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Author Topic: Low Impedance  (Read 28381 times)
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dennis100
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« on: August 22, 2017, 05:37:41 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
« Last Edit: July 05, 2018, 10:46:39 PM by dennis100 » Logged
dennis100
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« Reply #1 on: August 22, 2017, 05:38:27 AM »

Model Number 300-30
Device Problem Low impedance
Event Date 12/13/2016
Event Type  Malfunction   
Manufacturer Narrative
(b)(4).
 
Manufacturer Narrative
Device information, corrected data: the initial report inadvertently reported the incorrect device information. Implant date, corrected data: the initial report inadvertently reported the incorrect implant date. Device manufacture date, corrected data: the initial report inadvertently reported the incorrect manufacture date.
 
Manufacturer Narrative
Follow-up report #2 inadvertently listed the incorrect results and conclusion codes.
 
Event Description
The generator and lead were received. Analysis on the generator was approved. The device performed according to functional specifications. Analysis of the generator concluded that no abnormal performance or any other type of adverse condition was found. Analysis on the lead has not been approved to date.
 
Event Description
Information was received indicating that the patient was not feeling stimulation like she did before. She was now feeling pain in her ear and jaw when stimulation was delivered along with an increase in gagging and choking sensations. The patient also reported that she was experiencing a shocking sensation when she turned her head to the right occasionally which resulted itching at the electrode site. The patient also reported that the muscles in her neck would tense up for 30 seconds and then relax. The patient's generator was disabled and the tension resolved. Diagnostics showed that the impedance on the patient's generator was at dcdc 0, which could be indicative of a short circuit issue under certain circumstances. The patient then had her device prophylactically replaced in (b)(6) 2017. No additional relevant information has been received to date. The explanted generator and lead have not been received to date.
 
Event Description
Analysis on the lead was approved. Note that the lead assembly (body) including the electrodes was not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product. The condition of the returned lead portions was consistent with conditions that typically exist following an explant procedure. No obvious anomalies were noted. The set screw marks found on the lead connector pins provided evidence that, at one point in time, a good mechanical and electrical connection was present. Continuity checks of the returned lead portions were performed with no discontinuities identified.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6404233
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dennis100
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« Reply #2 on: August 22, 2017, 05:39:07 AM »

Model Number 300-30
Event Date 12/01/2010
Event Type  Malfunction   
Manufacturer Narrative
Corrected data: new information received indicates that the lead was not explanted.
 
Event Description
It was reported by a nurse that a vns patient reported buzzing and pain in the top of his head that had occurred 3 times within the last 3 weeks of initial report. The patient reported that placing the magnet on the generator ameliorated the pain. Moreover, the patient indicated the pain was not occurring with normal stimulation and no patient manipulation or trauma was reported. The nurse further stated that a generator diagnostic tests was performed and received a low impedance warning. The patient was interrogated and the device was found to be at 0 ma. The patient was re-programmed to 1. 5/25/500/30/1. 1 then performed system diagnostics which resulted within normal limits (ok/ok/1/no). Further information from the treating nurse indicated that the patient was scheduled for complete replacement. Moreover information from a company representative indicated the patient underwent surgery as scheduled. Good faith attempts to obtain the explanted devices have been unsuccessful to date. Additional information was received from the treating neurologist indicating the cause of the buzzing was related to generator with/ or wire malfunction. Moreover, the replacement surgery was done for patient comfort according to the neurologist.
 
Event Description
Further follow-up revealed that during the surgery a dual pin generator was not available. It was reported that the patient was closed and a dual pin generator was located and the patient was taken back to the operating room the same day for only generator replacement. The lead was not replaced as previously reported.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=1989992
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dennis100
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« Reply #3 on: August 22, 2017, 05:39:46 AM »

Model Number 300-20
Device Problem Low impedance
Event Date 10/18/2010
Event Type  Malfunction   
Event Description
The explanted generator was discarded by the hospital. No further relevant information has been received to date.
 
Event Description
It was reported that a patient was having generator replacement surgery due to normal battery depletion, and low impedance was identified during diagnostics. The surgeon used the test resistor in the new generator, and the impedance was within normal limits. The lead was not replaced at that time. Programming history indicated that there could have been a short circuit condition in the lead with the previous generator. No further surgical intervention has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6342618
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dennis100
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« Reply #4 on: August 22, 2017, 05:40:22 AM »

Model Number 302-20
Event Date 05/01/2004
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 patient's device, this file was found to be possibly related to a short-circuit condition. It was reported to manufacturer by the vns patient that the stimulation of the device did not feel as strong as it had previously, and that she had a recent increase in seizure activity as well as tooth pain. The patient further explained that she was involved in a physical altercation where she had been attacked and injured. The patient had been to see her neurologist following the incident, however, the altercation and subsequent adverse events that followed were not mentioned to the physician.
 
Manufacturer Narrative
Device failure is 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=1492071
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dennis100
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« Reply #5 on: August 22, 2017, 05:40:57 AM »

Model Number 302-20
Event Date 11/16/2010
Event Type  Malfunction   
Event Description
Reporter indicated a vns patient had low impedance with vns diagnostics testing (<600 ohms). The vns was disabled. Further review of vns programming history noted low impedance has been occurring since at least (b)(6) 2010, when it was noted to be 410 ohms. A short circuit condition of the lead is suspected. No trauma has been reported, but the patient's parents did manipulate the vns lead in the neck as they felt it was protruding under the skin. It is not known if this contributed to the low impedance. No x-rays have been performed. The plan of care is to refer for a surgical consult and revision surgery may occur in the future. The patient is currently stable on medications and doing well.
 
