It was reported that a patient's vns system was explanted and that no replacement devices were implanted due to a wrong epilepsy diagnosis by the patient¿s neurologist.The explanted devices were returned to the manufacturer.Analysis of the returned lead portions indicates that there was evidence to suggest a discontinuity.Visual analysis of the returned portion found that the quadfilar coil 1 appeared to be broken approximately 20mm from the electrode bifurcation.Scanning electron microscopy identified the area as being mechanically damaged, which prevented identification of the coil fracture type, with no pitting.It is unknown if the break occurred while stimulation was present due to the absence of metal pitting.With the exception of the observed discontinuity, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure, like abraded openings of the outer silicon tubing, cut ends and remnants of body fluids in the outer silicone tubing.No other obvious anomalies were noted.The electrodes were not returned for analysis and therefore a complete evaluation could not be performed on the entire lead.Analysis of the returned generator indicated that the device performed according to functional specifications.No abnormal performance or any other type of adverse condition was found.Review of the manufacturing records confirmed that the generator and lead passed all functional tests prior to distribution.Available programing history for the patient was reviewed through (b)(6) 2011.No anomalies were observed.Available diagnostics history was reviewed for the patient.System diagnostics and normal mode diagnostics returned impedance results within normal limits through (b)(6) 2010.
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