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Author Topic: Reddish Brown Deposits  (Read 273 times)
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dennis100
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« on: March 20, 2019, 10:31:01 AM »

Model Number 304-20
Device Problem Fracture
Event Date 10/14/2015
Event Type  Malfunction   
Event Description
It was reported that the patient had a fractured lead but underwent replacement on (b)(6)2015. It is unknown what specific devices were replaced (generator and/or lead). It is also currently unknown how the lead was determined to be fractured. No additional relevant information has been obtained to date.
 
Event Description
Additional information was received which clarified that both the generator and lead were explanted on (b)(6) 2015. No additional relevant information has been obtained to date.
 
Event Description
The explanted generator and lead were received on 01/29/2016. The reported "fracture of lead" allegation was not verified. Scanning electron microscopy images of the connector pin verified that pitting or electro-etching conditions have occurred on the connector pin. An energy dispersive spectrometry (eds) analysis performed on a sample of the reddish-brown deposits observed on the pin showed the presence of some elements present in stainless steel 316. The higher percentage of iron in this sample suggests oxidation may have occurred. An abraded opening of the outer tubing was observed in one location. Since a portion of the lead (including the electrode array) was not returned for analysis, an evaluation and resulting commentary could not be made on that portion of the lead. Other than the above mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead portions. The reported allegation of "high impedance" was not duplicated in the pa lab. Various electrical loads were attached to the pulse generator and results of diagnostic tests demonstrate that accurate resistance measurements were obtained in all instances. 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. In addition, a comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications. The battery, 3. 036 volts, shows an ifi=no condition. In addition, signs of discoloration were also observed on the pulse generator case, which is consistent with the adhered remnants of dried body fluids following an explant process. No other surface abnormalities (such as sharp edges, header delamination, open pockets, decomposition, corrosion or voids) were noted on this device. Observations under pa lab bench microscope revealed pitting on the negative connector block and setscrew. Other than the noted visual anomalies, there were no performance or any other type of adverse conditions found with the pulse generator.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5206930
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dennis100
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« Reply #1 on: March 20, 2019, 10:31:44 AM »

Model Number 300-20
Event Date 04/08/2014
Event Type  Malfunction   
Event Description
It was reported that a vns patient received a high impedance warning during diagnostic testing and that the patient¿s generator was disabled as a result. Last successful diagnostic results were reportedly obtained seven (7) months earlier. Surgery has not occurred to date.
 
Manufacturer Narrative
Device manufacturing records were reviewed. Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution. Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Event Description
On (b)(6) 2014 it was reported that the generator and lead would be returned for product analysis. A full revision surgery had taken place on (b)(6) 2014 due to the high impedance. The generator and lead were received for product analysis on (b)(4) 2014. Product analysis is still underway and has not yet been completed.
 
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
On august 18, 2014 product analysis was completed on the explanted generator. Results of diagnostic testing indicated that the battery status indicated ifi=no in the product analysis lab. The battery voltage was 2. 895 volts (not at ifi) as measured during completion of the final electrical test. 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. The review of the device's internal memory showed the impedance went from 9799ohms to 12299ohms on (b)(6) 2014, both of which are high impedance. Product analysis was completed on the lead on 9/2/14. Except for slight observed pitting on the negative connector pin and one abraded outer tubing observation, there were no observed product related issues with the returned lead portions. Scanning electron microscopy images of the unmarked connector pin show that pitting or electro-etching conditions have occurred on the connector pin surface at the areas where reddish-brown deposits were noted. An energy dispersive spectrometry (eds) analysis performed on the sample of the reddish-brown deposits observed on the pin showed the presence of some elements typically observed on stainless steel 316/316l. The higher percentage of iron observed in this sample suggests that an oxidation process may have occurred. The exact impact of this condition on any on the reported "high impedance" allegation is unknown. Note that since a portion of the lead (including the electrode array) was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. The outer silicone tubing is abraded open and the lead assembly has dried remnants of what appear to have once been body fluids inside the inner and the outer silicone tubing of the second portion of the returned lead. No obvious point of entrance was noted other than the identified tubing openings and the end of the returned lead portion.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=3786843
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dennis100
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« Reply #2 on: March 20, 2019, 10:34:14 AM »

Model Number 302-20
Event Date 12/08/2011
Event Type  Malfunction   
Event Description
On (b)(6) 2011 a vns treating physician reported that the vns patient has high impedance. The patient stated that in the past couple of months he has been noticing that when he swipes his magnet he doesn't feel the "tickle" he normally feels. There has been no trauma. The physician has referred the patient for a full revision surgery. The patient's settings were output=2. 5ma/frequency=20hz/pulse width=250usec/on time=30sec/off time=1. 8min/magnet output=2. 75ma/magnet on time=60sec/magnet pulse width=250usec. A battery life calculation was performed which showed 0. 41 years until eri=yes. Although surgery is likely, it has not yet occurred. No further information regarding the high impedance has been received from the physician to date.
 
Event Description
Additional information was received on (b)(6) 2012 when it was discovered that the vns patient was scheduled for surgery on (b)(6) 2011 but it was cancelled because the patient had something to drink. The surgery will be rescheduled. The patient was last seen by the physician on (b)(6) 2011 and this was when the high impedance was first observed. A system diagnostics test showed results of lead impedance=high/near end of service=no. The patient's device was then disabled that day due to the high impedance. Although surgery is likely it has not yet occurred.
 
Event Description
Additional information was received on (b)(6) 2012 when the physician reported that no x-rays had been taken by the physician. The patient has been scheduled for a full revision surgery in (b)(6) 2012.
 
Event Description
Additional information was received on (b)(6) 2012 when it was discovered that the vns patient had a full revision surgery on (b)(6) 2012. The generator had been replaced for prophylactic reasons and the leads were replaced due to high impedance. The lead impedance after surgery was reported to be within normal limits. The explanted lead and generator were returned to the manufacturer for product analysis on (b)(6) 2012 that has not yet been completed.
 
Event Description
Additional information was received on (b)(4) 2012, when product analysis was completed on the section of the lead assembly that was returned. The lead's electrodes were not returned for evaluation. Scanning electron microscopy images of the pin shows that pitting or electro-etching conditions have occurred on the connector pin at the region where the reddish-brown deposits were noted. An energy dispersive spectrometry analysis performed on a sample of the reddish-brown deposits identified fe, cr, ni, p, mo, na, si, and ca as the composition for the substance. The higher percentage of iron in this sample suggests oxidation may have occurred. Since a portion of the lead, including the electrode array, was not returned for analysis, an evaluation and resulting commentary cannot be made on that portion of the lead. Other than the mentioned observations and typical wear and explant related observations, no other anomalies were identified in the returned lead portion. Product analysis on the generator was completed on (b)(4) 2012. In the product analysis lab, the device output signal was monitored for more than 24-hrs, while the generator was placed in a simulated body temperature environment. Results showed no signs of variation in the pulse generator's output signal and demonstrated that the device provided the expected level of output current for the entire monitoring period. The pulse generator diagnostics were as expected for the programmed parameters. Magnet activations performed at the bench (at a distance of one-inch, spacer block, from generator) demonstrate the appropriate magnet output for the programmed settings. In addition, a comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications; there were no performance or any other type of adverse conditions found with the pulse generator.
 
Manufacturer Narrative
Device failure is suspected, but did not cause or contribute to a death or serious injury.
 
Manufacturer Narrative
Only a portion of the lead was returned for analysis which did not reveal any anomalies. Device failure is suspected in the lead portion not returned, but did not cause or contribute to a death or serious injury.

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2395574
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