change in medications. The physician said that the patient's last acceptable diagnostics were in (b)(6) 2011. The patient was showing no clinical signs of infection but the surgeon reported that he believes the patient has a chronic infection. The patient's vns was completely explanted that day. The explanted generator was returned for product analysis on (b)(6) 2011 that has not yet been completed. Good faith attempts for the return of the lead will also be made as the lead was not returned to the manufacturer with the generator. Additional information was received from the surgeon's nurse who reported that the lead pin was fully inserted into the generator and the high impedance was due to the lead malfunctioning. The nurse indicated that as the surgeon dissected down into the neck, there was a lot of puss, but no cultures were taken. They also found that one of the electrodes had "slipped off the nerve". They were never able to fully identify the vagus nerve as there was too much puss. The surgeon did remove the electrodes as well as the full lead and the wound was irrigated. There was no note of a lead break being present, and the puss was isolated to the neck region. After dissecting the neck completely the surgeon felt that the puss was from an infection. The patient was placed on post-op antibiotics as a preventative step but it is not certain if the puss was from an infection as cultures were not performed. The nurse indicated that there was no indication of infection prior to the surgery as the patient was not running a fever and there was no swelling. She did say that the patient was complaining of pain in the neck one week prior to the procedure which they attribute to the puss build-up and infection. The patient was last seen on (b)(6), 2011 and is doing fine now. The patient's x-rays will not be sent to the manufacturer for review. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution. When additional information is received, it will be reported.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution. Device failure is suspected, but did not cause or contribute to a death.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2217586


Title: Re: Electrodes
Post by: dennis100 on March 06, 2016, 03:51:56 AM
Event Date 07/01/2011
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported by a company representative that a nurse suspected a short circuit condition on a vns pt that had dcdc of 0 since 2006, but prior to that, dcdc was 2. Furthermore, it was thought the pt's seizures had worsened slightly since then, but the change in dcdc code was not associated with the possibility of therapy not being delivered. The pt had a new generator implanted and was seen in clinic due to unawareness of stimulation. X-rays were performed and examined by the hospital and company representative. No strain relief bend and no tie downs were visualized and possibly the anchor tether was not on the nerve. The x-rays were received by the manufacturer and evaluated. The generator was visualized in the left upper abdomen, with its front part facing the front side of the abdomen. The filter feed-through wires appeared to be intact. The lead connector pins appeared to be fully inserted into the generator connector block. The state of the lead wires at the connector pin could not be assessed due to high density areas in the x-rays. The negative electrode appeared to be placed in normal arrangement. The positive electrode appeared to be partially detached from the nerve. The lead could not be fully assessed because of high density areas in the x-rays that concealed portions of the lead. No acute angles or lead breaks were observed in the assessed portions of the lead. Review of programming history with the pt's last generator indicated that system diagnostics dc dc had always been at 0 while normal diagnostics was indicative of 2. Programming history was not available for the recently implanted generator. The pt was referred for lead revision surgery and possible generator replacement surgery due to lead compatibility. No trauma was reported to have contributed to the event. Furthermore, information from the area representative indicated that no interventions have been planned even through replacement is needed.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2241014


Title: Re: Electrodes
Post by: dennis100 on March 09, 2016, 03:17:24 AM
Event Date 05/31/2011
Event Type Injury
Event Description
It was reported by a physician that a vns pt experienced an infection at the electrode implant site. The pt was referred for removal of the electrode. At the moment, good faith attempts to obtain additional info regarding the infection are still in progress.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2149607


Title: Re: Electrodes
Post by: dennis100 on March 10, 2016, 05:11:41 AM
Model Number 300-20
Event Date 05/19/2011
Event Type Malfunction
Event Description
It was reported by a surgeon that a vns pt had a full vns revision on (b)(6) 2011. The reason for full revision was stated as high impedance which was confirmed by mfr's rep. However, the generator was not at end of service. It was unk if manipulation/trauma had occurred since pt is delayer and non-verbal. X-rays were taken but were not sent to mfr for review since they were taken during surgery and via fluoroscopy. Poor strain relief, abnormal placement of electrodes and age of the device was attributed to the high lead impedance per surgeon. The new set of electrodes were placed 2 cm above the previous electrodes. The surgeon set the new generator's settings 0. 25ma lower than the old generator's settings (programming settings not available). Good faith attempts to obtain more info regarding pt's high impedance and retrieve the products for product analyses have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2175864


Title: Re: Electrodes
Post by: dennis100 on March 23, 2016, 08:45:25 AM
Model Number 300-20
Event Date 01/01/2010
Event Type Malfunction
Event Description
It was reported that the pt's device was showing an increase in ohms value from 1916 ohms one year ago to 6583 ohms recently. Lead impedance was ok on diagnostics, however. Reporter also noted that the end of service projection was 7. 7 years remaining on year ago and now is showing 2. 9 years remaining. The device output current was turned down to preserve battery life. It was also reported that the pt had a serious fall with broken limbs. X-rays were taken and reviewed by the manufacturer. Upon review, the positive electrode appeared to be broken and the electrode placement may be off. No other anomalies were noted. Based on the x-ray images provided, the exact cause of the increased lead impedance is unk; however, the broken positive coil and electrode placement may be contributing factors. Attempts for further info have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1910125


Title: Re: Electrodes
Post by: dennis100 on March 24, 2016, 06:58:38 AM
Model Number 302-20
Event Date 07/28/2010
Event Type Injury
Event Description
Reporter indicated that a patient could not feel any vns stimulation, and that a consult with an ent specialist revealed there was no vocal cord movement with vns stimulation, which was not an expected event. There were no issues with the vocal cords themselves. The patient was recently implanted with the vns, and has never felt any stimulation, even when the stimulation was increased. Vns diagnostics results indicate normal device function. It is felt by the reporter the vns electrodes are likely not on the vagus nerve. The vns has been disabled. X-rays were received and reviewed by the manufacturer. No lead anomalies were visualized that may be contributing to the patient not feeling any stimulation; however, it cannot be determined by x-ray review alone if the electrodes are on the vagus nerve. Surgical intervention to explore the vns lead area is planned, but a surgery date has not been set.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Results: review of x-rays by the manufacturer did not reveal any obvious anomalies.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1843805


Title: Re: Electrodes
Post by: dennis100 on March 25, 2016, 02:04:53 AM
Model Number 302-20
Event Date 07/08/2010
Event Type Malfunction
Event Description
It was initially reported that high lead impedance was detected during diagnostics performed. The patient's device was disabled and she was referred for lead and pulse generator revision. There was no event or issue that was known to have specifically caused the lead fracture or high lead impedance. X-rays were taken by the physician, which reportedly showed a fracture in the lead body. He did not have the x-rays on hand and they were not sent to the manufacturer for review. When the neck area was opened to remove the electrode portion of the lead body, the surgeon noted that part of the metal coil had broken off. The surgeon was unable to remove the entire electrode portion completely due to scar tissue. The explanted lead and pulse generator were returned to the manufacturer for analysis, but it has yet to be completed.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1817192


Title: Re: Electrodes
Post by: dennis100 on March 27, 2016, 02:54:57 AM
Event Date 05/01/2010
Event Type Malfunction
Event Description
It was initially reported by the physician that the pt had a full revision surgery due to high lead impedance which was observed on system diagnostics test. During surgery, the surgeon noted that the electrodes were inverted on the vagus nerve and a lead break was observed which is believed to be the cause of high lead impedance. No pt manipulation or trauma was reported that might have contributed to the lead break. No x-rays were done. Explanted products are on their way to be returned to manufacturer for analysis.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1740121


Title: Re: Electrodes
Post by: dennis100 on March 31, 2016, 06:39:18 AM
Model Number 300-20
Event Date 01/01/2009
Event Type Malfunction
Event Description
It was reported that a patient presented high lead impedance readings during a recent office visit. The patient denies any recent trauma to the device. The device was programmed off and the patient was sent for x-ray. Information was received via clinic notes that the patient also experienced an increase in seizures several months ago ((b) (6)2009). X-ray were taken and sent to the manufacturer for review and no acute angels or obvious discontinuities were observed. There was a portion of the lead behind the generator that could not be assessed. The lead pin was fully inserted into the connector block. There was no strain relief present. Both the positive and negative electrodes did not appear to be properly aligned with the vagus nerve suggesting possible electrode/nerve detachment. The patient has been referred for revision surgery later this month.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspect, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1580795


Title: Re: Electrodes
Post by: dennis100 on April 04, 2016, 02:16:32 AM
Model Number 302-30
Event Date 11/21/2002
Event Type Malfunction
Event Description
As part of a retrospective complaint review associated with an investigation of low impedance events, the events in this complaint investigation were assessed for the possibility of a short-circuit condition in the implanted lead. Based on clinical symptoms and the diagnostic history of the pt's device, this file was found to be possibly related to a short-circuit condition. It was reported that a vns pt was unable to perceive stimulation after her initial implant surgery, even with the device programmed to maximum settings. The pt's implanting surgeon also stated that he was concerned by the fact that the pt did not experience any events of voice alterations at these settings as well. System and normal mode diagnostics were performed repeatedly and each test resulted in a dcdc code of zero. X-rays of the pt's device were reviewed by her surgeon and no anomalies were reportedly identified. Later the pt underwent exploratory surgery, during which the electrode portions of the pt's lead were repositioned on her vagus nerve. Follow up with the pt's implanting surgeon revealed that the pt was able to perceive stimulation following electrode repositioning.

Manufacturer Narrative
Implanting surgeon reviewed x-rays of implanted device. X-rays reviewed by the implanting surgeon, no gross lead discontinuities visualized.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1492063


Title: Re: Electrodes
Post by: dennis100 on April 15, 2016, 01:35:00 AM
Model Number 300-20
Event Date 01/01/2007
Event Type Malfunction
Event Description
Initial reporter indicated that their patient had high lead impedance, after a battery replacement in 2007. X-rays were reviewed by manufacturer that showed a clear lead discontinuity. Neither a strain relief loop or strain relief bend were visualized. No tie downs were present. It was noted in the location of the generator that there were two connectors in the lead body not from manufacture, and the connector pins were inserted past the connector blocks, but were not fully inserted. Manufacturer does not recommend the use of any kind of adapter on the lead body. In the electrode region it appeared that the negative electrode was broken and the positive electrode was separated from the lead. Good faith attempts are being made for additional details surrounding the event and any interventions planned.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Review of x-rays by the manufacturer revealed a gross lead discontinuity and a connector that is not a cyberonics manufactured product. Device failure occurred, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1436504


Title: Re: Electrodes
Post by: dennis100 on April 19, 2016, 04:15:15 AM
Model Number 302-20
Event Date 03/12/2009
Event Type Malfunction
Event Description
Reporter indicated a vns therapy lead was opened but not used during an implant surgery. It was reported the plastic on the helices was "too tight", and that the helices "looked like it was stuck together. " the lead has been returned to the manufacturer and is pending analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1438440


Title: Re: Electrodes
Post by: dennis100 on April 20, 2016, 03:59:38 AM
Event Date 01/01/2005
Event Type Injury
Manufacturer Narrative
"revision of vagal nerve stimulator electrodes for medically intractable epilepsy". Pp 1-5.

Event Description
It was reported in a scientific abstract that a vns pt had the electrodes removed two weeks after the first surgery due to implant site infection. Good faith attempts to obtain additional info have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1353221


Title: Re: Electrodes
Post by: dennis100 on April 20, 2016, 04:00:11 AM
Model Number 303-20
Event Date 02/09/2009
Event Type Malfunction
Event Description
It was reported that a lead was found to be defective. The physician stated that the product was opened in surgery and he noticed one of the helices was detached from the lead and left in the box. Product was returned to the mfr and is undergoing product analysis. Good faith attempts to obtain add'l info have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1396718


Title: Re: Electrodes
Post by: dennis100 on April 27, 2016, 03:52:20 AM
Model Number 302-20
Event Date 01/01/2008
Event Type Malfunction
Manufacturer Narrative
Method: manufacturer reviewed x-rays of implanted device. Results: x-rays reviewed by the manufacturer, and no gross lead discontinuities were visualized, although it is possible the electrode is off of the nerve. Conclusions: device failure is suspected, but did not cause or contribute to a serious injury or death.

Event Description
Reporter indicated that the patient had high impedance on both system and normal mode diagnostics. There has been no trauma or manipulation of the device and no patient adverse events. A battery life calculation was done and revealed approximately 2. 59 years remaining until end of service. X-rays were reviewed by the manufacturer, and no device anomalies were found, although it is important to note that it is possible the negative electrode was off the nerve as the electrodes were not aligned vertically as would be expected. Product has been requested, but has not been returned to manufacturer to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1232716


Title: Re: Electrodes
Post by: dennis100 on April 28, 2016, 02:04:46 AM
Model Number 300-20
Event Date 10/01/2008
Event Type Malfunction
Event Description
It was reported that the pt's system mode diagnostics showed high lead impedance. The pt also had a small increase in seizures. Follow up with the nurse revealed that pt was sick and was recently toxic on lamictal. The nurse indicated that these could have attributed to her seizures and cannot really tell if it is because of vns therapy. The nurse also stated that the pt had fell previously and injured her neck and head. The level of seizures is same as pre-vns baseline. X-rays were reviewed by the mfr and it was observed that the negative electrode was off the vagus nerve, no obvious lead discontinuities were observed.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the mfr, no gross lead discontinuities visualized. Negative electrode was observed to be off the vagus nerve.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1249826


Title: Re: Electrodes
Post by: dennis100 on April 28, 2016, 02:05:33 AM
Model Number 302-20
Event Date 09/05/2008
Event Type Malfunction
Event Description
Initial reporter indicated that their pt was having pain at their generator site "felt like an electrical sensation. " the pt's vns was disabled the week previously and the pain resolved. The vns was programmed back on and system and normal mode diagnostics performed were within normal limits. The pt was programmed to his usual settings at 1. 75/250/30/5 and he was not feeling any discomfort. The pt did have a large keloid in the area where they were reporting the pain. X-rays were received for review at mfr. During the review, it was noted the electrodes are implanted at the c7 level; however, the inferior electrode does not align vertically, suggesting it is not on the nerve. The strain relief bend and loop are not present. No tie downs are noted. No breaks or sharp angles are noted in the visible portion of the lead body. The lead wires appear intact at the connector pins. The superior electrode appears to be "torn. " the lead wire appears to be taut. At this time, no surgical plans have been made for the pt.

Manufacturer Narrative
Method - mfr reviewed x-rays of implanted device. Results - review of x-rays reveals the electrode may not be on the nerve.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1235732


Title: Re: Electrodes
Post by: dennis100 on April 29, 2016, 02:54:39 AM
Model Number 302-20
Event Date 08/27/2008
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
The reporter indicated that he was unable to place a lead on a patient's vagus nerve as the helical was unable to be opened. A new lead was implanted and the suspect device was returned to the manufacturer where it is currently awaiting analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1191492


Title: Re: Electrodes
Post by: dennis100 on April 30, 2016, 12:26:55 AM
Model Number 302-30
Event Date 07/01/2008
Event Type Injury
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. One of the electrodes did not appear to be fully wrapped around the nerve. One of the three tie-downs was not attached to the lead body.

Event Description
It was reported that a vns pt experienced a fall, and had approx 14 seizures the weekend prior to his routine office visit. He was taken to the er where he was treated and then released. At the neurologist's office a few days later, the pt experienced seizures and painful stimulation during diagnostic testing. The vns device was programmed off, and then the pt went into status epilepticus. The pt was taken to icu at the hospital. The pt was treated for toxic aed levels. The pt has been discharged from the hospital. Diagnostic testing showed the vns device to be functioning properly. X-rays were sent to the manufacturer for review. A review of the x-rays revealed that one of the electrodes does not appear to be completely wrapped around the nerve. Additionally, one of the three tie-downs present was not attached to the lead. Good faith attempts to obtain additional info have been unsuccessful to date. Revision surgery is likely.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1120744


Title: Re: Electrodes
Post by: dennis100 on May 01, 2016, 03:44:16 AM
Model Number 300-20
Event Date 05/12/2008
Event Type Injury
Event Description
Reporter indicated a vns patient underwent generator replacement surgery due to normal end of service. Pre-operative x-rays noted the leads were not attached to the nerve. Diagnostic testing was within normal limits. During surgery, the surgeon noted the negative lead and anchor tether were attached to the nerve but the positive electrode was not. The surgeon cleaned up some scar tissue and then re-attached the negative electrode to the vagus nerve. The generator was replaced as scheduled, and diagnostics confirmed proper device function. Good faith attempts to obtain additional information have been successful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1059653


Title: Re: Electrodes
Post by: dennis100 on May 02, 2016, 01:05:16 AM
Model Number 302-20
Event Date 01/01/2008
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implant device. X-rays reviewed by the mfr, no gross lead discontinuities visualized. It was noted that the negative electrode was not in the typically observed orientation, although this could be due to pt's anatomy. The strain relief was not placed according to recommendations in labeling. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
Reporter indicated that a diagnostic test resulted in high lead impedance. It was reported that the pt could not feel stimulation, and there was not believed to be any trauma or manipulation of the device. It was reported that the pt had not experienced an increase in seizures, but had experienced some seizures, which the physician attributed to a head injury and "maybe" to the high lead impedance. X-rays were reviewed by the mfr, and it was confirmed that the connector pin of the lead was fully inserted past the connector block of the generator. It was identified that the negative electrode was not in the typically observed orientation, although this may be due to pt's anatomy. It was also noted that the strain relief was not placed according to recommendations in labeling. Revision surgery is likely.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1033458


Title: Re: Electrodes
Post by: dennis100 on May 02, 2016, 01:05:59 AM
Model Number 302-20
Event Date 03/05/2008
Event Type Malfunction
Manufacturer Narrative
Method - mfr reviewed x-rays of implanted device. Results - x-rays reviewed by the mfr, although no gross lead discontinuities visualized, it could not be confirmed that the lead pin was fully inserted, the strain relief appeared in adequate, no tie downs were visible, and the orientation of the electrodes appeared atypical. Conclusions - device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
Reporter indicated that diagnostic tests indicated high lead impedance. It was reported that the pt had experienced an increase in seizures, which were at pre-vns baseline levels. It was also reported that the pt falls "quite a bit". X-rays were reviewed by the mfr, and it could not be confirmed that the lead pin was fully inserted. Additionally, the strain relief was not placed according to labeling with a sharp angle below the positive electrode, no tie-downs were visible, and the electrodes did not appear to be in the typically observed orientation. Revision surgery is likely.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1022732


Title: Re: Electrodes
Post by: dennis100 on June 05, 2016, 07:04:39 AM
Model Number 304-20
Event Date 12/10/2015
Event Type Malfunction
Event Description
It was reported in clinic notes dated (b)(6) 2015 that the physician identified a mass on the left lateral portion of the patient's neck. At a follow-up visit on (b)(6) 2016 the patient was experiencing painful stimulation in the neck and the physician believed one of the vns electrodes on the nerve had become loose. It was reported that the vns generator settings were then adjusted in response to the pain. The physician referred the patient for generator replacement due to the painful stimulation, however no surgical interventions are known to have occurred to date. Attempts to obtain additional relevant information have been unsuccessful to date.

Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5597668


Title: Re: Electrodes
Post by: dennis100 on June 08, 2016, 02:03:09 AM
Model Number 304-30
Device Problems Break; High impedance
Event Date 09/17/2015
Event Type Malfunction
Manufacturer Narrative
(b)(4). Brand name; corrected data: this information was inadvertently left off of the initial mfr. Report. Model, serial#, lot#, expiration date; corrected data: this information was inadvertently left off of the initial mfr. Report. Device manufacture date; corrected data: this information was inadvertently left off of the initial mfr. Report. Additional manufacturer narrative and/or corrected data; corrected data: this information was inadvertently left off of the initial mfr. Report.

Manufacturer Narrative

Event Description
A patient's depleted m102 generator was replaced on (b)(6) 2015. Upon system diagnostic test with the new m106, high impedance (>10000 ohms) was recognized. The physician then exposed the vagus nerve to find the lead wire broken just inferior to the electrodes and tether. He excised the lead body leaving the coils. He determined the break was due to normal wear and motion in the neck. When attempting to attach a new lead, the surgeon damaged the middle coil/electrode with his instrumentation. This was purely a mistake and not a device related issue. The physician then removed the lead. The m106 generator remained in the patient with a test resistor pin in the port. A new lead was implanted on (b)(6) 2015 and connected to the previously implanted m106. Impedance was within normal limits (2075 ohms). The explanting facility discarded the explanted devices; therefore, no analysis can be performed.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5145849


Title: Re: Electrodes
Post by: dennis100 on June 17, 2016, 12:52:05 AM
Model Number 102
Event Date 12/01/2014
Event Type Injury
Event Description
It was reported by a company representative attending a clinic visit that the patient experienced pain in their neck electrode. The patient stated it to occur when lying on their left side. There was no report of trauma or manipulation. Systems and normal mode diagnostics were performed and the results were ok/ok/dc=2/eri=no. The patient's settings were 1ma/25hz/250us/30s/5min, magnet mode, 0ma. It was reported by a company representative attending a clinic visit that the patient experienced pain in their neck electrode. The patient stated it to occur when lying on their left side. There was no report of trauma or manipulation. Follow-up to the physician revealed that the patient also had increased hoarseness and pain, stated to be constant even with the device turned on or off, and was not getting better. The device was disabled to attempt to resolve the hoarseness. It was reported by the physician on (b)(6) 2016 that the patient plans to have the device removed due to the neck pain and hoarseness. Later follow-up to the physic revealed that the removal is due to the vns having been turned off for months but is giving the patient neck pain and hoarseness. Additional relevant information has not been received to-date. No known surgery has occurred to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5651579


Title: Re: Electrodes
Post by: dennis100 on June 22, 2016, 01:12:51 AM
Type of Device: stimulator, spinal-cord, totally implanted for pain relief
Device Brand Name: VNS Lead
Device Manufacturer's Name: Cyberonics
Date of this Report: 07/03/2011
(mm/dd/yyyy)
Describe the Event or Problem: Patient underwent implantation of her Vagus Nerve Stimulator (VNS) ~3 years ago. Initially, it worked well to reduce the frequency and severity of patient seizures. Patient was able to use the device to help abort her seizures. Patient is now having events 1-2 times a week. She has begun to experience auras again. Interrogation of her VNS indicates high impedance, suggesting a malfunction. Chest XRay performed and suspect the lower contact on the nerve may be fractured. The contact is sitting at an odd angle on the nerve, and does not seem to be winding around the nerve the way it should.

the device(s) may have caused or contributed to: Potential for patient harm

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/Medsun/medsun_details.cfm?id=25701


Title: Re: Electrodes
Post by: dennis100 on July 09, 2016, 01:30:51 AM
Model Number 304-20
Event Date 05/10/2016
Event Type Malfunction
Manufacturer Narrative
(b)(4).

Event Description
It was reported by a company representative that during an initial implant the lead was not used by the surgeon as the metal became detached from the helix on the positive coil. When the surgeon used a new lead, there were no further issues. Review of the device manufacturing records revealed that the device met specifications prior to distribution. The product has been received for analysis which is underway, but has not been completed to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5702908


Title: Re: Electrodes
Post by: dennis100 on November 29, 2016, 02:19:58 AM
Event Date 03/30/2016
Event Type Malfunction
Event Description
Xrays images were sent to the manufacturer by medical professional for review. Review of the images showed that the generator appears to be low in the chest, just above the diaphragm, in an abnormal placement. The filter feed-through wires appeared to be intact. The lead connector pin appeared to be fully inserted into the generator connector block. The electrodes appeared not to be placed in normal arrangement. The anchor tether seemed not to be fixed on the vagus nerve and the anode seemed to be partially dislocated from the nerve. No strain-relief loop and no strain-relief bend were found for the implant of the lead. Two tie-downs were used but their placement is not as recommended in the labeling. It could not be assessed from the images if a part of the lead is behind the generator. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. Further information was received from the physician that the reason xrays were taken is they could not communicate with the generator. It was reported that the generator was not implanted auxilliary. It was reported that the vns patient felt following a strong seizure. The generator has dropped from its original location, and is in a lower location in the patient's body which is the suspected cause of the inability to interrogate the generator.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6036347


Title: Re: Electrodes
Post by: dennis100 on December 08, 2016, 12:59:48 PM
Model Number 302-20
Event Date 02/10/2011
Event Type Malfunction
Event Description
A physician reported that a vns pt had high impedance that read greater than 10 kohms. The device was disabled at this time and xrays were going to be sent to the mfr for review. Meanwhile, the pt would be scheduled for a revision surgery. There had been no report or trauma or manipulation preceding the discovery of the high impedance. Xrays were reviewed by the mfr. There appeared to be an electrode orientation abnormality and also a suspect area in the lead body cephalic to the placement of the generator. Clinic notes were also rec'd from the physician and it indicated that on (b)(6) 2011, the pt was interrogated and a high impedance warning message appeared. The pt's settings at this time were 0. 5 ma/30 hz/500 microsec/30 sec/0. 8 min and 0. 5 ma/60 sec/500 microsec. A revision surgery in the future is likely.

Manufacturer Narrative
Mfr reviewed x-rays of implanted device. X-rays reviewed by the mfr, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2037541


Title: Re: Electrodes
Post by: dennis100 on December 09, 2016, 09:21:25 AM
Model Number 304-20
Event Date 10/15/2016
Event Type Malfunction
Manufacturer Narrative
(b)(4).

Event Description
The mdr with manufacturing number 1644487-2016-02598houses the reports of chest pain and device repositioning. The patient reported experiencing neck pain associated with stimulation. The device was then disabled. The patient's surgeon elected to perform an exploratory surgery. During a pre-operative system diagnostics test the patient had severe pain at their neck and it was decided that the exploratory surgery would open the neck incision. The surgeon opened the neck incision and found scarring and inflammation present. The surgeon then dissected the lead and discovered that the electrodes were placed on the wrong nerve. A tension lead fracture was also observed. The lead was then removed and a new lead was inserted. A significant drop in lead impedance was observed from 3944 ohms to 1208 ohms once the new lead was placed on the nerve and connected to the generator the explanting facility disposed of the explanted lead and thus no product return is expected. No other relevant information has been received to date.
 
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6122152


Title: Re: Electrodes
Post by: dennis100 on January 06, 2017, 08:06:30 AM
Model Number 304-20
Device Problem Mechanical issue
Event Date 11/07/2016
Event Type Malfunction
Manufacturer Narrative

Event Description
Product analysis for the lead was completed and found that the negative electrode ribbon did appear to be detached from the silicone helix, which has lost its helical shape. There were also creases present on the positive and negative electrodes along with remnants of dried body fluid. These finding are consistent with damage incurred during implant/explant surgeries.

Event Description
During implant surgery for the patient¿s lead, it was noticed that after the lead had been tunneled a deformity on the electrode was observed. The surgeon was able to connect the anchor and positive electrode with no issues, but when connecting the negative electrode he stated it appeared bent, and he didn¿t think it would attach to the nerve properly. There was no abnormality observed with the lead prior to the lead being removed from the packaging. It is unclear how the deformity occurred. The deformed lead was returned for product analysis which has not been completed to date. The design history record for the lead was reviewed and showed that the lead passed all quality control checks prior to being released for distribution.

Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6138374


Title: Re: Electrodes
Post by: dennis100 on February 07, 2017, 02:13:11 AM
Model Number 102
Event Date 01/21/2013
Event Type Malfunction
Event Description
On (b)(6) 2013, high impedance was noted during system diagnostics at a routine patient appointment on (b)(6) 2013. The device was disabled. X-rays were to be taken and submitted for review. Attempts for x-rays, additional information, and product information have been unsuccessful. Review of programming history showed the patient's current settings and the device disabled event. Surgery is likely but has not taken place.

Event Description
Product analysis was approved. The generator was explanted/returned for "prophylactic replacement". The generator performed according to functional specifications. During the product analysis there were no anomalies found with the pulse generator. Lead pa found that a break was identified in the positive coil. Scanning electron microscopy images of the positive coil suggest a stress-induced (fatigue) fracture has occurred in at least two of the coil wires. The mating end of the broken coil has what appear to be voids in one strand in the vicinity of the break. Abrasions were identified on the outer silicone tubing at multiple locations. There is also evidence to suggest incomplete insertion of the lead into the generator header. The lead connector was inserted completed in a pulse generator with no anomalies and no anomalies that could prevent proper insertion were identified. The closest electrode to the bifurcation is damaged showing bends on the electrode ribbon and partial detachment of the electrode ribbon and suture from the silicone helix. The furthest electrode to the bifurcation has bends on the electrode ribbon and partial detachment of the ribbon from the silicone helix. The lead assembly has remnants of what appears to be dry body fluids inside the inner and the outer silicone tubing. No obvious point of entrance was noted other than the identified tubing openings and the end of the returned pterion. Other than the above mentioned observations and typical wear and explant related observation, no other anomalies were identified in the returned lead portions. Review of programming history showed that the patient's last known settings are from (b)(6) 2012. System diagnostics on this date were within normal limits.

Manufacturer Narrative

Manufacturer Narrative
Brand name, corrected data: previously submitted mdr indicated that the suspect medical device was the lead; however, this is actually the generator. Type of device, corrected data: previously submitted mdr indicated that the suspect medical device was the lead; however, this is actually the generator. Model #, serial #, lot #, expiration date, corrected data: previously submitted mdr indicated that the suspect medical device was the lead; however, this is actually the generator. Operator of device, corrected data: previously submitted mdr indicated that the patient was the user; however, this should be the medical professional. Device manufacture date, corrected data: previously submitted mdr indicated that the suspect medical device was the lead; however, this is actually the generator. This report is being submitted to correct the aforementioned fields.

Event Description
X-rays were received and reviewed. The generator is visualized in the left upper chest; the front of the generator is facing forward. The filter feed-through wires appear to be intact. The lead connector pin is not fully inserted into the generator connector block. Parts of the lead were behind the generator and could not be assessed. The electrodes appear correctly aligned on the vagus nerve. No acute angles or obvious lead break could be identified in the visible portion of the lead. The patient underwent lead and generator revision on (b)(6) 2013. The explanted devices were returned on (b)(6) 2013 and are currently undergoing product analysis.

Manufacturer Narrative
Device failure occurred but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2966080


Title: Re: Electrodes
Post by: dennis100 on February 07, 2017, 02:14:01 AM
Model Number 304-20
Event Date 01/25/2013
Event Type Malfunction
Manufacturer Narrative

Event Description
Reporter indicated that during initial implant surgery on (b)(6) 2012 the lead "broke" and the surgeon replaced the lead with another lead. It was reported that the lead break occurred near the electrode portion of the lead. The entire lead was returned to device manufacturer for analysis. The reported lead break was not verified within the returned lead. The absence of setscrew marks indicates that the lead connector pin was not secured by the setscrew and thus no proper contact between the connector pin and the negative terminal on the pulse generator was present. The lead electrodes were found to be damaged and the most likely cause was manipulation of the lead during the attempted implant procedure. No other anomalies were identified with the lead.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2972787


Title: Re: Electrodes
Post by: dennis100 on February 10, 2017, 04:35:59 AM
Model Number 103
Event Date 04/06/2011
Event Type  Malfunction   
Event Description
Left vagal stimulator lead/generator explanted. Stimulator lead "broke, and not attached to nerve. ".

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2061432


Title: Re: Electrodes
Post by: dennis100 on February 11, 2017, 02:05:30 AM
Model Number 302-20
Event Date 03/01/2013
Event Type Malfunction
Event Description
On (b)(6) 2103, it was reported that high impedance was seen during diagnostics on (b)(6) 2013. The patient was at rapid cycling, but the device was disabled. Follow-up showed that the patient was hit in the neck that may have contributed to the high impedance. X-rays were taken but have not been provided to date. A blc was performed with 4. 83 years remaining. Attempts for additional information have been unsuccessful.

Event Description
An implant card was received which indicates the patient underwent generator and lead replacement on (b)(6) 2013. The implant card noted the lead impedance was ok. Attempts to have the products returned for analysis have been unsuccessful to date.

Manufacturer Narrative
Analysis of programming history. Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution. Device failure is suspected but did not cause or contribute to a death.

Event Description
On (b)(4) 2013, it was reported that x-rays were inconclusive and that the patient was referred for evoked potential testing. Attempts for results and additional information have been unsuccessful. X-rays have not been provided for review.

Event Description
On (b)(6) 2013 it was reported that the patient was seen that day by the physician and when system diagnostics were performed a dcdc of 4 was observed with high impedance and neo=no. The patient was scheduled for surgery. Although surgery is likely, it has not occurred to date. It was stated that the patient¿s vns is disabled and the patient does not want it turned on at this time because he feels painful stimulation. It was stated that fibrosis is suspected but it has not been verified. It was reported that the patient had worsening epilepsy in late 2012 that led to the discovery of a malfunction of the vns, ¿which appears to correspond to a lead problem/vns contact, fibrotic¿. It was stated that stimulation is tolerated until 0. 75ma but the patient has a severe cough from 1ma. The patient¿s mother thinks the patient has a worse clinical condition since stimulation was stopped; a problem with language/speech. Therefore the patient was re-programmed to output=0. 5ma/on time=14sec/off time=1. 1min. The physician also reported that ¿after the fight, there was a lesion of the electrode (the onset of pain was very sharp)¿.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3029714


Title: Re: Electrodes
Post by: dennis100 on February 12, 2017, 08:57:02 AM
Model Number 105
Event Date 03/04/2013
Event Type Malfunction
Event Description
On (b)(6) 2013 it was reported that the patient was undergoing a full revision surgery. The patient was implanted with a new lead and generator but when the new lead was connected to the new generator, the system diagnostics test showed high lead impedance with an impedance value greater than 10,000ohms. The surgeon then removed the neck retractors and bovie cords from the site. The next system diagnostics also showed high lead impedance with an impedance value greater than 10,000 ohms. The surgeon then checked the electrodes and said it looked like one was not on properly and re-positioned the electrode. The manufacturer's consultant confirmed that the electrode placement appeared normal. The next system diagnostics still showed high lead impedance. The surgeon re-verified that the electrodes were on properly. The scrub nurse noted to the surgeon that the lead pin was not fully inserted past the connector block. The surgeon removed the lead pin and re-inserted it. The next system diagnostics test still showed high impedance. The surgeon noted that the pin was still not past the connector block and therefore he removed the pin and reinserted it. Upon this second pin insertion he made sure the pin was visualized past the connector block, but there was no audible click when he tried to tighten the set screw and the screwdriver just kept spinning in place and 'would not catch. ' the manufacturer's consultant then obtained a different generator to be used. After the second new generator was connected to the lead, high impedance was again observed but the lead pin was not fully inserted. The pin was reinserted into the generator and the lead pin was verified to be past the connector block. There was a loud audible click. A system diagnostics test was performed and revealed results within normal limits; no high lead impedance was observed. Other diagnostics were performed and were also within normal limits. The manufacturer's consultant later clarified that they did hear the setscrew click the first time the torque wrench was used to tighten the setscrew down with the new generator and old lead and they heard the setscrew click the first time the torque wrench was used to tighten the setscrew down with the new generator and new lead. But upon second pin re-insertion, there was no click noise and the screwdriver just spun around. The generator and two hex screwdrivers were returned to the manufacturer for product analysis on (b)(4) 2013. Product analysis is still underway and has not yet been completed. The manufacturing records for the generator were reviewed; the device met all specifications prior to distribution.