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=2185413
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dennis100
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« Reply #6 on: August 22, 2017, 05:41:44 AM »

Model Number 300-20
Event Date 06/02/2009
Event Type  Malfunction   
Event Description
On (b)(6) 2011, the patient's programming history was reviewed and it was discovered that the patient has an impedance value of 558ohms on (b)(6) 2009. An impedance value less than 600 ohms indicates the potential presence of a short-circuit condition. (b)(4) attempts are underway by the manufacturer's consultant, but no further information has been received from the physician to date. When additional information is received, it will be reported.
 
Event Description
Additional information was received on (b)(6) 2013 when it was discovered that the patient underwent a full revision surgery on (b)(6) 2013. The lead impedance after surgery was noted to be "ok". The explanted products could not be returned to the manufacturer for product analysis as the hospital does not return them.
 
Event Description
Additional information was received on (b)(6), 2011 when the manufacturer's consultant reported that the physician is going to have the patient come back in for a clinical visit to run diagnostics since the last time the patient was seen was sometime in 2009. The patient was seen on (b)(6), 2011 and the physician saw a low impedance warning message upon interrogation. The manufacturer's consultant reported that the normal mode diagnostics test showed an impedance value of 602ohms and a systems diagnostic test showed low impedance. The programming history was sent to the manufacturer for review. The manufacturer's consultant reported that the patient is doing well and not having any adverse events; therefore no surgery will occur right now.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
On (b)(4) 2011, additional information was received when the manufacturer's consultant reported that she is trying to get the patient to see the physician in order to have diagnostics performed. The physician was not there last time the patient and manufacturer's consultant visited him to have diagnostics performed. The physician was not aware of any low impedance or clinical symptoms resulting from the low impedance. When additional information is received, it will be reported.
 
Event Description
On (b)(4) 2012 clinic notes were received dated (b)(6) 2011. Review of the notes revealed that the patient had borderline low impedance value of 558ohms. The patient's vns had not been checked since 2009. The patient's settings were noted to be output=1. 5ma/frequency=20hz/pulse width=250usec/on time=7sec/off time=0. 2min/magnet output=1. 75ma/magnet on time=60sec/magnet pulse width=250usec. System diagnostics showed the lead impedance to be 602ohms which was within normal limits although borderline low and the output status was "ok. " the lead impedance was checked again and it was found to be 600ohms. It was decided that this would be watched carefully. The physician checked the battery position and the leads and did not see any evidence of any abnormalities. The magnet test was also performed and was normal with an impedance value of 602ohms. Tympanic membranes showed some scarring but no acute anomalies. The patient's mother noted some possible drainage from the right ear but the physician did not see anything acute. The physician later reported on (b)(6) 2012 that the patient was shown to have "lead impedance as well as nearing end of service on his generator. " the patient was referred for surgery. Clinic notes from the (b)(6) 2012 visit were also received which indicated that the lead impedance was gain borderline low, around 600ohms. The patient's on time was decreased to 0. 3sec and the patient's lead impedance was re-checked with it still showing borderline low. The patient is having 3+ seizures a day according the patient's mother; they have not really changed in character over the last year. Although surgery is likely, it has not occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2232395
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dennis100
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« Reply #7 on: August 22, 2017, 05:42:29 AM »

Model Number 300-20
Event Date 10/23/2011
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that the patient has low lead impedance. The magnet current was turned up to 3 ma with no patient response at all. Patient underwent generator replacement surgery on (b)(6) 2011. Product has been returned to manufacturer, but analysis is pending. It was indicated that after generator replacement lead impedance was okay, but clarification on the event has not been received, so no conclusion can be drawn as to the cause of the low impedance.
 
Event Description
Analysis was completed on the returned generator. No anomalies were found during the analysis. As the lead was not explanted, no analysis can be performed on the lead. Attempts for further information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2344738
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dennis100
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« Reply #8 on: August 22, 2017, 05:43:15 AM »

Model
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« Reply #9 on: August 22, 2017, 05:44:50 AM »

Model Number 300-20
Event Date 06/10/2014
Event Type  Malfunction   
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.
 
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.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3985372
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« Reply #10 on: August 22, 2017, 05:45:34 AM »

Model Number 106
Event Date 05/14/2016
Event Type  Injury   
Manufacturer Narrative
(b)(4).
 
Event Description
A report was received indicating that a vns patient who underwent a full system revision on (b)(6) 2016 was in the intensive care unit on (b)(6) 2016 with bradycardia every five minutes, suspected to be related to vns stimulation. The patient's treating neurologist was at the hospital and elected to disable the device output. The physician ran system diagnostics and found readings within normal limits (lead impedance of 1,647 ohms). The physician indicated she would leave the device outputs off over the weekend and then try titrating the patient up from a low starting point on monday (b)(6) 2016. Follow up indicated that the device output was re-enabled on (b)(6) 2016 at an output current of 0. 25ma with no bradycardia events observed. It was stated that the patient has never experienced bradycardia with vns therapy over the 12 years he has had vns therapy. The device had previously been set to an output current of 1. 75ma in the operating room at the time of generator replacement on (b)(6) 2016. This is lower than the patient's setting with his prior device (2. 25ma), however, prior to the replacement surgery the patient's device had been turned off 3-4 weeks due to a low lead impedance condition with the prior vns system (reported in mfg rpt#1644487-2016-00958). Normal lead impedance values were observed via system diagnostics on (b)(6) 2016. The provider states that one possible cause of the newly observed bradycardia could be the re-instatement of vns therapy after approximately a year of not receiving intended stimulation due to the prior lead issue and the device disablement. The provider stated the other potential causes may be that the new lead electrodes may have been placed near the cardiac branch of the vagus nerve, or that the vagus nerve may have been ""raw"" (irritated) due to the lead revision surgery. The patient was discharged on (b)(6) 2016. On (b)(6) 2016 the patient was seen and device output currents were increased by the provider with no patient issues. Diagnostic values were within normal limits including lead impedance. The physician plans to continue a gradual titration of the patient on a bi-weekly basis.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5680024
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« Reply #11 on: August 28, 2017, 02:08:56 AM »

