Model Number 302-20 |
Device Problem
High impedance (1291)
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Patient Problem
Seizures (2063)
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Event Date 03/28/2014 |
Event Type
malfunction
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Event Description
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X-rays were provided to the manufacturer on (b)(6) 2014.X-rays dated (b)(6) 2014 were provided to the manufacturer for further review.The generator appears in the left chest in a normal placement.The filter feed-through wires appear to be intact.The lead connector pin appears fully inserted into the generator connector block.The electrodes appeared to be placed in normal arrangement.Part of the lead was behind the generator and could not be assessed.No clear lead breaks or sharp angles were found in the parts of the lead that could be assessed.Based on the images provided, the cause high lead impedance remains unknown.No known interventions have occurred to date.
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Manufacturer Narrative
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Manufacturer reviewed x-rays of implanted device.X-rays reviewed by manufacturer, no gross lead discontinuities visualized.Describe event or problem, corrected data: the initial manufacturer report inadvertently did not include that x-rays were received that were pending review.
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Event Description
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Additional information was received stating that the vns patient underwent generator and lead replacement surgery on (b)(6) /2014 due to lead discontinuity which was reportedly visualized near the lead pin.It was noted that the patient¿s generator was not fixed with a non-absorbable suture, so the generator may have turned while implanted.The patient¿s replacement device was programmed on to previous device settings.The explanted generator and lead were returned to the manufacturer where analysis is currently underway.
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Event Description
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It was reported that the vns patient visited the hospital due to an increase in seizures above pre-vns baseline levels.The physician reported that the event was related to vns stimulation.The patient¿s device was tested and system diagnostic results revealed high lead impedance (dc dc ¿ 6).The patient¿s device was not programmed off.X-rays and emg were planned but it is unknown it they have been taken to date.Patient manipulation or trauma is not believed to have caused or contributed to the high impedance.The patient had multiple seizure types that all increased.The seizure type, duration of the seizures, post-ictal period, and auras did not change.Review of the available programming and diagnostic history showed normal diagnostic results through (b)(6) 2013.No known interventions have occurred to date.Attempts for additional relevant information were made but have been unsuccessful to date.
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Manufacturer Narrative
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Device manufacturing records and available programming and diagnostic history were reviewed.Review of manufacturing records confirmed that the lead passed all functional tests prior to distribution.Device failure is suspected, but did not cause or contribute to a death or serious injury.
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Manufacturer Narrative
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Device failure occurred, but did not cause or contribute to a death.
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Event Description
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Analysis of the generator was completed on 09/23/2014.The generator performed according to functional specifications.During the product analysis there were no anomalies found with the pulse generator.Analysis of the lead was completed on 09/23/2014.Note that the electrodes were not returned for analysis; therefore, a complete evaluation could not be performed on the entire lead product.During the visual analysis portions of the returned lead assembly appeared to be compressed and twisted and numerous abraded openings were observed on the outer silicone tubing.During the visual analysis of the returned 216mm portion quadfilar coil 1 appeared to be broken approximately 32mm and 36mm from the end of the cut outer / inner silicone tubes.Scanning electron microscopy was performed on the quadfilar coil 1 coil break (found at 32mm) and identified the area as being mechanically damaged which prevented identification of the coil fracture type with pitting.Determination could not conclusively be made on the fracture mechanism.Pitting was observed on the coil surface.Scanning electron microscopy was performed on the quadfilar coil 1 coil break (found at 36mm) and identified the area on three of the broken coil strands as being mechanically damaged which prevented identification of the coil fracture type with pitting on two of the broken coil strands.The remaining broken coil strand was identified as having evidence of a stress induced fracture (fatigue appearance) with mechanical damage, no pitting and evidence of a stress induced fracture (torsional appearance) which most likely completed the fracture.Pitting was observed on the coil surface.It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting.Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution.The abraded openings found on the outer and inner silicone tubes and the cut ends that were made during the explanted process, most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids found inside the outer and inner silicone tubes.What appeared to be white deposits were observed in various locations.Eds (energy dispersion spectroscopy ¿ provides chemical or element identity/composition analysis) was performed and identified the deposit as containing silicon, phosphorus, sodium, magnesium, sulphur and calcium.With the exception of the observed discontinuities the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure.No other obvious anomalies were noted.The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present.Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.
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Search Alerts/Recalls
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