Event Description
Additional information was received on (b)(4) 2013 when product analysis was completed on the explanted generator. Examination of the set screw showed there was damage to the hex head. This could be an indication that the shaft of the torque wrench was not fully engaged into the hex head which would prevent the tightening of the setscrew on the lead pin or the test resistor. The damage to the hex head could also make it difficult to loosen the setscrew and remove the lead pin. Diagnostic test results demonstrated that the 4k ohm electrical load resistance (test resistor) is accurately measured by the pulse generator with no noted adverse performance. Product analysis confirmed stripped setscrew socket that was most likely caused by incomplete insertion of the torque wrench shaft into the socket of the screw; most likely user related issue; no device malfunction was observed. Product analysis of the hex screwdrivers confirmed rounded edges on end of shaft. Product analysis stated that this was due to incomplete insertion into setscrew; user-related issue.

Manufacturer Narrative
Device failure occurred, but this was likely due to user error; this did not cause or contribute to a serious injury or death.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed device met all specifications prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3023688


Title: Re: Electrodes
Post by: dennis100 on March 10, 2017, 05:20:38 AM
Model Number 302-20
Device Problems Corrosion; Fracture
Event Date 12/22/2016
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that the patient was referred for a lead and generator replacement due to high impedance being observed. During the replacement surgery it was noted that the patient's vagus nerve appeared to be damaged. The surgeon reported that the nerve appeared atrophic and discolored immediately around and under the positive and negative electrodes. The surgeon could not determine the cause of the nerve's appearance but noted that the electrodes seemed to be more degenerated than usual. The explanted lead and generator were discarded following the surgery. Therefore product analysis cannot be completed. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6300905


Title: Re: Electrodes
Post by: dennis100 on April 18, 2017, 11:14:53 PM
Model Number 303-20
Device Problem Detachment of device component
Event Date 02/01/2017
Event Type Malfunction
Event Description
It was reported via clinic notes that a patient was experiencing an increase in seizure frequency and duration. The patient had recently begun experiencing daily seizures for several weeks. One of the patient's medications was increased at a clinic visit two months prior. The physician noted that the patient's battery was at one-quarter remaining as of the current clinic visit and believed that the patient's vns was not as helpful as it used to be. The patient was referred for generator replacement surgery. It was later reported that during generator replacement surgery, the lead was found detached from the nerve and was coiled up in the generator pocket. The surgeon planned to proceed with a full revision. A photograph of the lead was provided, which showed that the patient¿s lead was wrapped around itself inside the generator pocket. When the patient¿s generator pocket was opened during the surgery, the surgeon found the electrodes detached from the vagus nerve and the lead wrapped around itself several times in a large knot. The electrodes were also detached from the lead. The patient¿s generator suture was still intact, and there was scar tissue in the generator pocket that most likely provided contact between the lead and the tissue. It was reported that there was very little scarring on the patient¿s vagus nerve. The patient¿s neurologist did not notify the surgeon or company representatives of any diagnostic issues, consistent with the diagnostic test results reported via clinic notes. Diagnostics performed in the operating room prior to surgery were also within normal limits. The surgeon believed that the patient manipulated the lead and caused it to coil up inside the generator pocket. The patient¿s parents denied any occurrences of their daughter manipulating the lead, adding that the patient¿s disability caused low finger dexterity. The existing lead and generator were discarded after explant and thus were not returned for analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6382903


Title: Re: Electrodes
Post by: dennis100 on April 18, 2017, 11:15:35 PM
Model Number 302-20
Device Problem Fracture
Event Date 02/28/2017
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that a patient had an "electrode fracture" identified when the vns device was checked in a clinic. The patient had reportedly not been seen for quite some time and was in the hospital for an eeg for unrelated reasons. A review of the device history record for the implanted lead confirmed it passed all quality inspections prior to release for distribution. No known surgical intervention has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6416870


Title: Re: Electrodes
Post by: dennis100 on April 20, 2017, 01:06:00 AM
Model Number 302-30
Event Date 03/01/2008
Event Type Malfunction
Event Description
Reporter indicated that a system diagnostic test showed high lead impedance. It was reported t hat the pt had recently slipped and fallen, and then within a week of that incident the pt no longer felt vns stimulation and experienced a change in mood. The physician attributed both of these events to loss of therapy due to high lead impedance. X-rays were reviewed by the mfr. The electrodes did not appear to be in the typical orientation, although this could be due to pt anatomy. It was also noted that the strain relief bend was inadequate and the tie-downs were not placed according to recommendations in labeling. Additionally, due to quality of the x-rays, it could not be confirmed that the lead pin was fully inserted past the connector block. Revision surgery is likely.

Event Description
Information was received on 08/16/2016 indicating that the patient had declined to undergo lead revision surgery and had their generator programmed off. The generator was programmed off five years ago according to the physician; a specific date was not available. Diagnostic information confirmed that the patient's generator indicated high impedance was present.

Manufacturer Narrative
Mfr reviewed x-rays of implanted device. Results: x-rays reviewed by the mfr, no gross lead discontinuities visualized. The electrodes were not in typical orientation and the strain relief bend appeared inadequate.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1023674


Title: Re: Electrodes
Post by: dennis100 on April 20, 2017, 05:52:34 AM
Model Number 102
Event Date 09/01/2007
Event Type Injury
Event Description
Reporter indicated that a vns pt had experienced coughing, shortness of breath, and pain in the area of the electrodes on the left side of his neck. It was reported that the output current had been adjusted in an attempt to alleviate the events. It was reported that the pt wanted to have the vns device explanted. F/u with the treating physician revealed that the pt thought that the events were related to vns stimulation and that the "vns caused seizures", and the vns output current was then set to 0ma. The surgeon reported that the vns generator and leads were explanted due to pain and an increase in seizures, as the pt had experienced "more seizures than ever before". It was reported that the pt had at one time achieved good efficacy and seizure reduction after beginning vns therapy.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=983383


Title: Re: Electrodes
Post by: dennis100 on April 21, 2017, 03:36:23 AM
Model Number 302-20
Event Date 01/01/2003
Event Type Malfunction
Event Description
Reporter indicated that a vns pt "has had a high impedance". It was reported that the pt "has had consistently high impedance, but clinically unit appears to be functioning". X-rays were reviewed by the mfr, and although the cause of the event could not be confirmed, it was found that the lead pin may not be fully inserted into the connector block of the generator. It was also noted that the electrodes do not appear to be placed in the orientation typically observed, although this may be due to pt's anatomy.

Manufacturer Narrative
Mfr reviewed x-rays of implanted device. Review of x-rays by the mfr, no gross lead discontinuities found. It was noted that the lead pin may not be fully inserted into the connector block of the generator and the orientation of the electrodes appeared unusual. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=964560


Title: Re: Electrodes
Post by: dennis100 on April 21, 2017, 03:37:08 AM
Model Number MODEL 250
Event Date 08/21/2007
Event Type Malfunction
Event Description
Reporter indicated that the physician was having some difficulty with programming. The physician reported that the pt felt "shocking" at the electrode site when she walked past a magnetic board. The physician reported that he had checked to confirm the magnet mode was at 0ma; however, review of programming history shows that during an interrupted systems diagnostic test the magnet mode output current had been inadvertently set to 1ma. Although a final interrogation was performed which showed this setting, the physician did not reprogram the generator at that time. Another systems diagnostic test was performed and was within normal limits. At the next office visit the magnet mode output current was reprogrammed to 0ma.

Manufacturer Narrative
Analysis of programming history.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=958702


Title: Re: Electrodes
Post by: dennis100 on April 21, 2017, 03:37:53 AM
Model Number 302-20
Event Date 11/20/2007
Event Type Malfunction
Event Description
It was reported to mfr that a sys diagnostic test performed on the vns pts device revealed high lead impedance with output status ok. A second system diagnostic test performed at the same office visit revealed high lead impedance with the out put status at the limit. The pt presented at the physicians office with continuous neck pain and extreme coughing during stimulation of the device, which began the previous day. The pt reported having had pulled his left neck muscle the day prior. Additionally, the physician stated that the pt is a truck driver and does "a lot of movement in his neck, so he may have stretched the leads". It was recommended to set the normal mode and magnet mode output current ot 0ma, however the physician opted to decrease the settings from 1ma to 0. 75ma decrease the pulse width from 500usec to 250usec. The coughing and the pain improved with the setting change. The pt was referred to the implanting surgeon to have the device replaced. Preoperative interrogation of the device revealed that at some point the device output current had been set to 0ma. During surgery, it was observed that the negative coil was a "burnt yellowish color" and that the "nerve was burnt at the site where the negative electrode was in contact with the nerve". The area above and below the burnt area on the nerve was swollen. The entire lead, including the electrodes was removed,and a new lead was implanted. The generator was replaced prophylactically. Additionally, the surgeon reported that the pt was experiencing hoarseness prior to the device being removed. Attempts to obtain the explanted devices for analysis have been made, but have been unsuccessful to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2998029


Title: Re: Electrodes
Post by: dennis100 on April 24, 2017, 03:50:31 AM
Model Number 302-20
Event Date 09/01/2009
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was initially reported by the physician that patient showed high lead impedance with lead impedance 7116 ohms. Normal mode showed ok, lead impedance 6993 ohms. Surgeon had ordered x-rays and treating physician wanted total revision because patient had a hard fall after prophylactic battery replacement surgery in (b) (6)2009. Follow-up with the company rep revealed that the patient had a full revision surgery. It was indicated that the last good diagnostics were obtained at the time of initial battery replacement surgery ((b) (6)2009) which showed everything within normal limit. Company rep stated that the treating physician believed that the reason for high lead impedance was due to a fall which might have caused the lead to break, however, the surgeon indicated that the reason was due to a build of a lot of scar tissue around the electrode region. She indicated that x-rays were taken, and it did not show any lead break. X-rays were not available for manufacture review. Lead was discarded by the hospital since they were torn into pieces at the time of revision surgery. The surgeon did not notice any break on the lead while removing it but he did notice a lot scar tissue around the electrode region. Patient's previous generator programming history was reviewed and it was observed that the dcdc code had dropped to 0. Given the fact that the dcdc code had dropped from 2 to 0, it is suspected that a short circuit condition likely existed which eventually lead to a lead fracture. It is unlikely that fibrosis could be a part of the high lead impedance given that the dcdc code cannot jump from a 0 to such high ohms value unless there is a lead failure.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1581033


Title: Re: Electrodes
Post by: dennis100 on April 27, 2017, 01:19:02 AM
Model Number 302-20
Event Date 11/01/2009
Event Type Malfunction
Event Description
Reporter indicated high lead impedance readings were obtained for a vns pt at an office visit. The vns was disabled. The pt had fall trauma in (b) (6) 2009, and has a history of falls, but it is not certain if this contributed to the high lead impedance. Two sets of x-rays were reviewed by the manufacturer which did not identify any lead breaks; however, it does appear that the electrodes are not in alignment. In addition, the lead pin was fully inserted. A lead fracture is suspected. Vns lead revision surgery is planned for (b) (6) 2009.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1571643


Title: Re: Electrodes
Post by: dennis100 on May 05, 2017, 03:21:04 AM
Model Number 103
Event Date 04/10/2014
Event Type Malfunction
Event Description
It was reported that the vns patient was having difficulty breathing and had a slight choking sensation. The neurologist lowered the patient¿s device settings. The patient subsequently had an increase in petit mal seizures so the neurologist decreased the device off time which helped with the patient¿s seizures. The patient continued to have difficulty breathing. Further follow-up revealed that the patient continued to have an increase in seizures. X-rays were provided to the manufacturer where analysis is currently underway. Review of the available programming and diagnostic history showed normal diagnostic results through (b)(4) 2010.

Manufacturer Narrative
Review of the available programming and diagnostic history.

Event Description
It was reported on an implant card received on (b)(6) 2014 that the reason the lead was replaced was because of a ¿lead discontinuity¿. The lead impedance after the full revision was 1852 ohms, within normal limits.

Manufacturer Narrative
Corrected data: the initial mfr. Report inadvertently reported that x-rays had not been received; however, the x-rays had been received for review.

Event Description
X-rays were received and reviewed. Review of x-rays identified that the negative lead electrode may not be fully attached to the patient's nerve as the orientation of the electrode appears more parallel to the nerve rather than wrapped around it. No other obvious discontinuities were identified with the vns system. The patient was referred for vns replacement surgery. No known surgical intervention has been performed to date.

Event Description
On (b)(6) 2014 it was reported that the patient¿s lead impedance was around 4,000ohms. The patient all of a sudden started having shortness of breath with stimulation; he couldn¿t breathe in or out. After two days, he went the physician and the vns was turned down three times. The patient was referred for surgery. Although surgery is likely, it has not occurred to date.

Manufacturer Narrative
Corrected data: inadvertently did not include information on follow-up report #3.

Event Description
On (b)(6) 2014 it was reported that they were not certain about a lead break, the physician just insisted that a full revision be done because the patient was complaining of pain at the lead site. X-rays had been obtained but the source of the pain and relatively high impedance could not be located. The physician suspected that there was a lead break; however it could not be confirmed. The therapeutic consultant noted that it did look like the lead casing had been breached as there was blood and debris within the silicone casing of the lead, which is why the physician suspected lead discontinuity. It was noted that it appears like the patient¿s symptoms have resolved since this revision.

Event Description
On (b)(6) 2014 it was reported that the patient underwent a full revision surgery. It was reported that the explanted products cannot be returned to the manufacturer for product analysis as the hospital does not return explanted products.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3884994


Title: Re: Electrodes
Post by: dennis100 on May 06, 2017, 10:03:15 AM
Model Number 302-20
Device Problems Detachment of device component; Fluid leak; High impedance
Event Date 01/12/2015
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported by the physician's office that the patient was referred for a vns consult for an unknown reason and the plan was for vns generator replacement, but a lead replacement may also be needed. No information was initially provided. An implant card was later received showing the patient underwent a full vns revision. The diagnostics for the old device showed high impedance. It was also explained that the lead had visible "holes" and fluid within the silicone tubing. Diagnostics with a new generator and the old lead still showed high impedance. Adequate insertion of the lead pin into the generator was confirmed, but the high impedance did not resolve. The new generator was tested using the resistor pin and confirmed good diagnostics. Upon exposing the electrodes within the neck, it could be seen that one of the electrodes was no longer wrapped around the vagus nerve. Per the anesthesiologist, the patient had been known to have severe falls due to seizure activity and the compromises in the lead may have occurred during one of the falling evens. Once both the lead and the generator were replaced, diagnostics were within normal limits. The explanted generator and lead were reported to be discarded after the surgery.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6461922


Title: Re: Electrodes
Post by: dennis100 on May 06, 2017, 10:04:08 AM
Model Number 304-20
Device Problem Mechanical issue
Event Date 03/27/2017
Event Type Malfunction
Event Description
It was reported that the surgeon was performing an initial vns implant procedure when the new vns lead was opened the surgeon determined that one of the electrodes appeared to be deformed. It was noted that the \positive electrode appeared too small and the surgeon expressed concerned that it may not have been manufactured properly. A different lead was then implanted. Photos of the suspect lead were received by the manufacturer however it was difficult assess if the size of the electrode met specification based on the images. The suspect lead has not been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6512601


Title: Re: Electrodes
Post by: dennis100 on May 06, 2017, 10:04:52 AM
Device Problem Fracture
Event Date 01/01/2017
Event Type Malfunction
Event Description
It was reported that a patient underwent a full revision surgery. The patient's generator was replaced due to normal battery depletion and the lead was replaced due to a defective electrode. Attempts to obtain additional information from the physician was made to determine what was meant by the "defective electrode" but no additional information has been provided to date. The lead model and serial number were reportedly unknown and the product was discarded after surgery. The post-op impedance values were within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6515558


Title: Re: Electrodes
Post by: dennis100 on May 08, 2017, 11:19:56 AM
Model Number 302-20
Event Date 09/16/2014
Event Type Malfunction
Manufacturer Narrative
Initial reporter phone #, corrected data: the initial report inadvertently did not report this data.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that the patient had generator and lead replacement surgery on (b)(6) 2014. During surgery, it was discovered that the coils on the existing lead were not on the vagus nerve which was likely the cause of the high impedance. Good faith attempts for product return were performed. The explanted products have not been received to date.

Event Description
It was reported that the vns patient¿s device was tested during an office visit on (b)(6) 2014 and system diagnostic results revealed high impedance (dc dc ¿ 7). The patient¿s device was not disabled following the high impedance observation. Patient manipulation or trauma is not believed to have caused or contributed to the high impedance. The patient was referred for surgery but no known surgical interventions have occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4163511


Title: Re: Electrodes
Post by: dennis100 on May 09, 2017, 01:00:24 AM
Model Number 102
Event Date 09/15/2014
Event Type Injury
Manufacturer Narrative
Evaluation not related to event.

Event Description
Additional information was received that product analysis was completed on the lead. A coil break was identified in both the positive and negative lead coils. Scanning electron microscopy images of the lead coils show that a stress-induced fracture (due to rotational forces) occurred at the coil ends. Secondary fractures were observed in at least two strands of the quadfilar coils. The negative coil shows what appears to be wear (flat surfaces) resulting in reduction of the strand diameter. Although not conclusive the appearance of the lead break location is consistent with patient manipulation of the implanted device, a ¿twiddler¿. The patient had reported painful stimulation for months and the identified coil breaks may confirm this to be a contributing factor. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead. The report issue found with the lead was reported on medwatch 1644487-2014-02836.

Event Description
Additional clinic notes dated (b)(6) 2014 were received stating that the patient experienced wound dehiscence following the explant surgery on (b)(6) 2014. Patient's stitches were taken out and replaced with steri-strips. The patient's chest incision was reported to be open with yellow drainage from it. Patient was provided with antibiotics and was noted to be seeing the surgeon in a few days.

Event Description
It was initially reported that the patient had their vns explanted. After the explant, the patient picked at the incision and opened the pocket. There was nothing implanted in the patient at that time of the incision being picked open.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4147147


Title: Re: Electrodes
Post by: dennis100 on May 11, 2017, 12:35:01 AM
Model Number 102R
Event Date 01/01/2008
Event Type Injury
Manufacturer Narrative
X-rays reviewed by the mfr, no anomalies or cause for the event identified.

Event Description
Reporter indicated that a pt would have the vns generator and lead replaced due to painful stimulation at the electrode site. Follow up with the physician revealed that there had been no trauma and that the vns settings had been decreased to a tolerable level. It was reported that although the pain is believed to be related to vns stimulation, the generator has not been set to 0ma to determine if the pain stops without stimulation. X-rays were reviewed by mfr and no anomalies or causes for the event were identified.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=998869


Title: Re: Electrodes
Post by: dennis100 on May 11, 2017, 12:35:40 AM
Model Number 302-20
Event Date 11/07/2007
Event Type Injury
Event Description
Reporter indicated that a patient had left vocal cord paralysis confirmed by an ent following initial implantation of the vns device. The device had not been programmed on. The reporter believed the vocal cord paralysis was due to the electrode size being too small and constricting the nerve. Lead revision surgery was performed, and the 2 mm lead was replaced with a 3 mm lead. Following the lead revision surgery, the vocal cord paralysis resolved. Explanted lead was discarded by the hospital.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=992789


Title: Re: Electrodes
Post by: dennis100 on May 12, 2017, 12:46:52 AM
Model Number 300-20
Event Date 07/11/2007
Event Type Malfunction
Event Description
It was reported that a vns pt underwent full revision surgery due to high impedance. The specific device diagnostic results were not provided. The site indicated the explanted product is not available for return to the manufacturer. Followup with the physician revealed that there had been no pt manipulation or trauma that could have contributed to the high impedance. During the revision surgery, it was noted that there was an excessive amount of fibrosis on the electrode site.

Manufacturer Narrative
Conclusions: device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1216041


Title: Re: Electrodes
Post by: dennis100 on May 14, 2017, 12:27:09 AM
Model Number 300-20
Event Date 01/01/2008
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that a vns patient received high impedance readings. X-rays were received and reviewed by the manufacturer. No gross discontinuities were identified, but found that the lead electrodes were inverted and that strain relief was not placed per labeling.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1133179


Title: Re: Electrodes
Post by: dennis100 on May 14, 2017, 12:28:12 AM
Model Number 300-20
Event Date 01/01/2008
Event Type Malfunction
Event Description
It was reported that the patient was having revision surgery due to end of service and a potential lead break. Attempts to obtain further information from the neurologist were unsuccessful. Product analysis was performed on the explanted lead. A coil break and pitting was identified in the positive coil. Other than typical wear and explant related observations, no other adverse findings, or anomalies were identified in the returned lead portions.

Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1172159


Title: Re: Electrodes
Post by: dennis100 on May 14, 2017, 12:28:50 AM
Model Number 102
Event Date 08/22/2008
Event Type Injury
Event Description
It was reported to the manufacturer that the vns patient has been experiencing pain in the neck at the electrode site. Exploratory surgery was performed and the surgeon repositioned the patient's lead. Good faith attempts to obtain additional information regarding this event have been successful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1169943


Title: Re: Electrodes
Post by: dennis100 on May 23, 2017, 01:00:26 AM
Model Number 302-30
Event Date 03/12/2008
Event Type  Malfunction   
Manufacturer Narrative 
Mfr reviewed x-rays of implanted device. Review of x-rays by the mfr revealed that the electrodes may not be placed on the nerve. Device failure suspected, but did not cause or contribute to a death or serious injury.
 
Event Description 
Reporter indicated that diagnostic testing on a vns pt resulted in high lead impedance. The pt was reported to not be able to feel stimulation. X-rays were sent to the mfr for review. Review of the x-rays revealed that the lead electrodes may not be placed on the vagus nerve. Revision surgery is likely. Good faith attempts for add'l info have been unsuccessful to date.
 
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1029072


Title: Re: Electrodes
Post by: dennis100 on May 23, 2017, 01:01:56 AM
Model Number 102
Event Date 03/01/2008
Event Type  Injury   
Event Description 
Reporter indicated that a vns pt experienced a seizure increase, relationship to pre-vns baseline unk. The pt also did not feel stimulation as she did previously, had pain at the generator site, and there was an obvious change in her voice. Diagnostic test results were within normal limits. Exploratory surgery was performed and "it was immediately obvious that there was blood and fluids between the lead pins and the generator header. In the lead there was some fluid (liquid), on the place where the platinum electrode is located. " the generator was replaced and scar tissue was removed from the incision. Good faith attempts for additional info and product return have been unsuccessful to date.
 
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1028162


Title: Re: Electrodes
Post by: dennis100 on June 01, 2017, 12:39:38 AM
Model Number 300.20
Event Date 07/01/2009
Event Type  Malfunction   
Manufacturer Narrative 
"electrode detach from nerve is beyond the scope of activities performed in the product analysis lab". The portion of the lead that was returned for analysis did not reveal any anomalies. However, a device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description 
It was reported by the surgeon that the patient underwent a full revision surgery due to lead disconnected from nerve. X-rays were taken which clearly showed top lead disconnected from the nerve. X-rays were not available for further manufacturer review. No patient manipulation or trauma was reported. Explanted products were returned to manufacturer for further review. Analysis was completed on the lead and reported allegation of high lead impedance was not confirmed. Condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted.
 
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1497730


Title: Re: Electrodes
Post by: dennis100 on June 01, 2017, 06:30:16 AM
Model Number 302-30
Event Date 04/04/2006
Event Type Malfunction
Event Description
Reporter indicated a vns patient had systems diagnostics results with dcdc = 0 and was concerned this may indicate a short circuit condition in the vns lead. The dcdc = 0 was first noted on (b) (6) 2006 and is still occurring as of (b) (6) 2009. The patient is non-verbal and cannot report if vns stimulation is felt. The patient has had decreasing efficacy over the last 6 months and increased seizures that are not greater than pre-vns baseline levels. X-rays were reviewed. The electrodes appeared in alignment but also appeared stretched. A sharp angle was noted in a suspicious area of the lead boy just superior to the generator header. No obvious lead discontinuities were noted. All attempts for further information from the reporter have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by manufacturer, no gross lead discontinuities visualized.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1496318


Title: Re: Electrodes
Post by: dennis100 on June 12, 2017, 12:58:37 AM
Event Date 01/01/2000
Event Type  Malfunction   
Event Description 
Manufacturer review of the published article entitled "revision of vagal nerve stimulator (vns) electrodes: review and report on use of ultra-sharp monopolar tip. Child's nervous system, (b)(6)2010: online. Ng wh, donner e, go c, abou-hamden a, rutka j. " identified that a vns patient underwent vns lead and generator revision surgery due to high lead impedance. It was noted during surgery the lower coils were dislodged. Attempts to the author for additional information, and if this event was previously reported, have been unsuccessful to date.
 
Manufacturer Narrative 
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1660765


Title: Re: Electrodes
Post by: dennis100 on June 22, 2017, 02:15:49 AM
Model Number 302-20
Event Date 05/18/2010
Event Type Malfunction
Event Description
It was reported to the manufacturer that the vns patient's device showed high lead impedance during diagnostic testing at an office visit. The patient has not experienced any adverse events as a result of loss of therapy from the reported event. It is unknown if there was any patient manipulation or trauma at the device site. X-ray views of the device were taken to assess the integrity of the system and sent to the manufacturer for review. Review of the x-rays did not reveal any anomalies in the visible portion of the device which may have contributed to the reported event. During review, it was also noted that the electrodes appeared to be aligned properly, but were inverted. The patient is being scheduled for full revision surgery. Diagnostic tests performed on the device revealed proper device function in 08/2008. Good faith attempts to obtain additional information regarding the reported event have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1755480


Title: Re: Electrodes
Post by: dennis100 on June 23, 2017, 01:37:38 AM
Model Number 300-20
Event Date 01/01/2010
Event Type Malfunction
Manufacturer Narrative
Method: manufacturer reviewed x-rays of implanted device. Results: review of x-rays by manufacturer revealed a gross lead discontinuity. Conclusions: device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that diagnostics on the pt's device showed high impedance on (b)(6) 2010. No trauma or manipulation was reported to have occurred. X-rays were taken and sent to the manufacturer for review. Upon review of x-rays, a gross lead fracture was identified in the neck region. It was also noted that the electrodes appeared to be inverted which may have contributed to the lack of efficacy for the pt. The pt's mother stated that she didn't feel the vns had been working for a few years. Pt was referred for full revision surgery, but surgery has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1731035


Title: Re: Electrodes
Post by: dennis100 on June 25, 2017, 12:30:41 AM
Model Number 302-20
Event Date 05/04/2010
Event Type Malfunction
Event Description
Reporter indicated a 302-20 vns lead was noted to be broken at the distal electrode after it was connected to the vns generator during an initial implant surgery. Another vns lead was used to complete the procedure. The reporter stated, the lead was not accidentally damaged. The suspect lead has been returned and is in product analysis.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1720408


Title: Re: Electrodes
Post by: dennis100 on June 30, 2017, 01:27:18 AM
Model Number 302-20
Event Date 08/13/2010
Event Type Malfunction
Event Description
It was reported to the mfr that the vns pt's device could not be interrogated. Notes were received from the office in which the pt was indicated to have experienced an increase in seizure activity since 2008. Follow-up revealed that the increase was not related to vns therapy as the therapy has proven beneficial for the pt's seizure activity. The cause of the increase is most likely due to stress or other external factors. It was also indicated that the pt's device was believed to be at end of service since the programming system functioned properly with other pt's devices. A battery life calculation has been performed on the pt's device that revealed the device is most likely at end of service. Diagnostic tests performed during (b)(6) 2009 were within normal limits. The reported increase in seizures event has been determined to be unrelated to vns therapy. The generator's suspected end of service condition is most likely the root cause for the reported failure to program event. It was later noted that during the generator replacement surgery, the pt's lead was noted to no longer be on the nerve, so a full revision was performed. Good faith attempts to obtain additional info are in progress. The explanted device was said to not be returned to the mfr for analysis as it has been discarded by the hospital.

Manufacturer Narrative
Device malfunction is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1834541


Title: Re: Electrodes
Post by: dennis100 on July 02, 2017, 01:47:22 AM
Model Number 302-20
Event Date 08/06/2010
Event Type Injury
Event Description
It was reported that a vns pt experienced voice alteration and hoarseness after vns implant surgery. The pt's device was not programmed on at the time of the events. The pt's device was programmed on by the treating neurologist, who indicated the pt's hoarseness was related to surgery and referred the pt to an ent. F/u from a company rep revealed the pt visited the ent and results were positive for vocal cord paralysis. At the moment, good faith attempts to obtain additional information from the treating neurologist have been unsuccessful to date. Moreover, additional information was rec'd from the surgeon's office through a company rep indicating the x-rays were taken. Review of the x-rays by the surgeon indicated that in his opinion the electrodes were not aligned properly. Moreover, the reported x-rays have not been rec'd by the manufacturer.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1846175


Title: Re: Electrodes
Post by: dennis100 on July 04, 2017, 03:47:38 AM
Model Number 302-20
Event Date 09/01/2010
Event Type Malfunction
Event Description
It was reported that the pt had high impedance on system diagnostics. The pt fell down from his bed one week prior to the high impedance being found which may have caused direct trauma to his chest. The device has been programmed off. X-rays were taken of the device and reviewed by the mfr. Upon review, it was noted that the electrodes did not appear to be linearly aligned as is commonly seen along the vagus nerve. No other anomalies were noted and no definite cause could be determined for the high impedance. Revision surgery is likely, but has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1867231


Title: Re: Electrodes
Post by: dennis100 on July 04, 2017, 10:58:09 AM
Model Number 103
Event Date 10/01/2010
Event Type Injury
Event Description
It was initially reported by the physician that the patient was being referred to the surgeon to look at the placement of the electrode and see if there is a better option because the patient is complaining of severe hoarseness. They want to have the electrodes relocated as it is so close to his vocal cords that you can barely hear him talk when it goes off and it really affects his day to day living. Patient has been great to vns so he is motivated to have the revision done. Good faith attempts to obtain additional information has been unsuccessful till date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1909634


Title: Re: Electrodes
Post by: dennis100 on July 06, 2017, 05:07:12 AM
Model Number 103
Event Date 11/01/2010
Event Type Injury
Manufacturer Narrative

Event Description
It was initially reported by the physician at the hospital that the pt was experiencing painful stimulation at the electrode site. Device was checked and confirmed to be functioning within normal limits. After lowering the settings, the pt was doing fine. Follow up with the treating physician revealed that the device was turned off as pt's pain was not resolved after reducing the vns settings. Pt did well initially but the event came back. The pt requested to have the device turned off as he could not tolerate the pain and he was referred to the surgeon for a possible revision surgery. Per physician, the pain was quite serious for the pt and therefore, he had to refer the pt for a revision of vns. Surgery has not been planned at the moment but it will likely take place. The pain occurs with vns stimulation.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1943832


Title: Re: Electrodes
Post by: dennis100 on July 06, 2017, 08:26:21 AM
Model Number 300-20
Event Date 10/01/2007
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Results: x-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Conclusions: device malfunction is suspected but did not cause or contribute to a death or serious injury.

Event Description
It was reported to us by our country representative in (b)(4) that a vns programming physician's office has contacted them and reported that they had a vns patient with high lead impedance on their system diagnostic testing. In (b)(6) 2007, diagnostics gave a high impedance reading. This was rechecked in (b)(6) 2008 and impedance was normal, output status ok, and dc-dc code of 4. In (b)(6) 2009, 7/limit/high was attained and it was reported that the site reviewed an x-ray and it was reported as normal with no obvious lead break. The patient was seen again (b)(6) 2010 with the same results as (b)(6) 2009. There are no patient adverse events reported in conjunction with their high lead impedance. The patient's parent feels like they are still getting benefit from the vns. Advice has been provided to the site to program their vns off related to their high lead impedance. No surgical interventions are planned at this time. No injury or fall was reported, but the patient does experience frequent seizures, so a fall cannot be ruled out. X-rays were received and reviewed at the manufacturer and no obvious lead discontinuity was noted in the portions of the lead that could be seen. Only one view was available. The majority of the lead could not be visualized. The positive electrode appeared to be more uncoiled around the vagus nerve than the negative electrode. No other views were available to see if there was an issue in that area or to view from another angle. It is unknown based on the review if the anchor tether is in alignment. There was no strain relief bend or loop present. No further portions of the lead or generator were in the view. Based on the x-ray review no obvious lead discontinuities were observed in the x-ray images provided. The generator area and majority of lead body could not be seen. An issue with the positive electrode region cannot be ruled out based on the one view available. The pin being fully inserted could not be assessed or the presence of an unpronounced lead discontinuity cannot be ruled out.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1963839


Title: Re: Electrodes
Post by: dennis100 on July 06, 2017, 08:27:25 AM
Model Number 302-20
Event Date 07/29/2009
Event Type Malfunction
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Results: x-ray reviewed by the manufacturer, no gross lead discontinuities visualized. Conclusion: device malfunction is suspected but did not cause or contribute to a death or serious injury.

Event Description
It was reported to us by our country representative in (b)(4) that a vns programming physician's office has contacted them and reported that they had a vns patient with high lead impedance on their system diagnostic testing. It was reported that their diagnostics were normal until (b)(6) 2009, when found out to have 7/limit/high. The site was reported to have reviewed the patient chest x-ray and it was reported as normal with no break. The patient has not experienced any adverse events related to their high lead impedance. Their vns device has been checked 3 times since and is still displaying high lead impedance. The patient's parent is unsure if they are getting any benefit from the vns. Advice has been provided to the site to program their vns off related to their high lead impedance. No surgical interventions are planned at this time. No injury or fall was reported, but the patient does experience frequent seizures, so a fall cannot be ruled out. X-rays were received and reviewed at the manufacturer and no obvious lead discontinuity was noted in the portions of the lead that could be seen. Only one view was available. The majority of the lead could not be visualized. The electrodes were visible and it was noted that the electrodes were implanted on the nerve inverted. There were two tie downs in the electrode location securing the lead body but no strain relief loop or bend were present. The lead was then routed down towards the generator. Only a small section of the lead body could be visualized. No further portions of the lead or generator were in the view. Based on the x-ray review no obvious lead discontinuities were observed in the x-ray images provided. The generator area and majority of lead body could not be seen. The pin being fully inserted could not be assessed or the presence of an unpronounced lead discontinuity cannot be ruled out.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1963862


Title: Re: Electrodes
Post by: dennis100 on July 06, 2017, 08:28:12 AM
Event Date 11/19/2010
Event Type Injury
Event Description
It was reported that the pt had her settings turned down due to pain at the electrode site in her neck, down her back and in her arm and leg. She has also experienced an increase in seizures recently and the magnet has had no effect. Attempts for further information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1938613


Title: Re: Electrodes
Post by: dennis100 on July 07, 2017, 01:32:24 AM
Model Number 106
Device Problem No Known Device Problem
Event Date 02/07/2017
Event Type  Injury   
Manufacturer Narrative

Event Description
A patient reported that while getting a head mri, the battery had not been turned off and she stated it got hot at the battery and at the attachment to the vagus nerve. The department was aware that she has a vns and was given her id (implant) card. The patient reported having passed out from pain. Follow-up by the company representative provided that the patient was last seen on (b)(6) 2017 and systems diagnostics were normal. The patient's generator was turned off. Additional relevant information has not been received to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6676919


Title: Re: Electrodes
Post by: dennis100 on July 09, 2017, 09:29:39 AM
Model Number 302-XX
Event Date 01/01/2010
Event Type  Malfunction   
Event Description
It was reported that the pt had high impedance on diagnostics. It was also indicated that the pt has experienced an increase in seizures recently which the physician attributes to the high lead impedance. The relationship to pre-vns baseline levels is unk. No trauma or manipulation has occurred. X-rays were taken of the pt's device. Upon review, the electrodes appeared to be placed on the nerve in an inverted orientation and there was an area of suspicion in the lead body. However, no obvious lead discontinuities were visualized. Revision surgery is likely, but has not occurred to date.
 