Event Date 01/01/2011
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was initially reported that a physician received a low impedance message on interrogation of a patient. The impedance value was between 500 and 550. They said the patient has had impedance about that before and they had not received that message before. There are no interventions that are planned for the low impedance and the patient has not had any adverse events. The office refused to provide the patient's name, dob or any other information.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2385163
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« Reply #12 on: August 29, 2017, 12:36:50 AM »

Model Number 302-20
Event Date 12/02/2009
Event Type  Malfunction   
Event Description
A vns pt was scheduled for generator replacement surgery due to generator end of service. It was reported on (b)(6) 2011, that the pt's lead was replaced in addition to the generator, but the previous lead was left in place for an unk reason. The return product form was received which revealed that the lead was retained in the pt and the generator was replaced for an unk reason, but the lead was replaced due to lead discontinuity. Follow up with the surgeon's office revealed that the lead was replaced because upon running diagnostics with the newly implanted generator, a low impedance was observed. The impedance was reported as being less than 200 ohms, so new leads were implanted which solved the problem. The diagnostics were ok after full revision. It was also reported that no troubleshooting steps were performed during surgery. Further follow up with the surgeon's office revealed that the pt was experiencing an increase in seizures that are believed to be related to low impedance. No pt manipulation or trauma is believed to have occurred that may have caused or contributed to the low impedance, and no x-rays were taken of the pt's vns prior to surgery. Attempts for add'l info from the neurologist regarding the pt's increased seizures and low impedance have been unsuccessful thus far. The generator was returned and received by the mfr for analysis on (b)(4) 2011. However, product analysis has not been completed to date. The lead could not be returned for analysis, as it was retained within the pt. A battery life calculation was performed using the history available in the in-house programming database which resulted in approx 0. 57 years until eri=yes.
 
Manufacturer Narrative
Device failure is suspected, which is believed to be related to the serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2419719
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dennis100
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« Reply #13 on: August 29, 2017, 12:37:58 AM »

Model Number 300-20
Event Date 12/01/2011
Event Type  Malfunction   
Manufacturer Narrative

Event Description
Good faith attempts for product return 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.
 
Event Description
Additional information was received that product analysis was completed on the generator and lead. 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 with the generator. One of the connector pins was returned without the connector boot. The unmarked connector pin and coil appear to have been extracted/exposed from the connector boot and pushed back in to the connector boot as indicated by the portion of the coil and pin partially exposed. Based on the appearance of the lead portions, it is believed that this was most likely caused during the explant procedure. Note that 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 the above mentioned observations and typical wear and explant related observations, no product-related anomalies were identified within the returned lead portion.
 
Event Description
Additional information was received that there was no reported trauma or manipulation. There were no causal or contributory programming changes, medication changes, or other external factors precede the onset of the event. The patient had their lead and generator replacement. Good faith attempt for product return are in process.
 
Event Description
It was initially reported that the patient had low impedance at a recent diagnostics (dcdc-0). The patient has always had lower dcdc codes of 0 and 1 so it was unclear if there was normal or an indication of a problem. For the week prior to the initial report the patient reported feeling painful stimulation and an increase in seizures. The physician feels that there is an issue with the lead. The patient was temporally disabled and the symptom resolved. X-rays were taken and were sent to the manufacturer for evaluation. Based on the x-rays received there was no anomaly visualized that could have been contributing to the low impedance and clinical symptoms. As the entire lead could not be assessed, continuity in that portion of the lead cannot be confirmed. A full revision is planned, but has not occurred to date. Good faith attempts for more information have been unsuccessful to date.
 
Event Description
Additional information was received that the generator and lead were returned to the manufacturer for evaluation. Product analysis is planned, but has not been completed.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2384345
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« Reply #14 on: August 30, 2017, 12:38:06 AM »

Model Number 302-20
Event Date 10/18/2011
Event Type  No Answer Provided   
Manufacturer Narrative
Device failure occurred, but did not cause or contribute to a death or serious injury.
 
Event Description
X-rays were received and evaluated by the manufacturer. The generator was able to be visualized and its placement appeared normal in the upper left chest. The filter feedthru wires appeared intact, and the lead wires appeared intact at the connector pin. Furthermore, the pin appeared to be fully inserted into the connector block. The lead was placed in a normal orientation, but there was a small portion of the lead body behind the generator that could not be assessed. What appeared to be a gross lead fracture was observed in the lead body as it stretches from the generator pocket to the neck site.
 
Event Description
(b)(4). Additional information was received on (b)(6) 2012, indicating that the patient underwent a full revision on (b)(6) 2012. The lead and generator have been returned for analysis. Analysis on the lead has been completed. Note that the majority of the lead assembly (body) including the electrodes was not returned for analysis and therefore a complete evaluation could not be performed on the entire lead product. During the visual analysis it appeared the connector ring quadfilar coil was not returned. Incisions were made to expose the inside of the connector pin / connector ring assembly. Two quadfilar coil strands were observed inside the connector ring area. Scanning electron microscopy was performed and identified the area as having evidence of a stress induced fracture (tension overload appearance) and no pitting. 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 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. Based on the findings in the product analysis lab, there is no evidence to suggest an anomaly with the returned portions of the device.
 
