Clinical Usefulness of Somatosensory Evoked Potentials for Detection of Brachial Plexopathy Secondary to Malpositioning in Scoliosis Surgery

In Brief Study Design. A retrospective longitudinal study of 434 consecutive pediatric patients who underwent surgical correction of scoliosis, while being monitored for positional brachial plexopathy. Objective. To evaluate the effectiveness of intermittent monitoring of ulnar nerve somatosensory evoked potentials (SSEPs) for detecting brachial plexus injury caused by malpositioning during scoliosis surgery. Summary of Background Data. Continuous intraoperative SSEP monitoring for spinal cord function has been well reported, and is widely accepted as the standard for spinal deformity correction surgery to detect and avoid neurologic injury. The use of SSEPs for the monitoring of ulnar nerve function intraoperatively as an indicator of brachial plexus function is becoming more accepted as a valid and useful technique to minimize intraoperative neurologic injuries during deformity corrections. Methods. A review was conducted to assess the effect of ulnar nerve SSEP monitoring, as a measure of brachial plexus function, during anterior, posterior, or combined approach surgeries. The type of scoliosis, type of surgery and positioning, and surgical event at noted amplitude decrease were included in an analysis of variance for repeated measures, and a Student t test was performed for significant differences. Results. A total of 27 patients had ulnar nerve amplitude decreases of ≥30%, resulting in a point prevalence of 6.2% for positional brachial plexopathy during positioning for all scoliosis surgeries. A significant difference was noted between the types of positioning, with prone positioning accounting for a higher rate of brachial plexopathy compared with anterior approach positioning (P < 0.01). No statistical difference exists as to the type of scoliosis present and the incidence of brachial plexopathy (P < 0.01). Conclusions. Avoidance of neurologic injury to the brachial plexus during scoliosis surgery is possible by early detection with ulnar nerve SSEP monitoring. A total of 434 pediatric patients who underwent surgical correction of scoliosis were monitored for positional brachial plexopathy. Prone positioning accounted for a higher rate of brachial plexopathy compared to anterior approach positioning (P < 0.01). Avoidance of neurologic injury to the brachial plexus during scoliosis surgery is possible by early detection with ulnar nerve somatosensory evoked potential monitoring.