Manufacturer Narrative
Mfr reviewed x-rays of implanted device. X-rays reviewed by the mfr, no gross lead discontinuities visualized. Device failure suspected.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1937070


Title: Re: Electrodes
Post by: dennis100 on July 15, 2017, 06:21:43 AM
Model Number 102
Event Date 01/01/2007
Event Type  Injury   
Event Description
Additional info was received from the pt indicating she continued to have a hurting sensation in the neck area where the electrodes were. The pt indicated that the event had been occurring ever since vns implant and her implanting physician would not remove her electrodes. Further info from a company rep indicated the pt was scheduled to see a surgeon for explant consult. F/u was made with the surgeon's office and indicated the pt is scheduled to undergo vns generator removal surgery as the pt complains of pain at the generator site. The pt's device is off and pt wants it out. The surgeon's office indicated the surgery was to preclude a serious injury and had no additional info regarding the pt's treating neurologist. Additional info from the surgeon's office indicated the pt underwent generator removal surgery as scheduled. Good faith attempts to obtain the explanted generator have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1959461


Title: Re: Electrodes
Post by: dennis100 on July 23, 2017, 07:12:12 AM
Model Number 302-20
Event Date 01/01/2009
Event Type  Injury   
Event Description
It was reported that the pt was very sensitive to stimulation and was feeling pain during stimulation. The pt was not able to tolerate stimulation at 0. 50ma, so the device was disabled for several months. The pt was then set to 0. 25ma in (b)(6) 2010 and was able to tolerate the stimulation as she could not feel it. Diagnostics were not able to be performed at this time. The pt was later programmed to 0. 75ma and able to feel the stimulation. X-rays were received by the mfr for review, which revealed no anomalies. Later, it was indicated that it was very difficult from the very beginning to increase the output current, due to pt's sensitivity. The physician tried for a year and a half to raise the output and managed to do so up to 0. 5ma with the pulsewidth at 250 and 130. The stimulator was stopped (b)(6) 2010 and started again in (b)(6) 2010. The pt was said to be feeling the painful stimulation since being turned on and the physician confirmed that is believed to be related to the vns therapy. There is no known pt manipulation or trauma that occurred that is believed to have caused/contributed to the painful stimulation. No programming changes were taken as the pt was already at low settings. The pt later had vns lead revision surgery due to the painful stimulation. At the time of surgery, the surgeon noted that the electrodes were placed a little too low on the nerve in his opinion. The pt is doing much better since surgery and is currently having a new vns titrated up. The explanted lead was returned to the mfr, but no anomalies were noted with the device.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2075905


Title: Re: Electrodes
Post by: dennis100 on July 26, 2017, 12:53:35 AM
Model Number 302-20
Event Date 03/24/2011
Event Type  Malfunction   
Event Description
On (b)(6) 2011, a vns treating physician reported to the manufacturer's consultant that the vns patient presented with an increase in seizures and low impedance during a systems diagnostics test that day. The patient was sent for x-rays and refered to a surgeon. The physician reported that the low impedance could be due to "one of the wires being loose. " the patient's x-rays were received by the manufacturer for review on (b)(6), 2011. Based on the x-ray review, possible gross fractures or discontinuities could exist since the lead could not be fully assessed due to tight coiling from patient manipulation. Sharp angles existed in the lead body from patient manipulation and could also be the cause of the low impedance. Also, the electrodes were placed upside down, opposite of labeling, and there was no strain relief loop or bend; therefore unable to rule out as potentially contributing to the patient's low impedance. Whether the connector pin appeared to be fully inserted into the connector block could not be assessed based on the generator not being fully visible in the x-ray views available. Good faith attempts for further information from the physician have been to no avail thus far. No surgery has been scheduled as of yet and the surgeon the patient was referred to has no record of the patient. If additional information is received, it will be reported.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2074640


Title: Re: Electrodes
Post by: dennis100 on July 30, 2017, 04:54:51 AM
Model Number 102
Event Date 01/01/2011
Event Type  Injury   
Event Description
It was reported that the pt was explanted today as she never really received much benefit from vns and she claimed the generator was uncomfortable. The surgeon removed the system and said that the generator was in the axillary area and he could see where it would be uncomfortable when lying on her side. It was also noted that the coils were placed upside down on the nerve with the anchor tether proximal to head. Attempts for further info have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2083049


Title: Re: Electrodes
Post by: dennis100 on August 04, 2017, 03:37:07 AM
Event Date 01/02/2017
Event Type  Injury   
Event Description
An article was received that reported multiple adverse events and a malfunction. The current report captures the adverse events associated with the lead. Mfr. Report # 1644487-2017-04155 captures the malfunction reported by the article. Mfr. Report # 1644487-2017-04153 captures adverse events associated with the generator. There was one intraoperative event associated with the lead. This patient experienced mild oozing from the jugular vein that was controlled by bipolar cautery. One patient had a prominent electrode in his neck which presented as pain and discomfort within a week post operatively. Two other patient's also had pain due to prominent electrodes, but these were associated with trauma to the vns area. These three patient's neck wounds were revised and the electrodes repositioned. The article later describes these electrodes as being "dislodged. " no further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6723266


Title: Re: Electrodes
Post by: dennis100 on August 04, 2017, 03:37:59 AM
Device Problem No Known Device Problem
Event Date 05/01/2017
Event Type  Injury   
Manufacturer Narrative

Event Description
A nurse reported that a patient began experiencing bruising on his left hand, difficulty moving his left arm, jerking in his left arm, and some pain. The patient's symptoms had reportedly begun after the patient's device had been programmed up to a certain level. X-rays were reviewed for the patient having these issues by a company representative and it was found that the patient's electrodes had been inverted during placement. No other anomalies were identified in the x-ray images. No further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6724226


Title: Re: Electrodes
Post by: dennis100 on August 04, 2017, 08:24:03 AM
Model Number 302-20
Device Problem High impedance
Event Date 06/19/2017
Event Type  Malfunction   
Event Description
It was reported that the patient was referred for a prophylactic generator replacement initially, but the generator battery was found to be depleted to the point of being unable to be interrogated during pre-op. During surgery, after the new generator was connected to the lead, high impedance was observed. Pin insertion troubleshooting was performed three times and the high impedance was not resolved. The surgeon observed that the electrodes were encapsulated by scar tissue around the lead and indicated that he believed the high impedance was caused by the fibrosis. No lead fractures were observed. Impedance was found to be within normal limits with the new lead. The lead was not explanted and left fully intact in the patient. No additional information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6724696


Title: Re: Electrodes
Post by: dennis100 on August 05, 2017, 12:14:32 AM
Model Number 302-20
Event Date 06/06/2011
Event Type  Malfunction   
Event Description
Patient underwent implantation of her vagus nerve stimulator (vns) ~3 years ago. Initially, it worked well to reduce the frequency and severity of patient seizures. Patient was able to use the device to help abort her seizures. Patient is now having events 1-2 times a week. She has begun to experience auras again. Interrogation of her vns indicates high impedance, suggesting a malfunction. Chest xray performed and suspect the lower contact on the nerve may be fractured. The contact is sitting at an odd angle on the nerve, and does not seem to be winding around the nerve the way it should.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2150756


Title: Re: Electrodes
Post by: dennis100 on August 12, 2017, 06:30:32 AM
Model Number 302-20
Event Date 08/19/2011
Event Type  Malfunction   
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device review of x-rays by the manufacturer revealed a gross lead discontinuity. Device failure occurred, but did not cause or contribute to a death or serious injury.
 
Event Description
Analysis was completed on the returned products. Analysis of the returned generator revealed the generator performed according to functional specifications. Analysis of the returned lead indicated that scanning electron microscopy images of both the positive and negative coils show that pitting or electro-etching conditions have occurred at the break locations. Appearance of one positive coil strand indicates a stress-induced fracture has occurred. However, due to mechanical distortion the initial fracture mechanism cannot be determined. The early stages of secondary fractures were identified in at least two strands of the positive coil. The fracture mechanism of the other positive coil strands cannot be ascertained due to metal dissolution and surface contamination. Inspection of the negative coil shows that a stress-induced fracture (due to rotational forces) has occurred in at least one strand of the quadfilar coil. Also, the appearance of a third strand indicates a stress-induced fracture has occurred. However, due to mechanical distortion on this strand the initial fracture mechanism cannot be determined. Note that since the electrode array portion was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.
 
Event Description
It was reported by a company representative that a vns pt was being referred for revision surgery due to high lead impedance. Good faith attempts to obtain additional info from the treating neurologist have been unsuccessful to date.
 
Event Description
Additional information was received from the area representative indicating the patient was seen by her treating neurologist and had a seizure that sent the patient to the er. The patient was referred for x-rays and revision surgery. X-rays were received by the manufacturer. Review of x-rays indicated that most the lead was on the chest near the generator and it seemed the patient suffers from "twiddler's condition" as the lead was seen coiled in the chest area. A view from the neck area indicated the electrodes were on the nerve; however continuity could not be confirmed. At the moment the patient is having an increase in seizures due to the previously reported high impedance and revision surgery is likely.
 
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received from the area representative indicating the patient underwent generator and lead replacement surgery. The area representative indicated the lead appeared to be completely broken upon opening the chest incision. Moreover, the surgeon indicated the leads were not on the nerve. Manipulation of the lead by the patient was suspected as the lead was coiled and broken. The explanted generator and lead were returned to the manufacturer and remain under analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2271333



Title: Re: Electrodes
Post by: dennis100 on August 19, 2017, 03:07:29 AM
Event Date 05/30/2011
Event Type  Malfunction   
Event Description
It was reported that the pt underwent full revision surgery for an unk reason on (b)(6) 2011. Further info received reveals that the reason for the surgery was high impedance on her device. Attempts for further info have been unsuccessful to date.
 
Event Description
Additional information was received regarding the patient. The high impedance was first seen (b)(6) 2011 and the last good diagnostics were (b)(6) 2011. X-rays were taken but were no sent to the manufacturer for review. The x-rays showed that there was scar tissue formation around the nerve and inside the electrode coils and there were no discontinuities or sharp angles that were visualized. There was not reported manipulation or trauma. The product will not be returned to the manufacturer since the hospital will only returned to the patient and the patient can then return to the manufacturer. The hospital will not return to the manufacturer.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2320220


Title: Re: Electrodes
Post by: dennis100 on August 20, 2017, 07:16:43 AM
Model Number 302-20
Event Date 09/06/2011
Event Type  Malfunction   
Event Description
It was reported by a nurse that high lead impedance was observed during a follow-up visit (7/limit/high). The pt's mother indicated that the voice change was no longer preset when the device activated and high lead impedance was received during diagnostics. The perception of stimulation decreased as well with the finding of high impedance. The pt had trauma to the chest area in jan in which the pt claimed the generator stimulated continuously. Diagnostics after the reported trauma were within normal limits indicating proper device function (normal mode ok/ok/4). X-rays were received by the mfr and reviewed. Review of x-rays indicated the generator was visualized in the left chest. The filter feedthrough wires were intact and the lead pin was fully inserted passed the connector blocks. There was a small portion of the lead behind the generator and continuity in that portion of the lead cannot be assessed. The electrode placement appeared to be normal and the lead was routed down to the generator. The lead appeared to be detached from the negative electrode. There were no other gross discontinuities or acute angles found in the visible portions of the lead body.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2281445


Title: Re: Electrodes
Post by: dennis100 on August 21, 2017, 04:37:07 AM
Model Number 300-20
Event Date 09/08/2011
Event Type  Malfunction   
Event Description
Additional information was received from the surgeon indicating that manipulation and trauma were not suspected, and x-rays were not taken. He was unable to provide any additional programming history and no additional information was provided.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.
 
Event Description
It was reported on (b)(6) 2011 that during a generator replacement procedure for end of service, a lead fracture was identified. The generator and lead were replaced at that time. The explanted products have been returned to the manufacturer; however product analysis has not yet been completed. Prior to the replacement, it was reported that the generator could not be interrogated as it had reached normal end of service. It was also reported that the patient was experiencing an increase in seizures as well as cognitive changes, which at that time were attributed to the end of service. It is unknown if the lead fracture contributed to the patient's reported adverse events.
 
Event Description
Product analysis on the explanted generator and lead has been completed. During product analysis on the generator, the alleged end of service was verified and determined to be the result of normal battery depletion. The depletion was an expected event as determined by a battery life calculation and battery voltage measurement. The module performed according to functional specifications. There was no condition noted during the product analysis evaluation that would suggest any anomaly with the device. During product analysis of the lead, a lead fracture was identified in both the marked and unmarked connector quadfilar coils. Scanning electron microscopy was performed on the marked connector quadfilar coil break and identified the area as having extensive pitting which prevented identification of the coil fracture. Scanning electron microscopy was performed on the unmarked connector quadfilar coil break and identified the area as being mechanically damaged which prevented identification of the coil fracture type, no pitting and flat spots on coil surface. A third break was also identified approximately 2 mm from the end of the abraded open / torn outer silicone tubing. Scanning electron microscopy was performed and identified the areas as being mechanically damaged which prevented identification of the coil fracture type, no pitting and flat spots on coil surface. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. The abraded openings found on the outer and inner silicone tubes, most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the outer and inner silicone tubes. The positive electrode ribbon was returned embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the electrode ribbon from coming in contact with the vagus nerve; therefore contributing to the reported allegations. With the exception of the observed discontinuities and tissue-covered positive electrode ribbon, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The resistance measurement taken during decontamination verified an electrical and mechanical contact between the generator and connector pins at one point in time. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified. Note that since a portion of the lead assembly (body) was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2349367


Title: Re: Electrodes
Post by: dennis100 on August 21, 2017, 04:37:50 AM
Model Number 300-20
Event Date 10/25/2011
Event Type  Malfunction   
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. However based on the significant twisting of the leads, it is likely a lead fracture is present.
 
Manufacturer Narrative
Device failure is suspected.
 
Event Description
Reporter indicated via an implant card received to the manufacturer that the vns generator only was replaced, and that vns diagnostics with the new generator and resident lead were within normal limits. A device malfunction is not occurring with the vns lead. The explanted generator was returned for analysis and found to be performing as intended. The generator was not at end of service. All attempts to the reporter for additional information have been unsuccessful to date.
 
Event Description
Reporter indicated a patient had vns lead and generator replacement due to high lead impedance and increased seizures. The generator has been returned and is pending product analysis. Attempts for return of the lead are in progress. Attempts for additional information regarding the high lead impedance and increased seizures are in progress.
 
Manufacturer Narrative
Date of event, corrected data: the incorrect event date was inadvertently reported on the initial mdr. The correct event date is provided.
 
Event Description
On (b)(6) 2013 the patient¿s programming history was reviewed and on date of implant for the patient's new generator, (b)(6) 2011, high impedance was observed but appears to have resolved during surgery. A copy of the patient¿s x-rays dated (b)(6) 2013 were received for review. The connector pins are fully inserted inside the connector block. The feedthru wires appear to be intact. The electrodes are not in alignment. Significant twisting of the lead is noted distal to the generator, and gives the appearance of the patient manipulating the leads. The lead wires are intact at the lead pins. There is a portion of the lead behind the generator; therefore, this portion of lead cannot be assessed for continuity. Based on the x-rays images received, there is likely a lead fracture in the area of twisting distal to the generator. Also, the portion of the lead behind the generator could not be assessed, therefore a lead fracture in that portion of the lead cannot be ruled out. The presence of an additional micro-fracture in the lead also cannot be ruled out.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2349756


Title: Re: Electrodes
Post by: dennis100 on August 25, 2017, 03:27:33 AM
Model Number 302-20
Event Date 12/01/2011
Event Type  Malfunction   
Event Description
On (b)(6) 2011, a physician reported that the vns patient has high impedance. The physician reported that they discovered the high impedance from a recent report from the patient's psychiatrist. The patient has also been experiencing painful stimulation in her chest described as almost a shocking sensation. The patient also reported that she feels that her generator has migrated and the patient's depression has worsened. The physician did not know the relationship of the increase in depression to pre-vns baseline levels. No interventions had been planned at that point. The patient's settings were disabled that day but were previously at output=0. 25ma/frequency=20hz/pulse width=500usec/on time=30sec/off time=5min/magnet=0ma. The system diagnostics showed output=limit/lead impedance=high/dcdc=7/eri=no. X-rays were received by the manufacturer on (b)(6) 2011. Based on the x-rays received, the cause of the high lead impedance could not be identified. The lead pin appeared to be fully inserted into the connector block, and there did not appear to be any sharp angles or discontinuities in the visible portions of the lead. However, an unpronounced lead discontinuity cannot be ruled out. A battery life calculation was performed which showed 7. 32 years until elective replacement indicator (eri) shows yes. Although surgery is likely, it has not yet occurred. Additional information has been requested from the physician but no further information has been received to date.
 
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received on (b)(6) 2012, when the explanted lead and generator were returned to the manufacturer for product analysis. Product analysis is still underway and has not yet been completed.
 
Event Description
Additional information was received on (b)(6) 2012, when product analysis was completed on the explanted generator. In the product analysis lab, the device output signal was monitored for more than 24-hrs, while the generator was placed in a simulated body temperature environment. Results showed no signs of variation in the pulse generator's output signal and demonstrated that the device provided the expected level of output current for the entire monitoring period. The pulse generator diagnostics were as expected for the programmed parameters. In addition, a comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications and there were no performance or any other type of adverse conditions found with the pulse generator. Product analysis of the lead was completed on (b)(6) 2012. During the visual analysis the electrode coil appeared to be broken near the electrode bifurcation area. Scanning electron microscopy was performed and identified the area as being mechanically damaged with pitting which prevented identification of the coil fracture type. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. The coil showed characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.
 
Event Description
Additional information was received on (b)(6) 2012, when it was discovered that the vns patient was scheduled for a full revision surgery. The surgery took place on (b)(6) 2012. The leads were replaced due to high impedance, but the generator was replaced for prophylactic reasons. Attempts were made for the return of the explanted lead and generator but they have not yet been received.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2391601


Title: Re: Electrodes
Post by: dennis100 on August 30, 2017, 01:10:50 AM
Event Date 01/01/1999
Event Type  Injury   
Event Description
During manufacturer review of the published article "operative and technical complications of vagus nerve stimulator implantation, operative neurosurgery, december 2010, vol. 67, ons490; spuck, s, tronnier, v, orosz, i, schonweiller, r, sepehrnia, a, nowak, g, and sperner, j", it was identified that a patient had possible electrode migration which felt to be causing sternocleidomastoid muscle contractions. Replacement of the electrode resolved the issue. The time of the event is unknown, as the article was a retrospective review from 1999 through 2008. Attempts to the author for further information have been unsuccessful to date.
 
Manufacturer Narrative
Article citation:operative and technical complications of vagus nerve stimulator implantation, operative neurosurgery, december 2010, vol. 67, ons490; spuck, s, tronnier, v, orosz, i, schonweiller, r, sepehrnia, a, nowak, g, and sperner, j.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2360255


Title: Re: Electrodes
Post by: dennis100 on September 01, 2017, 01:33:19 AM
Model Number 300-30
Event Date 01/03/2012
Event Type  Malfunction   
Event Description
The explanted vns generator and lead have been returned from the hospital and are pending analysis.
 
Event Description
Manufacturer follow-up with the hospital revealed the explanted vns generator and lead had been discarded.
 
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
Reporter indicated the patient had vns lead and generator replacement surgery performed on (b)(6) 2012. An implant card was also received to the manufacturer on (b)(6) 2012, indicating the reason for the surgery was due to a lead discontinuity. Diagnostics with the new generator and lead were within normal limits. Attempts for return of the explanted lead and generator are in progress.
 
Event Description
Reporter indicated high lead impedance was obtained with vns diagnostics. The vns was not disabled at the patient's request. No patient adverse events were reported. Vns revision surgery is tentatively planned for (b)(6) 2012. X-rays were received and reviewed by the manufacturer. The negative lead pin appears to not be as fully inserted into the generator header as the positive pin, but the film angle prevents complete assessment. Due to poor film quality, it is unable to be assessed if the lead body is intact at the lead pins. The electrode site was able to be visualized. The electrodes appeared out of alignment, but this may be an anatomical variant. The electrodes are implanted in the correct orientation lower than what is usually seen; exact cervical location cannot be assessed due to film angle. Based on the x-ray review, the cause of the high lead impedance cannot be assessed but may be due to incomplete negative lead pin insertion or a lead fracture that is not visualized. No trauma or device manipulation occurred.
 
Event Description
Product analysis was completed on the returned vns generator and lead. Analysis of the generator did not identify any anomalies, and the generator performed per specifications. The setscrew marks found on the lead connector pins provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, with no discontinuities identified. Based on the findings in the product analysis lab, there is no evidence to suggest a discontinuity in the returned portion of the device. However, since a portion of the lead assembly (body) including the electrode array section was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2421285


Title: Re: Electrodes
Post by: dennis100 on September 08, 2017, 02:02:53 AM
Model Number 304-20
Device Problems Detachment of device component; High impedance
Event Date 10/21/2015
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported in october 2015 that the patient had been experiencing a sore throat, earaches and headaches since the suspect device was implanted 5 months prior. The issues had began when her physician had began to titrate her device settings. Due to the symptoms, then turned back on to lower settings in (b)(6) 2015. Device diagnostics were within normal limits at this time. In (b)(6) 2016, the patient again began to experience jaw pain, ear aches and headaches after her physician increased her settings. Device diagnostics were within normal limits, per the physician. Her output current was reduced. In (b)(6) 2017 the patient reported that she was still unable to increase vns settings due to tolerability issues. The physician indicated that the patient had had x-rays and the radiologist indicated that the patient's electrodes had moved in comparison to x-rays from (b)(6) 2015. The manufacturer reviewed the x--rays from (b)(6) 2017 and no obvious anomalies or lead discontinuities were found. The lead's strain relief was not per labeling. The physician's office indicated that the patient had high impedance in (b)(6) 2015. No further relevant information has been received to date. No known relevant surgical intervention has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6822969


Title: Re: Electrodes
Post by: dennis100 on September 08, 2017, 11:06:45 AM
Model Number 304-20
Device Problem No Known Device Problem
Event Date 07/17/2017
Event Type  Injury   
Event Description
It was reported that a vns patient who had previously had her generator and her lead except for the electrodes removed was experiencing pain and discomfort from her electrodes which remain in place and says that she has "lumps in her neck", indicating they were protruding. The patient is looking to have the remaining electrodes removed. Follow-up from the patient provided that she has subtle symptoms that some of her physicians have said may be related to vagus nerve damage. Additional relevant information has not been received to-date. No known surgery has occurred to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6786355


Title: Re: Electrodes
Post by: dennis100 on September 08, 2017, 11:07:40 AM
Model Number 304-20
Device Problem Mechanical issue
Event Date 07/07/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that during a full vns revision surgery that the surgeon did not like the way the lead manipulated when he was attempting to implant it. Therefore, a second lead was used in its place and implanted without issue. Follow up with the company representative revealed that the surgeon was unable to get one of the electrode coils wrapped around the nerve and asked for a second lead. A review of device history records was performed and revealed that the lead passed quality control inspection prior to distribution. The lead was received by the manufacturer and is pending product analysis. No additional data has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6766837


Title: Re: Electrodes
Post by: dennis100 on September 11, 2017, 03:50:33 AM
Model Number 302-20
Event Date 03/22/2012
Event Type  Malfunction   
Event Description
It was reported that the patient's vns indicated high lead impedance with dcdc=7 and eri=no on a normal mode diagnostics test. The device was not disabled as recommended in labeling when high impedance is found but the site indicated it does not plan to unless the patient begins experiencing an adverse event. Last good diagnostics were taken on (b)(6) 2011. No trauma or manipulation was noted. No adverse events have occurred at this time. Surgery to replace the patient's lead and generator is likely.
 
Event Description
Additional information was received indicating surgery to replace the patient's lead and generator has occurred. During the surgery, it was noted that the patient had grown considerably since the original implant surgery. The explanted lead and generator were returned and underwent analysis. An implant card and returned product form were received that both indicated that the reason for replacement was "lead discontinuity. " analysis of the generator found it performed to specifications. No anomalies were observed. The electrode portion of the lead was not returned. A discontinuity in the positive coil was observed in the region of the lead closest to the electrodes. Pitting was present at the site of the fracture. An abraded opening was observed in the outer tubing that allowed for the entry of body fluids.
 
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury. Type of report, corrected data: initial report inadvertently did not indicate "30-day. ".
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2548959


Title: Re: Electrodes
Post by: dennis100 on September 11, 2017, 03:51:27 AM
Model Number 302-20
Event Date 02/01/2012
Event Type  Malfunction   
Manufacturer Narrative
Device failure occurred. Type of report, corrected data: initial report inadvertently did not indicate "30-day. ".
 
Event Description
It was reported via implant card received that the patient's vns lead and generator had been replaced due to a lead discontinuity. A manufacturer representative present at the surgery indicated that the patient had been referred for surgery due to worsening seizures the month prior to replacement that were believed to be related to the vns. During surgery, the high impedance was found. No medication changes had been made prior to the increase. The physician had been unable to perform diagnostics prior to the surgery due to handheld computer issues as noted in manufacturer report # 1644487-2012-00923. Increased seizures had unknown relationship to pre-vns baseline seizure frequency. No x-rays were taken prior to surgery. The helices appeared to not be on the vagus nerve per the surgeon. Attempts for the return of the explanted lead and generator have been unsuccessful to date.
 
Event Description
Analysis of the lead has been completed. Only the negative electrode was not returned. A break in the negative coil was observed at 35. 1cm from the connector boot. Pitting was observed at the site of the break. An abraded opening in the inner and outer tubing was observed at the location of the lead fracture. Dried body fluids were observed inside the inner and outer tubing.
 
Event Description
The explanted lead and generator have been returned. Analysis of the generator found that it performed to specifications and no anomalies were found. The lead is still undergoing analysis.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2548966


Title: Re: Electrodes
Post by: dennis100 on September 13, 2017, 02:09:02 AM
Model Number 304-20
Event Date 08/01/2010
Event Type  Injury   
Event Description
Additional information was received from the physician indicating that the patient was explanted because she was a non-responder to therapy and was informed of the infection and electrode migration by the surgeon. No trauma or manipulation was believed to have occurred. The patient was reportedly able to feel when the vns was stimulating. The physician indicated that vns diagnostics were normal close to the time of removal however specifics were not provided. Follow-up with the surgeon's office found that approximately six weeks after the vns implant on (b)(6) 2010, the patient's vns electrodes began to extrude at the neck site. Surgery was performed to correct this however infections occurred intermittently requiring treatment with antibiotics. After battling infections for some time and no efficacy observed, the decision to explant the vns was made. At the time of surgery, drainage was noted at the neck site and a "pointing abscess" had developed at the generator site.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution. Date of event, corrected data: additional information received indicates date of event is earlier than previously indicated.
 
Manufacturer Narrative

Event Description
It was reported that the patient would be having her vns explanted because "it did not work for her. " additional information was received from the physician indicating that the patient's device became infected following surgery and was not improving the patient's seizure control. The patient's vns was removed since it did not appear to help the patient's seizures. During removal of the patient's vns, it was noted that the electrodes had migrated off of the vagus nerve per the neurologist. Further follow-up with the physician's office found that no trauma or manipulation was believed to have occurred. The infection was present at the electrode site and is believed to be related to vns surgery. Cultures taken on (b)(6) 2012 indicated (b)(6). No vns diagnostics were available upon request; however, the site indicated the patient was last programmed in (b)(6) 2011. Attempts for the return of the explanted lead and generator were unsuccessful as per hospital policy, all explants are discarded. Attempts for further information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2527430


Title: Re: Electrodes
Post by: dennis100 on September 30, 2017, 12:33:10 AM
Event Date 10/26/2012
Event Type  Malfunction   
Event Description
Additional information was received. Their device was disabled (b)(6) 2013. Further information was received indicating that it remained unknown whether trauma or manipulation were possible, as the patient does not speak.
 
Event Description
Reporter indicated high lead impedance was obtained for a patient with vns diagnostics testing on (b)(2012. The patient wears a corset, but it is not certain if this may have contributed to the high lead impedance. The reporter indicated the plan of care was to disable the vns. It is not known if any trauma or device manipulation occurred. X-rays were reviewed by the manufacturer. The lead pin insertion could not be assessed due to the film angle. The electrodes appeared to be placed in an abnormal arrangement, as the polarity is clearly reversed. No strain-relief or tie-downs were used. No acute angles or fractures could be found in the portions of the lead that could be fully assessed. Based on the x-ray review, a cause for the reported high impedance could not be found. Attempts for additional information are in progress.
 
Manufacturer Narrative
The previously submitted mdr inadvertently provided the wrong suspect device for the event.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
Further information was received indicating that the patient underwent a full replacement surgery on (b)(6) 2016. The lead was replaced due to lead fracture and the generator was prophylactically replaced. The patient's vns system was tested upon connection of the new lead to the new generator and system diagnostics returned impedance results within normal limits, with 1579 ohms. It was reported by the physician that the device was not replaced earlier because at that time, the patient, who has a handicap, was wearing a corset for scoliosis and that one was incriminated to be the origin of lead fracture. The explanted devices were not returned to the manufacturer for analysis to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2878861


Title: Re: Electrodes
Post by: dennis100 on October 06, 2017, 09:46:31 AM
Model Number 302-20
Device Problem High impedance
Event Date 08/02/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that the patient's device was showing high impedance before a prophylactic generator replacement. During the surgery, the lead was pulled from the old generator and reinserted to rule out a pin insertion issue. High impedance was still observed after reinserting the pin. The generator was explanted and generator diagnostics were performed to rule out a generator malfunction. The generator diagnostics were ok, so the surgeon went forward with the lead replacement. When the surgeon went to remove the lead, it was noted that there was a lot of scar tissue. The lead also appeared to be hanging off the nerve by only the top electrode. The lead and generator were replaced. Further information was received from the physician that high impedance had been observed at a clinic visit prior to the referral for generator replacement and the high impedance was thought to have been caused by a lower battery. The products have not been received by the manufacturer to date. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6851648


Title: Re: Electrodes
Post by: dennis100 on October 18, 2017, 12:45:49 AM
Event Date 01/24/2012
Event Type Injury
Manufacturer Narrative

Event Description
It was reported that the patient has been experiencing pain at the electrode site since 2012. It was reported that the device was programmed off; however, the pain has not subsided. The physician indicated that the patient may undergo vns system explant in (b)(6) 2013. Attempts to obtain additional information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3292289


Title: Re: Electrodes
Post by: dennis100 on October 25, 2017, 01:35:22 AM
Model Number 103
Event Date 12/12/2012
Event Type Malfunction
Event Description
The patient underwent generator and lead replacement on (b)(6) 2014. It was reported that the generator was replaced prophylactically and that the high impedance was likely attributed to the lead pin not being fully inserted into the generator header. The generator and lead were returned for analysis. Analysis of the lead was completed on 05/06/2014. During the visual analysis a half set of setscrew marks was found at the end of the connector pin, indicating the connector pin had not been fully inserted into the cavity of the pulse generator at one time. The marks are evidence of a potentially insufficient mechanical contact between conductive surfaces of the generator and connector ring, resulting in a suspect electrical connection to the lead. However, based on the location of the setscrew marks on the pin, it is unknown whether a good electrical connection was present for the connector ring. During the visual analysis what appeared to be pitting was observed on the surface of the connector ring. Scanning electron microscopy was performed and identified evidence of pitting on the surface of the connector ring. Eds (energy dispersion spectroscopy - provides chemical or element identity/composition analysis) was performed on the connector ring pit deposit and identified the area as consisting of silicon, potassium, chromium, iron, nickel, sodium, manganese, fluorine and molybdenum. A definite cause for the pitting could not be determined based on the lead portion returned. However, a review of the patient x-rays' issue file correspondence suggest the electrodes may not have been attached to the nerve as intended. Other than observed pitting on the connector ring surface, no other obvious anomalies were noted except for the half set of setscrew marks found at the end of the connector pin indicating the lead had not been fully inserted into the cavity of the generator. The additional setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, and no discontinuities were identified. There is no evidence to suggest a discontinuity in the returned portion of the device which may have contributed to the stated allegations of 'hgh impedance'. Note that since a portion of the lead assembly including the electrode array section was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Analysis of the generator is underway, but has not been completed to date. N.

Event Description
Analysis of the generator was completed on (b)(6) 2014. Electrical test results showed that the pulse generator performed according to functional specification. Visual inspection results revealed no external device abnormalities. There were no adverse functional, mechanical, or visual issues identified with the returned generator.

Event Description
A review of programming and diagnostic data was performed which identified a high impedance event. The high impedance was observed on (b)(6) 2012. Follow up with the nurse found that the high impedance was observed the same day the patient's generator was being replaced due to a depleted battery. The lead was not replaced. The patient was implanted with a new generator and diagnostics were all fine. Additional information from the physician found that the high impedance was initially seen as 10,000 ohms. Diagnostics two weeks after surgery showed an impedance value of 5,000 ohms, and then 10,000 ohms months later. The physician stated that before the high impedance was observed, the patient did fall. It was confirmed that the high impedance was initially observed during surgery. Ap and lateral chest and neck x-rays were taken and sent to the manufacturer for review. The generator was seen in the left chest. The filter feedthru wires were intact. The connector pin inside the connector block does not appear to be completely inserted. The lead wire was intact at the location of the connector pin. There did not appear to be any lead discontinuities or sharp bends, however there was a portion of the lead located behind the generator that could not be assessed. The electrode placement was not done as per labeling as the electrode placement is inverted. There appeared to be no propper strain relief bend or loop per labeling. There were two tie downs present, but they did not appear to be placed per labeling to secure the strain relief bend. No additional information has been provided.

Manufacturer Narrative
New information received corrects the suspect device.

Event Description
The physician reported that he may not refer the patient for replacement and may just leave the device off; however, the plan was unclear. It was later reported that the surgeon reported that he would correct the patient's lead and that the generator would be replaced also if need be. Surgery is planned, but has not occurred to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Device manufacturing records and programming history were reviewed. Review of manufacturing records confirmed the device met all final testing specifications prior to distribution. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized; however, lead pin not fully inserted past the connector block. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3589007


Title: Re: Electrodes
Post by: dennis100 on October 26, 2017, 12:31:14 AM
Model Number 102
Event Date 02/12/2004
Event Type Injury
Event Description
It was reported that the vns patient was re-implanted with a generator and lead on (b)(6) 2014. The patient was initially implanted with a generator and lead in 2004; however, the devices were explanted three months post-implant due to infection at an implant site and a broken electrode on the lead (lead fracture reported on medwatch report # 1644487-2014-00543). A review of programming and diagnostic history for the device revealed no diagnostic test results. Attempts for additional information are in progress.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution.

Event Description
Additional information was received indicating that the device was removed before switching it on. It was reported that the patient underwent surgery on (b)(6) 2014 to have a new vns system (generator and lead) implanted. Review of manufacturing records confirmed that both, the generator and the lead passed all functional tests prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3651755


Title: Re: Electrodes
Post by: dennis100 on November 03, 2017, 02:48:08 AM
Model Number 105
Event Date 07/22/2014
Event Type Malfunction
Event Description
Follow-up revealed that the patient was experiencing a ¿pinching¿ sensation across her chest and down her left side during stimulation on-times. The patient¿s device frequency and pulse width were decreased from 30hz to 20hz and from 500usec to 250usec, respectively. The patient¿s symptoms subsequently improved. The patient reportedly continued to have pain in her chest, but the physician indicated that the pain was not related to vns.