Manufacturer Narrative
Only a small 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
Analysis on the generator was completed on (b)(6) 2012. 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
It was reported that the pt's device registered a low impedance reading of less than 600 ohms. X-rays of the device were being ordered. The pt was stated to be well controlled and was not having any side effects. The pt's clinic notes were received which stated on (b)(6) 2011, "evaluate vns device for possible lead wire fracture of pin displacement". The pt's settings and diagnostic info were also provided in the notes. There had been no reported trauma or manipulation. Attempts for further info have been unsuccessful to date. A revision surgery in the future is likely.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2361009
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« Reply #15 on: September 01, 2017, 12:54:22 AM »

Model Number 302-20
Event Date 11/14/2011
Event Type  Malfunction   
Manufacturer Narrative
Device failure 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
Analysis was completed on the returned products. No anomalies were found with the generator. However, a fracture was confirmed in the lead portions. During the visual analysis of the returned 216 mm portion the end of the connector ring quadfilar coil appeared to be broken approximately 278 mm from the end of the connector boot. 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. 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 abraded openings on two adjacent sections of inner tubing created a condition whereby the exposed conductive coils could come in contact with each other. With the exception of the observed discontinuity and abraded open silicone tubes, 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. Based on the findings in the product analysis lab, there is evidence to suggest a discontinuity in the returned portion of the device which may have contributed to the stated allegations of the lead break. The abraded openings on two adjacent sections of inner tubing created a condition whereby the exposed conductive coils could come in contact with each other contributing to the low impedance condition. Note that since a large portion of the lead assembly (body) including the electrodes was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead.
 
Event Description
It was reported that the patient was referred for revision surgery as the vns was showing low impedance. It was noted that about (b)(6) ago, the patient fell off a swing set which may have contributed to event. Further information was received indicating that the patient underwent revision surgery on (b)(6) 2012 and during surgery, the surgeon noted that the lead was broken. Products were returned to manufacturer, but analysis is pending. Attempts for further information have been unsuccessful to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2420944
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« Reply #16 on: September 02, 2017, 01:30:48 AM »

Model Number 302-20
Event Date 12/12/2011
Event Type  Malfunction   
Event Description
On (b)(4), 2012 it was discovered that there was an error in the manufacturer's receiving department; the lead was in fact not returned for product analysis and has not been explanted.
 
Event Description
An article was found which contained information regarding the in situ repair of the vns lead product for 6 patients. It was noted that 5 of the 6 patients had low impedance values pre-operatively, and the 6th patient had normal impedance, but was found during the course of an elective generator replacement to have fractured electrode insulation. It was noted that where the lead insulation was noted to be compromised, it was irrigated with antibiotic-containing solution and dried with a gauze sponge. An appropriate length of silastic tubing that was sufficient to cover the damaged outer sheath with an additional 1-2 cm of tubing extending beyond the damage on either side was then cut. A fresh no. 11 surgical scalpel was used to make a lengthwise cut down one side of the catheter tubing, opening the catheter so it could be slipped over the damaged area. The cut catheter was then delicately placed around the damaged sheath and secured at multiple points with circumferential 2-0 silk ties until there was no longer a bend in the lead or exposed inner electrode wires. Cyanoacrylate glue was then introduced into the open side of the cut catheter as a sealant in and around the damaged external insulation, up to either end of the repair. The glue was then allowed to fully dry. At this point, the repaired segment was handled in a similar fashion to the undamaged wiring and reimplanted. It was noted that one patient had some internal wiring exposed. For this patient, the physician performed the same steps for the internal wiring and then performed the steps again for the external wiring. Follow up for the patients ranged from 12 to 87 months. All 6 patients have maintained unchanged seizures control. Two of the patients have since undergone generator replacement surgery due to end of vns generator battery life. Both of the patients remain with the original repaired leads and unchanged appropriate lead impedance. A search of the manufacturer's internal databases found that one of the patients was already reported through this mfr. Report, and a second patient was reported through mfr. Report # 1644487-2012-00030. However, the 4 remaining patients were unable to be identified with the information provided and were reported through mfr. Report # 1644487-2016-02421.
 
Event Description
Additional information was received on (b)(4), 2012 when the patient's lead was returned to the manufacturer for product analysis. The date the lead was explanted was unknown. Product analysis on the lead is currently underway and has not been completed.
 
Manufacturer Narrative
Follow-up report #1 inadvertently listed that lead was returned for product analysis.
 
Manufacturer Narrative

Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
On (b)(6) 2011, a vns treating nurse practitioner reported that during the patient's prophylactic battery replacement surgery that day, low impedance was discovered when the new generator was attached to the patient's old leads. There was no manipulation or trauma that was believed to have caused the low impedance. Diagnostics prior to surgery showed a dcdc value of 0, but did not show low impedance. Instead of replacing the leads which is what the manufacturer recommends, the surgeon decided to try and "repair" the lead by shunting the lead with electrode tubing from a different manufacturer's tubing kit and then applying dermabond to the lead. The manufacturer's consultant reported that the surgeon was aware of the manufacturer's recommendation to replace the lead, but the surgeon decided to try and "repair" the lead himself despite this. System diagnostics performed after this showed the impedance as being within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2404326
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« Reply #17 on: September 02, 2017, 01:31:57 AM »

Model Number 302-20
Event Date 11/28/2011
Event Type  Malfunction   
Event Description
On (b)(6) 2011 a vns treating nurse practitioner reported that during the patient's prophylactic battery replacement surgery on (b)(6) 2011, when the new generator was attached to the lead low impedance was discovered. The impedance value was 680ohms. The surgeon decided to close up the patient. The patient's old generator had shown dcdc=0 prior to surgery. The patient was seen in the physician's office on (b)(6) 2011 and diagnostics still showed low impedance. The nurse decided to increase the patient's settings to see if efficacy can be reached despite the low impedance. The nurse stated that if the patient is having an increase in seizures, below pre-vns baseline levels, and if the patient continues to have seizures she will refer the patient for a revision surgery. The increase in seizures started on (b)(6) 2011. Additional information has been requested from the nurse but no further information has been received to date.
 
