It was reported that a patient had high impedance after an mri.The patient's device was programmed off prior to the mri, and the nurse reported that she performed diagnostics at that time.The diagnostics were reported to be within normal limits prior to the mri, but there was high impedance after the mri when the device was being programmed back on.The patient did not have any adverse events during/after the mri and was at baseline in terms of neurological status and seizure frequency with no complaints of pain or discomfort.X-rays were reviewed.It could not be confirmed that the lead pin was fully inserted into the generator header, due to the angle of the image.No gross fractures were identified with the provided images.No sharp angles were noted.Additionally, a portion of the lead was identified to pass behind the generator, and an assessment could not be made on that portion of the lead.The physician acknowledged that the device should be programmed off due to the high impedance, but the patient requested that the stimulation be left on because she did not want to lose therapy.The patient denied any recent trauma, but she did fall with some seizures.However, she could not remember any specific incident of trauma to the lead area.No further relevant information has been received, and no known surgical intervention has occurred to date.
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Analysis on the generator was approved.The device performed according to functional specifications.Analysis of the generator concluded that no abnormal performance or any other type of adverse condition was found.Analysis of the lead was approved also.Note that a portion of the negative electrode inner silicone tubing and quadfilar coil was not returned for analysis and therefore a complete evaluation could not be performed on the entire lead product.During the visual analysis of the returned portion the negative electrode quadfilar coil appeared to be broken past the end of the cut / torn inner silicone tubing.Scanning electron microscopy was performed and identified the area as having extensive pitting with mechanical damage which prevented identification of the coil fracture type.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.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.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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