Manufacturer Narrative

Event Description
It was reported that the recently implanted vns patient¿s device was tested during an office visit on (b)(6) 2014 and system diagnostic results revealed high impedance (impedance value - 7503 ohms). The patient¿s device was tested a second time and the device continued to show high impedance. The neurologist had the patient¿s device programmed on during the office visit. Diagnostic results from the implant procedure showed lead impedance within normal limits. X-rays dated (b)(6) 2014 were provided to the manufacturer for further review. The generator appears in the left chest in a normal placement. The filter feed-through wires appear to be intact. The lead connector pin does not appear fully inserted into the generator connector block. The electrodes appear to be aligned at a steep angle away from the nerve, nearly perpendicular to the nerve. Part of the lead was behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. Based on the images provided, the cause of the high lead impedance is likely due to incomplete lead pin insertion. The patient experienced a seizure cluster so she swiped her magnet. Immediately, she began feeling intense chest pain and went to the er. The patient was hospitalized overnight. No known surgical interventions have occurred to date.

Manufacturer Narrative
Corrected data: the initial manufacturer report inadvertently did not include that the patient device had been disabled.

Event Description
Follow-up revealed that the patient铠device was disabled. Additional information was received indicating that the vns patient's medications were increased and the patient had gone to the er on two occasions to received iv anti-epileptic medications. The patient's seizure frequency was back to pre-vns baseline levels (2-3 small seizures per week). The patient's seizure cluster is not believed to be due to vns. Prior to the seizure cluster, the patient was given a new medication. After the seizure cluster, the patient was taken off the medication but it is unknown if this medication was the source of the seizure cluster. It was noted that the patient had poor seizure control prior to implant surgery. The patient underwent surgery on (b)(6) 2014. Pre-operative system diagnostic results showed high impedance (impedance value - 7076 ohms). The surgeon noted that the lead pin was not fully inserted into the generator header. The patient's lead pin was reinserted and multiple diagnostic results showed lead impedance within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4013657


Title: Re: Electrodes
Post by: dennis100 on November 11, 2017, 02:22:53 AM
Model Number 304-20
Device Problem Mechanical issue
Event Date 08/31/2017
Event Type Malfunction
Event Description
It was reported that the surgeon opened a lead package for a new patient implant and was concerned about the way the lead coils looked. The surgeon thought something was wrong with the lead coil and felt the lead coils were fractured in the package and thus did not use it. A different lead was successfully used for the surgery. A review of device history records for the lead shows that no unresolved non-conformances were found. Analysis is underway but has not been completed to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6922020


Title: Re: Electrodes
Post by: dennis100 on November 11, 2017, 02:23:44 AM
Model Number 303-20
Device Problem High impedance
Event Date 10/04/2017
Event Type Malfunction
Event Description
Report received that a patient's vns was interrogated and a system diagnostic was run which showed high impedance. The patient reportedly did not have any adverse events associated with the high impedance. The patient reportedly had a generator replacement about 11 months prior to the high impedance being present. X-rays were taken and returned to the manufacturer for analysis. The complete insertion of the connector pin into the connector block could not be accurately assessed because of the quality and angle of the image. The feedthru wires appeared fully intact. There appeared to be a strain relief bend present secured by two tie-downs. However, there was no strain relief loop present. A lead fracture was not identified in the image. The lead wire did appear to be fully connected at the connector pin. The electrodes appeared to be placed adjacent to one another instead of vertically. A review of the programing history did not indicate whether high impedance was present prior to this finding. There was reportedly no trauma that would have caused the high impedance. Surgical intervention has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6988483


Title: Re: Electrodes
Post by: dennis100 on November 14, 2017, 02:05:35 AM
Model Number 102
Event Date 03/06/2015
Event Type Malfunction
Event Description
It was reported that the vns patient believed his lead had migrated and was concerned that his device was not functioning. X-rays were provided to the manufacturer for review. The generator appears in the left chest in a normal placement. The filter feed-through wires appear to be intact. The lead connector pin appears fully inserted into the generator connector block. Part of the lead was behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. It was noted that the electrodes appear to be placed low on the nerve superior to the clavicle plane. Attempts for additional relevant information have been unsuccessful to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by manufacturer, no gross lead discontinuities visualized.

Event Description
Additional information was received that the medical professional does indeed believe the electrodes have migrated inferiorly down the patient's vagus nerve, although diagnostics were reported to still be within normal limits for this patient. The patient was concerned the device was not functioning because he could no longer feel stimulation, which the medical professional attributes to the patient's acclimation to the vns settings. Furthermore, it was reported that the patient's job requires constant bending down and stretching of the neck. The medical professional believes this stretching may have caused the lead to pull the electrodes down along the vagus nerve. A battery life calculation using the available programming history showed approximately 4. 4 years left until battery depletion. No known surgical interventions have occurred to date.

Manufacturer Narrative
Review of the available programming history was performed.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4640549


Title: Re: Electrodes
Post by: dennis100 on November 18, 2017, 02:41:06 AM
Model Number 105
Device Problem Battery issue
Event Date 05/11/2015
Event Type Injury
Event Description
The infection was believed to have cleared so the patient was taken off antibiotics. After a week post-explant, the patient presented with pus and blood at the neck incision site. The patient was placed back on antibiotics and was admitted to the hospital on (b)(6) 2015. While in the hospital, the patient was told that the "remaining coil" was infected. The patient was released on (b)(6) 2015. The patient has not been re-implanted to date.

Manufacturer Narrative
Device manufacturing records were reviewed. Review of the device history records confirmed sterilization was performed prior to distribution for the generator and lead.

Manufacturer Narrative
"it was reported that the patient had a dime-sized hole exposing the generator as well as infection at the leads. " this information was inadvertently left off of supplemental mfr. Report #01.

Event Description
The patient reported that she had developed an infection at the generator site, confirmed by her primary care physician. The patient had generator replacement surgery on (b)(6) 2015. The patient noted that it has been swollen since just shortly after implant and the primary care physician was concerned that it was (b)(6). The patient was given an antibiotics shot and prescribed a 28-day regiment of antibiotics. The surgeon's office was aware of the infection. The surgeon reported seeing the patient a week prior and showed no signs of infection at that time.

Event Description
Additional information was received from the patient stating that her incision was ¿getting larger and a large blister formed. ¿ follow-up with the surgeon¿s office revealed that the patient was seen on (b)(6) 2015. The incision site was still infected and discharge was noted. The patient later reported that the infection reportedly cleared but reoccurred. The physician stated that the lead electrodes needed to be removed from the nerve to clear the infection. No known surgical interventions have occurred to date.

Event Description
It was reported that the explanted lead was not available for return. Sterilization records for the explanted lead and generator were performed and were found to be sterile upon release for sale.

Event Description
It was reported that the patient had a dime-sized hole exposing the generator as well as infection at the leads. The patient reported that the infection was (b)(6).

Event Description
The physician reported that the incision did not heal correctly. The patient reported that pathology identified infected material and "bugs" in the lead. The patient reported that the physician plans to reimplant another vns system in approximately six months.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4782349


Title: Re: Electrodes
Post by: dennis100 on December 08, 2017, 11:24:57 PM
Model Number 302-20
Device Problem High impedance
Event Date 10/06/2017
Event Type Malfunction
Event Description
It was reported that the patient fell due to a seizure. The patient was then evaluated by the physician and it was noted that the electrodes were projecting in the soft tissue of the patient's neck. The physician requested that the company representative come and perform diagnostic testing to check the device. X-rays were then taken and sent to the manufacturer to be reviewed for a potential lead fracture. No obvious lead fractures were observed and it appeared that the connector pin was fully inserted into the generator. However the presence of a micro-fracture cannot be ruled out. It was unclear why the physician suspected there was an issue with the lead as diagnostic results had not been reported. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7012443


Title: Re: Electrodes
Post by: dennis100 on December 09, 2017, 01:36:45 AM
Model Number 106
Device Problem No Known Device Problem
Event Date 07/19/2017
Event Type Injury
Manufacturer Narrative

Event Description
It was reported that a vns patient developed an infection at the implant site after the device was turned on. The device was turned off and the generator was relocated and the patient was treated with antibiotics. On (b)(6) 2017 the device was turned on again. It was provided there is evidence of a form of keloid, and the electrodes appear exposed. Washing and antibiotics were prescribed. The patient was hospitalized and treated with antibiotics and was receiving continuous washing at the electrode. Review of the manufacturing records for the lead and generator confirmed the devices were sterilized prior to distribution. Additional relevant information has not been received to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6996660


Title: Re: Electrodes
Post by: dennis100 on December 10, 2017, 01:43:27 AM
Model Number 304-20
Event Date 01/22/2016
Event Type Malfunction
Event Description
It was reported that during replacement surgery on (b)(6) 2016, the surgeon noted that the negative helix on the replacement lead was deformed and could not be placed on the patient's nerve. A backup lead was used for the procedure. A company representative who attended the procedure did not observe any anomalies in the handling of the suspect lead prior to the procedure; the surgeon reported his visual observation quickly after opening the lead packaging. Review of manufacturing records confirmed that the lead passed all functional tests and quality inspection criteria prior to distribution. The suspect lead has been returned to the manufacturer where analysis is currently underway.

Event Description
Analysis of the unused lead was completed and it was found that the positive electrode was stretched and the helical was misshaped. The negative electrode presented an electrode ribbon that was stretched and partially detached from the helical and the helical was misshapen. The observations were attributed to manipulation of the lead during the attempts to implant the lead. The observation of dried bodily fluids on the helices did reveal that there was actually an attempt to implant the lead.

Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5466264


Title: Re: Electrodes
Post by: dennis100 on December 10, 2017, 01:44:25 AM
Model Number 106
Event Date 02/02/2016
Event Type Malfunction
Event Description
Information was received that patient underwent surgical intervention on (b)(6) 2016. After checking the lead connector pin, it was observed that the pin was not inserted properly into the generator. Once the lead was connected correctly, lead impedance value was confirmed to be within normal limits.

Event Description
On (b)(6) 2016, an email was received from a patient school staff reporting that "the vns stopped working and has only recently been repaired. " further clarification was received from staff member that one of the internal wires of the vns became detached and needed to be repaired under general anesthesia. The nurse was contacted for further clarification reported that she expects they mean that they were not using her magnet before and now they can. Nurse stated that she last reviewed patient on (b)(6) 2016 and interrogation is satisfactory, lead impedance was 3165 ohms.

Event Description
It was reported that vns patient had high lead impedance found during a follow up visit on (b)(6) 2015; the impedance value was 5590 ohms. It was reported that the last good lead impedance result was obtained on (b)(6) 2016 and the impedance value was 3196 ohms. It was reported that the vns system was switched off due to high impedance. It was reported that patient felt during a seizure two weeks prior to the visit. No patient discomfort upon stimulation is reported. X-rays dated (b)(6) 2014 were provided to the manufacturer for further review. The generator appears in the left chest in a normal placement. The filter feed-through wires appear to be intact. The lead connector pin appears fully inserted into the generator connector block. Part of the lead was behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. From the images, assuming where the anchor tether will be located then the vagus nerve is not in a straight line, including the lack of strain relief it means the electrodes are more than likely being pulled from the nerve, this in turn can allow fibrosis to move in underneath the electrode. It was reported that patient was seen again on (b)(6) 2016, the lead impedance was 6031 ohms. Additional information received that the nurse switched device back on to the settings of 0. 5ma as set previously, not further ramp up of the device. Nurse swiped with magnet to review patient's response and no discomfort was noted; patient showed signs of device activating with exaggerated swallow but this did not cause any pain. It was reported that patient will be seen for follow up in (b)(6) 2016. No known surgical interventions have occurred to date. Review of manufacturing records confirmed all tests passed for the lead prior to distribution.

Manufacturer Narrative
(b)(4).

Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5462603


Title: Re: Electrodes
Post by: dennis100 on January 06, 2018, 03:25:54 AM
Model Number 304-20
Device Problem Fracture
Event Date 11/30/2017
Event Type Malfunction
Event Description
It was reported that this patient was going in for a generator replacement due to battery depletion, and high impedance was found during pre-op. The patient was taken in for a full lead revision, and the original lead electrodes were so scarred down that they could not be removed safely. The new lead could not be implanted on the left side due to the fibrosis, and therefore the new generator and lead were implanted on the right side. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7120774


Title: Re: Electrodes
Post by: dennis100 on January 07, 2018, 03:24:52 AM
Model Number 302-30
Device Problem High impedance
Event Date 09/26/2017
Event Type Malfunction
Manufacturer Narrative

Event Description
During generator replacement surgery due to battery end-of-service, the new generator was placed and high impedance was detected after several diagnostics tests. Generator diagnostics were then performed and the generator read okay impedance. Lead pin re-insertion was tried and was fully inserted and tightened. The surgeon then clipped the leads and checked the leads but didn't notice any fracture. He noted that the electrodes may have been loose on the nerve. The surgeon then implanted a new lead. The site disposed of the old generator and lead. Additional relevant information has not been received to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7077935


Title: Re: Electrodes
Post by: dennis100 on January 10, 2018, 01:56:20 AM
Model Number 103
Event Date 04/09/2009
Event Type Injury
Event Description
Initial reporter indicated to a manufacturing consultant that their pt had their vns explanted related to severe infection. Significant scarring had formed around electrode placement. The pt's infection was first noted in 2009. No pt trauma or manipulation of their vns site was reported prior to the pt's infection. The pt had antibiotics administered prior to having their vns explanted. The pt had their vns lead and generator explanted and the products are at manufacture pending completion of product analysis. A staph infection was reported in the generator and lead sites.

Manufacturer Narrative
Device manufacturing records were reviewed. Results - review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1402167


Title: Re: Electrodes
Post by: dennis100 on January 11, 2018, 01:58:55 AM
Model Number 302-20
Event Date 08/08/2014
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death.

Event Description
It was reported that the vns patient was having issues with pain and with device migration. Clinic notes were received indicating that the patient had severe fatigue and tremors over the last two months. She later reported having a strange tremor in her head that occurred several times per day. It was noted that patient¿s device had migrated from its original position and was located at the wall of the axilla. Chest and neck x-rays were ordered because the patient reported occasional shocking sensations to the left side of the neck. The patient was instructed to temporarily disable her device with the magnet to determine whether her symptoms would subside. An implant card was received indicating that the patient underwent generator and lead replacement surgery due painful stimulation, shocking sensations and lead discontinuity. The patient¿s lead reportedly fell off the patient¿s vagus nerve and caused high impedance. The explanted generator and lead have not been returned to date. Attempts for additional relevant information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4103125


Title: Re: Electrodes
Post by: dennis100 on January 27, 2018, 02:05:25 AM
Model Number 302-20
Event Date 09/27/2010
Event Type Malfunction
Event Description
It was reported that a surgeon saw a kink on the pt's electrode along with severe adhesion to the vagus nerve during the surgery on (b)(6) 2010, and decided to replace the lead as well as generator. Follow-up with the surgeon revealed that fibrosis can happen even in normal tissue and he did not visualize a lead fracture while doing surgery, only a lead kink. Good faith attempts to obtain the explanted products have been unsuccessful to date.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1885049


Title: Re: Electrodes
Post by: dennis100 on February 02, 2018, 02:22:32 AM
Model Number 304-20
Device Problem Mechanical issue
Event Date 12/21/2016
Event Type Malfunction
Event Description
It was reported that in an initial implant case, the second electrode of the lead appeared to be bent and have a metallic "foil-looking substance" wrapped around it. The issue was immediately discovered as the implanting surgeon was attempting to wrap the electrode around the vagus nerve. The implanting and attending surgeons observed that it appeared the lead had ¿extra coiling. ¿ by their account, there was apparently extra material, as if it was thicker than normal. The lead device history record was reviewed and found that all specifications were met prior to distribution. The lead was not implanted and was returned to the manufacturer. Product analysis on the lead is underway.

Manufacturer Narrative

Event Description
Product analysis for the returned lead was completed. The closest electrode to the bifurcation was damaged, showing bends on the electrode ribbon and partial detachment from the silicone helix. This silicone helix also exhibits what appear to be tool imprints. The most likely reason for the observed damaged to the closest electrode was manipulation of the lead not consistent with vns labeling. The measured dimensions were within the specified tolerances. Resistance values were within tolerances and exhibited no evidence of discontinuities. Other than the above mentioned observations and typical conditions that exist after a surgical procedure, no anomalies were identified in the returned lead.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6252939


Title: Re: Electrodes
Post by: dennis100 on February 06, 2018, 01:49:56 AM
Model Number 304-20
Event Date 05/17/2011
Event Type Malfunction
Event Description
It was reported that the vns lead coils of the 2. 00mm were too small and could not fit around the nerve after multiple attempts and system diagnostic tests showed high impedance. The vns lead was returned to the mfr for analysis. The pt was implanted with another lead that was later found to be a 3. 00mm lead. It is currently unk if the lead did not perform as intended or if the surgeon failed to measure the lead prior to selecting a lead size. Attempts for further info have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2139274


Title: Re: Electrodes
Post by: dennis100 on February 09, 2018, 02:51:14 AM
Model Number 302-20
Device Problem High impedance
Event Date 01/05/2018
Event Type Malfunction
Manufacturer Narrative

Event Description
It was reported that high impedance was observed during interrogation of the patient's vns. X-ray images were reviewed by the medical professional and it was stated that the bottom electrode may not be placed properly on the vagus nerve. The new vns generator was connected to the lead and the high impedance did not resolve. It was reported that while dissecting down to the nerve, a large pocket of pus was found surrounding the vagus nerve and vns electrodes. The surgeon believed this was likely the cause of the high impedance. The pus was removed along with the vns lead and electrodes. The new vns lead diagnostics were within normal limits. A review of device history records revealed that the generator and lead were sterilized and passed quality control inspection prior to distribution. During attempts at product return, it was revealed that the facility discarded the explanted products. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7231151


Title: Re: Electrodes
Post by: dennis100 on February 09, 2018, 11:14:34 AM
Model Number 300-20
Device Problems Detachment of device component; No code available
Event Date 12/12/2017
Event Type Malfunction
Event Description
During a patient's prophylactic, full revision surgery, the positive and anchor electrodes were found to be detached from the vagus nerve and covered in scar tissue. Also, inadequate strain relief was found to have been provided by the original implanting surgeon. System diagnostics were performed before the revision surgery and indicated the device was functioning normally. Also, the patient's neurologist stated that no physical trauma or manipulation had occurred that may have caused the detachment. The lead has been returned and analysis is underway. No additional or relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7168033


Title: Re: Electrodes
Post by: dennis100 on February 17, 2018, 04:32:01 AM
Model Number 304-20
Event Date 11/22/2011
Event Type Malfunction
Event Description
It was reported on (b)(6) 2011 that a patient was in for an initial implant and during implant, high lead impedance readings were obtained when systems diagnostics were performed. The diagnostics were performed twice and both resulted in high lead impedance. The surgeon backed out the setscrew and connected the generator to the test resistor to perform generator diagnostics which resulted in ok/ok/4000 ohms/ifi no. The lead pin was re-inserted and confirmed to be fully inserted past the connector blocks. The setscrew was tightened back and systems diagnostics were performed again which resulted in limit/high/10,000 ohms/ifi=no. The surgeon then replaced the lead and diagnostics were repeated which gave acceptable results (specific results not provided). The explanted lead has been returned to the manufacturer and is currently pending product analysis.

Manufacturer Narrative

Event Description
Product analysis has been completed on the returned lead. The entire lead was returned to the manufacturer. During the analysis, a cut was identified in the positive coil at the end of the electrode bifurcation. Based on the appearance of the lead, it is believed that this condition occurred during the attempted implant procedure. Other than the above mentioned observations and conditions that exist after manipulation and attempted implant of the lead, no additional anomalies were identified in the returned lead.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2381294


Title: Re: Electrodes
Post by: dennis100 on February 28, 2018, 02:03:37 AM
Model Number 302-20
Event Date 05/14/2014
Event Type Malfunction
Event Description
It was reported that the vns patient¿s device was tested during an office visit on (b)(6) 2014 and diagnostic results showed high lead impedance (dc dc ¿ 7). The patient¿s device settings were increased during the office visit. Patient manipulation or trauma is not believed to have caused or contributed to the high impedance. X-rays dated (b)(6) 2014 were provided to the manufacturer for further review. The generator appears in the left chest in a normal placement. The filter feed-through wires appear to be intact. The lead connector pin appears fully inserted into the generator connector block. The electrodes appeared to be placed in an abnormal arrangement. The second electrode appears to either be placed upside down or possibly has come off the nerve. Part of the lead was behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. Based on the images provided, the cause of the high lead impedance may be due to detachment of the second electrode but no definitive conclusions can be made. Further follow-up revealed that the patient¿s device had been disabled and the patient still had good seizure control. Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2011. No known surgical interventions have occurred to date.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Device manufacturing records and available programming and diagnostic history were reviewed. X-rays reviewed by manufacturer, no gross lead discontinuities visualized. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3857029


Title: Re: Electrodes
Post by: dennis100 on March 04, 2018, 01:24:37 AM
Model Number 302-20
Event Date 07/29/2011
Event Type Malfunction
Manufacturer Narrative
Date of event, corrected data: the correct event date for the high lead impedance is provided. Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
Reporter indicated the painful stimulation was felt to be related to a "short-circuit" of the vns. X-rays were taken but were not forwarded to the manufacturer. The high lead impedance was first noted on (b)(6) 2011, and the patient had reported feeling electrical shock sensations in her neck when turning her head to the left for the previous month. Vns diagnostics were last within normal limits in (b)(6) 2010. Analysis of the explanted vns generator and lead was completed. No anomalies were identified with the vns generator and the generator performed per specifications. During the lead visual analysis of the returned 35mm lead portion, the green (-) electrode quadfilar coil appeared to be broken approximately 12mm from the distal end of the anchor tether. Scanning electron microscopy was performed and identified the area as being mechanically damaged and pitted which prevented identification of the coil fracture type. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.

Manufacturer Narrative
Device failure is suspected.

Event Description
Reporter indicated a patient was noted to have high lead impedance with vns diagnostics in (b)(6) 2011. The patient was also experiencing painful vns stimulation in her shoulder. The vns was disabled, but no other interventions were done as the patient was pregnant at the time. The patient does have a history of falling with her seizures. The patient delivered her baby in (b)(6) 2012 and surgical replacement of the vns lead and generator occurred on (b)(6) 2012. Diagnostics with the new generator and resident lead still indicated high lead impedance, ruling out a lead pin issue and making a lead fracture more likely. Diagnostics with the new lead and new generator were within normal limits. However, during explant of the resident lead, the jugular vein was nicked which required a vascular surgeon to assist with the repair. The new vns system was left disabled. The explanted generator and lead have been returned and are pending analysis. Attempts for further information are in progress.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2513252


Title: Re: Electrodes
Post by: dennis100 on March 05, 2018, 02:18:36 AM
Model Number 302-20
Event Date 04/02/2012
Event Type Malfunction
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.

Event Description
On (b)(6) 2012, a vns implanting surgeon's nurse stated that the vns patient had their leads replaced on (b)(6) 2012, due to the surgeon observing electrode damage when replacing the generator due to end of service. When the new generator had been implanted, diagnostics performed showed high impedance and the electrodes appeared to be damaged; therefore the leads were replaced. The explanted lead and generator were returned to the manufacturer for product analysis on (b)(6) 2012, that has not yet been completed. The surgeon later reported that the generator had been at end of service so the lead impedance could not be tested prior to surgery. Surgery was the first time the high impedance we observed. The surgeon was unsure if x-rays were taken prior to surgery or if patient manipulation or trauma occurred that is believed to have caused or contributed to the high impedance. A battery life calculation was performed with the patient's programming history which showed negative years until the elective replacement indicator is flagged as yes.

Event Description
Additional information was received on (b)(6) 2012, when product analysis was completed on the explanted generator. The generator was found to be at end of service and was determined to be the result of normal battery depletion. The depletion was an expected event as determined by battery life calculation and battery voltage measurement. The module performed according to functional specifications and there was no condition noted during the product analysis evaluation that would suggest any anomaly with the device. Product analysis on the lead was completed on (b)(6) 2012. The electrodes were not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis a lead break was observed. Scanning electron microscopy was performed and identified the areas as having evidence of being worn to the point of fracture with flat spots on the coil surface, no pitting and residual material. It is unknown if the breaks occurred while stimulation was present due to the absence of metal pitting on the broken coil wire surfaces. The abraded openings found on the outer silicone tubing, most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the outer silicone tubing. The abraded opening found on the connector ring inner silicone tubing, most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the inner silicone tubing. There was no obvious path found for the fluid ingress observed inside the connector pin inner silicone tubing. With the exception of the observed discontinuity, the condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, and no other discontinuities were identified.

Manufacturer Narrative
(b)(4).

Manufacturer Narrative
Analysis of programming history. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2572452


Title: Re: Electrodes
Post by: dennis100 on March 08, 2018, 09:42:10 AM
Event Date 06/03/2011
Event Type Injury
Event Description
It was reported that the vns patient has been experiencing "vocal cord issues" since implant. The patient was seen by an ent physician who indicated that he believes the lead was implanted too close to the vocal cords. It was also noted that the patient has not seen much efficacy since implant. The patient was reportedly going to see the implanting surgeon for further evaluation however the surgeon's office indicated that the patient has not been seen or made an appointment. Attempts for further information from the neurologist's office have been unsuccessful to date. Attempts for the product information were unsuccessful.

Event Description
Additional information was received indicating the patient's vocal cord issue has resolved.

Event Description
On (b)(6) 2012, additional information was received indicated that the patient had hoarseness and awakening at night with vns stimulation noted in (b)(6) 2011. It was confirmed that vocal cord issues were related to electrodes being placed too close to the larynx. No hoarseness was noted (b)(6) 2011. On (b)(6) 2011, the hoarseness was intermittent but then constant on in (b)(6) 2011. A note indicated the hoarseness appeared to have resolved following the thyroidectomy. The thyroid issues were not believed to be related to vns.

Manufacturer Narrative

Manufacturer Narrative
Type of report, corrected data: initial report inadvertently did not indicate "30-day. ".

Manufacturer Narrative
Event date, corrected data: previously submitted mdr indicated an incorrect event date. The patient's physician believes that the vocal cord issues are related to the electrodes being placed too close to the larynx at the time of implant; therefore, the event date is the date of implant: (b)(6) 2011. This report is being submitted to correct this data.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2603575


Title: Re: Electrodes
Post by: dennis100 on March 12, 2018, 01:27:02 AM
Device Problem Fracture
Event Date 02/07/2012
Event Type Malfunction
Event Description
Additional information was received on (b)(6) 2012, when product analysis was completed on the explanted generator. Bench interrogation/diagnostic test showed that the nearing end-of-service indictor (neos) was set to yes. Results of the bench diagnostic testing indicated the device was operating properly with neos yes. The data in the memory locations revealed that 100. 148% of the battery had been consumed. A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications, with the exception of the expected low battery voltage. The battery voltage value stored within the generator, 2. 171 volts, suggests an neos battery partially depleted condition. The electrical test results showed that the pulse generator module performed according to functional specifications. However, the measured 2. 285 battery voltage (generator module post open can) is lower than expected for the percentage of battery consumed value of 100. 148%. Further review revealed that the explanted generator was returned with the output current programmed to 3. 00 ma. The data from the generator shows a high impedance (22183 ohms) estimated occurrence on (b)(6) 2012 (explant (b)(6) 2012) and remained until received into decontamination on (b)(6) 2012 (generator output current programmed to 0. 0ma). The combination of a high impedance value and output current setting required a "vboost" compliance voltage that exceed the maximum compliance voltage capability for the device (>10. 5 v). Longevity estimates are not guaranteed at compliance voltages greater than 10. 5v. In this situation a significant amount of additional current consumption exists, based on the need for a component to remain on (asic remains in a trickle charge state) in order to support the higher electrical load demand. This condition contributes to the disparity between the battery voltage and percent battery capacity that has been consumed, based on the device's internal eos projection system. Other than the noted error, there were no performance or any other type of adverse conditions found with the pulse generator.

Event Description
On (b)(6), 2012 it was discovered that the vns patient also underwent prophylactic generator replacement on (b)(6), 2012. The explanted generator was returned for product analysis on (b)(6), 2012 but the leads were not returned. Product analysis is still underway and has not yet been completed.

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
On (b)(6) 2015 during review of the patient's programming history it was found that the patient has had high impedance since the generator was implanted on (b)(6) 2012. There was programming history through (b)(6) 2012 indicating that the generator was not replaced on (b)(6) 2012 like previously reported. It was also reported that the patient's current generator was implanted on (b)(6) 2012. The patient currently has high impedance; therefore it is unclear if the patient did in fact have a lead replacement on (b)(6) 2012 as planned since there was no confirmation indicating that the lead was replaced. Good faith attempts for further information regarding whether the patient did have a lead revision on (b)(6) 2012 were made but were unsuccessful.

Event Description
On (b)(6) 2012 a nurse reported that the vns patient was scheduled for a chest and neck x-ray tomorrow as the neurologist thinks there may be an issue with lead breakage or lead not functioning properly. She stated that a copy of the x-rays would be sent to the manufacturer for review. Attempts for further information have been made but no additional information has been received from the physician. The manufacturer's consultant stated that the epileptologists are not forthcoming with information due to hippa. The patient's implanted product information has been requested from the implanting hospital, but the hospital stated that they would not provide that information without patient consent or attorney request. Since the manufacturer does not have either of these, the product information cannot be obtained. A/p and lateral views of the neck and chest were received and reviewed on (b)(6) 2012. Due to x-ray films provided, it could not be confirmed that the lead pin is fully inserted into the generator connector block. There appeared to be lead behind the generator, so continuity in that portion of the lead could not be fully assessed. No lead discontinuities were seen in the visible portions of the lead. The electrodes could be visualized in the neck, but they appeared to be at an angle to one another. Based on the images provided and given the angle of the electrodes, proper alignment of the electrodes on the nerve could not be confirmed. However, it is noted that there are two previous sets of electrodes present that do not appear to be parallel in relation to the current electrodes. Therefore, the angle of the electrodes may be due to the patient's anatomy, and the electrodes may in fact be placed on the nerve. Based on the x-ray film images provided, no clear cause for the high lead impedance could be found, however it is possible that the lead pin is not fully inserted, there is an unpronounced break in the lead, or a micro-fracture that cannot be seen on the x-ray films provided. In addition, improper alignment of the electrode(s) could not be ruled out as a contributory cause. The patient underwent lead revision surgery on (b)(6) 2012. Attempts for product return will be made.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2638515


Title: Re: Electrodes
Post by: dennis100 on March 12, 2018, 01:29:47 AM
Event Date 08/22/2011
Event Type Malfunction
Manufacturer Narrative
Device failure is suspected but did not cause or contribute to a death or serious injury.

Event Description
During the periodic programming history review, it was noted that high impedance was observed on (b)(6) 2011. No further diagnostics are available. Follow up with the physician confirmed that the replacement surgery which occurred on (b)(6) 2012 was for high impedance. The physician could not recall if the vns device was disabled to 0ma after the high lead impedance was observed and was uncertain if x-rays were taken as the "patient ran away for almost one year. " there was no manipulation or trauma that occurred which is believed to have caused or contributed to the lead fracture.

Manufacturer Narrative
Corrected data: additional information was received which indicates the date reported on the initial mdr was incorrect. Analysis of programming history.

Event Description
On (b)(6) 2012, a surgeon reported that he was performed a battery replacement. Prior to surgery there was no evidence of high impedance; however, after a new generator was connected, high impedance was seen. The surgeon stated that he removed the pin and then reinserted; however, a dcdc code of 7 was reported (the actual evidence of high impedance is unknown as the generator that was connected would provide an impedance value in ohms, not a dcdc code). The surgeon stated that there he was in the process of revising the lead. The physician phoned in a second time and reported that high impedance was seen after the lead was revised. The surgeon replaced the generator that had been implanted earlier in the surgery and reported that everything was okay. No additional information was provided regarding why the high impedance was attributed to the new generator. The high impedance on the generator is captured in mfr report #1644487-2012-01872. Follow up with the surgeon's office on (b)(6) 2012, revealed that no additional information was available; however, operative notes would be provided. Pre-operative diagnoses indicated there was a malfunction of the neurologic device. Postoperative diagnoses also indicated a malfunction of the neurologic device. Operative findings indicated high lead impedance, fracture of the rostral most electrode, and a defective model 103 generator. The patient's settings were provided. It was stated that as the battery had reported a near end of life message, the patient opted for revision. During the procedure, electrocautery was used to reach the generator. The generator was removed and a new generator (m103) was connected. High lead impedance was seen. The old generator was reattached and high impedance was seen again, reportedly consistent with an electrode malfunction. The incision at the neck was reopened, and the electrode wire was found to be fractured at two points: after the level of bifurcation of the electrode wire into two single wires and the wires. The wire was reportedly heavily scarred in. The electrode coils were removed, and a new electrode was placed. The new generator was attached to the new electrode, and high lead impedance was seen again. The notes stated that, at this point, the patient was clear with all scar tissue having been resected; therefore, "the problem at this point laid in the generator". A second new generator was programmed to the patient's pre-implant settings and replaced in the anterior chest wall pocket. The electrode distal to the electrode coils was secured was plastic pledgets and 3-0 silk suture. Care was taken to maintain a generous strain relief loop and to avoid any tension or kinks in the electrode within the neck. Attempts for product return have been unsuccessful as the facility only releases explanted devices to patients. Attempts for product information have been unsuccessful.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2669008


Title: Re: Electrodes
Post by: dennis100 on March 15, 2018, 01:52:32 AM
Model Number 302-20
Event Date 08/29/2012
Event Type Malfunction
Manufacturer Narrative
Analysis of programming history. Device failure is suspected but did not cause or contribute to a death or serious injury.

Event Description
On (b)(6) 2012, it was reported that the patient was experiencing painful stimulation in the neck area for the last day or so. X-rays were taken, and no lead issue was seen. The x-rays would not be sent to the manufacturer for review. High lead impedance was seen the day before and the patient's device was disabled late on (b)(6) 2012, or early on (b)(6) 2012. The patient underwent surgical consult. The patient was reported to have been seizure-free for three years, and there was no reported increase in seizures. There was no known trauma. On (b)(6) 2012, the patient reported that, during interrogation earlier in the day, an error message popped up which said that her leads are detached or there is tissue build up. The patient stated that x-rays were taken but did not show any detachment. The patient stated that the device was programmed off and that she was referred for lead replacement due to the detachment issue. The patient stated that there had been no trauma or manipulation that she was aware of; however, she occasionally lifted heavy things. The generator and lead were replaced on (b)(6) 2012. X-rays were observed prior to surgery and a definitive lead break was observed in the lead just above the bifurcation. During surgery, it was noticed that the electrode coils appeared to be pulling off of the nerve but that they were scarred in tightly. The patient's generator was replaced prophylactically. The lead and generator were returned on (b)(4) 2012 and are currently undergoing product analysis. A battery life calculation on (b)(4) 2012, resulted in 7. 67 years to neos.

Manufacturer Narrative
Device failure occurred but did not cause or contribute to a death or serious injury.

Event Description
Product analysis for the explanted generator was approved on (b)(6) 2012. The device performed according to functional specifications. Analysis of the generator in the (b)(4) lab concluded that no abnormal performance or any other type of adverse condition was found. Product analysis for the explanted lead was approved on (b)(6) 2012. The electrodes of the lead were not returned for product analysis. Setscrew marks on the connector pin provided evidence that proper contact between the setscrew and lead pin existed at least once. Abrasions were identified on the outer silicone tubing at multiple locations and on the connector boot. The outer silicone tubing had cuts at several locations. Some cuts did reach the inner silicone tubing. Abrasions were identified on the silicone tubing of the lead coils. The silicone tubing of the positive coil appears to be abraded and open in the vicinity of the coil end. It is believed that this condition could potentially contribute to the patient "pain" allegation. However, the exact impact of this condition and when it occurred is unknown. Scanning electron microscopy images of the positive coil show that pitting or electro-etching conditions have occurred in the vicinity of the coil cut end. Note that since the electrode array portion was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified within the returned lead portion.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2758863


Title: Re: Electrodes
Post by: dennis100 on March 20, 2018, 01:18:02 AM
Model Number 300-20
Event Date 09/10/2012
Event Type Malfunction
Event Description
The patient's device was programmed off on (b)(6) 2014. No known surgical interventions have been performed to date.