Manufacturer Narrative

Event Description
Additional information was received on (b)(6) 2012, when the manufacturer's consultant reported that the vns patient's low impedance was not discovered until surgery. X-rays were taken and although they were reported to be sent to the manufacturer for review, they have not yet been received. No patient manipulation or trauma occurred that is believed to have caused or contributed to the low impedance. The physician attributes the low impedance issue to be the cause of the patient's increase in complex partial seizures. The patient is being referred for a revision surgery. Although surgery is likely, it has not yet occurred.
 
Event Description
On (b)(6) 2012, a vns treating nurse practitioner reported that the vns patient was having surgery for a lead replacement that day. However it was then later reported that the surgeon was able to fix the leads without replacing them and diagnostics showed results within normal limits. Instead of replacing the leads which is what the manufacturer recommends, the nurse practitioner reported that the surgeon decided to try and "repair" the lead by shunting the lead with electrode tubing from a different manufacturer's tubing kit and then applying dermabond to the lead. The manufacturer's consultant reported that the surgeon was aware of the manufacturer's recommendation to replace the lead but the surgeon decided to try and "repair" the lead himself despite this. The patients will be followed on a monthly basis to determine impedance.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
An article was found which contained information regarding the in situ repair of the vns lead product for 6 patients. It was noted that 5 of the 6 patients had low impedance values pre-operatively, and the 6th patient had normal impedance, but was found during the course of an elective generator replacement to have fractured electrode insulation. It was noted that where the lead insulation was noted to be compromised, it was irrigated with antibiotic-containing solution and dried with a gauze sponge. An appropriate length of silastic tubing that was sufficient to cover the damaged outer sheath with an additional 1-2 cm of tubing extending beyond the damage on either side was then cut. A fresh no. 11 surgical scalpel was used to make a lengthwise cut down one side of the catheter tubing, opening the catheter so it could be slipped over the damaged area. The cut catheter was then delicately placed around the damaged sheath and secured at multiple points with circumferential 2-0 silk ties until there was no longer a bend in the lead or exposed inner electrode wires. Cyanoacrylate glue was then introduced into the open side of the cut catheter as a sealant in and around the damaged external insulation, up to either end of the repair. The glue was then allowed to fully dry. At this point, the repaired segment was handled in a similar fashion to the undamaged wiring and reimplanted. It was noted that one patient had some internal wiring exposed. For this patient, the physician performed the same steps for the internal wiring and then performed the steps again for the external wiring. Follow up for the patients ranged from 12 to 87 months. All 6 patients have maintained unchanged seizures control. Two of the patients have since undergone generator replacement surgery due to end of vns generator battery life. Both of the patients remain with the original repaired leads and unchanged appropriate lead impedance. A search of the manufacturer's internal databases found that one of the patients was already reported through this mfr. Report, and a second patient was reported through mfr. Report # 1644487-2012-00043. However, the 4 remaining patients were unable to be identified with the information provided and were reported through mfr. Report # 1644487-2016-02421.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2399046
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« Reply #18 on: September 05, 2017, 01:02:25 AM »

Model Number 300-20
Event Date 01/01/2012
Event Type  Malfunction   
Event Description
It was reported that a patient was seen by her neurologist on (b)(6) 2012 in which normal mode and systems diagnostic tests showed low impedance with a dcdc code of 0. The last time the patient was seen was in (b)(6) 2011, and the dcdc code was 2 at that time. The patient was seen by her neurologist on (b)(6) 2012 because she had experienced an increase in seizures the last few weeks and was no longer feeling stimulation during magnet mode. The neurologist suspected a short circuit condition with the dcdc code of 0 and the patient's clinical symptoms. The neurologist referred the patient for x-rays and fur surgery. No trauma was reported to the neurologist. Although surgery is likely, it has not occurred to date. Attempts for additional information from the neurologist have been unsuccessful to date. A battery life calculation was performed with the history available in the in-house database and resulted in approximately 4. 38 years until eri=yes.
 
Manufacturer Narrative
Device failure is suspected to have caused the event.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2455645

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« Reply #19 on: September 08, 2017, 10:06:05 AM »

Model Number 302-20
Device Problem Low impedance
Event Date 06/26/2017
Event Type  Malfunction   
Event Description
Clinic notes reported that a low impedance warning message was observed on a patient's device. The patient was noted to have fallen two weeks prior, but the physician's office were unsure if the patient's fall contributed to the low impedance. After observing the low impedance message, diagnostics were performed three times on the patient's device and returned low impedance results each time. The medical assistant requested chest x-rays be performed to check the status of the patient's leads. The patient was also referred for surgery. The hospital's internal x-ray review did not identify any abnormalities with the patient's vns. The x-rays were not reviewed by the manufacturer. No additional relevant information has been received to date. No known surgical intervention has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6767296

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« Reply #20 on: September 08, 2017, 10:07:20 AM »

Device Problem Low impedance
Event Date 07/13/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported by a medical professional that a vns patient was experiencing discomfort over the medial side of the generator, and on palpation describes some tenderness when palpating that area. She reported that when she checked the device the diagnostics she was concerned of a short circuit condition. The patient was noted to have had 2 seizures that have been more severe over the past 2 months. A chest x-ray was taken and nothing abnormal was reported by the clinician. The x-rays have not been received by the manufacturer for review to-date. Additional relevant information has not been received to-date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6772168
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« Reply #21 on: September 08, 2017, 10:08:04 AM »

Model Number 304-20
Device Problem Low impedance
Event Date 07/17/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that low impedance was seen on the patient's device, but the output current was still ok. The patient's device was programmed off, and the patient was referred for revision surgery. No surgery has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6790859

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« Reply #22 on: September 09, 2017, 12:01:03 AM »

