Revision surgeries following vagus nerve stimulator implantation

Lead Failure After Vagus Nerve Stimulation Implantation: Radiographic Examination and Revision Surgery

OBJECTIVE

The present study assessed the most common types of lead failures, identified the causes, and discussed the potential procedures for revision surgery after vagus nerve stimulator implantation in patients with epilepsy.

METHODS

In a retrospective study during an 8-year period, 13 patients had undergone revision surgery because of lead failure. Lead failure was classified as either lead intrinsic damage or lead pin disengagement from the generator header. On the radiographic image, we defined a rear lead connector (RC) ratio that represented the portion of the rear lead connector in the header receptacle. It was used to quantitatively evaluate the mechanical failure of the lead-header interface. The optimal procedures to identify and manage lead failure were established.

RESULTS

All 13 patients presented with high lead impedance of ≥9 kOhms at the time of revision. Of 10 patients with lead damage, 7 had presented with an increased seizure frequency after a period of seizure remission. In contrast to lead damage occurring relatively late (>15 months), lead pin disengagement was usually found within the early months after device implantation. A significant association was found between an elevated RC ratio (≥35%) and lead pin disengagement. The microsurgical technique permitted removal or replacement of the lead without adverse effects.

CONCLUSIONS

The method of measuring the RC ratio developed in the present study is feasible for identifying lead disengagement at the generator level. Lead revision was an effective and safe procedure for patients experiencing lead failure.

Vagal Nerve Stimulator Lead Revision Using Needle-Tip Cautery: Case Series, Literature Review, and Technical Note

BACKGROUND

Vagal nerve stimulators (VNs) have been in use in the United States since the 1990s as a palliative treatment option for drug-resistant epilepsy. Over time, the electrode coils wrapped around the vagus nerve become encapsulated by extensive scar tissue, making complete electrode removal challenging. We present a case series of lead revision surgeries with a unique way to remove the scar tissue around the vagus nerve, demonstrating a technique for complete electrode removal.

METHODS

This was a case series of 9 consecutive patients who underwent complete removal of an existing VNs electrode using needle tip monopolar electrocautery.

RESULTS

Complete removal of the entire VNs electrode array was achieved in all patients with no permanent complications seen at postoperative follow-up at 3 months.

CONCLUSIONS

Complete VNs electrode array removal can be safely achieved by using needle tip monopolar electrocautery.