Intraoperative neurophysiological monitoring during sacrectomy procedures

Previously intraoperative neurophysiological monitoring (IONM) has not been used along with a computer based navigation system for en bloc resection of a sacral Ewing sarcoma. In order to improve the post-operative neurological outcome of the patient we decided to include IONM in our procedure. A partial or complete resection of a sacral tumor may result in the loss of neurological functions due to close proximity of vascular, neural, and visceral structures. A prolonged two-stage surgical procedure may be a high risk procedure for position related brachial plexus injury. An 18-year-old male presented with left lower extremity weakness, which worsened with gait. His MRI was consistent with a sacral mass causing compression on the left S1 and S2 roots. A surgical resection was planned with anterior and posterior approaches. IONM helped guide the surgical team to prevent damaging the sacral roots on the normal side (right) and position related upper extremity brachial plexus injuries. Our technique involving IONM can be used safely for accurate en bloc removal of a sacral tumor with a safe margin while protecting the neural function and minimizing recurrence. This case report demonstrates that intraoperative neurophysiological monitoring was useful in identifying and reversing impending nerve injury during sacrectomy surgery. Significant changes were seen in ulnar and posterior tibial somatosensory evoked potentials (SSEPs). We recommend that IONM should be considered for safe margin en bloc sacral tumor resection and prevention of injury to the sacral root and brachial plexus.