Model Number 302-20
Event Date 08/01/2011
Event Type  Malfunction   
Event Description
It was reported on 02/13/2012 that the patient experienced a cluster of seizures which occurred in (b)(6) 2011. Diagnostics performed in august gave results of 840ohms and 760ohms, with intensified follow-up indicator = no. Impedance values were observed and were found to have decreased over time from 1500ohms down to 760ohms. Diagnostics were performed on (b)(6) 2012 with varying results depending on the patient's head position: with the patient's head to the left - impedance value: 1369ohms. With the patient's head to the right - impedance value: 847ohms. It is likely that the patient has a positional lead fracture which is causing the varying impedance values. There was no manipulation or trauma suspected, and the patient is non-verbal so it is unknown if the patient is experiencing any pain. It was also indicated that there were no changes in medications in last 6 months and no recent change in settings. X-rays were taken, and the patient was referred for revision. Ap and lateral chest and neck x-rays dated (b)(6) 2012 were received for the on (b)(4) 2012 and reviewed. The generator appeared to be in the left chest in a normal orientation. The filter feedthru wires appear to be intact. The electrode alignment appears to be normal. The lead at the connector pin appears to be intact. There is some lead behind the generator that could not be evaluated. No gross lead discontinuities or sharp angles can be visualized. Based on the x-rays received, no gross lead discontinuities or sharp angles appear to be present; however an unpronounced lead fracture cannot be ruled out. Additional information was received indicating that the patient's increase in seizures was below baseline. The patient underwent a revision surgery on (b)(6) 2012 and the explanted products were returned on (b)(4) 2012. Analysis is not yet complete.
 
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
Product analysis on the explanted lead and generator was completed on (b)(6) 2012. An analysis was performed on the returned lead portions and a condition was observed that could potentially contribute to the reported low impedance. Abraded openings on two adjacent sections of inner tubing created a condition whereby the exposed conductive coils could come in contact with each other contributing to the :"low impedance" condition. Multiple abraded openings were found on the outer and inner silicone tubes, and most likely provided the leakage path for what appeared to be remnants of dried body fluids found inside the outer and inner silicone tubes. With the exception of the abraded inner tubing openings, the condition of the returned lead portions is consistent with those that typically exist following an explant procedure. No obvious anomalies, beyond the inner tubing openings, 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 evidence to support a potential short circuit condition (low impedance). Note that since a large portion of the lead assembly (body) including the electrodes was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Product analysis on the explanted generator was also completed. Results of diagnostic testing indicated the device was operating properly and communicated properly. Electrical test results showed that the pulse generator performed according to functional specifications.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2490039

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« Reply #23 on: September 14, 2017, 12:17:59 AM »

Model Number 302-30
Event Date 07/01/2011
Event Type  Malfunction   
Event Description
A vns consultant was at a physicians office and reported that she noted when she was looking at programming history on his handheld computer that their was a patient with a dcdc 0 on a system diagnostic test. The patient's records were reviewed and noted that the patient had been having some increase in seizures since their office visit in (b)(6) 2011. She reported that the diagnostic results she noted were low impedance with dcdc 0 on a system test. The patient's current settings are 2/20/250/30/1. 8. Clinic notes were received for review and noted the patient having increased seizures not above baseline, stimulation not perceived and they were having more choking episodes, since being implanted with their vns the patient does not have anymore grand mal seizures. Surgery is going to be planned sometime this summer but no date set at this time. (b)(4) attempts have been made and no further information has been attained.
 
Event Description
A vns consultant was at a physician's office and reported that she noted when she was looking at programming history on his handheld computer that there was a patient with a dcdc 0 on a system diagnostic test. The patient's records were reviewed and noted that the patient had been having some increase in seizures since their office visit in (b)(6) 2011. She reported that the diagnostic results she noted were low impedance with dcdc 0 on a system test. The patient's current settings are 2/20/250/30/1. 8. Notes were received documenting several events of increased seizures. Some seizures not above baseline and some were above baseline and a change in frequency and possibly type. The patient does not feel their vns stimulation and they were having more choking episodes since their last programming change. Since being implanted with their vns the patient does not have any more grand mal seizures. Additionally noted (b)(4) 2012, that the patient had had several seizures after his last visit. He missed his next visit because of a hospitalization. His seizure control is better now. He has never had much benefit from activating the vns. He never has felt it go off. His seizures are less severe now. Reported (b)(6) 2011 clinic visit. His wife reports that since his last visit he has continued to have increase numbers of seizure averaging about 8 to 13 seizures per month. His wife also says that he used to just tighten up with his seizures and now he is starting to have more rhythmic movement, and she is worried that they are increasing in severity along with frequency. She says that over the years his best seizure control has been about 2 to 3 per month, and he has had a vns for years. She worries his vns is less effective. His vns was interrogated to make sure the generator and battery were working well. There is no evidence that his vns is failing at this time. However, given that he is 4 years out i his doctor recommended more frequent interrogation, and they plan on rechecking that in 3 months. For further treatment of his seizures as he has not tolerated higher settings on his vns they will be adding vimpat. The patient does have a history of falls. Their surgery will be planned for some time this summer no date set at this time.
 
Manufacturer Narrative
Adverse event corrected data: omitted clinic information on initial mdr.
 
Event Description
The patient had their vns generator replaced. The explanted generator is in product analysis pending completion. The patient did not have their lead replaced.
 
Manufacturer Narrative

Manufacturer Narrative
Operator of device; corrected data: updated to patient. Type of event: corrected data omitted 30 day report on initial mdr.
 
Event Description
The pulse generator was returned due to prophylactic replacement. Although the reported allegations of "increased seizures", "dysphagia", "stimulation not perceived", "lack of efficacy", "change in seizure pattern", and "increased seizure intensity", cannot be evaluated in the pa laboratory setting, proper functionality of the pulse generator in its ability to provide appropriate programmed output currents can be verified. 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.
 
