Analysis of the returned generator was completed.It indicates that the generator performed according to functional specifications.During the product analysis there were no anomalies found with the pulse generator.An analysis was performed on the returned lead portions and the reported allegations were confirmed.During the visual analysis of the returned portion, the (-) green electrode quadfilar coil appeared to be broken.Scanning electron microscopy (sem) was performed on the connector end of the (-) green electrode quadfilar coil break and identified the area on two of the broken coil strands as being mechanically damaged (smooth surfaces) which prevented identification of the coil fracture type.The area on a third broken coil strand was identified as having evidence of a stress induced fracture (fatigue appearance) with mechanical damage and pitting.The area on the fourth broken coil strand was identified as having evidence of a stress induced fracture (rotational forces) with mechanical damage and no pitting.Pitting and flat spots were observed on the coil surface.Sem was performed on the electrode (mating) end of the (-) green electrode quadfilar coil break and identified the area on two of the broken coil strands as being mechanically damaged (smooth surfaces) which prevented identification of the coil fracture type.The area on the remaining two broken coil strands was identified as having extensive pitting which prevented identification of the coil fracture type.Extensive pitting and flat spots were 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.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.No other obvious anomalies were noted except for the set of setscrew marks found near the end of the connector pin indicating the lead had not been fully inserted into the cavity of the generator.The additional 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.Based on the findings in the product analysis lab, there is evidence to suggest a discontinuity in the returned portions of the device which may have contributed to the stated allegations of high impedance.
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