A physician assistant reported that (high) lead impedance was identified for a patient's device upon interrogation.The patient was referred for full revision surgery.Diagnostics were reported to be abnormal because (high) impedance was detected.Multiple parameter changes were undertaken to optimize efficacy and tolerability.Clinic notes were later received confirming that high impedance was observed and it was also mentioned the patient has noticed discomfort with the vns around the generator and left portion of her neck as though the setting is higher than normal.Settings were adjusted due to the impedance and pain.Patient is somewhat satisfied with seizure control, but not with vns side effects.During patient's previous appointment, high impedance was not observed and patient was satisfied with seizure control and side effects, indicating that the vns side effects are related to the high impedance.No known surgical interventions have occurred to date.
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A break was identified in the negative coil.Scanning electron microscopy images of the negative coil show that pitting or electro¿etching conditions have occurred at the break location.However, due to mechanical distortion (smoothed surfaces the fracture mechanism cannot be ascertained.Also, a suspected inclusion was noted in one of the broken wires of the quadfilar coil.The lead assembly has dried remnants of what appear to have once been body fluids inside the inner and the outer silicone tubing.No obvious point of entrance was noted other than the identified tubing openings and the cut ends of the returned lead portions.Proper functionality of the pulse generator in its ability to provide appropriate programmed output currents was successfully verified in the lab.In addition, the septum was not cored, thus eliminating the possibility of a potential unintended electrical current path through body fluids.The pulse generator diagnostics were as expected for the programmed parameters.There were no performance or any other type of adverse conditions found with the pulse generator.
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