Event Description
A vns consultant went to a clinic visit and it was noted after review of programming history in the site's handheld that there had been a generator diagnostic test performed on (b)(6) 2012. This test is addressed in medwatch report number: 1644487-2012-01176. The patient's generator had been reset to 0. 00ma. The patient's settings were not reviewed with a final interrogation prior to the patient leaving the office and was subsequently programmed to unintended settings from the test. The patient would not have been receiving therapy. The patient returned to the office on (b)(6) 2012 and the settings were corrected at that time. The site is now aware how to prevent this from happening. The patient is scheduled to have their generator replaced on (b)(6) 2012. Loss of therapy likely attributed to the patient's seizure events since (b)(6) 2012. It is not suspected that the patient has a lead issue at this time. Likely a normal mode diagnostic test was performed when the device was programmed off. No further information has been received about the patient's reported events.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2512499
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« Reply #24 on: October 01, 2017, 12:02:56 AM »

Model Number 302-20
Event Date 10/06/2012
Event Type  Malfunction   
Event Description
Their explanted products were returned for analysis. Reported they had low impedance under 600 ohms. Product analysis is pending completion.
 
Manufacturer Narrative
Device failure caused event but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received that the patient had surgery. It was reported that it was noted that the patient was a twiddler as their lead body in surgery was all twisted. Their generator was a prophylactic replacement. The explanted product at this time has not been returned for analysis.
 
Event Description
An analysis was performed on the returned lead portions. A condition was observed that could potentially contribute to the reported "low impedance" allegation. The report indicated that during surgery it was noted that the patient was a twiddler as their lead body in surgery was all twisted. During the visual analysis the quadfilar coils appeared to be stretched and spiraled and the majority of the lead assembly (body) appeared to be twisted with numerous abraded openings, throughout and both bare coils extending through one of the openings. These findings are consistent with patient manipulation/rotation of the device while it was implanted (twiddler). 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. During the visual analysis the (+) white electrode ribbon appeared to be embedded in what appeared to be a remnant 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 abraded inner silicone tubes and observed 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 except for the twisted appearance of the majority of the lead assembly (body). 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. During the resistance measurement of the returned 391mm portion a high resistance reading was observed on both coils. The high resistance measurement was most likely due to the bare twisted coils that were contacting each other. 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 discontinuities (other than the one broken coil strand) in the returned portions of the device which may have contributed to the stated complaints. However, based on the overall condition of the returned lead, there appears to be evidence of significant manipulation, which may have contributed to the "high impedance" allegation. The exposed and twisted conductive coils (most likely patient-related) may be a contributing factor to the "low impedance" allegation. The abraded openings on two adjacent sections of inner tubing created a condition whereby the exposed conductive coils came in contact with each other contributing to the "low impedance" condition. The generator was returned. Results of diagnostic testing indicated that the battery status indicated ifi=no in the lab. The battery voltage was 2. 965 volts, (not at ifi) as measured during completion of test parameter 7. 16. 10. 2 of the final electrical test. The data in the diagaccumconsumed memory locations revealed that 10. 728% of the battery had been consumed. 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 malfunction suspected but did not cause or contribute to a death or serious injury.
 
Event Description
Additional information was received that this patient has not followed up and their treating physician has been unable to contact them. The patient had a low impedence reading on (b)(6) 2012. Surgical intervention was planned for lead revision but family did not follow up. Prior to that date test was within normal limits on (b)(6) 2012.
 
Event Description
It was reported to our consultant that there was a vns patient who needed to have revision surgery related to high lead impedance. The patient is a twiddler and they replaced their battery (b)(6) 2012 but did not change the lead. They knew eventually it would be an issue as she was turning her device under the skin. Good faith attempts are underway for further information about the reported event. Surgery has not been performed at this time.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2854693
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« Reply #25 on: October 06, 2017, 09:12:06 AM »

Model Number 302
Device Problems Fracture; Low impedance
Event Date 08/08/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that the physician performed a diagnostic test during a visit and observed a low impedance warning. Chest x-rays were reviewed by the physician and a lead fracture was observed. These images have not been reviewed by the manufacturer to date. It is unknown if the patient sustained an injury which could have caused the lead fracture. The device was programmed off and the patient was referred for surgery. No surgical interventions are known to have occurred to date.

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« Reply #26 on: October 07, 2017, 01:38:41 AM »

Model Number 303-20
Device Problems Detachment of device component; Low impedance
Event Date 08/24/2017
Event Type  Malfunction   
Event Description
Report received that low impedance was found on a patient's lead. Low impedance was initially found after a system diagnostic test run in the clinic. The patient later returned for more positional testing and low impedance was still found. The vns generator was turned off. System diagnostic results from the implant were provided and showed normal results. The patient reportedly did not have the ability to manipulate the device and there was no reported trauma. X-rays were reportedly taken by the physician and did not show any lead breaks in the lead. Pin insertion was also verified. These x-rays were not evaluated by the manufacturer. The patient returned to the or for a lead replacement. During the surgery, the silicone tubing appeared detached at the lead pin. The surgeon attempted to salvage the generator by removing the lead from the generator, but the septum plug was removed. It was also noted that fluid was found in the generator header. The septum plug removal and fluid in the generator were reported in mfr. Report # 1644487-2017-04472. Both the lead and generator were replaced. A device history record of the lead indicated all quality inspections had been completed and passed prior to release for distribution. The lead and generator have not been received to date. No further relevant information has occurred to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=6874733

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« Reply #27 on: October 13, 2017, 11:40:56 PM »

Model Number 102
Event Date 05/15/2013
Event Type Malfunction
Event Description
On (b)(6) 2013 it was reported that the patient was scheduled for generator replacement on (b)(6) 2013 due to end of service on (b)(6) 2013 and there was concern of low impedance being observed during interrogation on this date as well. It was reported that on (b)(6) 2013 an eri flag was observed and low impedance. The manufacturer¿s consultant mentioned that the low impedance might have been due to a generator diagnostics test being performed by mistake instead of a system diagnostics test. It was reported that x-rays were not taken. It was stated that a copy of the patient¿s programming history would be sent in for review but it has not been received to date. The patient underwent generator replacement on (b)(6) 2013. The explanted generator was returned for product analysis on (b)(4) 2013. Product analysis is still underway and has not yet been completed. Device manufacturing records were reviewed. Review of manufacturing records confirmed that the generator passed all functional tests prior to distribution.

