Neurophysiological Monitoring During Spinal Cord Stimulator Placement Surgery.

Abstract

The objective of this retrospective study was to study the frequency of intraoperative neuromonitoring (IONM) alerts during the spinal cord stimulator (SCS) placement surgery, postoperative neurological complications and effectiveness of Somatosensory evoked potential (SSEP) and electromyography (EMG) methods to determine laterality of the SCS lead placement. Records of 111 consecutive SCS placement surgeries monitored by a commercial IONM company between August 1, 2013 and December 31, 2013 were reviewed. IONM alerts, surgical interventions, and patient outcomes were assessed. Significant decreases of lower extremity SSEPs following the placement of the SCS paddle electrodes into the epidural space were recorded in two (1.9%) patients prompting alerts to the surgeons and removal of the electrode. Somatosensory system dysfunction due to stimulated limb malpositioning was identified by continuous SSEP in four cases (3.8%). All waveform changes resolved and SSEP waveforms returned back to baselines in all six patients after adjustments were made. There was no evidence of sustained neurological injury in any patients in this study. The location of the stimulator was adjusted based on IONM feedback in 8/43 (18.6%) cases. IONM is an effective tool in detecting potential neurological event and facilitating lead placement and potentially avoiding revision surgery.