It was reported by the neurologist the patient was scheduled for vns surgery as the vns was checked showing high impedance and it is unsure if the lead pin is out or if a new lead needs to be placed.It was also reported the patient's device was turned off on (b)(6) 2015.It was later reported the patient underwent surgery on (b)(6) 2015 and the lead and the generator were both replaced.The lead was replace due to high impedance and the generator was prophylactically replaced.Additionally, it was reported there was a lead break at the strain relief bend, right by the tie down.It was also clarified the generator was replaced prophylactically as the physicians were unclear how long the device had been broken and were not comfortable using the old device due to the broken lead and risk of infection from taking the generator out, then putting it back in after removing and replacing with the new lead.The lead and the generator were received.Analysis is expected but has not been completed to date.
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Product analysis found that the high impedance most likely occurred on (b)(6) 2015 as the impedance value was noted to have changed from 1224 ohms to 11619 ohms on that date.It was found through testing that the generator performed according to functional specifications.The final electrical test shows and ifi = no condition.There were no performance or any other type of adverse conditions found with the pulse generator.Analysis was completed on the returned lead portions and lead fractures were confirmed.It should be noted that portions of the electrodes were not returned for analysis; therefore a complete evaluation could not be performed on the entire lead product.Fractures were found on all three coil strands.One of the coils had extensive pitting that prevented identification of the fracture type.It was noted that all three broken coil strands were mechanically damaged which prevent identification of the fracture type, with evidence of a stress induced fracture, which most likely completed the fracture on all three broken coil strands.One of the coil strands was identified as having evidence of a stress induced fracture with mechanical damage and pitting.Determination could not conclusively be made on the fracture mechanism.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 silicone most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids inside the outer silicone tubing.White deposits were observed in various locations.Energy dispersion spectroscopy was performed on the deposit observed on the connector boot and identified the deposit as containing silicon, phosphorus, sodium, magnesium, and calcium.It was found that the returned white electrode ribbon appeared to be embedded in what appeared to be remnants of dried body tissue.This condition may have prevented the white electrode ribbon from coming in contact with the vagus nerve.With exception of the observed discontinuities and the 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.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 evidence to suggest discontinuities in the returned portions of the lead which may have contributed to the stated allegations.
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