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Author Topic: Electrodes  (Read 116581 times)
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dennis100
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« Reply #420 on: June 07, 2019, 05:05:13 AM »

Model Number 302-20
Device Problem High impedance
Event Date 04/15/2019
Event Type  Malfunction   
Event Description
High lead impedance was observed by the surgeon during a generator replacement surgery due to battery depletion. The patient's previous generator was unable to communicate with the programmer due to an end of service condition; and therefore, the diagnostics/settings could not be obtained prior to surgery and lead impedance could not be verified. The generator was then replaced, with previous lead still implanted, and the diagnostics were performed to verify lead impedance. The diagnostic test resulted in high lead impedance, so the lead pin was re-inserted and diagnostics were performed again. Once again high lead impedance registered. The surgeon then proceeded to open the patient's neck and inspect existing lead. Upon visual inspection, he discovered that the there were no lead electrodes on the vagal nerve. The surgeon attempted to find the electrodes, and he could see that they were in neck, but was not sure where they were implanted. He did not want to attempt to remove electrodes due to excessive scar tissue and only cut lead. He left remaining electrodes in neck and still was unsure exactly where the electrodes were implanted. He implanted a new lead on vagal nerve and when connected to the newly implanted generator resulted in ok lead impedance. Both the explanted lead and generator were discarded during surgery; and therefore, the explanted product will not be returned for product analysis. No other relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=8595064
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dennis100
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« Reply #421 on: June 18, 2019, 12:35:47 AM »

Model Number 302-20
Device Problem Fracture
Event Date 11/28/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that high lead impedance was observed with the patient's device as a result of normal mode and system diagnostic tests. The device was disabled and the patient was referred for surgery. No surgical interventions are known to have occurred to date. No additional relevant information has been received to date.

Event Description
It was reported that the patient underwent lead and generator replacement surgery. The surgeon noted he experienced difficulty explanting the electrodes due to scar tissue however the nerve's condition appeared good. Following the surgery the lead was discarded and was not returned to the manufacturer. However the explanted generator was received and is pending analysis.
 
Event Description
Product analysis was completed on the explanted generator. Visual analysis showed that device had scratches on the can and header. These markings are consistent with the manipulation that occurs during the explant procedure. Upon interrogation it was noted that the battery end of service flag was not set and during testing the generator performed to functional specification.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7131163
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dennis100
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« Reply #422 on: June 22, 2019, 03:28:13 AM »

Model Number 106
Device Problem Adverse Event Without Identified Device or Use Problem
Event Date 12/14/2017
Event Type  Malfunction   
Manufacturer Narrative
(b)(4).
 
Event Description
It was reported by the physician's office that they suspected that the patient's vns electrodes were loose as the patient was not perceiving stimulation. However, the physician reviewed x-rays and lead detachment was not observed. It was noted that at an appointment, the patient did not perceive normal or magnet mode stimulation. It was reported that the output current was increased all the way and the patient felt nothing. It was unclear what the office meant by "all the way. " it was noted that the patient typically experiences slight hoarseness, but did not have any when turning the device up, which lead to the suspicion that there was a lead break or loose leads. The patient's seizures seemed worse at the time that the patient reported not feeling stimulation. The patient's friend noted seeing a bruise at the vns electrode site several days prior to an appointment and the physician noted that there was a bruise at the generator site. The physician's office mentioned that the patient normally experiences severe drop seizures and has multiple in a day. Follow up with the company representative revealed that the representative had seen the patient and diagnostics were within normal limits. The patient's vns settings were low and she could not feel stimulation, even with a magnet swipe. The patient reported that the vns worked for a while, but she experienced a recent increase in seizures. The x-rays have not been received by the manufacturer to date. No additional relevant information has been received to date.
 
