Identification of Safe Zone with Intraoperative Neurophysiological Monitoring during Surgical Removal of Peripheral Nerve Tumor

Abstract

During resection of peripheral nerve tumor, it is essential to identify and protect the neighboring neural elements to the tumor itself prior to attempting direct resection. The authors present the techniques of intraoperative electrophysiologic monitoring and nerve stimulation during resection of schwannoma of the peripheral nerve tumor in the upper extremity. After performing a longitudinal epineurotomy in a ‘bare area’ of the tumor (devoid of fascicular structure), an intraoperative bipolar nerve stimulation was given (0.5-1 msec, 1 mA) to identify safe zones to assist to determine functioning and nonfunctioning fascicles, and therefore facilitate resection. With the aid of microscopic dissection and intraoperative nerve stimulation, the schwannoma could be removed by opening the epineurium at a ‘bare area’ and separating the uninvolved fascicles until the single feeding fascicle was identified. Intraoperative neurophysiology and nerve stimulation is a helpful technique to facilitate complete removal of peripheral nerve tumor unassociated with neurologic deficit.