Event Description
It was reported that the patient will not undergo lead replacement. It was reported that the decision to lead the vns off was made. It is believed that the patient may not be a good candidate for lead replacement surgery. No additional relevant information has been received to date.

Event Description
Attempts for additional information from the treating neurologist have been unsuccessful to date. While revision is likely it has not occurred to date as per the surgeon, the decision for replacement has been left up to the patient's parents.

Event Description
A review of programming history, available in house revealed that during initial implant, two system diagnostic tests were run; the first resulting in high impedance while the second resulted in a dc/dc code of 0. It is unclear at this time if a lead fracture was present at the time of implant. Additionally programming history was provided by the physician who indicated that on (b)(6) 2012, prior to the generator replacement, the diagnostics showed a dc/dc of 0 on a system test and a dc/dc 1 on a normal mode test. On (b)(6) 2012 the impedance was a dc/dc equal to 7. It was noted by the physician that no trauma has been reported.

Event Description
Further follow-up revealed that the patient met with the surgeon and they are worried about how the patient will tolerate surgery. For this reason, the surgery has been placed on hold for now. The patient's family believes that the magnet does shorten and stop the patient's seizures.

Event Description
It was reported that the patient was scheduled for surgical consult. Surgery is likely, but has not occurred to date.

Event Description
The patient's neurologist reported that high lead impedance was found on the patient's system and normal diagnostic tests. Ap and lateral x-rays of the chest and neck were taken on (b)(6) 2012 and sent to the company for review. The generator was seen in the left chest. The filter feedthru wires were intact and the lead pins could be seen past the connector blocks indicating that they were fully inserted into the generator. A portion of the lead appeared to be located behind the generator and could not be assessed. There appeared to be a suspect area located in the coiled lead near the generator. It was possible that a break occurred in this area; however, due to the contrast and image quality of the x-rays provided, a break could not be confirmed. The electrodes were observed in the neck, but they did not appear to be aligned. In the images provided it does not appear that the anchor tether is on the nerve. The lead was seen routed down towards the generator and the lead wires appear intact at the connector pins. Based on the x-ray images provided, the cause of the high impedance cannot be determined. However, the suspect area identified in the lead or the improperly aligned electrodes may be contributing factors. The presence of micro-fractures in the lead or fractures in the portion of the lead that could not be assessed cannot be ruled out.

Manufacturer Narrative
Analysis of programming history.

Manufacturer Narrative
Date received by manufacturer; corrected data: the information reported on supplemental mfr. Report #3 should have been (b)(4) 2013 rather than (b)(4) 2013.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Review of x-rays by manufacturer revealed a suspected lead break; however, due to the image quality and lack of contrast, this could not be confirmed. Device failure suspected to have occured, but cannot be confirmed due to image quality and lack of contrast. Suspected device failure did not cause or contribute to a death or suspected injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2777500


Title: Re: Electrodes
Post by: dennis100 on March 31, 2018, 01:07:20 AM
Model Number 300-20
Event Date 11/23/2011
Event Type Malfunction
Event Description
It was reported to our country representative in france that there was a vns patient with high lead impedance on a system diagnostic test, dcdc 7. No trauma previously reported and surgery will be planned. X-rays received for review. The generator is placed in a normal position in the upper left chest. The filter feed-through wires appeared to be intact. The lead connector pins appeared to be fully inserted. The lead wires at the connector pin appeared to be intact. The electrodes appeared to be broken and not fully attached to the vagus nerve. No strain relief-loop or bend was viewed. No tie-down was viewed either. Per labeling, a strain relief bend should be placed starting 3cm from the anchor tether and should be secured with a tie-down parallel to the anchor tether. A large loop should then be formed and secured with an additional tie-down to allow for full neck movement in all directions. Portions of the lead appeared to be behind the generator and could not be fully assessed. No acute angles or lead breaks were found. The lead body follows a straight line below the electrodes and then appears to be wound in loops around the placement of the generator. Based on the x-rays images, the reported high impedance is caused by the broken/detached electrodes.

Event Description
Additional information was received that diagnostics in (b)(6) 2011 were within normal limits. No manipulation of the vns system by the patient is suspected. No surgery is planned.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer and a lead discontinuities was visualized. Device malfunction suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2858611


Title: Re: Electrodes
Post by: dennis100 on April 03, 2018, 12:42:21 AM
Model Number 302-20
Event Date 12/20/2012
Event Type  Malfunction   
Manufacturer Narrative
Serial #, lot #, expiration date: corrected data: previously submitted mdr provided incorrect lead product information. This report is being sent to correct this information. Date of implant, corrected data: previously submitted mdr provided incorrect lead product information. This report is being sent to correct this information. Device manufacture date, corrected data: previously submitted mdr provided incorrect lead product information. This report is being sent to correct this information.
 
Event Description
On (b)(6) 2013, this patient underwent lead revision. The explanted lead was returned on (b)(6) 2013 and is currently undergoing product analysis.
 
Manufacturer Narrative
Device failure occurred but did not cause or contribute to a death or serious injury.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
An analysis was performed on the returned lead portions, and the reported allegations of high impedance was confirmed. During the visual analysis of the returned portion, the (-) green electrode quadfilar coil appeared to be broken at the proximal end of the anchor tether. Scanning electron microscopy was performed on the connector end of the (-) green electrode quadfilar coil break and identified one of the broken coil strands as having evidence of a stress induced fracture (fatigue appearance) with mechanical and no pitting. Scanning electron microscopy was performed on the electrode (mating) end of the (-) green electrode quadfilar coil break and identified one of the broken coil strands as being pitted and mechanically damaged. The remaining broken coil strands were identified as being mechanically damaged which prevented identification of the coil fracture type and no pitting. Pitting was observed on the coil surface. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.
 
Event Description
Reporter indicated a patient had high lead impedance 10,000 ohms with vns diagnostics testing at an office visit. The vns was disabled. X-rays were reviewed by the manufacturer on (b)(6) 2013. No obvious lead breaks were observed. The lead pin is fully inserted into the generator header, ruling out a lead pin issue and making a lead fracture the more likely cause of the high lead impedance. The lead electrodes are situated in an unusual angle towards the general direction of where the vagus nerve is located, suggesting the electrodes may not be placed per labeling. Lead replacement surgery is planned, but has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2916973


Title: Re: Electrodes
Post by: dennis100 on April 05, 2018, 12:49:21 AM
Model Number 302-20
Event Date 07/11/2011
Event Type  Injury   
Manufacturer Narrative

Manufacturer Narrative
Correction: patient identifier was inadvertently reported incorrectly on the initial medwatch and has been corrected. (b)(4).
 
Event Description
It was reported by a neurologist that a vns patient experienced coughing, hoarseness, and difficulty swallowing after his vns settings were increased from. 75 ma to 1 ma. The treating physician indicated the patient then experienced vocal cord paralysis and the patient has not recovered. Moreover, the neurologist indicated that when the patient had vns explanted due to high impedance (mfr report # 1644487-2011-01816), the surgeon saw that the superior electrode had been pulled partially from the nerve and the tissue was scarred. The patient's mother indicated the patient did not have a physical injury that could have contributed to the event. At the moment, good faith attempts to obtain further information regarding the event have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2372099



Title: Re: Electrodes
Post by: dennis100 on April 06, 2018, 01:56:02 AM
Model Number 102
Event Date 11/19/2012
Event Type  Injury   
Event Description
Additional information was received which indicates that the physician who reported the tests from the microbiology lab were negative was mistaken. It was found that there were, in fact, no tests performed. It was stated that the patient's primary vns treating physician has the most accurate information on the patient, which indicates that the patient has been pain free since (b)(6) 2013 and all tests have been cancelled. No additional information has been provided.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for the generator prior to distribution.
 
Event Description
On (b)(6) 2013 it was reported by the physician that the patient may have an infection at the generator site. However, follow up with the neurologist found that there is not much evidence to support an infection and that a scan is being performed simply to rule out all possibilities of one. It was originally reported that the patient was feeling continuous stimulation and shocks in the neck at the electrode site. However, the neurologist stated that it is unknown what the cause of the pain is and if there is a relation to vns. The neurologist performed diagnostic tests on the device which showed that it was within normal limits and stated that no trauma or patient manipulation had taken place which could have caused or contributed to the event. No medical interventions were taken or planned at this time. X-rays of the patient were taken, but no abnormalities were noted. A review of the x-rays by the manufacturer found no obvious lead discontinuities in the areas that could be assessed. The generator was seen in the left chest area in a normal orientation and the filter feedthru wires appeared intact. The lead pin could be seen past the second connector block indicating that it is fully inserted into the generator. Due to the image quality, it could not be assessed if the lead is intact at the connector pin. The lead was seen routed from the electrodes to the generator. A portion of the lead appeared to be behind the generator and could not be assessed. The electrodes were observed in the neck and appeared to be in proper alignment; however, the positive electrode appeared to be at a slightly different angle than the negative electrode. This could be due to the electrode beginning to come off or due to patient anatomy. No gross lead fractures or sharp bends were visualized. Follow up with the neurologist found that the patient felt the pain as a continuous sensation of electric shock over the left cervical thoracic region which persisted even when both the output current and magnet output current were set at 0ma. The device was turned off for 15 minutes to test if the pain continued without stimulation. The patient's settings were found to be output current = 1. 5ma, frequency = 30hz, pulsewidth = 500usec, on time = 30 sec, off time = 10 min, magnet current = 0ma, magnet on time = 30 sec, magnet pulsewidth = 500usec. Normal diagnostic results showed communication = ok, output current = ok, dcdc=2, eos = no. A system diagnostic test was not performed. An exploratory surgery is being considered to determine the cause; however, surgery has not been scheduled yet. Per the surgeon, if the exploratory surgery occurs it would be for patient comfort. No medical or surgical intervention has been planned or taken to preclude a serious injury. Attempts have been made for additional information; however, they have been unsuccessful. No additional information has been provided.
 
Event Description
Follow up with a physician on (b)(6) 2012 found that the results from the microbiology lab were negative. It was stated that the patient still feels pain on her chest so the surgeon will probably remove the device. However, follow up with the primary treating physician found that the patient was no longer feeling pain as of (b)(6) 2013 and that all tests have been cancelled. The primary treating physician stated that he never suspected an infection and that this hypothesis was evoked by the surgeon on (b)(6) 2013 but never proven. It was stated that the source of these symptoms are still unknown. No additional information has been provided.
 
Manufacturer Narrative
Name and address, corrected data: incorrect initial reporter listed in initial mdr inadvertantly.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2975611


Title: Re: Electrodes
Post by: dennis100 on April 08, 2018, 12:47:38 AM
Model Number 302-20
Event Date 08/25/2006
Event Type  Injury   
Event Description
Reporter indicated that during a patient's vns generator replacement surgery due to end of service on (b)(6) 2006, it was noted by the surgeon that the lowest lead connection was off of the nerve, which was putting traction on the nerve. Releasing the tension moved the nerve back to a more normal position. The surgeon described the patient's tissue as "weakened", and that the tissues might be consistent with an underlying collagen vascular disorder. The patient's "tissue", specifically the fascia and collagenous tissues were described as weakened and lacking the usual texture that these tissues should demonstrate and it is suspected the patient has an underlying collagen vascular disorder. It is unclear if the possible collagen disorder caused the lead to migrate. No trauma occurred. The patient was also reported as experiencing neck pain at the time along with the lead migration.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3023975


Title: Re: Electrodes
Post by: dennis100 on April 14, 2018, 12:26:27 AM
Model Number 303-20
Event Date 02/01/2013
Event Type  Malfunction   
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, lead pin not fully inserted past the connector block of generator.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a serious injury.
 
Event Description
Reporter indicated intermittent high lead impedance was noted for a patient who recently had vns generator replacement on (b)(6) 2013. The patient had no known trauma. The patient is also experiencing painful stimulation at the electrode site in the neck. X-rays were reviewed by the manufacturer. The electrodes are visualized at approximately t1 and are in alignment; the electrodes are implanted lower than what is usually seen. The generator is implanted in the left axilla. This is much more lateral than what is normally seen. The view does not allow full assessment of the lead pin insertion. The lead wire is intact at the lead pin. The filter feedthroughs are intact. There is a small amount of lead behind the generator that cannot be assessed. The cause of the high lead impedance is unknown at this time, but may be due to inadequate pin insertion or a lead fracture. Attempts for additional information are in progress.
 
Event Description
Reporter indicated the patient had vns lead pin reinsertion surgery performed on (b)(6) 2013. After the lead pin was reinserted into the generator header, diagnostics were within normal limits (3218 ohms). No new devices were implanted.
 
Event Description
Manufacturer review of the device history records for the vns lead and generator confirmed both devices passed all final testing prior to distribution.
 
Event Description
Additional x-rays were reviewed by the manufacturer. The lead pin did not appear to be fully inserted. No additional anomalies were noted. The surgeon indicated he felt the lead pin had been fully inserted as two audible clicks were heard when tightening the setscrew. However, the possibility of a lead fracture may also exist. Reporter indicated the patient was also having increased seizures and that the plan of care is to have vns revision surgery; however, this has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2993250


Title: Re: Electrodes
Post by: dennis100 on April 22, 2018, 12:46:10 AM
Model Number 304-20
Event Date 04/29/2013
Event Type  Malfunction   
Event Description
On (b)(6) 2013, it was reported that high impedance was observed for this patient (impedance; 10. 000 ohms). The patient was recently implanted, and no trauma/manipulation was reported. The device was not disabled. X-rays were taken but have not been received. Attempts for additional information have been unsuccessful. Surgery is likely but has not taken place.
 
Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. X-rays reviewed by the manufacturer, no gross lead discontinuities visualized. Device failure is suspected but did not cause or contribute to a death or serious injury.
 
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received that the patient had generator and lead replacement and the explanted product were returned to the manufacturer for evaluation. When received, the ram and flash data were downloaded from the generator. The data in the diagaccumconsumed memory locations revealed that 3. 456% of the battery had been consumed. Visual examination showed tool marks on the pulse generator case and header most likely associated with manipulation of the device during the explant procedure. Burn marks were observed on the pulse generator case indicating that the pulse generator may have been exposed to an electro-cautery tool. The septum was not cored. No other surface abnormalities were noted on this device. An interrogation and system diagnostics test were performed, with a one inch spacer between the generator and the programming wand. Resulting status checks for; communication were ok, lead impedance and current delivered were normal for all diagnostic tests performed. The generator was subjected to and successfully completed a final electrical test. The generator is operating within specification. The pulse generator diagnostics were as expected for the programmed parameters. A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. The battery, 2. 974 volts as measured shows a non-ifi condition. The data in the diagaccumconsumed memory locations revealed that 3. 456% of the battery had been consumed. There were no performance or any other type of adverse condition found with the pulse generator. The lead was returned for the allegation of explanted due to high lead break/high impedance. No obvious anomalies were noted. The condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. The lead assembly was returned in two portions and the tie downs were not returned. On the returned 4234mm portion, setscrew marks were observed on the connector pin, providing evidence of a proper mechanical contact between conductive surfaces of both the generator and connector pin. Continuity testing could not be performed during the decontamination procedure because the returned lead was not connected to a generator when received into pa. Incisions were made to allow for continuity checks. Abrasions were observed on the inner silicone tubes, but did not penetrate. Incision marks were observed on the inner silicone tubes and the marks penetrated the insulation and the quadfilar coils appeared to be kinked, in these areas. No discontinuities were identified during the continuity check. An analysis performed on the returned lead portions did not confirm the allegation. Based on the findings in the product analysis lab, there is no evidence to suggest a discontinuity in the returned portions of the device which may have contributed to the stated allegations of explanted due to lead break/high impedance.
 
Event Description
Clinic notes dated (b)(6) 2013 were received. The notes indicated that the patient was seen and complained of a vns system malfunction of high impedance. The patient felt he was not improving.
 
Event Description
X-rays were received on (b)(4) 2013. The generator was seen in the left chest area in normal orientation. The filter feedthru wires appear intact and the lead appears intact at the connector pin. The lead pin could not be seen past the second connector block indicating that it may not be fully inserted into the generator. The electrodes were observed in the neck, but do not appear to be in proper alignment. In the images it appears that the electrodes are placed in the opposite alignment with the positive electrode on the bottom, followed by the negative electrode on top. The lead is routed upwards from the electrodes then down toward the generator. No gross discontinuities or sharp angles were observed in the portion that could be assessed. Clinic notes dated (b)(6) 2013 indicated that the patient was seen for vns system malfunction of a high impedance error. The patient did not feel that he was improving, the patient¿s vns incisions were well-healed. Surgery is likely but has not taken place.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3122782


Title: Re: Electrodes
Post by: dennis100 on April 23, 2018, 12:36:54 AM
Event Date 10/01/2001
Event Type  Malfunction   
Event Description
An article titled ¿vagus nerve stimulation after lead revision¿ was received and reviewed by the manufacturer. The authors reviewed all vns lead revisions performed between october 2001 and august 2011 at the university of hospitals and clinics. Twenty-four patients underwent 25 lead revisions. In all cases, the helical electrodes were removed, and a new lead was placed on the previously used segment of vagus nerve. All inpatient and outpatient records of the 25 lead revisions were retrospectively reviewed. All patients were treated by a single neurosurgeon. Twenty-four patients underwent 25 vns revisions between october 2001 and august 2011. Of these 25 revisions, 4 were second and 21 were first lead revisions. ¿the patients in 18 cases (72%) presented with high impedance at the time of revision, 2 cases (8%) involved a short circuit within the system, 4 cases (16%) demonstrated normal impedance, and 1 case (4%) had no implanted vns system and therefore no impedance reading since the system had been previously removed at another institution because of infection. ¿ ¿sixteen (64%) of the 18 cases with high impedance at the time of revision had no visible damage or fracture within the lead and/or cable, suggesting an intrinsic lesion within the lead and/or cable. Other causes of lead failure included visible fractures of the lead in 3 cases (12%), increasing seizure frequency and an impedance indicating a short circuit in 2 cases (8%), normal impedance but pain and shock-like sensations suspect for device malfunction in 2 cases (8%), electrode coil dislocation from the vagus nerve in 1 case (4%), and a previous hardware infection and vns system removal in 1 case (4%). ¿ symptoms varied depending on the etiology of lead failure. The patients in 18 cases (72%) presented with increased seizure frequency; in 4 cases (16%), with neck and/or chest pain, paresthesias, or shock-like sensations¿ all probably the result of a short circuit within the system; and in 6 cases (24%), with no new symptoms. Additionally, 3 cases (12%) had a history of vns-related infection, and 3 cases (12%) had a recent history of head and/or neck trauma. ¿ during lead revision surgery in all cases, the vagus nerve was found encased in fibrous scar tissue which was surgically dissected. There were no postoperative infections. ¿only 1 patient experienced a complication requiring additional surgery; in this patient the lead cable was taut, creating a pulling sensation on neck turning. " in conclusion, the authors ¿found that lead failure occurs for a variety of reasons and in our series was most commonly observed in cases of high impedance within the vns lead, which was found in 72% of [the] lead revisions. The majority of patients (89%) who presented with high impedance had no visible damage or gross fracture of the lead or cable. The etiology of high impedance and lead failure is not entirely clear in these cases. ¿ it was found that the ¿placement of a new vns lead at the previously used segment of vagus nerve provided a proper contact in all 16 such cases as well as normal impedance, implying that the presence of dense scar tissue was probably not the cause of lead failure. ¿ ¿in addition to an intrinsic increase in lead impedance and device failure, [it was] observed other factors resulting in lead failure. ¿ ¿vns lead failure most commonly resulted in an increased seizure frequency. In some cases, a very dramatic increase in seizure intensity and frequency was observed. However, other symptoms alerted patients to device malfunction and included neck and chest pain, shock-like sensations, and paresthesias. Short circuits within the system may cause these types of symptoms. ¿ the shock-like sensations, pain, and paresthesias resolved after revision. The article also noted that ¿other confounding variables include the changing antiepilepsy drugs patients potentially received over the follow-up period. Furthermore, the clinical absence of dysphonia or aspiration does not preclude the possibility of vagus nerve injury, and therefore underreporting of actual injury may be present. ¿ attempts for additional information, including patient information, have been unsuccessful to date. This report captures a patient's high impedance with no patient adverse events reported. The patient's history of vns infection is captured in mfg report number: 1644487-2013-01457. The events of high impedance accompanied with increased seizures are captured in mfg report numbers: 1644487-2013-01426, 1644487-2013-01428, 1644487-2013-01431, 1644487-2013-01432, 1644487-2013-01434, 1644487-2013-01435, 1644487-2013-01436, 1644487-2013-01443, 1644487-2013-01445, 1644487-2013-01448, and 1644487-2013-01451. The events of lead fracture accompanied with increased seizures are captured in mfg report numbers: 1644487-2013-01427 and 1644487-2013-01438. The other events of high impedance with no reported patient adverse events are captured in mfg report numbers: 1644487-2013-01429, 1644487-2013-01430, and 1644487-2013-01441. The event of high impedance due to electrode detached/dislocated from the vagus nerve is captured in mfg report number: 1644487-2013-01440. The event of high impedance accompanied with increased seizures and shock sensation is captured in mfg report number: 1644487-2013-01433. The event of postoperative ¿bowstring complication requiring surgery 1 month later¿ is captured in mfg report number: 1644487-2013-01465. The event of lead fracture (with normal lead impedance value) with no reported patient adverse events is captured in mfg report number: 1644487-2013-01458. The events of short circuit accompanied with increased seizures are captured in mfg report numbers: 1644487-2013-01442 and 1644487-2013-01455. The other events of infection are captured in mfg report numbers: 1644487-2013-01437 and 1644487-2013-01454. The events of increased seizures with one patient experiencing it with shock sensation and with one patient experiencing it with neck/chest pain are captured in mfg report numbers: 1644487-2013-01446 and 1644487-2013-01452, respectively. The event of an unknown of amount of patients with increase in seizure intensity is captured in mfg report number: 1644487-2013-01466.
 
Manufacturer Narrative
Device failure is suspected, and did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3120029


Title: Re: Electrodes
Post by: dennis100 on May 04, 2018, 12:43:45 AM
Model Number 302-20
Device Problem Detachment of device component
Event Date 08/21/2010
Event Type  Malfunction   
Event Description
It was reported that the patient was undergoing generator replacement surgery when the surgeon identified abraded openings in the lead tubing (reported in mfr. Report #1644487-2018-00663), so a lead revision was then performed. It was then identified that there was no strain relief, and the electrodes were detached from the nerve. The surgeon and ear, nose, and throat specialist stated that the nerve was bubbled and severely scarred from the electrodes rubbing on it. The impedance was within normal limits prior to the surgery, which indicated that the electrodes were in contact with patient tissue while implanted. It was believed that the electrodes rubbed against the nerve after becoming detached, which caused the damage to the nerve. The lead was received by the manufacturer, and analysis was performed (reported in mfr. Report #1644487-2018-00663). However, the electrode portion of the lead was not returned, so no analysis could be performed on the portion of the lead relevant to this report. No further relevant information has been received to date.
 
Manufacturer Narrative
(b)(4).

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7467612


Title: Re: Electrodes
Post by: dennis100 on May 04, 2018, 11:49:48 PM
Model Number 303-20
Device Problem No Known Device Problem
Event Date 03/14/2018
Event Type  Injury   
Event Description
It was reported by the company representative that a surgeon was having difficulty placing the lead on the nerve. The surgeon wanted to use a clip on the electrode to secure it to surrounding soft tissue. The surgeon had claimed that the nerve looked ¿ragged¿ and was the reason the electrode was having difficulty staying in position. Additional relevant information has not been received to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7403413


Title: Re: Electrodes
Post by: dennis100 on May 06, 2018, 01:16:14 AM
Model Number 304-20
Device Problems Extrusion; Human-Device Interface Issue
Event Date 06/01/2013
Event Type  Injury   
Event Description
Patient will undergo exploratory surgery on (b)(6) 2015 to try to remove the object that is in his neck. The surgeon plans to remove the object and will not remove it if it is affecting a vein. No additional information has been received after the exploratory surgery.
 
Event Description
It was reported that the patient cut himself of the neck area (near the electrodes) while shaving a few weeks prior and that he has now developed an infection at the site. It was reported that the patient has a thin frame and that the electrodes are visible through the wound. It was reported that the wound was full of pus and was "looking bad". The surgeon prescribed antibiotics and has scheduled the patient for explant. The surgery was scheduled; however, no information has been received that the explant has occurred as scheduled.
 
Event Description
Further investigation revealed that the patient's generator and lead were explanted on (b)(6) 2013.
 
Event Description
It was reported on 06/22/2015 that this patient, who had his device explanted in 2013, went to the er and the xray showed a "square piece of metal" under the skin. The patient was under the impression that the entire device was explanted. It is unknown at this time of the piece of metal found was left over from the vns explant surgery or is unrelated. Attempts for additional relevant information have been unsuccessful to date.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3282396


Title: Re: Electrodes
Post by: dennis100 on May 12, 2018, 12:59:56 AM
Model Number 302-20
Event Date 10/02/2013
Event Type  Malfunction   
Event Description
On (b)(6) 2013, it was reported that the patient had a full vns replacement due to the battery being at end of service and because the lead "didn't work either". Follow up with the physician found that the patient had the lead replaced due to high lead impedance observed during surgery. When the patient as opened up, it was found that the electrodes were originally placed on another nerve and not the vagus nerve. Instead, the electrodes were placed on the ansa cervicalis nerve, which is about one third of the size of the vagus nerve, per the surgeon. This led to the patient developing scarring around the nerve and electrodes, which is what the physician believes is the cause of the high impedance. However, as the patient reported some benefit from vns, the physician believes that some stimulation was being delivered. The lead appeared intact, per the physician, so the high impedance was attributed to the scarring. Review of the lead device history records confirmed all quality tests were passed prior to distribution. The explanted device was returned to the manufacturer and product analysis was performed. Product analysis of the lead found no product related anomalies. Note that since a portion of the lead (including the electrode array) was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than typical wear and explant related observations, no anomalies were identified in the returned lead portion. Attempts were made for additional information; however, no additional information was provided.
 
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3443385



Title: Re: Electrodes
Post by: dennis100 on May 15, 2018, 07:53:22 AM
Model Number 302-20
Event Date 01/01/2008
Event Type  Malfunction   
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to death or serious injury.
 
Event Description
It was reported to mfr that the vns pt was having surgery due to high lead impedance. X-rays were taken and reviewed prior to surgery and according to the surgeon they were inconclusive. During surgery, the surgeon noted a lead break "at the connector boot area. " the surgeon removed all but approx 2 cm of the lead. Additionally, the surgeon was not able to implant a new lead on the left vagus nerve as there was "not enough room on the nerve" due to scar tissue formed. A new generator was implanted but the lead was not replaced. Attempts to obtain add'l info and the explanted devices for analysis are underway.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/detail.cfm?mdrfoi__id=1040828


Title: Re: Electrodes
Post by: dennis100 on May 15, 2018, 07:54:07 AM
Model Number 302
Event Date 07/02/2015
Event Type  Malfunction   
Manufacturer Narrative

Event Description
During review of the in-house programming/diagnostic history database, it was observed that high impedance was observed at office visit on (b)(6) 2015. It is unknown if any patient manipulation or trauma occurred that could have caused or contributed to the high impedance reading. Further follow-up found that the patient had been referred for generator replacement surgery. At the time, the surgeon did not want to replace the lead because he was concerned that there may not be enough room on the nerve for a new lead. However it is unclear how the surgeon made this assessment. The generator was replaced on (b)(6) 2015 and the existing lead was connected to the new generator. Following generator replacement a system diagnostic test observed high lead impedance with the newly implanted generator. Programming history indicated that as of (b)(6) 2016 the high impedance had not resolved. The physician was notified of the high lead impedance and the manufacturer's recommendations for addressing high lead impedance events. It was then reported that since the high impedance was observed the non-verbal patient has been agitated and experiencing dysphagia, loss of appetite and trouble sleeping. The device was programmed off on (b)(6) 2016. Following device disablement the patient's behavior and symptoms improved however the patient was still not eating well and appeared to be fearful of food. Attempts to obtain additional information have been unsuccessful to date. It is not known if the lead has been replaced to date.
 
Event Description
The patient's mother provided an update on her daughter's condition since the device was disabled. She reported that prior to the device being disabled she had taped the magnet over the generator and the patient's behavioral issues improved. However when the mother went to place the magnet she accidentally swiped the magnet and activated a magnet stimulation. The patient reacted to "defend herself" and appeared to be in pain from the magnet swipe. She also reported that the patient had undergone a barium swallow test in (b)(6) 2016 which showed that the patient was suffering from muscle spasms. She was placed on prevacid in response to the muscle spasms. However since the vns device has been disabled the patient is no longer suffering from issues with swallowing. The patient is still exhibiting an aversion for eating however the mother believes this may be a defensive response from the previous issues that were caused with the high impedance. The patient had been previously placed on 4 different sleep medications however none of them improved her sleeping difficulties. The patient is still suffering from issues sleeping since the device has been disabled.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5972991


Title: Re: Electrodes
Post by: dennis100 on May 15, 2018, 07:54:47 AM
Model Number 302-20
Event Date 06/25/2012
Event Type  Malfunction   
Event Description
It was reported that a vns patient had high lead impedance with a dcdc 7. The patient is having seizures which they think is from their vns not working. No x-rays have been ordered. The patient did not have any fall or injury preceding the event. The patient is referred for surgery (b)(6) 2012.
 
Manufacturer Narrative
Device malfunction occurred, but did not cause or contribute to a death.
 
Event Description
An analysis was performed on the returned lead portion. Note that the electrode section was not returned for analysis and therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis the connector pin quadfilar coil appeared to be broken approximately 240mm (connector end) and 243mm (electrode mating end) from the end of the connector boot in the area of observed abraded openings. Visual analysis was performed and identified the areas as having extensive pitting which prevented identification of the coil fracture type and mechanical damage. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. What appeared to be remnants of dried body fluids and white deposits were observed inside the outer and connector pin inner silicone tubing, throughout the majority of the returned portion. The abraded openings found on the outer and connector pin inner silicone tubing, most likely provided the leakage path for what appeared to be remnants of dried body fluids / white deposits found inside the outer and inner silicone tubing. With the exception of the observed discontinuity, the condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, and no other discontinuities were identified.
 
Manufacturer Narrative
Device failure suspected, but did not cause or contribute to a death.
 
Event Description
The patient had surgery (b)(6) 2012. Our consultant attended the surgery reported that when the surgeon exposed the carotid sheath, he stated there was not enough room remaining on the vagus nerve to place another lead. For this reason, the lead was cut and the electrodes remain on the nerve. No new system was implanted. The explanted portions of the lead were not returned for analysis. Their explanted generator was returned for analysis. The generator performed according to functional specifications. During the product analysis there were no anomalies found with the pulse generator.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2664590


Title: Re: Electrodes
Post by: dennis100 on May 27, 2018, 12:08:26 AM
Model Number 102
Event Date 03/05/2014
Event Type  Death   
Manufacturer Narrative

Event Description
It was reported that the patient passed away from an unknown reason. It was reported that the device was explanted and would be sent to manufacturer for analysis. The medical examiner indicated that the patient's vagus nerve was explanted with the lead attached to avoid damaging the lead electrodes. The relationship between vns and the death is known. The generator and lead were returned for analysis. The reason for explant was reported as sudden unexpected death with recent history of myocardial infarct (non-ischemic) and possible arrhythmia. The generator analysis was completed on (b)(6) 2014. The device performed according to functional specifications. Analysis in the pa lab concluded proper functionality of the pulse generator and that no abnormal performance or any other type of adverse condition was found. The lead analysis was completed on (b)(6) 2014. The slice marks found on the outer and inner silicone tubes most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids found inside the outer and inner silicone tubes. The marks appeared to have been made by a sharp object which could have occurred during the explant procedure, however this cannot be confirmed. During the visual analysis the (+) white and (-) green electrodes appeared to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the (+) white and (-) green electrode ribbons from coming in contact with the vagus nerve. With the exception of the observed tissue-covered (+) white and (-) green electrodes the condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, with no discontinuities identified. Based on the findings in the product analysis lab, there is no evidence to suggest an anomaly with the returned portion of the device.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3738321


Title: Re: Electrodes
Post by: dennis100 on June 09, 2018, 01:32:11 AM
Model Number 304-20
Device Problem No Known Device Problem
Event Date 04/14/2018
Event Type  Malfunction   
Event Description
It was reported that a vns patient was scheduled for generator replacement due to battery depletion. The communication was reported to be okay prior to generator replacement, but after the generator replacement high impedance was found. The surgeon found a broken electrode. A new electrode was installed, and the patient was in good condition with impedance measurements within normal limits of 1,416, 1,562, and 1,445 ohms. The explanted devices were received and analysis is underway, but has not been completed to-date. Additional relevant information has not been received to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7500445



Title: Re: Electrodes
Post by: dennis100 on June 15, 2018, 01:13:33 AM
Model Number 303-20
Device Problem No Known Device Problem
Event Date 08/09/2017
Event Type  Injury   
Event Description
Report was received that a patient started experiencing arrhythmia while under anesthesia. The patient was receiving a full revision surgery. After the new generator and lead were implanted, system diagnostics were run and showed high impedance (reported in mfr. Report #1644487-2017-04401). A second lead was tried but the surgeon had difficulty wrapping the electrodes around the nerve. The surgeon reported this was related to the vagus nerve being too big for the 2 mm lead used. This led to extended time under anesthesia. Due to this duration of surgery and the manipulation of the vagus nerve, the patient experienced arrhythmia. The anesthesiologist reportedly recommended that the surgery be terminated as a result. The generator was reportedly left implanted without any lead attached. Further information was received that the arrhythmia was not occurring with stimulation as it appeared about an hour after the last system diagnostic had been performed. It was also reported that the arrhythmia was benign. The lead passed all quality inspections prior to release for distribution. Device evaluation is not necessary due to the arrhythmia not being related to delivery of therapy. No further information has been received to date.
 
Manufacturer Narrative
Device evaluation not necessary due to the event not being related to delivery of therapy at all.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6844458


Title: Re: Electrodes
Post by: dennis100 on June 30, 2018, 02:36:09 AM
Model Number 102
Event Date 01/18/2007
Event Type  Injury   
Event Description
Reporter indicated that a vns patient had bradycardia with vns stimulation. The vns was disabled on (b)96) 2007 and the bradycardia resolved. The vns has been disabled since this date, and will remain disabled at the reporter's discretion. The patient does not have a pre-vns history of bradycardia. Medication therapy will be utilized for the patient's seizure control. The bradycardia was felt to be due to the normal delivery of vns stimulation. It was not known if the patient had been referred to a cardiologist at the time the bradycardia occurred.
 
Event Description
Exploratory surgery for the patient to verify if the vns electrodes are aligned properly on the nerve is likely, but has not occurred to date. It is also possible a new vns lead and generator will be implanted.
 