Event Description
Follow up with the physician's office revealed that the reference to increasing the output current "all the way" was to 1. 00 ma per protocol. It was stated that the patient could not feel the stimulation as she had previously and that the patient could not feel the 1. 50 ma magnet stimulation. It was reported that the increase in seizures was just the same as before the vns. The bruising was thought to be the result of a seizure. It was stated that the physician thought that the increase in seizures were due to the electrodes not being connected well. The physician believes that a seizure may have caused electrode detachment and the patient was sent for evaluation, despite the diagnostics showing as within normal limits and detachment not being verified in x-rays.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7176252
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dennis100
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« Reply #423 on: June 23, 2019, 03:52:13 AM »

Model Number 302-20
Device Problems Corroded ; Fracture; High impedance; Mechanical Problem
Event Date 06/17/2017
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that the company representative was asked to attend a surgery she thought was only a generator replacement. However upon checking the device prior to surgery high impedance was observed. The lead and generator were then replaced. The explanted products have not been received to date. No additional relevant information has been received to date.
 
Event Description
The explanted lead and generator were received and are pending analysis. The lead's product information was identified following the explant. It indicated that the lead had been implanted for several years. A review of the diagnostic history from the internal database showed that impedance was within acceptable limits in the most recent history.
 
Event Description
Analysis was completed on the returned lead and generator. The generator case had scratches, tool marks and burn marks which are consistent with manipulation and exposure to electrocautery during the explant procedure. Upon interrogation the battery indicator was found to be ifi = yes. A series of interrogations and diagnostics were performed on the generator and the results were normal. During testing the generator performed to functional specification and passed electrical testing. The lead assembly was received in two pieces with the lead¿s pin still connected to the generator. The furthest electrode to the bifurcation was not returned for evaluation. Prior to decontamination a continuity check was performed while the lead pin was still inserted into the lead and the continuity check verified there was proper contact between the set screw and the lead pin was present. Visual analysis of the lead completed for both lead segments. It was found that the lead was tangled and the outer tubing was abraded in the segment which included the lead pin. In both segments the lead coils were kinked and the electrode was noted to be damaged and partially detached, this was potentially related to the explant procedure. A fracture was identified in the lead coil in the lead assembly that was not attached to the lead pin and therefore not part of the continuity check. Pitting was observed at the point of fracture which indicates that the stimulation was being provided while the fracture was present.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7167569
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dennis100
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« Reply #424 on: June 25, 2019, 01:11:14 AM »

Model Number 106
Device Problems Detachment Of Device Component; High impedance
Event Date 01/18/2018
Event Type  Malfunction   
Manufacturer Narrative

Event Description
It was reported that high impedance was observed on the patient's vns generator. The patient was referred to the surgeon for evaluation. Follow up with the surgeon's office revealed that it was unknown if there was any trauma or patient manipulation that could have contributed to the high impedance. It was stated that x-rays were performed to assess lead pin insertion. The patient was referred for vns lead replacement surgery. The x-rays have not been reviewed by the manufacturer to date. No relevant surgical intervention is known to have occurred to date. No additional relevant information has been received to date.
 
Event Description
It was reported that the patient underwent surgery to address the high impedance observed on the vns. It was stated that the surgeon thought it looked like the electrodes were not fully on the nerve. The surgeon removed the electrodes and then placed them back onto the nerve as well as relieved tension in the lead. Multiple diagnostics were performed during surgery and post-op and the impedance values were within normal limits.
 
Event Description
It was reported that high impedance was observed on the patient's vns again. The patient was referred for lead replacement surgery. Follow up with the tc revealed that the during surgery, the surgeon observed that the vns lead pin connector was loose in the generator header and appeared to not be properly secured. Lead pin insertion troubleshooting was performed and the high impedance was resolved. Several additional diagnostics were performed with the patient's neck in various positions to test the impedance values. The results were within normal limits.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7265105
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dennis100
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« Reply #425 on: July 04, 2019, 12:51:25 AM »

Model Number 304-20
Device Problem Adverse Event Without Identified Device or Use Problem
Event Type  Injury   
Manufacturer Narrative
 
Event Description
It was reported that the lead had "fused" to the patient's vagus nerve, which indicated that fibrosis had likely occurred at the location of the nerve and lead electrodes. In addition, the patient had surgery that appeared to be related to the fibrosis. The patient reported no complications with the surgery. No additional or relevant information has been received to date.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=7630304
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