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dennis100
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« Reply #60 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
« Last Edit: September 25, 2015, 06:22:12 AM by dennis100 » Logged
dennis100
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« Reply #61 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
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dennis100
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« Reply #62 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
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dennis100
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« Reply #63 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
« Last Edit: September 25, 2015, 06:22:44 AM by dennis100 » Logged
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« Reply #64 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
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dennis100
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« Reply #65 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
« Last Edit: September 25, 2015, 06:23:05 AM by dennis100 » Logged
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« Reply #66 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
« Last Edit: September 25, 2015, 06:23:30 AM by dennis100 » Logged
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« Reply #67 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
« Last Edit: November 10, 2015, 04:07:16 AM by dennis100 » Logged
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« Reply #68 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
« Last Edit: September 25, 2015, 06:23:58 AM by dennis100 » Logged
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« Reply #69 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
« Last Edit: March 02, 2016, 03:15:18 AM by dennis100 » Logged
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« Reply #70 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
« Last Edit: September 25, 2015, 06:24:32 AM by dennis100 » Logged
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« Reply #71 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
« Last Edit: September 25, 2015, 06:24:53 AM by dennis100 » Logged
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« Reply #72 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
« Last Edit: September 25, 2015, 06:25:21 AM by dennis100 » Logged
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« Reply #73 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
« Last Edit: September 25, 2015, 06:25:50 AM by dennis100 » Logged
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« Reply #74 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
« Last Edit: September 25, 2015, 06:26:13 AM by dennis100 » Logged
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« Reply #75 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
« Last Edit: September 25, 2015, 06:26:55 AM by dennis100 » Logged
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« Reply #76 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

« Last Edit: September 30, 2015, 02:58:16 AM by dennis100 » Logged
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« Reply #77 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
« Last Edit: September 25, 2015, 06:27:49 AM by dennis100 » Logged
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« Reply #78 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
« Last Edit: September 30, 2015, 02:58:39 AM by dennis100 » Logged
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« Reply #79 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
« Last Edit: September 25, 2015, 06:28:39 AM by dennis100 » Logged
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« Reply #80 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
« Last Edit: September 25, 2015, 06:28:56 AM by dennis100 » Logged
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« Reply #81 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
« Last Edit: September 25, 2015, 06:29:30 AM by dennis100 » Logged
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« Reply #82 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
« Last Edit: September 25, 2015, 06:29:57 AM by dennis100 » Logged
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« Reply #83 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
« Last Edit: September 25, 2015, 06:30:19 AM by dennis100 » Logged
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« Reply #84 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
« Last Edit: September 25, 2015, 06:30:34 AM by dennis100 » Logged
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« Reply #85 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
« Last Edit: September 25, 2015, 06:30:57 AM by dennis100 » Logged
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« Reply #86 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
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« Reply #87 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
« Last Edit: September 25, 2015, 06:31:25 AM by dennis100 » Logged
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« Reply #88 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

« Last Edit: September 25, 2015, 06:34:00 AM by dennis100 » Logged
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« Reply #89 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
« Last Edit: September 25, 2015, 06:34:44 AM by dennis100 » Logged
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