Event Description
It was reported that the patient has been referred for generator and lead replacement. The physician believes that the electrodes were not placed correctly due to the patient suffering life-threatening bradycardia when initially implanted. No known surgical interventions have been performed to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2052578


Title: Re: Electrodes
Post by: dennis100 on July 03, 2018, 12:09:20 AM
Model Number 304-20
Device Problems Detachment of device component; No Known Device Problem
Event Date 10/30/2015
Event Type  Injury   
Event Description
The patient had full revision surgery. The generator was not sutured to the fascia, but was merely buried in subcutaneous tissue, which allowed for generator migration. The generator not being secured and the possible relationship to the pain experienced at the chest will be reported together in mfr. Report #1644487-2018-00847 as these issues now appear to be separate from the events in this report. The tie-downs were not sutured in place, and the surgeon noted that the electrodes were not properly coiled around the nerve. The explanting facility discards of product, so no evaluation could be performed on the devices. No further relevant information has been received to date.
 
Event Description
It was reported that the patient was experiencing multiple adverse events. The patient felt throbbing pain in her left neck and significant pain/tenderness at the neck incision and up her neck to her ear for four days. She also reported that she could feel the "clamp" prominently under the incision when she touched her neck. The patient also felt painful stimulation for the past four days, and she had not felt stimulation up to that point. She had been having left ear pain/trouble hearing/feeling like her ear was "stopped up" for about four months, but the physicians did not identify any ear infections. The patient also felt pain in her chest, neck, and left shoulder for two to three days after her vns magnet was swiped. The patient had been feeling pain since she was implanted, but the pain had just recently gotten unbearable. The patient was taking pain medication four times a day, but that did not make the pain go away. The patient's ear hurt so badly that she could not let the wind hit it. The patient's treating physician believed that the surgeon had poor implant technique and the pain was related to the placement of the device. The physician did not know the cause of the pain during magnet swipes, and he didn't know if the hearing loss was related to vns or not. The patient was referred for surgery, and it was being done to preclude a serious injury as the patient was in excruciating pain that was getting worse. X-rays were ordered, but they have not been reviewed to date. No surgical intervention has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7373200


Title: Re: Electrodes
Post by: dennis100 on July 31, 2018, 03:34:19 AM
Model Number 302-20
Event Date 10/15/2013
Event Type  Malfunction   
Event Description
It was reported that the patient would have vns replacement surgery on (b)(6) 2013; however, follow-up information was received which indicated that vns was not implanted on this date. At the time of surgery, it was believed that the electrodes were not on the vagus nerve. The nerve was "disintegrated" and the surgeon had no assessment of what caused the event. No interventions were taken or planned. The generator and lead were explanted and discarded. The patient was not implanted with another vns device. It was unknown if this event was related to vns. No other information was provided.
 
Event Description
On (b)(6) 2013 it was reported that the patient was found to have high lead impedance during an office visit on (b)(6) 2013. The physician requested x-rays and the device was not disabled. The physician sated that the only trauma was that the patient recently had a mammogram which was a little rough but he did not think it would have caused any issues with the device. Clinic notes were received from the (b)(6) 2013 visit which indicated that the diagnostics test showed high lead impedance with a dcdc of 7. The physician indicated that the high impedance may be related to some scar tissue. The patient reported no seizure since her previous appointment in (b)(6) 2013. The patient was referred for surgery. A copy of the patient¿s x-rays were received for review. Due to image angle and quality, complete lead pin insertion cannot be assessed. The lead portion behind the generator cannot be assessed. There are no sharp angles in the lead; however, there is a suspect area of continuity in the lead portion in the chest. The assessment of community in this area is limited by image quality. Based on the images available, the suspect area of continuity in the lead may be a cause for the high impedance. The presence of a microfracture or a discontinuity in the lead portion not visible cannot be ruled out. Although surgery is likely, it has not occurred to date. Review of the lead device history records confirmed all quality tests were passed prior to distribution.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3484513


Title: Re: Electrodes
Post by: dennis100 on August 07, 2018, 01:11:19 PM
Model Number 304-20
Device Problem Mechanical issue
Event Date 05/07/2018
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that during surgery the surgeon was attempting to implant patient, and he was not able to place the positive electrode on the nerve. The surgeon claimed that the electrode was too tight, and he was unable to get it to uncoil in order to place it on the nerve. The surgeon did not believe there was anything abnormal about the patient's anatomy that caused the difficulty, and when a new lead was opened, the surgeon was able to quickly implant the patient with no issues. A review of device history records showed that the implanted lead passed all other quality prior to distribution. The suspect lead was received for analysis; however, analysis has not been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7562990


Title: Re: Electrodes
Post by: dennis100 on August 10, 2018, 03:33:54 AM
Model Number 304-20
Device Problem Fracture
Event Date 07/02/2018
Event Type  Malfunction   
Event Description
It was reported that a vns patient¿s device had been programmed off because it was "misfiring", and the lead was not working, and a full revision was scheduled. High lead impedance was observed prior to surgery, and also during the surgery when the new generator was connected to the lead. The lead was reportedly tangled and kinked, and the lower electrode had become detached from the nerve. Full revision surgery occurred. The explanted devices were received. Analysis is underway, but has not been completed to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7714030


Title: Re: Electrodes
Post by: dennis100 on August 16, 2018, 02:22:35 AM
Model Number 304-20
Device Problem Mechanical Problem
Event Date 12/21/2016
Event Type  Malfunction   
Event Description
Product analysis for the returned lead was completed. The closest electrode to the bifurcation was damaged, showing bends on the electrode ribbon and partial detachment from the silicone helix. This silicone helix also exhibits what appear to be tool imprints. The most likely reason for the observed damaged to the closest electrode was manipulation of the lead not consistent with vns labeling. The measured dimensions were within the specified tolerances. Resistance values were within tolerances and exhibited no evidence of discontinuities. Other than the above mentioned observations and typical conditions that exist after a surgical procedure, no anomalies were identified in the returned lead.
 
Manufacturer Narrative

Event Description
It was reported that in an initial implant case, the second electrode of the lead appeared to be bent and have a metallic "foil-looking substance" wrapped around it. The issue was immediately discovered as the implanting surgeon was attempting to wrap the electrode around the vagus nerve. The implanting and attending surgeons observed that it appeared the lead had ¿extra coiling. ¿ by their account, there was apparently extra material, as if it was thicker than normal. The lead device history record was reviewed and found that all specifications were met prior to distribution. The lead was not implanted and was returned to the manufacturer. Product analysis on the lead is underway.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6252939


Title: Re: Electrodes
Post by: dennis100 on September 06, 2018, 01:35:39 AM
Model Number 302-20
Device Problems Corroded ; Fracture
Event Date 05/01/2011
Event Type  Malfunction   
Event Description
Attempts for additional information have been made to both the patient's treating neurologist and surgeon, and no information has been made available by either site.
 
Event Description
Additional information was received indicating that the patient has declined replacement. His device has since been disabled. Attempts for additional information have been unsuccessful to date.
 
Event Description
Product analysis of the returned generator was completed. Visual analysis showed only observations consistent with the explant procedure; no surface abnormalities were noted on this device. The pulse generator communicated normally and the eri flag was not set. The device performed according to functional specifications. No abnormal performance or any other type of adverse condition was found.
 
Event Description
Additional information was received stating that the vns patient underwent generator and lead replacement surgery due to lead discontinuity on (b)(6) 2014. Attempts to have the product returned for analysis were made but were unsuccessful.
 
Event Description
The explanted lead and generator were received by the manufacturer for product analysis. Product analysis was completed on the returned portions of the explanted lead. During the visual analysis of a returned 3. 5mm portion of the negative green electrode, it was observed that the coil portion of this segment was not present. What appeared to be a greenish tint was observed inside the inner silicone tubing. This was an indication the coil had most likely dissolved and became detached from the ribbon at one point in time. Stimulation was present for a certain period of time as evidenced by the presence of greenish tint inside the inner silicone tubing. Based on the findings, there was evidence to suggest a discontinuity in the returned portions of the device. With the exception of the discontinuity, the condition of the returned lead portions was consistent with conditions that typically exist following an explant procedure. Continuity checks of the returned lead portion were performed and no other discontinuities were identified. The set screw marks found on the lead connector pin provided evidence that, at one point in time, a good mechanical and electrical connection was present. The returned generator is undergoing product analysis.
 
Event Description
Additional information was received that the patient would have the device explanted and go for a surgical work-up. The nurse indicated that the patient is not likely a surgical candidate, so will have a new vns implanted at a later date. No additional information was provided. Surgery is likely, but has not occurred to date.
 
Event Description
It was reported that a patient was experiencing pain in his neck and had lost his voice. Diagnostics performed on the patient's generator showed high impedance with a dc/dc of 7. The generator was programmed to 0ma and the patient was sent for x-rays. It is unclear if the x-rays will be sent to the manufacturer for review. The patient has been scheduled to see an ent and has been referred for surgery. Surgery is likely, but has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2229120


Title: Re: Electrodes
Post by: dennis100 on October 06, 2018, 04:49:19 AM
Model Number 300-20
Device Problem Detachment of Device or device Component
Event Date 08/24/2018
Event Type  Malfunction   
Manufacturer Narrative
(b)(4).
 
Event Description
It was reported that the patient was feeling irritation in her neck and that the physician had taken x-rays of the neck. It was stated that the physician believed that the electrodes had migrated. The physician wanted to disable the vns to reduce the irritation. The x-rays have not been reviewed by the manufacturer to date. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7887044


Title: Re: Electrodes
Post by: dennis100 on October 20, 2018, 12:27:20 PM
Model Number 300-20
Event Date 08/08/2012
Event Type  Malfunction   
Event Description
It was reported that a vns patient was going to be scheduled for a battery replacement for eos. An x-ray was taken, but not sent to the manufacture for review. It was reported that "radiology report came back and stated that there is a fracture of one of the electrodes". At this time no surgery is planned but may be scheduled at a later date. No further information has been attained at this time.
 
Event Description
Additional information was received that there was no surgery date set at this time. The patient does have a history of falls, but it was unknown if they had a fall prior to their lead break. X-rays will not be provided to the manufacturer for review. No previous diagnostics are available for review.
 
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.
 
Event Description
Product analysis was completed on the returned lead and generator. Note that since a portion of the lead (including the electrode array) was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than typical wear and explant related observations, no anomalies were identified in the returned lead portion. Analysis was completed on their explanted generator. During the analysis, there was no indication from the device that an end of service condition existed. A battery life estimation resulted in 4. 17 years remaining before the eri flag would be set. However, an incomplete programming history (last 6 years are missing) indicates the estimation does not use all the data required to make an accurate estimation. The device performed according to functional specifications of the current automated final test. Analysis of the generator in the lab concluded that no abnormal performance or any other type of adverse condition was found.
 
Manufacturer Narrative
Device malfunction occurred, but did not cause or contribute to a death or serious injury.
 
Event Description
The patient had full revision surgery. No lead break was observed in the surgery. The patient's old electrodes were not removed. A portion of the lead body and explanted generator is being returned for analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2736900


Title: Re: Electrodes
Post by: dennis100 on October 25, 2018, 01:42:30 AM
Model Number 102
Event Date 06/18/2010
Event Type  Injury   
Event Description
Although vns explant surgery is likely, it has not occurred to date.
 
Manufacturer Narrative

Event Description
A nurse practitioner at a neurologist's reported on (b)(6) 2012, that a patient was experiencing bradycardia with vns stimulation, and the patient will likely have his device removed as a result. The patient is also being monitored by a cardiologist who has noted that the patient has second- and third-degree heart block during stimulations. She also indicated that he was having a drop in blood pressure during these bradycardia events causing syncope. Due to the adverse events, she expects the device to be explanted, but they are waiting for the cardiologist evaluation to be completed. They first confirmed the bradycardia and syncope on (b)(6) 2012, but she suspects that this has been an on-going issue since the patient was turned on ((b)(6) 2010). The patient is noted as being a poor historian due to issues with alcohol abuse and appointment compliance, and she feels that he cannot tell the difference between a seizure and a syncopal event, which is why she feels that this has been an issue since after implant. She does not feel that the device is malfunctioning, but the placement of the electrodes is the likely cause. She mentioned that they were able to induce an event with the magnet activation, which is how they confirmed the events occurring with stimulation. When asked if the events are occurring with normal mode stimulation, she said that she believed so, which is why there is question about the previous seizures possibly being syncopal events. The events were not occurring with every normal mode activation. The patient's device is now disabled and is wearing a holter monitor to further determine if this event is occurring without stimulation. An ecg/cardiology monitor report was received indicating the patient's average heart rate is 64 bpm. The minimum heart rate was measured as 27 bpm, and the maximum heart rate was 101 bpm. The study concluded that the patient has complete heart block on (b)(6) 2012, at one point. A cardiology consult was placed for the electrophysiologist. The arrhythmia questionnaire was received from the neurologist's office reporting that the patient does not have a prior history of cardiac events nor does his family. The patient does have pre-existing medical conditions of tuberous sclerosis, sleep apnea, and major depression which are unrelated to vns. The patient has experienced 2nd degree type 1 and type 2, in addition to 3rd degree heart block. The patient's normal heart rate is about 64 bpm, but during the bradycardia it dropped to 27 bpm. This did not occur intraoperatively. No traumatic events, medication changes, or vns settings changes were experienced prior to the arrhythmia. The bradycardia occurs with the on time of vns stimulation but not during diagnostics. The neurologist's office believes the arrhythmia is related to vns stimulation. The patient has not been hospitalized for this event. Since the device was disabled, the patient reports that the bradycardia has not occurred again, but they are awaiting the holter monitor results.
 
Manufacturer Narrative
Article citation: american journal of therapy; 2013 jun 21. [epub ahead of print]; late-onset advanced heart block due to vagal nerve stimulation. Schevchuck a, west mb. Department of internal medicine, division of cardiology. (b)(6).
 
Manufacturer Narrative
Describe event or problem, corrected data: the initial report inadvertently did not include this information.
 
Event Description
On (b)(4) 2013 information was received from the reporter that a case study was being published on this patient and event and that an abstract for the article had been received for the article. The article is ¿late-onset advanced heart block due to vagal nerve stimulation¿ by a. Schevchuck and m. B. West, published in the american journal of therapy on june 21, 2013. Figures #1 and #2, which display ekgs of the patient¿s normal sinus rhythm and sinus rhythm during vns stimulation showing advanced atrioventricular block, respectively, are figures not received in the past.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2728697


Title: Re: Electrodes
Post by: dennis100 on October 27, 2018, 12:44:41 AM
Model Number 102
Event Date 09/19/2012
Event Type  Injury   
Manufacturer Narrative
 
Event Description
On (b)(6) 2012, it was reported that this vns patient experienced an arrhythmia during initial implant surgery that day. The patient was successfully implanted. An in-pocket system diagnostic was normal, and a final interrogation confirmed that the normal mode and magnet mode output currents were 0. 00 ma. During the first system diagnostic test, the surgeon noticed a heart arrhythmia during the vns stimulation period. He stated it was not bradycardia, just an abnormal arrhythmia. The system diagnostic test was repeated multiple times, all tests were within normal limits, and the arrhythmia was still present. Following each test, the surgeon attempted to re-position the coils on the nerve to maximize the distance between the coils and the cervical branch of the vagus nerve. He stated the arrhythmia was minimized but was still present after the repositioning of the coils. He stated this was likely due to the very small size of the patient and the short length of nerve he had to work. Attempts for additional information have been unsuccessful.
 
Event Description
A fax was received on (b)(6) 2012, from the patient's physician. The fax indicated that additional interventions included "cardiology consult and simultaneous". The patient did not have a previous history or family history of cardiac events. The patient's pre-existing conditions included neonatal cerebral abscesses, infantile spasms, intractable epilepsy, and global developmental delay. The patient experienced bradycardia. Prior to the event, the patient's heart rate was 109 bpm. During the event, the patient's heart rate was 104 bpm.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2792641


Title: Re: Electrodes
Post by: dennis100 on November 06, 2018, 07:07:45 AM
Model Number 304-20
Device Problem Device Dislodged or Dislocated
Event Date 03/09/2015
Event Type  Malfunction   
Event Description
It was later reported through clinic notes the patient experienced widespread muscle spasms in the neck and face prior replacing the lead.
 
Manufacturer Narrative
 
Event Description
It was reported that the patient is feeling a bulging sensation with stimulation. The vns device was tested and no high impedance was found so the neurologist chose to keep the vns device programmed on. X-rays were taken and it was reported that the electrodes appear dislodged from the nerve. The neurologist believes the electrodes were dislodged because the patient began golfing too soon after surgery. It was also reported that the bulge was not visible from the outside; no protrusion. The patient had lead revision surgery on (b)(6) 2015, the generator was not replaced. After the new lead was implanted and connected to the vns generator, diagnostics were performed and were within acceptable levels. Attempts to obtain additional relevant information have been unsuccessful to date. The explanted generator has not been received to date. It was reported that it was likely discarded by the explanting facility.
 
Event Description
It was verified that the lead was detached from the nerve. It was also reported that the lead revision surgery resolved the bulging sensation that the patient was feeling previous to the revision.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4953543


Title: Re: Electrodes
Post by: dennis100 on November 13, 2018, 07:02:41 AM
Model Number 304-20
Event Date 12/20/2012
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported by a vns implanting surgeon that during implantation of this patient's lead the green sutures came off of the anchor tethers and that the electrodes were coming off the nerve. Ultimately the electrodes stayed on the nerve and diagnostics performed were within normal limits. The surgeon asked if the leads had been made differently because of this and that he said that the electrodes looked like they were 'slightly tilted. ' this surgeon has been using the 304 leads for quite some time and has only used 2mm coils, except for in rare instances when the 3mm was needed. Review of manufacturing device history records for the helical lot used was performed to ensure that all assembly steps were signed off and there were no anomalies or unresolved defects/ncr's. It appears that the lead in this patient has met all specifications prior to shipment.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2959687


Title: Re: Electrodes
Post by: dennis100 on November 15, 2018, 08:29:19 AM
Model Number 302-20
Event Date 02/01/2013
Event Type  Malfunction   
Event Description
The patient had generator and lead replacement surgery on (b)(6) 2013 due to painful stimulation and the patient felt as if the device was flipping. The explanted products were received by the manufacturer on (b)(4) 2013. However, product analysis has not been completed to date.

Event Description
An analysis was performed on the returned lead portions which identified observed abraded openings on the outer and inner tubing sections have the potential for contributing to the painful stimulation allegation. The abraded opening found on the outer and one inner silicone tubing, most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the outer and one of the inner silicone tubes. For the observed inner tubing fluid remnants found inside the second inner silicone tubing, there was no obvious path for fluid ingress other than the cut ends that were made during the explanted process. The condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. Other than the abraded openings of the outer and inner tubing, no additional obvious anomalies were noted. The setscrew marks found on the lead connector pins provide evidence that, at one point in time, a good mechanical and electrical connection was present. One set of setscrew marks was found near the end of the connector pin, indicating the connector pin had not been fully inserted into the cavity of the pulse generator at one time. However, based on the location of the setscrew marks on the pin, it is unknown whether a good electrical connection was present for the connector ring. Continuity checks of the returned lead portion were performed, during the visual analysis, with no discontinuities identified. Based on the findings in the product analysis lab, there is evidence of an abraded opening in the inner tubing, which may have contributed to the stated painful stimulation complaints. The generator performed according to functional specifications. During the product analysis, there were no anomalies found with the pulse generator.

Manufacturer Narrative
Suspect medical device, corrected data: with the product analysis results, the initial report inadvertently reported the suspect device incorrectly. Device manufacture date, corrected data: with the product analysis results, the initial report inadvertently reported the suspect device incorrectly. Device failure occurred, and may have contributed to the patient's pain. Review of lead manufacturing records confirmed that all quality tests were passed prior to distribution.

Manufacturer Narrative

Event Description
It was initially reported that the patient was referred for surgery due to the device slipping. Diagnostics are fine but the patient feels pain. Clinic notes dated (b)(6) 2013 were received due to the patient being referred for surgery. The generator was disabled due to currently experiencing "pain in her neck over the scm muscle as it did once prior in 2006 when revision was needed, because the device had slipped out of place". The events in 2006 were previously reported in mfg report number: 1644487-2013-00840. It was noted by the surgeon that the lowest lead connection was off of the nerve, which was putting traction on the nerve. Releasing the tension moved the nerve back to a more normal position. The surgeon described the patient's tissue as "weakened", and that the tissues might be consistent with an underlying collagen vascular disorder. The patient's "tissue", specifically the fascia and collagenous tissues were described as weakened and lacking the usual texture that these tissues should demonstrate and it is suspected the patient has an underlying collagen vascular disorder. It is unclear if the possible collagen disorder caused the lead to migrate. No trauma occurred. It was further indicated in the notes that the patient had noted pain with vns stimulation on times for the past month described as focal pain at the electrode site. The patient's seizures are under good control, but the vns device was turned off due to "lead impedance problems and elevated dc code and pain". However, diagnostics were within normal limits. System diagnostics showed dcdc=2, and normal mode diagnostics showed dcdc=3. Additionally, the lead impedance was indicated as "ok". The physician also stated the generator is not at eos, "but we believe it is disconnected. " x-rays were ordered, and the patient was referred for vns replacement surgery due to painful stimulation which the physician indicated the pain could preclude injury. Upon follow-up with the treating physician, it was reported that they are unable to establish communication with the device currently but then it was later indicated that the device could be interrogated to show the impedance. Current x-rays do not show any obvious discontinuities, but they have not been provided to the manufacturer for review to date. The x-ray report indicates the x-rays were compared to those dated (b)(6) 2006 and there were no evidence of lead disruption or significant displacement identified. Additionally, there was no gross discontinuity involving the stimulator although evaluation was reported to be quite limited. No patient or manipulation is believed to have contributed to the events. The physician does not believe the leads are disconnected and does not believe that there is lead migration at this time. There were no causal or contributory programming or medication changes that preceded the onset of the events. After the device was turned off due to pain in the generator and lead area, the pain stopped. Although surgery is likely, it has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3027440


Title: Re: Electrodes
Post by: dennis100 on November 15, 2018, 08:30:06 AM
Model Number 300.20
Event Date 07/01/2009
Event Type  Malfunction   
Manufacturer Narrative
"electrode detach from nerve is beyond the scope of activities performed in the product analysis lab". The portion of the lead that was returned for analysis did not reveal any anomalies. However, a device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported by the surgeon that the patient underwent a full revision surgery due to lead disconnected from nerve. X-rays were taken which clearly showed top lead disconnected from the nerve. X-rays were not available for further manufacturer review. No patient manipulation or trauma was reported. Explanted products were returned to manufacturer for further review. Analysis was completed on the lead and reported allegation of high lead impedance was not confirmed. Condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1497730


Title: Re: Electrodes
Post by: dennis100 on November 15, 2018, 08:31:24 AM
Model Number 304-20
Event Date 01/10/2013
Event Type  Injury   
Manufacturer Narrative

Event Description
It was initially reported that the patient went back into surgery following implant. The surgeon believed that he placed the electrode on the nerve upside down and took the patient back in to surgery to correct the placement. Diagnostics were within normal limits at implant surgery and were within normal limits following the electrode placement correction. There were no adverse events, the surgeon simply recalled that he placed them upside down and schedule the patient for surgery to correct them. There were no x-rays taken to confirm the event prior to the surgery.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2942632


Title: Re: Electrodes
Post by: dennis100 on December 01, 2018, 01:44:43 AM
Model Number 302-20
Event Date 06/21/2013
Event Type  Malfunction   
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
On (b)(6) 2013 it was reported that the vns patient¿s vns lead was referred for replacement due to high lead impedance. Battery life calculations revealed that the vns generator had 0. 0 years left til end of service. Good faith attempts have been performed and it was later reported that the high impedance issue was first observed on (b)(6) 2013. The patient did not experience pain or any other adverse events. The office reported that their patient¿s vns devices are not turned off unless they are in pain. Thus, the patient¿s device was not changed to 0 ma. No x-rays were taken. No patient manipulation or trauma is believed to have caused or contributed to the high impedance. However, the physician was not able to provide a reason as to why the high impedance issue occurred.

Event Description
On (b)(6) 2013, it was reported that the patient had the vns generator and lead replaced on (b)(6) 2013. Diagnostics were performed which were all ok and the patient was interrogated prior to leaving the operating room to ensure the device was programmed off. However, when the patient came back into the office for a follow up visit, it was found that the device was turned on (reported in mfr #: 1644487-2013-02883). No other information was provided. The explanted device has not been returned.

Event Description
The generator and lead were returned to manufacturer for analysis on (b)(4) 2013. The lead analysis was completed on (b)(4) 2013. During the visual analysis the white (+) and green (-) ribbons appeared to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the electrode ribbons from coming in contact with the vagus nerve; therefore contributing to the reported allegations. With the exception of the observed tissue-covered (+) white and (-) green electrode ribbons the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The slice marks found on the outer and inner silicone tubes and the cut ends that were made during the explanted process, most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the outer and inner silicone tubes. What appeared to be white deposits were observed on the connector boot. Eds (energy dispersion spectroscopy ¿ provides chemical or element identity/composition analysis) was performed and identified the deposit as containing silicon, phosphorus, sodium, magnesium, zirconium, sulphur, chlorine and calcium. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no discontinuities were identified. Based on the findings in the product analysis lab, there is no evidence to suggest a discontinuity in the returned portions of the device which may have contributed to the high impedance. However the "as-received" condition of the helicals suggest they were not mounted on the vagus nerve during some portion of the implant life. The generator analysis was completed on (b)(4) 2013. The end of service condition was the result of normal, expected battery depletion based on the battery life calculation, the electrical test results and the bench evaluation. The device performed according to functional specifications. Analysis of the generator in the pa lab concluded that no abnormal performance or any other type of adverse condition was found.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3242310


Title: Re: Electrodes
Post by: dennis100 on December 12, 2018, 01:49:00 AM
Model Number 302-20
Event Date 08/16/2013
Event Type  Malfunction   
Manufacturer Narrative
Device manufacturing records and programming history were reviewed. Review of manufacturing records confirmed the device met all final testing specifications prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Event Description
It was reported that the patient was seen on (b)(6) 2013 and high lead impedance was observed. The physician programmed the patient's device off to 0ma output current. The patient was referred to the surgeon for evaluation and x-rays were ordered, but will likely not be sent to the manufacturer. The physician does not believe that trauma or manipulation contributed to the event. Revision surgery was completed on (b)(6) 2013. Review of the lead device history records confirmed all quality tests were passed prior to distribution. It was noted that the patient previously experienced high impedance after implant in (b)(6) 2010 due to the electrode not being adequately seated on the nerve (reported in mfr #: 1644487-2010-02723). The explanted generator and lead were returned on (b)(6) 2013 and are pending product analysis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3363567


Title: Re: Electrodes
Post by: dennis100 on December 22, 2018, 09:43:58 AM
Type of Device:                      Stimulator
Device Brand Name:               VNS Demipluse
Device Manufacturer's Name:  Cyberonics
Date of this Report:                04/07/2011
(mm/dd/yyyy)
Describe the Event                  Left vagal stimulator lead/generator explanted. Stimulator lead "broke,
or Problem:                            and not attached to nerve".
the device(s) may
have                                      Potential for patient harm
caused or contributed to:         

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/Medsun/medsun_details.cfm?ID=24452


Title: Re: Electrodes
Post by: dennis100 on December 23, 2018, 10:33:35 AM
Model Number 302-30
Event Date 10/05/2013
Event Type  Malfunction   
Manufacturer Narrative
Device manufacturing records and programming history were reviewed. Review of manufacturing records confirmed the device met all final testing specifications prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

Manufacturer Narrative
Initial mfr. Report inadvertently listed the incorrected suspect device.

Event Description
It was reported that the patient underwent generator and lead replacement. Preoperative diagnostics were within normal limits. The physician's assistant reported that diagnostics in the physician's office were also within normal limits. During the surgery, the lead (including electrodes) and generator were removed. The surgeon indicated that the electrodes were wrapped tight around the vagus nerve and a "branch" and that there was a lot of scar tissue. The surgeon was certain that it was not the cardiac branches or the laryngeal branches. A new lead was placed on the vagus nerve and new generator was attached to the new lead. Diagnostic tests were within normal limits with the new system. The explanted devices were sent to the hospital pathology and the operating room nurse indicated that the hospital does not usually send back explanted devices. A returned product kit was given and a request to have the explanted devices was provided. It was reported that a company representative went to the site to assess diagnostics on the device prior to surgery being scheduled. It was reported that device diagnostics were unable to be performed due to the patient's complaints of pain and swelling in the neck area. It was reported that the patient was told by the physician that he recommended system replacement based on the patient';s pain and swelling and not based on "bad" diagnostics. The physician left the patient to decide on replacement. The patient reportedly decided on having the device replaced because it was felt that the device was of benefit to the patient. The generator and lead were received for analysis. Analysis of the generator was completed on 04/01/2014. The generator performed according to functional specifications. During the product analysis there were no anomalies found with the pulse generator. Analysis of the lead was completed on 04/01/2014. The puncture mark found on the outer silicone tubing and the cut ends that were made during the explanted process, most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids inside the outer silicone tubing. For the observed inner tubing fluid remnants, there was no obvious path for fluid ingress other than the cut ends that were made during the explanted process. What appeared to be white deposits were observed in various locations. Eds (energy dispersion spectroscopy - provides chemical or element identity/composition analysis) was performed and identified the deposit as containing silicon, phosphorus, chlorine and calcium. The condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, with no discontinuities identified. Based on the findings in the product analysis lab, there is no evidence to suggest an anomaly with the returned portion of the device which may have contributed to the stated complaints.

Event Description
On (b)(4) 2013, it was reported that the patient had the vns device disabled by an unknown doctor in (b)(6) due to chest and neck pain. This was found out by the physician when the patient was hospitalized and admitted to the epilepsy monitoring unit (emu) for an increase in seizures. The physician turned the device back on and performed diagnostics on (b)(6) 2013 (emu admit date) and the results showed low impedance. The patient continued to have chest and neck pain with stimulation. The neurologist turned off the device and it has been off since (b)(6) 2013. Follow up indicates that although the device was implanted since 2004, it was only turned on for the last year or so (per the patient). The patient may be proceeding with device replacement, but no surgery has taken place to date. Attempts for additional information have been unsuccessful. No additional information has been provided.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3527747


Title: Re: Electrodes
Post by: dennis100 on December 29, 2018, 04:26:34 AM
Model Number 102R
Event Date 05/02/2013
Event Type  Death   
Event Description
Additional information was received stating that the vns patient was born on (b)(6) 1946, not (b)(6) 1949 as initially reported. The patient¿s death certificate was obtained. The death certificate listed the immediate cause of death as cardiopulmonary arrest with probable acute coronary syndrome and probable coronary artery disease as sequential conditions that contributed to the death. The patient had other significant health conditions may have contributed to the patient¿s condition. Nurse¿s notes regarding the patient¿s death were received. The notes indicate that the patient was being closely monitored due to treatment with continuous positive airway pressure (cpap). It was noted that the patient¿s cpap mask had be adjusted frequently. No issues were noted with the patient when he was evaluated at 11:00 pm on (b)(6) 2013. At 11:45 pm, the notes indicate that nurse required assistance adjusting the patient¿s cpap mask because the patient kept removing it. At midnight, nurse reported that the patient was pale, warm to touch, breathless, non-responsive, and pulseless. Cpr was immediately initiated and the paramedics that arrived approximately ten minutes later continued cpr until the patient was pronounced dead at 12:33 am on (b)(6) 2013. Follow-up with the nurse revealed that the patient was not having a seizure at the time of death the patient¿s seizure record indicated that the patient experienced several seizures from (b)(6) 2013 which consisted of stiffening, jerking, some forward head drops, flinging of the arms. The patient¿s postictal periods were uneventful with good recovery. With the available information, an internal classification determined that the death was unlikely sudep. The patient¿s body was donated to science and the patient¿s devices were explanted. The explanted generator and lead have been returned to the manufacturer where analysis is currently underway.
 
Event Description
Analysis of the returned generator and lead was completed. There were no performance or any other type of adverse conditions found with the pulse generator. The device was confirmed to be at end of service as result of normal battery depletion. The depletion was an expected event as determined by the blc and battery voltage measurement. The module performed according to functional specifications. There is no evidence to suggest an anomaly with the returned portions of the lead. During the visual analysis, the (+) white and (-) green electrodes appeared to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the ribbons from coming in contact with the vagus nerve. With the exception of the tissue-covered (+) white and (-) green electrodes, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. The setscrew marks found on the lead connector pins provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no discontinuities were identified. Note that since a large portion of the lead assembly (body) was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.
 
Event Description
Additional information was received stating that the vns patient¿s device was at end of service on (b)(4) 2010.

Manufacturer Narrative

Event Description
Additional information was received stating that the vns patient passed away on (b)(6) 2013. The patient was found dead on his bed in a supine position. The patient device¿s was disabled at the time of death and was not explanted. It was reported that the patient¿s death was not related to vns. An internal review of the available information determined that the patient¿s death was possible sudep.
 
Manufacturer Narrative
Additional information indicates that the patient¿s dob was (b)(6) 1946.
 
Event Description
It was reported that the patient passed away approximately 3-4 months ago. The cause of death is not know at this time. It was reported that the patient had a pacemaker and known cardiac issues which was previously reported in mfr. Report # 1644487-2013-00834. Attempts to obtain additional information will be made, but no information has been obtained to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3506710


Title: Re: Electrodes
Post by: dennis100 on January 08, 2019, 07:47:16 AM
Model Number 300-20
Event Date 02/28/2014
Event Type  Malfunction   
Event Description
It was reported that the vns patient¿s device was tested and diagnostic results revealed high lead impedance (impedance value >= 10,000 ohms). The patient¿s device was not programmed off. Clinic notes were received stating that the high impedance was first observed during an office visit on (b)(6) 2014. The patient has not experienced any changes in her seizure control. The notes also indicate that the battery appeared to be depleting too quickly even with the high duty cycle. No known interventions have occurred to date. Attempts for additional relevant information were made but have been unsuccessful to date.
 
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to death or serious injury.
 
Event Description
The patient underwent generator and lead replacement on (b)(6) 2014. The lead and generator were received on (b)(4) 2014. Analysis is underway, but has not been completed to date. Attempts to obtain additional relevant information have been unsuccessful to date.
 
Event Description
Additional information was received stating that the vns patient did not have any trauma, changes in device settings, or changes in medications that may have contributed to the high impedance. The patient's device was disabled on (b)(6) 2014. The patient was doing well following replacement surgery. Analysis of the returned generator and lead was completed. Monitoring of the generator's device output signal showed no signs of variation in the pulse generator's output signal and demonstrated that the device provided the expected level of output current. A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. The battery shows a non-ifi condition. There were no performance or any other type of adverse conditions found with the pulse generator. During the visual analysis of the returned 385mm lead portion, the (-) green electrode quadfilar coil appeared to be broken approximately 3mm from the electrode bifurcation. Scanning electron microscopy was performed identified the area as having evidence of a stress induced fracture (fatigue appearance) with mechanical damage and fine pitting. Pitting was observed on the coil surface. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity. During the visual analysis of the returned 385mm portion the (+) white electrode and ribbon appeared to be embedded in remnants of dried body tissue. This condition may have prevented the (+) white electrode ribbon from coming in contact with the vagus nerve. With the exception of the observed discontinuity and the tissue-covered (+) white electrode and ribbon the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. Abrasions were observed in various locations, possibly caused by wear. Coils appeared slightly stretched, kinked and wavy in some areas which most likely occurred due to manipulation of the lead during the explant process. The setscrew marks found on the lead connector pins provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, with no other discontinuities identified. Based on the findings, there is evidence to suggest a discontinuity in the returned portions of the device which may have contributed to the high impedance. However, the positive electrode condition may have contributed to the reported high impedance.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3710150


Title: Re: Electrodes
Post by: dennis100 on January 08, 2019, 07:48:47 AM
Model Number 105
Event Date 02/25/2014
Event Type  Injury   
Event Description
Clinic notes were received for the vns patient¿s neurosurgery consultation on (b)(6) 2014. The notes indicate that the patient was experiencing a recent increase in seizures along with a shocking sensation at the generator site; therefore, the patient was admitted to the hospital through the emergency room on (b)(6) 2014. The patient stated that his seizure frequency had increased from five seizures a day to a seizure every hour. The baseline seizures appeared to last approximately 15 seconds and were tonic-clonic or absence seizures. Radiology reported that neck x-rays showed that lead wires were ¿off. ¿ chest x-rays were reported to be unremarkable. Operative notes were received stating that the patient underwent generator and lead replacement surgery on (b)(6) 2014. The notes indicate that the patient was experiencing a shocking sensation in his neck with stimulation. Imaging revealed abnormal placement of the lead electrodes. The generator was replaced during the procedure as it was nearing end of service. An implant card was received stating that the lead was replaced due to lead discontinuity. Diagnostic results with the replacement generator and lead revealed lead impedance within normal limits (impedance value ¿ 1906 ohms). Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2012. Attempts for additional relevant information were made, but have been unsuccessful to date. The explanted generator and lead have been returned to the manufacturer where analysis is currently underway.
 