Manufacturer Narrative
Date of event, corrected data: previously submitted mdr indicated that the low impedance during a generator diagnostic was seen on (b)(6) 2013; therefore, this should be the event date. This report is being submitted to correct this information.

Event Description
On (b)(4) 2013 product analysis was completed on the explanted generator. The reported ¿low impedance¿ allegation is beyond the scope of pa activities and could not be determined; however, the depleted battery condition may have been a contributing factor. Analysis in the pa lab determined that the device had reached an end of service condition; an open can measurement of the battery voltage confirmed that the battery was depleted. 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.

Event Description
Additional programming history was received that confirmed that the physician performed a generator diagnostics. A system diagnostics test performed the same day shows everything was functioning. Low impedance would be expected if a generator diagnostics that was performed while implanted on in a patient.

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« Reply #28 on: October 18, 2017, 12:14:15 AM »

Model Number 103
Event Date 07/11/2013
Event Type Malfunction
Event Description
It was reported that device diagnostic testings resulted in low impedance. It was reported that the patient had undergone generator replacement two weeks prior and that the patient would be sent for x-rays and referred back to implanting surgeon. It was later reported that the vns is displaying "high impedance". The neurologist reported that the patient has been experiencing a slight increase in the intensity of the seizures, but not a marked increase in frequency. The x-rays were sent to device manufacturer for analysis. Based on the x-ray images provided, the cause of the high impedance cannot be determined. A portion of the lead could not be visualized in the chest, and the presence of a micro-fracture in the lead cannot be ruled out. Additionally due to the quality of images, the lead pin not being fully inserted or fracture at the filter feedthru wires or lead wires at the connector pins could not be ruled as a potential cause of the high impedance. Attempts to obtain additional information have been unsuccessful to date.

Event Description
Follow up while the patient was in the operating room found that the physician was not planning to replace the lead for the patient, but wanted to test the generator. Diagnostics were performed on the old generator with the lead pin in, and the generator diagnostics came back with high impedance. The patient was set at 0. 25ma at the time of these diagnostics. System diagnostics were then performed which came back fine as compared to the high impedance. It was reported that they were likely not going to replace the lead; however, when they opened up the patient, blood was seen in the lead and there was a possible microtear. The patient's device was turned back to previous settings and the patient was scheduled for a follow up visit in two weeks to re-perform diagnostics. Additional follow up found that the patient was seen in the clinic on (b)(6) 2013 for routine evaluation after his routine generator replacement three weeks prior. To the nurse's understanding, the patient was programmed back to original settings in the operating room during that replacement surgery. The patient presented with high impedance found on a diagnostic test at the visit. There was no recent trauma to the neck or chest. The vns output currents were disabled to 0ma on this date. The patient was referred for x-rays which found no visible lead break. It was confirmed that the patient had surgery on (b)(6) 2013, but no devices were replaced. The lead pin was re-inserted into the generator and it is believed that this resolved the high impedance. However, it was mentioned that there was light fluid collection around the sheath per the surgeon.

Event Description
Additional clarification showed that the initial report was of high impedance, not low impedance with an impedance values of 5826 ohms. During the surgery on (b)(6) 2013, re-seating the pin resolved the impedance issue: 1840 ohms.

Manufacturer Narrative
Manufacturer reviewed x-rays of implanted device. Device manufacturing records were reviewed. X-rays review by the manufacturer, no gross lead discontinuties. 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.

Manufacturer Narrative
Date of event, corrected data: additional information was receiving indicating that the incomplete pin insertion that caused the high impedance was due to implant surgery on (b)(6) 2013. This report is being submitted to correct this information. Brand name, 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 this information. Type of device, 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 this information. 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. This report is being submitted to correct this information. Operator of device, corrected data: previously submitted mdr indicated that the patient was the user; however, this should be the medical professional. This report is being submitted to correct this information. 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 this information.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3309059
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dennis100
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« Reply #29 on: October 23, 2017, 12:06:15 AM »

Model Number 103
Event Date 10/25/2013
Event Type Malfunction
Manufacturer Narrative
Describe event or problem, corrected data: previously submitted mdr indicated that the reported event was high impedance; however, review of the available data showed that the warning messages received would have indicated low impedance. This report is being submitted to correct this information.

Event Description
On (b)(6) 2013, it was reported that high impedance was observed during vns replacement surgery. The lead was removed and re-inserted into the generator several times; however, the high impedance message persisted. Review of the lead device history records confirmed all quality tests were passed prior to distribution. Follow up with the physician's office found that the patient was seen and system and normal diagnostics showed the device was ok and no further action is being taken at this time. Attempts have been made for additional information; however, they were unsuccessful. No additional information has been received.

Manufacturer Narrative
Device manufacturing records 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
Review of the available programming and diagnostic history and internal device data. Additional information indicates that the suspect device is the generator.

Event Description
Review of the available programming and diagnostic history showed three diagnostic tests were performed on (b)(6) 2013 and all were within normal limits. Review of the internal device data indicated that no system diagnostic tests were performed at the time of implant. Review of data from (b)(6) 2013 showed that the impedance changed from 0 ohms to 2174 ohms on (b)(6) 2013. The 0 ohms appeared to a be a value stored from final electrical testing prior to distribution suggesting that this value was not cleared by performing a system diagnostic test on the day of implant.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3481873
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