Event Description
Analysis of the returned generator and lead was completed. Analysis of the returned generator showed no signs of variation in the pulse generator¿s output signal and demonstrated that the device provided the expected level of output current. The pulse generator diagnostics were as expected for the programmed parameters. In addition, a comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. There were no performance or any other type of adverse conditions found with the pulse generator. Review of the as-received internal device data showed high impedance never occurred. Analysis of the returned lead portion found abraded openings on the outer silicone tubing which most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids inside the outer silicone tubing. The condition of the returned lead portion is consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, with no discontinuities identified. Based on the findings, there is no evidence to suggest an anomaly with the returned portion of the device which may have contributed to the stated complaints. Note that since the electrode array section was not returned for analysis, an evaluation cannot be made on that portion of the lead.
 
Manufacturer Narrative
Review of the available programming and diagnostic history. Device failure is suspected, but did not cause or contribute to a death.
 
Manufacturer Narrative
Adverse event and/or product problem; corrected data: additional information indicates that a device malfunction did not occur. Brand name; corrected data: additional information indicates that the suspect device is the generator. Type of device, name; corrected data: additional information indicates that the suspect device is the generator. Model #, serial #, lot#, expiration date; corrected data: additional information indicates that the suspect device is the generator. Date of implant; corrected data: additional information indicates that the suspect device is the generator. Type of reportable event; corrected data: additional information indicates that a device malfunction did not occur. Device manufacture date; corrected data: additional information indicates that the suspect device is the generator.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3701858


Title: Re: Electrodes
Post by: dennis100 on January 12, 2019, 03:55:22 AM
Model Number 302-20
Event Date 03/06/2014
Event Type  Malfunction   
Event Description
Additional information was received stating that the vns patient underwent lead replacement surgery on 09/05/2014 due to lead discontinuity. The explanted lead has been returned to the manufacturer where analysis is currently underway.
 
Manufacturer Narrative
Device manufacturing records and available programming and diagnostic history were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received indicating that the patient underwent surgery. During the surgery, a new generator was attached to the existing lead and device diagnostics were within normal limits (3767 ohms). It was reported that the patient's head and neck were placed in different positions and subsequent diagnostics were within normal limits. The surgery was finalized with only generator replacement. It was later reported that device diagnostics again resulted in high impedance (>10,000 ohms). The generator was programmed off and the patient was referred for lead replacement. No known surgical intervention have been performed to date. The generator was received for analysis on (b)(4) 2014. Analysis is underway, but has not been completed to date.
 
Event Description
Analysis of the generator was completed on 08/07/2014. Results of the analysis will be reported on the quarterly remedial actions exemption report.
 
Event Description
Analysis of the returned lead was completed. During the visual analysis, connector pin and connector ring quadfilar coils appeared to be broken. Pitting was observed on the coil surfaces. Remnants of dried body tissue were observed wrapped around a portion of helical and green electrode ribbon. This condition may have prevented the green electrode ribbon from coming in contact with the vagus nerve. The abraded openings found on the outer and inner silicone tubes most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids found inside the outer and inner silicone tubes. With the exception of the observed discontinuities and the tissue-covered green electrode ribbon, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure.
 
Event Description
It was reported that the vns patient¿s device was tested and diagnostic results showed high lead impedance (impedance value - 6709 ohms) during an office visit on 03/06/2014. X-rays were taken but have not yet been provided to manufacturer for evaluation. The device was not disabled. The patient is often injured because she has drop attack seizures, which may have caused or contributed to the reported high impedance. However, no definitive conclusions can be made with the available information. Review of the available programming and diagnostic history showed normal diagnostic results through 08/01/2013. No known interventions have occurred to date. Attempts for additional relevant information were made but have been unsuccessful to date.
 
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to death.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3733255


Title: Re: Electrodes
Post by: dennis100 on January 14, 2019, 03:55:03 AM
Model Number 304-20
Event Date 03/24/2014
Event Type  Injury   
Event Description
Analysis of the returned generator was completed. Results of diagnostic testing indicated the device operated and communicated properly. Electrical test results showed that the pulse generator performed according to functional specifications. There were no adverse functional, mechanical, or visual issues identified with the returned generator.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution.
 
Event Description
It was reported that the recently implanted vns patient¿s incision sites were red and swollen about 2-4 weeks after implant surgery so the patient was given an antibiotic regiment. The patient¿s lead was reported to be extruding from her neck. It was noted that the patient may have been picking at her neck incision site following implant surgery. Clinic notes were received indicating that the patient had a grand mal seizure that lasted several minutes and subsequently caused her lead the extrude from the left side of her neck. The patient went to the emergency room on (b)(6) 2014 and was admitted to the hospital due to lead extrusion. The patient did not have a fever or any neck swelling. There was no change in the patient¿s seizure frequency. The lead was observed to be extruding from the neck incision site with minimal erythema. The patient¿s chest had a puffy area that was fluctuant but not especially erythematous with no surrounding induration. The surgeon stated that it was most consistent with a seroma with a possible foreign body reaction. The patient underwent surgery on (b)(6) 2014 to explant her generator and revise the lead. Operative notes indicate that there was a mass of inflammatory tissue in the chest wall upon opening the epithelium. An exuberant amount of inflammatory tissue was observed around the patient¿s generator. No abscess was encountered. Other than granulation tissue in the left neck, the lead incision site looked normal and without any sign of infection. A portion of an electrode and a tie-down were observed to be extruding from the neck. The tie-down was removed from the lead. The patient¿s device was tested and diagnostic results revealed lead impedance within normal limits. The inflammatory tissue in the chest wall was removed and the patient¿s generator was explanted. The surgeon explanted the generator because he felt it was too big to be sterilized in the contaminated generator site. The generator pocket was debrided and rinsed with an antibiotic solution. The neck incision was then reopened and the granulation tissue was removed. The surgeon pulled down the disconnected lead in the chest wall and was able to reposition the lead into the deep intramuscular tissues in the neck. The neck incision site was irrigated and then closed. Antibiotic ointment was applied to the neck incision site. The lead was secured in the chest wall with sutures and the chest incision was closed. The patient was given a postoperative antibiotic regiment. A review of device history records showed that both the lead and generator were sterilized prior to distribution. The explanted generator was returned to the manufacturer where analysis is currently underway.
 
Event Description
It was reported that the patient had another surgery about three months after the generator explant to have her leads explanted due to foreign body reaction in the left neck and upper left chest. The surgeon removed an inflammatory mass of in the left chest cavity (4cm). No further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3827886


Title: Re: Electrodes
Post by: dennis100 on January 17, 2019, 02:31:40 AM
Model Number 103
Event Date 01/14/2014
Event Type  Injury   
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution.
 
Event Description
It was reported that the recently implanted vns patient underwent surgery to explant her device on (b)(6) 2014. High levels of serous secretion and signs of infection were observed at the generator site with 50% wound dehiscence. There were no signs of trauma at the generator site. The generator site had not improved since implant so the patient¿s device was explanted. The generator pocket was washed out with antibiotics following generator explant. One of the electrodes could not be explanted due to fibrosis which the physician attributed to vns. The remaining portion of the lead was explanted and the wound was washed out with antibiotics. Cultures were (b)(6) and the patient was given an antibiotic regiment. Further follow-up revealed that the infection developed at the generator site approximately three month following implant surgery. The patient is not expected to be re-implanted. Review of manufacturing records confirmed sterilization for both the generator and lead prior to distribution.
 
Event Description
The lead and generator were returned for analysis on 02/27/2015. Product analysis for the lead was completed on 03/18/2015. Since a significant portion of the lead (including the electrode array) was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than typical wear and explant related observations, no anomalies were identified in the returned lead portion. Product analysis for the generator was completed and approved on 03/24/2015. Potential contributing factors to the infection have been considered / evaluated and none were found to exist in this situation. A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. The battery, 3. 023 volts as measured during completion of the final electrical test, shows an ifi=no condition. There were no performance or any other type of adverse conditions found with the pulse generator.
 
Event Description
The patient was discharged in (b)(6) 2014 because the infection was resolved.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3899763


Title: Re: Electrodes
Post by: dennis100 on January 22, 2019, 04:43:53 AM
Model Number 304-20
Event Date 12/18/2014
Event Type  Injury   
Event Description
Additional information was received from the neurologist that the patient required a revision of her vns in (b)(6) 2015 secondary to a possible allergic reaction to silicone sheathing. She subsequently had slow wound healing. Patient was seen on (b)(6) 2015 after apparently expressing a ruptured suture. It was not felt by the neurosurgeons to be infected at that time. Patient likely developed a uri in (b)(6) 2016 and then developed a left breast cellulitis necessitating removal of the device.
 
Event Description
Additional information was received that the patient completed her iv antibiotics on (b)(6) 2016 & her picc line was removed. Patient was told that vns could not be re-implanted as she has too much scar tissues. Due to patient's severe allergic reaction to the device & her body rejecting it, the surgeon will not be implant vns again for patient.
 
Event Description
On (b)(6) 2016 an email was received that the patient developed a cellulitis that needs to be removed. Additional information was received that the patient had her battery and lead wires removed on (b)(6) 2016 due to an infection. Patient is not sure if the coils are still intact on the vagus nerve as one of the coils came through the small open wound on patient's neck incision that never healed after she was implanted on (b)(6) 2014. Patient could not remember the month or year this happened. The opening was big enough to insert tip of qtip. Patient stated that the open wound happened approximately about a month after sutures were removed by the surgeon. Patient was instructed to use neosporin on the open wound, keep it dry and let air get to it. No oral antibiotics were given. Patient did not go to primary care provider at this time either. When one of the tie-downs was pushed through the wound opening in patient's neck, patient consulted the surgeon, who discussed that it was patient's body rejecting the device and that patient should be ok since there were two other tie downs in place. In 2015, patient had a mammogram. Patient thinks that the compression from the mammogram machine pulled the wires and made the generator move. Patient had to have surgery on the leads after that because the leads were displaced. Patient underwent repositioning surgery on (b)(6) 2015 for patient comfort. After the leads were repositioned and tied down, patient stated she was ok but still had the small wound on her neck and that it would open and close up on its own and at times leak some fluid. Patient was referred to wound care center for treatment for a couple of months. Patient later got a very bad sore throat, ear ache and was coughing up mucus in (b)(6) 2016. A throat culture was performed but no antibiotics were given. A review of device history records showed that both the lead and generator were sterilized prior to distribution. Additional relevant information has not been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5867152


Title: Re: Electrodes
Post by: dennis100 on January 28, 2019, 05:51:42 AM
Model Number 304-20
Event Date 08/01/2014
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that the lead being placed on the nerve upside down was confirmed during lead replacement surgery. Further follow-up revealed that the patient requested that the vns be explanted due to ear pain. The patient's device was programmed off, but the patient requested explant. It was reported that despite the lead replacement. The patient claims to still have a buzzing noise along with severe constant ear pain. It was reported that device diagnostics have been within normal limits and there is no belief of device malfunction. There is no relationship of the vns to the patient't buzzing noise and ear pain. The patient underwent vns explant on 12/12/2014.
 
Event Description
Additional information was received stating that the vns patient was referred for surgery to explant her generator. The patient reportedly was hearing a buzzing noise from her device. The patient¿s generator has not been explanted to date.
 
Event Description
It was reported that the vns patient¿s lead was implanted upside-down on the patient¿s nerve. It is unclear how the physician made this determination. An implant card was received stating that patient underwent lead replacement surgery on (b)(6) 2014 due to lead failure. The explanted lead has not been returned to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4110421


Title: Re: Electrodes
Post by: dennis100 on January 28, 2019, 05:52:28 AM
Model Number 304-20
Event Date 09/03/2014
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that during generator and lead replacement surgery on (b)(6) 2014 due to lead discontinuity, the vns patient¿s replacement lead was opened but not used. The surgeon stated that the opened lead was defective and could not be used as the middle helical could not be wrapped around the patient¿s nerve. Another lead was used to complete the procedure. The unused lead has not been returned to date. The lead discontinuity was reported in manufacturer report #1644487-2014-01204.
 
Event Description
The unused lead was received for analysis. Analysis was completed on 02/10/2015. During the visual analysis the (+) white electrode ribbon appeared to be stretched and twisted and the helical appeared to be misshaped. What appeared to be remnants of dried body fluids were observed. The (-) green electrode ribbon appeared to be stretched and the helical appeared to be misshaped. What appeared to be remnants of dried body fluids were observed. The anchor tether helical appeared to be misshaped. What appeared to be specs of dried body fluids were observed. This most likely occurred due to manipulation of the lead during the attempted implant procedure while attempting to place the electrodes on the vagus nerve. Setscrew marks were not observed on the connector pin. The condition of the lead assembly returned is consistent with conditions that typically exist following an attempted implant procedure; therefore the absence of setscrew marks on the connector pin and abrasions on the connector boot and outer silicone tubing is evidence that the lead assembly was not fully implanted. No other obvious anomalies were noted. Continuity checks of the returned lead assembly were performed with no discontinuities identified. Overall length and resistance measurements of the complete returned lead were determined to be in compliance with those defined in the manufacturing specifications.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4110329


Title: Re: Electrodes
Post by: dennis100 on February 07, 2019, 02:11:34 AM
Event Date 01/01/1998
Event Type  Injury   
Event Description
A case study titled ¿optimizing outcomes in refractory childhood epilepsy with vns therapy¿ was presented which included a vns patient who was experiencing painful stimulation and choking sensations months following vns implant surgery. The patient¿s device settings were very low and not high enough to perform system diagnostics. In (b)(6) 2013, an evoked potential test was performed but no abnormalities were observed. The patient underwent generator and lead replacement surgery on (b)(6) 2014. During the procedure, the surgeon noted that the vagus nerve was located more anteromedial to the common carotid arteries than expected possibly due to the large amount of fibrosis. The surgeon did not observe any issues with the patient¿s lead but noted that the electrodes were implanted more proximal to the nerve. The patient¿s physicians determined that the patient¿s issues were due to the electrodes being implanted too high and the nerve being superficial to the larynx. It was noted that the patient had been doing well with vns following the procedure.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4461163


Title: Re: Electrodes
Post by: dennis100 on February 07, 2019, 02:12:23 AM
Model Number 302-20
Event Date 04/16/2004
Event Type  Injury   
Event Description
Initially, it was reported that the patient experienced blurry vision and eyes spasms so the device was programmed off which reportedly resolved the issue. The neurologist and surgeon did not believe this was related to vns therapy. The patient later reported that the vns electrodes were placed too close to the optic nerve and that she went blind for 9 months. The patient had the device explanted. Attempts to obtain additional relevant information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4459777


Title: Re: Electrodes
Post by: dennis100 on February 12, 2019, 03:11:48 AM
Model Number 304-20
Event Date 06/11/2014
Event Type  Malfunction   
Manufacturer Narrative
Device manufacturing records and available programming and diagnostic history were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution.
 
Event Description
It was reported that a patient had undergone surgical lead revision on (b)(6) 2015 due to high impedance and that stimulation pulses were not perceived. The impedance following the lead replacement was reported to be correct. It was reported that high impedance had been observed on (b)(6) 2014. Review of programming history found that the pulse generator was enabled on (b)(6) 2014. No diagnostics were performed on that date. System diagnostics on (b)(6) 2014 resulted in high impedance, dcdc 7, neos no. It was reported that the suspected cause of high impedance was a wrong implant site of the lead electrodes. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. The explanted lead has not been returned to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4549105


Title: Re: Electrodes
Post by: dennis100 on February 15, 2019, 03:28:25 AM
Model Number 302-20
Event Date 01/01/2010
Event Type  Malfunction   
Event Description
It was initially reported by the physician that the patient was having a full revision surgery due to high lead impedance. Patient no longer feels stimulation and she is not certain when this occurred. Patient was taken into surgery and it was observed that there was a lot of lead near the generator. Surgeon replaced the generator first and performed diagnostics and found high impedance. The surgeon then attempts to remove the old lead and he noticed that there was a lot of fibrosis at the nerve. He also observed that the negative electrode was not on the nerve. The vagus nerve appeared to be bent at 90 degrees angle indicating something was likely pulling on the nerve. The surgeon removed the old lead and replaced it with the new lead. Fibrosis was removed from the nerve. Good faith attempts to obtain additional information has been unsuccessful.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1634008


Title: Re: Electrodes
Post by: dennis100 on February 15, 2019, 03:29:27 AM
Model Number 302-20
Event Date 03/05/2015
Event Type  Malfunction   
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
On (b)(6) 2015 it was reported that the patient¿s vns was interrogated and found to be at end of service with pulse disabled as well as high impedance during diagnostics. Surgery took place that day and when the generator was replaced, high impedance was still observed. Therefore they did a full revision. There was no noticeable lead fracture but the electrodes were in an inverted position. It was reported that the explanted products could not be returned for product analysis as the hospital discards them.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4625691


Title: Re: Electrodes
Post by: dennis100 on February 19, 2019, 03:24:14 AM
Model Number 302-20
Event Date 03/19/2015
Event Type  Injury   
Event Description
It was reported that the hospital does not return explanted products.
 
Manufacturer Narrative

Event Description
The patient had previously had generator and a portion of the lead explanted. During scheduled replacement surgery on (b)(6) 2015, the surgeon decided to abort the surgery. There was reportedly too much scar tissue, and the lead was unable to be removed from the nerve. The surgeon also believes that it would have been very difficult placing the new electrodes.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4725195


Title: Re: Electrodes
Post by: dennis100 on February 21, 2019, 01:47:48 PM
Model Number 105
Device Problems Fracture; High impedance
Event Date 03/16/2015
Event Type  Malfunction   
Event Description
The explanted generator and lead have been received by the manufacturer for analysis. However, analysis has not been completed to date.
 
Event Description
Analysis was completed on the explanted generator and lead. Analysis of the generator showed no anomalies. The device output signal was monitored for more than 24 hours, while the generator was placed in a simulated body temperature environment. Results showed no signs of variation in the pulse generator's output signal and demonstrated that the device provided the expected level of output current for the entire monitoring period. The pulse generator diagnostics were as expected for the programmed parameters. In addition, a comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications analysis of the lead showed a set of setscrew marks near the end of the connector pin indicating the lead had not been fully inserted into the cavity of the generator. The marks are evidence of a potentially insufficient mechanical contact between conductive surfaces of the generator and connector ring, resulting in a suspect electrical connection to the lead. X-ray suggests canted spring was marginally connected to the connector ring. Canted spring indentations were observed on the rear end of the small front o-ring. During the visual analysis of the returned 373mm portion the (+) white and (-) green electrode ribbons were observed to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the electrode ribbons from coming in contact with the vagus nerve. With the exception of the observed tissue-covered electrode ribbons and the set of setscrew marks observed near the end of the connector pin the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. Continuity checks of the returned lead portions were performed, during the visual analysis, and no discontinuities were identified.
 
Event Description
It was reported that device diagnostics resulted in high impedance. No patient manipulation or trauma occurred that is believed to have caused or contributed to the high impedance. It was reported that device diagnostics were within normal limits during implant. X-rays were taken and sent to manufacturer for review. Review of x-rays did not identify any obvious discontinuities with the vns system. The presence of a micro-fracture could not be ruled out.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received that the patient's vns system was explanted due to death (b)(6) 2015. The death is not thought to be related to vns. Additional information was received that high impedance was not seen for this patient during initial implant. Also, the patient's device was not disabled following high impedance observation. Review of manufacturing records confirmed that the generator and lead passed all functional tests prior to distribution.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4673669


Title: Re: Electrodes
Post by: dennis100 on March 06, 2019, 01:31:49 AM
Model Number 302-20
Device Problems Detachment Of Device Component; High impedance
Event Date 07/17/2015
Event Type  Malfunction   
Event Description
Additional information was received that the patient's pain had been occurring in the patient's neck prior to the generator and lead replacement surgery. The pain began occurring following a settings increase. Thus, the settings were decreased which helped the pain. The pain was thought to perhaps have been caused by the detached electrode. No additional relevant information has been obtained to date.
 
Event Description
Analysis was completed on the patient's explanted generator. Analysis showed that the generator performed according to functional specifications. Analysis of the generator concluded that no abnormal performance or any other type of adverse condition was found. An analysis was performed on the returned lead portion. Note that a portion of the lead assembly including the electrodes was not returned for analysis and therefore a complete evaluation could not be performed on the entire lead product. No obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portion were performed, during the visual analysis, and no discontinuities were identified.
 
Manufacturer Narrative
Describe event or problem; corrected data: the previously submitted mdr inadvertently failed to report the device evaluation.
 
Manufacturer Narrative

Event Description
Clinic notes were received and indicated that the patient had experienced pain associated with stimulation. There was also a report of a settings adjustment which helped with the pain. The patient then underwent a prophylactic generator replacement surgery on (b)(6) 2015. However, pre-operative system diagnostics resulted in high impedance detected on the patient's vns system. Thus, the lead was replaced as well. It was reported that during the lead replacement, it was seen that the positive electrode and anchor tether of the lead had become detached from the patient's vagus nerve, leaving only the negative helical electrode still attached. No lead fractures were noted. It was unknown how the lead had become partially detached form the nerve. The diagnostics were normal following the generator and lead replacement. The explanted generator and lead were received by the manufacturer for analysis. However, analysis has not been completed to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5002392


Title: Re: Electrodes
Post by: dennis100 on March 09, 2019, 02:11:32 AM
Model Number 303-20
Device Problem Detachment of Device or device Component
Event Date 01/03/2019
Event Type  Malfunction   
Event Description
It was reported by a company representative that the patient experienced a shocking feeling in their neck soon after lead and generator placement surgery. The physician indicated that x-rays were taken that indicated the electrodes were not securely placed on the nerve. The physician indicated that the patient underwent a generator and lead replacement surgery. The suspect product (lead) was reportedly not available for return. No further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8296459


Title: Re: Electrodes
Post by: dennis100 on March 12, 2019, 03:07:42 AM
Model Number 302-20
Event Date 10/01/2014
Event Type  Malfunction   
Event Description
On (b)(6) 2014 it was reported that the patient has high impedance on all diagnostics, so they turned the device off and ordered x-rays for the patient. The patient¿s last visit was in (b)(6) 2014 and the diagnostics were normal at that time. The patient¿s caretaker said she hadn¿t noticed the patient¿s voice go hoarse with stimulation in a while so thinks it may not have been working properly for a few months. They have not had any major falls or injuries. Although surgery is likely, it has not occurred to date. An x-ray assessment was performed on the x-ray images for the patient. The generator was visualized in the patient¿s left chest. The lead appeared to be intact at the lead pin. The filter feed thru wires appeared to be intact. The lead pin appeared to be fully inserted into the connector block. The electrodes appeared to be in alignment; however, the electrodes appear to be inverted on the patient¿s vagus nerve. Based on the x-rays received, the cause of the high impedance cannot be determined. However, a micro-fracture cannot be ruled out.
 
Event Description
The patient had lead revision surgery on (b)(6) 2016. The generator was not replaced. System diagnostics were performed during the surgery, and high impedance was identified prior to the lead replacement. Once the lead was replaced, there was normal impedance. The explanted lead has not been received to date.
 
Event Description
The device history record of the lead was reviewed, and the device conformed to all specifications prior to release. The explanted lead was received on 05/09/2016. Analysis was approved on 06/02/2016. A break was identified in the positive coil. The positive coil showed that pitting of electro-etching conditions have occurred at the break location. One strand of the positive quadfilar coil showed minor appearance suggesting that a stress-induced fracture occurred in at least one strand. However, due to pitting and mechanical distortion (smoothed surfaces) the fracture mechanism of strands could not be ascertained. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=4268315


Title: Re: Electrodes
Post by: dennis100 on March 14, 2019, 06:00:48 AM
Model Number 302-20
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 10/04/2015
Event Type  Malfunction   
Event Description
It was reported that vns device diagnostics resulted in high impedance (dcdc converter 7). It was reported that the patient experienced an increase in seizures. It was reported that the device was turned off on (b)(6) 2015. X-rays were taken but not provided to the manufacturer to date for assessment. Review of manufacturing records confirmed that both, the generator and the lead passed all functional tests prior to distribution. Further information was later received indicating that the patient underwent full replacement surgery on (b)(6) 2015. It was reported that device diagnostics with the new lead and generator were within normal limits. The explanted devices were not returned to the manufacturer for analysis.
 
Event Description
X-rays were provided to the manufacturer for review. The generator appears on the x-rays to be placed in upper chest in normal arrangement. The pin connector appears to be not fully inserted. But due to the quality and angle of the provided images, this could not be confirmed. The electrodes appeared to be placed in abnormal arrangement. The upper of the electrode was implanted very low in the neck, not as specified in labeling. Strain-relief bend and loop seemed to have been used. One tie-down was found holding the lead but it's unable to assess if they are placed as specified in labeling. A portion of lead behind the generator could not be assessed. No suspected lead break was found on the visible part of the lead. Further information received confirmed that the lead was implanted very low in the neck, as found on the provided x-rays, because as indicated by the surgeon: "this is his surgical technique".

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5182947


Title: Re: Electrodes
Post by: dennis100 on March 16, 2019, 01:39:13 AM
Model Number 302-30
Device Problems Break; High impedance
Event Date 05/17/2015
Event Type  Malfunction   
Event Description
It was reported by the neurologist the patient was scheduled for vns surgery as the vns was checked showing high impedance and it is unsure if the lead pin is out or if a new lead needs to be placed. It was also reported the patient's device was turned off on (b)(6) 2015. It was later reported the patient underwent surgery on (b)(6) 2015 and the lead and the generator were both replaced. The lead was replace due to high impedance and the generator was prophylactically replaced. Additionally, it was reported there was a lead break at the strain relief bend, right by the tie down. It was also clarified the generator was replaced prophylactically as the physicians were unclear how long the device had been broken and were not comfortable using the old device due to the broken lead and risk of infection from taking the generator out, then putting it back in after removing and replacing with the new lead. The lead and the generator were received. Analysis is expected but has not been completed to date.
 
Event Description
Product analysis found that the high impedance most likely occurred on (b)(6) 2015 as the impedance value was noted to have changed from 1224 ohms to 11619 ohms on that date. It was found through testing that the generator performed according to functional specifications. The final electrical test shows and ifi = no condition. There were no performance or any other type of adverse conditions found with the pulse generator. Analysis was completed on the returned lead portions and lead fractures were confirmed. It should be noted that portions of the electrodes were not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product. Fractures were found on all three coil strands. One of the coils had extensive pitting that prevented identification of the fracture type. It was noted that all three broken coil strands were mechanically damaged which prevent identification of the fracture type, with evidence of a stress induced fracture, which most likely completed the fracture on all three broken coil strands. One of the coil strands was identified as having evidence of a stress induced fracture with mechanical damage and pitting. Determination could not conclusively be made on the fracture mechanism. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. The abraded openings found on the outer silicone most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids inside the outer silicone tubing. White deposits were observed in various locations. Energy dispersion spectroscopy was performed on the deposit observed on the connector boot and identified the deposit as containing silicon, phosphorus, sodium, magnesium, and calcium. It was found that the returned white electrode ribbon appeared to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the white electrode ribbon from coming in contact with the vagus nerve. With exception of the observed discontinuities and the tissue covered white electrode ribbon, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Based on the findings in the product analysis lab, there is evidence to suggest discontinuities in the returned portions of the lead which may have contributed to the stated allegations.
 
Manufacturer Narrative
This information was inadvertently left off of supplemental #01 mfr. Report.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5126663


Title: Re: Electrodes
Post by: dennis100 on March 18, 2019, 02:03:36 AM
Event Date 11/03/2015
Event Type  Malfunction   
Event Description
It was reported that high impedance (dc dc code - 7) was observed on vns patient's system. The device was then disabled. No patient adverse events were reported. X-rays were taken and sent to the manufacturer for review. The generator appears to be placed in the middle of the chest not as recommended in our labeling. The pin connector appears to be fully inserted. The electrodes appeared to be placed in abnormal arrangement: seems to be implanted too low in the neck, in the upper chest. It's unable to assess if a strain relief or loop were used, due to the quality of the provided x-rays. One tie-down was found holding the lead but not as specified by labeling. There is a large portion of the lead coiled around the electrode, which is unable to be assessed. There is no lead behind the generator. No clear lead breaks or sharp bends were found in the visible parts. A micro-fracture could not be ruled out. No known surgical interventions have been performed to date. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5251293


Title: Re: Electrodes
Post by: dennis100 on March 18, 2019, 02:04:37 AM
Model Number 302-30
Device Problems Low impedance; Device Displays Incorrect Message
Event Date 11/06/2015
Event Type  Malfunction   
Event Description
It was reported by the physician that the patient no longer feels stimulation. It was also reported the physician received the low impedance <600 ohms warning when interrogating the device. The patient was referred to a consultation for a full revision and replacement of the vns system. It was also reported the patient is severely mentally retarded and developmentally delayed. The patient is also prone to violent outbursts.
 
Event Description
It was reported the patient is a poor historian and the date of initial onset for the inability of the patient to perceive stimulation is not known. Additionally, it was reported there was no known trauma or incident suspected that could have caused or contributed to the reported event. No additional relevant information has been received to date.
 
Event Description
It was reported the patient underwent lead and generator revision surgery on (b)(6) 2016. Pre-operative testing of the vns verified the low impedance previously observed. The physician put a new generator on the existing lead and found 615 ohms. The decision was made to removed and replace the lead. It was found during surgery the electrodes were not on the nerve and there was no strain relief loop or anchor tethers present. The new lead was placed on the nerve, tethered and connected to the new generator. Diagnostics were performed and showed 2155 ohms. There was no known trauma or manipulation that could have caused the lead to come off of the nerve; however, the patient is autistic and combative. No additional relevant information has been received to date.
 
Event Description
Product analysis for the returned generator was completed. The generator output signal was monitored for more than 24 hours while in a simulated body temperature environment. Results showed no signs of variation in the generator's output signal and demonstrated the device provided the expected level of output current for the entire monitoring period. In addition, a comprehensive automated electrical evaluation showed the generator performed according to functional specifications. The battery voltage measured during analysis showed an ifi = yes (intensified follow-up indicator) condition. There were no performance or any other type of adverse conditions found with the generator.
 
Event Description
Pa for the returned lead portion was approved on (b)(6) 2016. The lead was found to have abraded openings on the outer and inner silicone tubing of the lead coils. Also, the positive and negative lead coils have what appear to be wear (flat surfaces) at the exposed portions located past the electrode bifurcation. The reported ¿low impedance¿ allegation was not verified. Though it was difficult to state conclusively, the identified exposed coil portions at the silicone tubing abraded openings may confirm this to be a contributing factor for the reported low impedance/short circuit condition. However, the exact point in time when the short occurred is unknown. Note that since the electrode array portion was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead portion.
 
Event Description
It was also observed, during lead product analysis, that the lead connector boot had partial detachment at the ring/backfill interface. The reason for this condition was unknown.
 
Manufacturer Narrative
Describe event or problem; corrected data: this information was inadvertently left off of the supplemental #04 mfr. Report.
 
Event Description
The lead assembly had dried remnant of what appeared to have once been body fluids inside the inner and the outer silicone tubing. No obvious point of entrance was noted other than the identified tubing openings and the end of the returned lead portion.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5257603


Title: Re: Electrodes
Post by: dennis100 on March 20, 2019, 10:45:40 AM
Model Number 302-20
Device Problems Retraction Problem; Low impedance
Event Date 10/28/2015
Event Type  Malfunction   
Event Description
It was reported that during generator replacement surgery for end of service the surgeon disconnected the generator from the lead and then attempted to pull the lead from the patient's back side to re-tunnel the lead to the chest area. When the surgeon pulled the lead it got hung up in the patient's body and when the surgeon pulled on it the lead wires started retracting in the tubing. A new generator was attached to the lead and device diagnostics showed low impedance (<600 ohms). The surgeon did not obtain consent for lead replacement, so the lead was cut and explanted and a new generator was not placed. The patient was closed and rescheduled for lead replacement. No known surgical interventions have been performed to date.
 
Event Description
It was reported that the explanted devices were discarded; therefore, no product analysis can be performed. An implant card was received indicating that the patient underwent generator and lead reimplant on (b)(6) 2015. The surgeon indicated that he believed the lead electrodes were not on the nerve which he identified while dissecting the lead electrodes off of the nerve to reimplant the new lead. The surgeon indicated that the patient's anatomy was a little different than normally seen and an ultrasound was used to help determine the lead placement. The new generator was placed at the patient's chest. Device diagnostics were within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5220659


Title: Re: Electrodes
Post by: dennis100 on March 21, 2019, 12:59:10 AM
Model Number 302-20
Event Date 10/06/2015
Event Type  Malfunction   
Event Description
It was reported that vns system implanted in the patient was tested and system diagnostics returned high impedance with dcdc code 7 and neos no. X-rays were taken and sent to the manufacturer for review. The generator appears to be placed under the right arm in an abnormal arrangement. The filter feed-through wires appears to be intact. The insertion of the lead-pin connector could not be fully assessed due to the orientation of the generator in the x-rays and the quality of images, it appears to be not fully inserted. The electrodes appeared to be placed in abnormal arrangement, not in the neck. A strain-relief bend and a loop were not used. Only one tie-down was found holding the upper lead body. Part of the lead appeared to be behind the generator and could not be assessed. No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed. It was reported by the physician that the device was not switched off yet. No known surgical interventions have occurred to date. No patient adverse events were reported to date.
 
Event Description
Further information was received from the facility, indicating that the patient underwent full replacement surgery on (b)(6) 2016. The lead was replaced due to lead discontinuity and the generator was prophylactically replaced. Review of manufacturing records confirmed that both, the generator and the lead passed all functional tests prior to distribution. It was reported that the explanted devices will not be returned to the manufacturer as they were discarded. Therefore, no analysis results could be provided. No additional information was provided to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5194237


Title: Re: Electrodes
Post by: dennis100 on March 26, 2019, 02:14:38 AM
Model Number 303-20
Device Problem Appropriate Term/Code Not Available
Event Date 12/01/2015
Event Type  Injury   
Event Description
It was reported on (b)(6) 2015 that the patient was experiencing a painful, jolting sensation in her neck. The pain was constant. The device was turned down from 1. 75ma to 1. 25ma, but the patient reported that it was still painful. The date of onset of the pain was unknown. No known trauma had occurred. The physician performed diagnostics, and the impedance was within normal limits at 2800 ohms. It was reported on (b)(6) 2015 that the patient was referred for generator and lead replacement surgery with the device likely programmed to not delivery therapy until surgery. An implant card was later received reporting that the patient had lead replacement on (b)(6) 2015 due to pain at the lead site. The generator was not replaced. No additional relevant information has been received to date. The explanted lead has not been received by the manufacturer for analysis to date.
 
Event Description
Additional information was received from the surgeon reporting that he was observed during lead replacement surgery that one of the helicals was off of the vagus nerve, so he believes this was causing the painful stimulation to the patient's muscles. There was no particular event that was known or believed to have contributed to the helical coming off the nerve, but he notes that she does have tonic-clonic seizures so it may have occurred from a seizure. The helical appeared to be pulled medially and pulled quite a bit. The device was turned off prior to surgery for the pain. He has not heard from the patient since surgery, so takes that as a good sign that her pain has improved/resolved. No further information was provided. The explanted lead was received by the manufacturer for analysis. However, analysis has not been completed to date.
 
Event Description
Analysis of the lead was also completed. No obvious anomalies were noted. The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no discontinuities were identified. Based on the findings in the product analysis lab, there is no evidence to suggest a discontinuity in the returned portions of the device. Note that since the (-) green electrode was not returned, an evaluation and resulting commentary cannot be made on that portion of the lead.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5359167


Title: Re: Electrodes
Post by: dennis100 on March 31, 2019, 07:11:33 AM
Model Number 302-20
Event Date 04/08/2016
Event Type  Malfunction   
Event Description
It was reported that high impedance was observed on vns patient's system. The patient was due to undergo generator replacement surgery, when high impedance was identified; the vns patient's device was tested and system mode diagnostic results revealed high impedance (dc dc code 7) and near end of service = no. It was reported that the device replacement surgery was performed. The patient's vns system was tested upon connection of the new generator to the existing lead and high impedance persisted. It was reported that the newly implanted device was disabled. Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2012. Additional information was received indicating that the generator was replaced due to battery depletion. The return of that explanted device to the manufacturer is expected but it has not been received to date. It was reported that a lead revision due to lead discontinuity is planned. No known surgical interventions have occurred to date.
 
Event Description
The explanted generator was received to the manufacturer on 04/28/2016. Analysis of the returned generator was completed. The generator performed according to functional specifications. During the product analysis there were no anomalies found with the pulse generator.
 
Event Description
Further information was received indicating that the patient underwent lead replacement surgery on (b)(6) 2016. The lead was replaced due to lead discontinuity. The patient's vns system was tested upon connection of the new lead to the generator and system diagnostics returned impedance results within normal limits with 1568 ohms. The explanted lead was returned to the manufacturer on 06/09/2016. Analysis is underway but it has not been completed to date.
 
Event Description
An analysis was performed on the returned lead portions and the reported allegations of "fracture of leads" were confirmed. Note that the (-) green electrode was not returned for analysis and therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis of the returned 40mm portion the (+) white electrode quadfilar coil appeared to be broken approximately 19mm from the electrode bifurcation. Scanning electron microscopy was performed and identified the area as having extensive pitting which prevented identification of the coil fracture type. Pitting was observed on the coil surface. During the visual analysis of the returned 9mm portion the end of the (+) white electrode quadfilar coil appeared to be broken approximately 18mm past the end of the cut inner silicone tubing. Scanning electron microscopy was performed and identified the area on two of the broken coil strands as having evidence of a stress induced fracture (fatigue appearance) with mechanical damage and pitting. The area on the remaining broken coil strands was identified as being mechanically damaged which prevented identification of the coil fracture with pitting. Flat spots and pitting were observed on the coil surface. It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting. Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution. What appeared to be white deposits were observed in various locations. Eds (energy dispersion spectroscopy ¿ provides chemical or element identity/composition analysis) was performed on the deposit observed on the outer silicone tubing and identified the deposit as containing silicon, phosphorus, sodium, magnesium and calcium. During the visual analysis the (+) white electrode ribbon appeared to be embedded in what appeared to be remnants of dried body tissue. This condition may have prevented the (+) white electrode ribbon from coming in contact with the vagus nerve. With the exception of the observed discontinuity and the tissue-covered (+) white electrode ribbon the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted. The setscrew marks found on the lead connector pins provide evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified. Based on the findings in the product analysis lab, there is evidence to suggest a discontinuity in the returned portions of the device which may have contributed to the stated allegations of high impedance. Note that since the (-) green electrode was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. However, the positive electrode condition may have contributed to the reported ¿high impedance¿.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5614469


Title: Re: Electrodes
Post by: dennis100 on April 01, 2019, 12:40:53 AM
Event Date 02/04/2016
Event Type  Malfunction   
Event Description
It was reported that high impedance (dcdc 7) was observed on vns patient's system. Normal mode and system mode diagnostics were run and high impedance were found (dcdc 7). It was reported that the device was then disabled. X-rays were taken and sent to the manufacturer for review. The generator appears in the upper left chest in a normal placement. The filter feed-through wires appeared to be intact. The lead connector pin is fully inserted into the generator connector block. The electrode appears to be placed in abnormal arrangement (the negative electrode appears to be placed distal to head) but this could not be confirmed due to poor quality of the image. It's unable to assess if the strain-relief bend and loop are presents. No tie-down was found holding the lead. A portion of lead behind the generator could not be assessed. No suspected lead break was found on the visible part of the lead. Further information was received from the physician, indicating that the patient's generator was implanted in 2014. It's unknown if any patient trauma or manipulation occurred that could be the cause of the suspected lead fracture. As reported by the parents to the physician, the patient's seizures were stable until (b)(6) 2016, without explanation. The last device checking in (b)(6) 2015 found that the parameters / settings were normal. During a clinic visit on (b)(6) 2016, high impedance was found. The device was then switched off that day. It was reported that lead revision is planned. No known surgical interventions have been performed to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5488882


Title: Re: Electrodes
Post by: dennis100 on April 04, 2019, 12:52:39 AM
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that vns patient was due to have lead and generator replaced. Additional information was received that the reason for replacement was high impedance. It was reported that patient had the lead broken in the axilla; moreover at surgery the lead was not on the vagal nerve and was placed quite superficial to it. Attempts for additional relevant information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5754828


Title: Re: Electrodes
Post by: dennis100 on April 04, 2019, 12:53:31 AM
Model Number 302-20
Event Date 05/31/2016
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that high impedance (>=10000 ohms. ) was observed on vns patient's system. It was reported that the patient had been feeling pain at neck for two weeks. On (b)(6) 2016, the patient's device was programmed at output current 1. 5ma, pulse width 500¿sec, frequency 30hz, on time 30sec and off time 5min. It was reported that the generator was turned off that day. It was reported that x-rays will be performed to see a possible lead discontinuity which could probably be due to a fall. A complete surgical revision will be scheduled but no known surgical interventions have been performed to date. Additional information was received indicating that x-rays have not yet been done, because the parents are quite reluctant about that. It was reported by the physician that in theirs records, there is a notification of the electrode wire-protuberance under the patient¿s skin on the neck; this was on (b)(6) 2014. No coincidental trauma and pain were observed; the device was working normally. It was reported that ultrasound investigation was performed that time, and no structural changes were described: the lead did not look interrupted.
 
Event Description
Further information was received indicating that the patient underwent lead revision surgery on (b)(6) 2016. The lead was replaced due to high impedance. The patient's vns system was tested upon connection of the new lead to the existing generator and system diagnostics returned impedance results within normal limits with 1480 ohms. Review of manufacturing records confirmed all tests passed for the concerned lead prior to distribution. It was reported that the explanted lead will not be returned to the manufacturer for analysis as it was disposed. Additional information from the physician indicated that the patient is now ok with a new e lead in place. It was reported that the patient never had any fall, blow or any other trauma in the neck region or area of vns generator. The lead protuberance appeared suddenly on (b)(6) 2010, under the skin on the lower part of her neck. When this happened, an ultrasound investigation was performed and no other intervention was taken; the patient was doing well, had no pain and very rare seizures and her mother reported that vns works well (hoarseness of patient voice). Later in (b)(6) 2016, the protuberance disappeared; the physician thinks that it was the moment when the electrode finally slipped completely from the vagal nerve. As it turned out during the revision, this protuberance was a part of electrode (a non-active one, the ground) that slipped from the vagal nerve. X-ray performed before the surgical procedure, indicated that one electrode was not in the correct place. It was reported by the physician that the reason must be an inappropriate position-fixation of electrodes when implanted.
 
Event Description
Additional information was received from the physician indicating that the day of the implant, on (b)(6) 2014, the device was tested and system diagnostics returned impedance results within normal limits with 1480 ohms. It was reported that on (b)(6) 2014 (after the lead protuberance appeared on (b)(6) 2014), the vns system was still ok and system diagnostics returned impedance results within normal limits with 2194 ohms.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5731782


Title: Re: Electrodes
Post by: dennis100 on April 06, 2019, 12:30:08 AM
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 09/12/2018
Event Type  Injury   
Event Description
Article titled "improved quality of life and cognition after early vagal nerve stimulator implantation in children" was reviewed and three adverse events were identified for the patients studied within the cohort. 3 of the patients developed infections post implant and 1 of those patients required revision surgery due to the infection. 1 patient passed away prior to the study (captured in mfr. Report # 1644487-2019-00452) 1 patient had disconnection of their electrodes from the vagus nerve that required revision surgery(captured in mfr. Report # 1644487-2019-00454). It was reported that there was no permanent morbidity due to these events. No further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8404598


Title: Re: Electrodes
Post by: dennis100 on April 10, 2019, 01:22:05 AM
Model Number 302-20
Event Date 06/30/2016
Event Type  Malfunction   
Event Description
It was reported that a patient had full revision surgery due to battery depletion. It was later reported that the lead was replaced due to the electrode being detached from the nerve. The explanted generator and lead were received on 07/05/2016. Analysis of the generator identified that the device exhibited current consumption rates that are within specification, thereby demonstrating normal battery depletion to an end-of-service condition. The electrical performance of the generator were used to conclude that no anomalies exist and the eos condition is an expected event. The module performed according to functional specifications. There was no condition noted during the product analysis evaluation that would suggest any anomaly with the device. The explanting surgeon confirmed that the lead was not detached from the nerve. High impedance was identified, and there was fluid inside the outer tubing that brought the surgeon to believe that the lead wires had been compromised. Analysis of the lead identified two lead breaks and corrosion at the break locations. Due to wear at one of the break locations, the fracture mechanism could not be determined. The other break appeared to be due to stress/mechanical damage. The electrodes were not returned for analysis, so a complete evaluation could not be performed on the entire product. With the exception of the observed discontinuity the condition of the returned lead portions was consistent with conditions that typically exist following an explant procedure. No other obvious anomalies were noted.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5821251


Title: Re: Electrodes
Post by: dennis100 on April 15, 2019, 12:37:54 AM
Model Number 302-20
Event Type  Malfunction   
Event Description
It was reported the patient needed to be scheduled for a full vns revision due to high impedance. Attempts for additional relevant information have been unsuccessful to date.
 
Event Description
It was later reported the patient underwent full revision surgery on (b)(6) 2016. It was noted the patient had to be implanted on the right side as there was too much scar tissue and too many electrodes and anchor tethers on the left vagus nerve and there was no more room for an additional implant. It was noted the generator was replaced due to neos = yes (near end of service) and that the lead was replaced due to the high impedance observed. After the new generator and lead were replaced, the diagnostics were confirmed as ok. Attempts for additional relevant information have been unsuccessful to date.
 
Event Description
Additional information was received noting the devices were discarded after surgery. Therefore, the devices are not expected for return and no analysis will be performed.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5857766


Title: Re: Electrodes
Post by: dennis100 on April 15, 2019, 12:38:42 AM
Model Number 303-20
Event Date 12/07/2015
Event Type  Injury   
Manufacturer Narrative
(b)(4).
 
Event Description
It was reported that the patient had significant swelling at the electrode and generator sites. It was initially thought that the patient had an infection, but that was ruled out. The patient then had a nuclear medicine scan, which showed that the patient had lymphatic fluid in the soft tissue surrounding the electrode site and was leaking down to the chest pocket as well. The patient was feeling painful stimulation in the neck, which the physician attributed to the electrode site being irritated and swollen. It was determined that the fluid collection was due to the implant location of the electrodes. The physician performed lead revision surgery on (b)(6) 2016 to replace the lead and position the new electrodes in a different location on the nerve. The physician did not observe any fluid when he was performing the lead revision surgery. The explanted lead was received on (b)(6) 2016. Analysis was approved on (b)(6) 2016. Note that since a portion of the lead (including the electrode array) was not returned for analysis, an evaluation and resulting commentary could not be made on that portion of the lead. Other typical wear and explant related observations, no anomalies were identified in the returned lead portion.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5851977


Title: Re: Electrodes
Post by: dennis100 on May 08, 2019, 10:19:39 AM
Model Number 303-20
Device Problem Mechanical Problem
Event Date 04/07/2017
Event Type  Malfunction   
Event Description
It was reported that a lead was identified with a misshaped helix out of the box. The helix was reportedly not lined up. The lead was not implanted in the patient and a replacement lead was used in its place. A review of the manufacturing record of the lead confirmed it had passed all quality inspections prior to release for distribution. The lead has been returned to the manufacturer, but analysis has not been completed to date.
 
Event Description
The returned lead assembly was analyzed in the product analysis lab where it was confirmed that the helices were misshapen. Visual analysis identified bends and creases on the positive and negative electrode ribbons. The positive ribbon was partially detached from the helical. No discontinuities were identified with the returned lead, no abrasions were noted, and no setscrew marks were observed, confirming that the lead had never been implanted. The misalignment of the helices as observed in the lab had no adverse effect on the lead's ability to perform as intended.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6529452


Title: Re: Electrodes
Post by: dennis100 on May 18, 2019, 12:44:15 AM
Model Number 304-20
Device Problems Detachment Of Device Component; Fracture
Event Date 04/27/2017
Event Type  Malfunction   
Event Description
It was reported that a neurologist observed high impedance on a patient's device during a clinic visit. The neurologist reported that high impedance was not observed during the previous clinic visit (b)(6) prior. The patient's family also reported that she had fallen during her seizures. The patient was referred for surgery. No additional relevant information has been provided to date. No surgical intervention has occurred to date.
 
Event Description
The patient's father reported that the patient was experiencing an increase in seizures due to the high impedance. According to the patient's father, the surgeon believed that the lead may have become dislodged from the patient's vagus nerve. The patient underwent full revision surgery. The surgeon and company representative confirmed that the electrode had become dislodged from the nerve, but the surgeon did not know what caused the electrode to come off of the nerve. The explanted lead and generator were discarded and are unavailable for analysis. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6586456


Title: Re: Electrodes
Post by: dennis100 on May 20, 2019, 09:16:26 PM
Model Number 106
Device Problem Adverse Event Without Identified Device or Use Problem
Event Type  Malfunction   
Event Description
It was reported that the patient had three breakthrough seizures, but the physician had also stopped the patient's vimpat. Diagnostics were performed, which confirmed that the device was functioning properly. No further relevant information has been received to date.
 
Event Description
It was reported that the patient's tie-down was protruding at the neck incision. It was stated that the patient has not had efficacy possibly from the lead being placed too low also causing side effects. It was alleged that the patient started feeling a burning sensation and vibrating in the throat with auto-stimulation. It was thought that the increase in seizures could have caused the patient to have more autostimulations than usual, which caused the burning/vibrating in the neck area. The device was then disabled in may due to the burning sensation and vibrating in throat. No additional relevant information has been received to date.
 
Event Description
Additional information was received that the device was likely disabled around (b)(6) as the patient was seen in the emu at this time. No additional or relevant information has been received to date.
 
Event Description
Information was received indicating that the patient is scheduled for a full replacement. Surgery is likely but has not been completed to date. No additional or relevant information has been received to date.
 
Event Description
The patient underwent a full explant. It was stated that x-rays were reviewed and revealed that the device was too low and the electrodes did not appear even on the nerve the explanted devices have not been received for analysis to date. No additional or relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6566145


Title: Re: Electrodes
Post by: dennis100 on June 01, 2019, 03:28:07 AM
Model Number 103
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 06/22/2017
Event Type  Injury   
Event Description
It was reported to a company representative that a patient has requested to have her device removed due to pain at the generator site. She is diagnosed with mental health problems and the patient¿s physician believes the pain is mostly psychological. Additional relevant information has not been received to-date. No known surgery has occurred to-date.
 
Event Description
Follow-up from the company representative who spoke to the provider indicated that the patient also had pain in the neck from when her grandson had slapped her on the neck. The device was turned off for a couple of weeks and was turned back on with no discomfort and the problem was considered resolved.
 
Event Description
Follow-up from the provider indicated that the neck pain had resolved and the most recent diagnostics were okay.
 
Event Description
Further follow-up from the provider indicated that trauma to the neck has partially dislodged, damaged the electrode and was causing pain. Lead revision surgery occurred, and the explanted device has not been received by the manufacturer to-date.
 
Manufacturer Narrative
Event description, corrected data: it was inadvertently not provided on follow-up report #3 that the device had been received by the manufacturer.
 
Event Description
The explanted device was received by the manufacturer. Documentation received indicated that the patient felt a lead pulling sensation and then painful stimulation. Analysis is underway, but has not been completed to-date.
 
Manufacturer Narrative
Event description, corrected data: the results of product analysis for the returned generator were inadvertently not provided in follow-up report #4.
 
Event Description
Analysis was completed for the returned lead. The electrode array portion was not returned for analysis, and evaluation could not be made on that portion of the lead. Other than typical wear and explant related observations, no anomalies were identified in the returned lead portion.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6727567


Title: Re: Electrodes
Post by: dennis100 on June 02, 2019, 01:05:46 AM
Model Number 304-20
Device Problems Fracture; High impedance
Event Date 05/13/2017
Event Type  Malfunction   
Event Description
It was reported on (b)(6) 2017 that the patient had high impedance. Her device was disabled. Clinic notes reported that the patient felt that the magnet wasn't working as the magnet swipes didn't make her cough like typically had before. No known surgical intervention has occurred to date. No further relevant information has been received to date.
 
Event Description
The patient underwent full revision surgery due to the high impedance. During explant of the lead, the surgeon noted that the patient's lead was not attached to the vagus nerve. All parts of the lead were anterior to the carotid artery. The surgeon said that the electrodes were around 0. 5 inches away from the vagus nerve. The suspect device has not been received to date. No further relevant information has been received to date.
 
Event Description
The patient's lead and generator were received into product analysis. Pa was completed on the returned lead. The lead was returned in 3 portions without tie-downs. Set screw marks were observed on the lead pin, indicating that at one point in time, there was a good electromechanical connection between the lead and generator. The condition of the returned lead portions was consistent with those that typically exist following an explant procedure. No obvious anomalies were noted. Continuity checks of the returned lead portions were performed during the visual analysis, and no discontinuities were identified. Product analysis was completed on the returned generator. The generator was monitored in a simulated body-temperature environment for over 24 hours. The generator provided the expected output current for the entirety of the monitoring period. Various electrical loads were attached to the pulse generator and results of diagnostic tests demonstrated that accurate resistance measurements were obtained in all instances. The generator performed according to functional specifications with no anomalies found. The surgeon and the treating physician indicated that they didn't know what caused the patient's electrode to migrate off the nerve. The treating physician did not know of any trauma to the neck site. No further relevant information has been received to date.
 
Manufacturer Narrative
Supplemental mdr 1-- describe event or problem, corrected data:supplemental mdr 1 inadvertently reported that the suspect product hadn't been received instead of "the suspect lead and the generator were received and pending completion of product analysis. " supplemental mdr 1-- device available for evaluation?, corrected data: supplemental mdr 1 inadvertently reported that the patient's product had not been received. However, prior to submission the mdr the product was received on 08/31/2017. Supplemental mdr 2-- date received by manufacturer (mo/day/yr), corrected data: supplemental mdr 2 inadvertently reported 08/31/2017 as the aware date instead of 09/13/2017.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6694894


Title: Re: Electrodes
Post by: dennis100 on June 03, 2019, 04:41:34 AM
Model Number 302-20
Device Problem Fracture
Event Date 05/09/2013
Event Type  Malfunction   
Event Description
Operative notes reported that the patient had a generator and lead replacement surgery performed on (b)(6) 2013 due to battery near end of life and a lead fracture. The notes stated that there was increased impedance. During surgery, the new generator was connected to the existing lead; however, the impedance remained high. Dense scar tissue was also noted during the surgery and as a result the electrodes could not be removed. The explant hospital does not return explanted products. No additional relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6836852


Title: Re: Electrodes
Post by: dennis100 on June 03, 2019, 04:42:28 AM
Device Problem High impedance
Event Date 07/27/2017
Event Type  Malfunction   
Event Description
It was reported by the patient's mother that the patient had a generator replacement surgery that was occurring due to battery depletion of the generator. During the surgery, it was stated that the surgeon felt he might have broken the lead. The patient's mother then stated that the lead issue could have started before the replacement surgery since the patient had not been able to feel magnet stimulation in a while. The lead was replaced due to the possible high impedance issue. The explanting facility historically does not return explanted devices, so product return is not expected. No additional relevant information has been received to date.
 
Event Description
Further information was received from the physician that there was no trauma that had occurred for the patient before hand that could have led to the lead break. The surgeon also stated that he was not aware of any high impedance being observed during pre-op diagnostics. The cause of the lead break was stated to be that it "was kinked and cracked when we exposed/explanted it. " it is unclear if the damage was observed upon exposing the lead or caused by the exposing of the lead. Further inquiry was done with the neurologist who stated that he had not heard about a report of the magnet not working for the patient from the patient or the mother.
 
Event Description
It was reported by the physician that he believed that the patient's leads were out of position and that the patient was not actually receiving stimulation. It was determined that this was a reference to the vns electrodes. Follow up with the surgeon revealed that the electrodes were found to be attached to the patient's vagus nerve in the expected manner at the replacement surgery. The surgeon stated that the cause of the lead failure was the crack in the lead near the generator.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6822941


Title: Re: Electrodes
Post by: dennis100 on June 05, 2019, 12:47:28 AM
Model Number 304-20
Device Problem Mechanical Problem
Event Date 07/07/2017
Event Type  Malfunction   
Event Description
It was reported that during a full vns revision surgery that the surgeon did not like the way the lead manipulated when he was attempting to implant it. Therefore, a second lead was used in its place and implanted without issue. Follow up with the company representative revealed that the surgeon was unable to get one of the electrode coils wrapped around the nerve and asked for a second lead. A review of device history records was performed and revealed that the lead passed quality control inspection prior to distribution. The lead was received by the manufacturer and is pending product analysis. No additional data has been received to date.
 
Event Description
Follow up with the surgeon revealed that the lead had been pulled taut in order reduce redundancy and fractured approximately 5 cm from the connector to the pulse generator. Product analysis was completed on the lead. No abnormalities were noted on the lead flexibility. The lead assembled was returned for analysis in one piece. The outer silicone tubing had punctured openings. Both the closest and furthest electrodes from the bifurcation are damaged, showing bends on the electrode ribbon and partial detachment of the electrode ribbon from the silicone helix with the silicone helices partially losing their helical shape. The observed damage to the closest and furthest electrodes from the bifurcation was most likely manipulation of the lead not consistent with labeling. Set-screw marks were seen on the connector pin, which indicates that proper contact was present at one point. A region with an opaque appearance was noted on the connector ring surface. No obvious pitting was noted at the region. Scratches on the connector ring likely caused by the canted spring in the header during lead pin insertion was observed. No anomalies were noted at the anchor tether. However, the positive coil was kinked at ¿0. 2 cm and the negative coil was kinked at ¿1. 2 cm past the anchor tether. No discontinuities were identified. Based on the appearance of the returned lead assembly, it is believed that the identified kinks and outer tubing punctured openings and electrode damage were most likely caused during the implant procedure.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6766837


Title: Re: Electrodes
Post by: dennis100 on June 07, 2019, 05:05:13 AM
Model Number 302-20
Device Problem High impedance
Event Date 04/15/2019
Event Type  Malfunction   
Event Description
High lead impedance was observed by the surgeon during a generator replacement surgery due to battery depletion. The patient's previous generator was unable to communicate with the programmer due to an end of service condition; and therefore, the diagnostics/settings could not be obtained prior to surgery and lead impedance could not be verified. The generator was then replaced, with previous lead still implanted, and the diagnostics were performed to verify lead impedance. The diagnostic test resulted in high lead impedance, so the lead pin was re-inserted and diagnostics were performed again. Once again high lead impedance registered. The surgeon then proceeded to open the patient's neck and inspect existing lead. Upon visual inspection, he discovered that the there were no lead electrodes on the vagal nerve. The surgeon attempted to find the electrodes, and he could see that they were in neck, but was not sure where they were implanted. He did not want to attempt to remove electrodes due to excessive scar tissue and only cut lead. He left remaining electrodes in neck and still was unsure exactly where the electrodes were implanted. He implanted a new lead on vagal nerve and when connected to the newly implanted generator resulted in ok lead impedance. Both the explanted lead and generator were discarded during surgery; and therefore, the explanted product will not be returned for product analysis. No other relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8595064


Title: Re: Electrodes
Post by: dennis100 on June 18, 2019, 12:35:47 AM
Model Number 302-20
Device Problem Fracture
Event Date 11/28/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that high lead impedance was observed with the patient's device as a result of normal mode and system diagnostic tests. The device was disabled and the patient was referred for surgery. No surgical interventions are known to have occurred to date. No additional relevant information has been received to date.

Event Description
It was reported that the patient underwent lead and generator replacement surgery. The surgeon noted he experienced difficulty explanting the electrodes due to scar tissue however the nerve's condition appeared good. Following the surgery the lead was discarded and was not returned to the manufacturer. However the explanted generator was received and is pending analysis.
 
Event Description
Product analysis was completed on the explanted generator. Visual analysis showed that device had scratches on the can and header. These markings are consistent with the manipulation that occurs during the explant procedure. Upon interrogation it was noted that the battery end of service flag was not set and during testing the generator performed to functional specification.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7131163


Title: Re: Electrodes
Post by: dennis100 on June 22, 2019, 03:28:13 AM
Model Number 106
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 12/14/2017
Event Type  Malfunction   
Manufacturer Narrative
(b)(4).
 
Event Description
It was reported by the physician's office that they suspected that the patient's vns electrodes were loose as the patient was not perceiving stimulation. However, the physician reviewed x-rays and lead detachment was not observed. It was noted that at an appointment, the patient did not perceive normal or magnet mode stimulation. It was reported that the output current was increased all the way and the patient felt nothing. It was unclear what the office meant by "all the way. " it was noted that the patient typically experiences slight hoarseness, but did not have any when turning the device up, which lead to the suspicion that there was a lead break or loose leads. The patient's seizures seemed worse at the time that the patient reported not feeling stimulation. The patient's friend noted seeing a bruise at the vns electrode site several days prior to an appointment and the physician noted that there was a bruise at the generator site. The physician's office mentioned that the patient normally experiences severe drop seizures and has multiple in a day. Follow up with the company representative revealed that the representative had seen the patient and diagnostics were within normal limits. The patient's vns settings were low and she could not feel stimulation, even with a magnet swipe. The patient reported that the vns worked for a while, but she experienced a recent increase in seizures. The x-rays have not been received by the manufacturer to date. No additional relevant information has been received to date.
 
Event Description
Follow up with the physician's office revealed that the reference to increasing the output current "all the way" was to 1. 00 ma per protocol. It was stated that the patient could not feel the stimulation as she had previously and that the patient could not feel the 1. 50 ma magnet stimulation. It was reported that the increase in seizures was just the same as before the vns. The bruising was thought to be the result of a seizure. It was stated that the physician thought that the increase in seizures were due to the electrodes not being connected well. The physician believes that a seizure may have caused electrode detachment and the patient was sent for evaluation, despite the diagnostics showing as within normal limits and detachment not being verified in x-rays.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7176252


Title: Re: Electrodes
Post by: dennis100 on June 23, 2019, 03:52:13 AM
Model Number 302-20
Device Problems Corroded ; Fracture; High impedance; Mechanical Problem
Event Date 06/17/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that the company representative was asked to attend a surgery she thought was only a generator replacement. However upon checking the device prior to surgery high impedance was observed. The lead and generator were then replaced. The explanted products have not been received to date. No additional relevant information has been received to date.
 
Event Description
The explanted lead and generator were received and are pending analysis. The lead's product information was identified following the explant. It indicated that the lead had been implanted for several years. A review of the diagnostic history from the internal database showed that impedance was within acceptable limits in the most recent history.
 
Event Description
Analysis was completed on the returned lead and generator. The generator case had scratches, tool marks and burn marks which are consistent with manipulation and exposure to electrocautery during the explant procedure. Upon interrogation the battery indicator was found to be ifi = yes. A series of interrogations and diagnostics were performed on the generator and the results were normal. During testing the generator performed to functional specification and passed electrical testing. The lead assembly was received in two pieces with the lead¿s pin still connected to the generator. The furthest electrode to the bifurcation was not returned for evaluation. Prior to decontamination a continuity check was performed while the lead pin was still inserted into the lead and the continuity check verified there was proper contact between the set screw and the lead pin was present. Visual analysis of the lead completed for both lead segments. It was found that the lead was tangled and the outer tubing was abraded in the segment which included the lead pin. In both segments the lead coils were kinked and the electrode was noted to be damaged and partially detached, this was potentially related to the explant procedure. A fracture was identified in the lead coil in the lead assembly that was not attached to the lead pin and therefore not part of the continuity check. Pitting was observed at the point of fracture which indicates that the stimulation was being provided while the fracture was present.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7167569


Title: Re: Electrodes
Post by: dennis100 on June 25, 2019, 01:11:14 AM
Model Number 106
Device Problems Detachment Of Device Component; High impedance
Event Date 01/18/2018
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that high impedance was observed on the patient's vns generator. The patient was referred to the surgeon for evaluation. Follow up with the surgeon's office revealed that it was unknown if there was any trauma or patient manipulation that could have contributed to the high impedance. It was stated that x-rays were performed to assess lead pin insertion. The patient was referred for vns lead replacement surgery. The x-rays have not been reviewed by the manufacturer to date. No relevant surgical intervention is known to have occurred to date. No additional relevant information has been received to date.
 
Event Description
It was reported that the patient underwent surgery to address the high impedance observed on the vns. It was stated that the surgeon thought it looked like the electrodes were not fully on the nerve. The surgeon removed the electrodes and then placed them back onto the nerve as well as relieved tension in the lead. Multiple diagnostics were performed during surgery and post-op and the impedance values were within normal limits.
 
Event Description
It was reported that high impedance was observed on the patient's vns again. The patient was referred for lead replacement surgery. Follow up with the tc revealed that the during surgery, the surgeon observed that the vns lead pin connector was loose in the generator header and appeared to not be properly secured. Lead pin insertion troubleshooting was performed and the high impedance was resolved. Several additional diagnostics were performed with the patient's neck in various positions to test the impedance values. The results were within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7265105


Title: Re: Electrodes
Post by: dennis100 on July 04, 2019, 12:51:25 AM
Model Number 304-20
Device Problem Adverse Event Without Identified Device or Use Problem
Event Type  Injury   
Manufacturer Narrative
 
Event Description
It was reported that the lead had "fused" to the patient's vagus nerve, which indicated that fibrosis had likely occurred at the location of the nerve and lead electrodes. In addition, the patient had surgery that appeared to be related to the fibrosis. The patient reported no complications with the surgery. No additional or relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7630304


Title: Re: Electrodes
Post by: dennis100 on July 26, 2019, 01:07:36 AM
Model Number 300-20
Device Problem Fracture
Event Date 01/07/2019
Event Type  Malfunction   
Event Description
X-rays were received of the patient's lead and it was stated that the patient's physician observed frays in the lead near the coil. X-rays were reviewed. Based on the scope of the image, the generator was not visible, so placement could not be determined as well as if the feed thru wires were intact, if the connector pin was fully inserted, if the lead was behind the generator, and if the lead wires were intact at the connector pins. The strain relief bend and loop were present, but were not per labeling as the loop was before the tie downs and appears to be too close to the bifurcation. A tie down could be visualized, but was not placed according to labeling. The lead was assessed and found to be a fracture of the lead. An item was also noted that something appears to have been wrapped around the electrodes which looks to be an unapproved material. Based on the x-rays received, the lead was found to be fractured before the coil. Note that the presence of a gross fracture in the portion of the lead excluded from the images or a micro-fracture along the lead body cannot be assessed. No known surgical intervention has occurred to date. No other relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8264303


Title: Re: Electrodes
Post by: dennis100 on July 30, 2019, 10:24:58 AM
Model Number 300-20
Device Problem Fracture
Event Date 05/18/2018
Event Type  Malfunction   
Event Description
Initial report was an implant card received indicating that a patient underwent generator replacement due to high impedance. It was noted on the implant card that the lead had an "electrode defect. " further information was received that the generator was replaced due to eos. It was stated that "the battery was so empty that the physicians could not do an interrogation. " after generator replacement high impedance was observed. It was stated that the surgeon spent 5 hours trying to explant the lead and the "gave up and decided to speak with the treated doctor how to proceed. " further information was received that there was "many fibrosis that the physician did not get through the vaugs. " the lead was not replaced. It was also stated that a dual pin lead was not available during the surgery for replacement. The operation was stopped to further consult the patient's treating physician. The explanted generator was reported to be given to the patient's parents. It was stated that due to the surgery circumstances and the lack of x-ray availability during the surgery, the surgeon speculated that the electrode may be broken. Further information was received indicating that patient physiology was the cause of the fibrosis and that no intervention was taken for the fibrosis. The only noted reason that the surgery took several hours was that the surgeon was attempting to clear the fibrosis for several hours before deciding to end the surgery and consult the referring physician. No known surgical intervention has occurred to date. No other relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8298957


Title: Re: Electrodes
Post by: dennis100 on August 09, 2019, 11:12:02 PM
Model Number 303-20
Device Problem Detachment of Device or device Component
Event Date 09/07/2018
Event Type  Malfunction   
Event Description
It was reported that the patient experienced pain at the neck associated with the stimulation of their vns generator. The patient felt the "great pain" every 5 minutes, and it was reported that the physician assessed this pain was due to the dislocation of the patient's electrodes. It was reported that the patient was referred for a lead revision. The physician suspected lead discontinuity, likely referring to the dislocation. There was no report of high impedance to date. The physician reported that the cause of the suspected dislocation was incorrect initial implant location. The patient was reportedly not receiving effective stimulation due to the dislocation. No known relevant surgical intervention has occurred to date. No further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8784977


Title: Re: Electrodes
Post by: dennis100 on August 09, 2019, 11:12:39 PM
Model Number 304-20
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 02/09/2019
Event Type  Injury   
Event Description
Patient admitted to the hospital because he was picking at his neck incision site. The incision site was opened and the patient pulled the electrodes and anchor off of the nerve. It was noted that the patient is severely autistic. The patient underwent generator and lead explant surgery the following day. The explanted products were noted to be discarded. No other relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8375680


Title: Re: Electrodes
Post by: dennis100 on August 09, 2019, 11:13:34 PM
Model Number 106
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 06/24/2019
Event Type  Injury   
Event Description
It was reported by the representative that the patient experienced an asystole drop when stimulation was initiated and that the patient continued to have a drop in asystole in mid 40 bpms after device was on and parameters were set to previous settings. The anesthesiologist suggested to monitor the patient in recovery with atrophene. The generator was programmed off. It was reported that the patient continued to have heart rate drops when the device was programmed back on. Surgeon made the decision to take patient back into surgery and remove old electrodes and reposition new electrodes, which reported resolved the patient's heart rate issues. Multiple attempts have been made to obtain additional information; however, no further relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8774235