Clinical Significance of Electrophysiologic Monitoring during Surgery for Lower Thoracic Cord Tumor: Report of Three Cases

Lee, Young Hee; Lee, Jong Min; Oh, Han Seon

Abstract

Electrophysiologic monitoring during surgery for the spinal cord tumor is necessary for identification of the nerve root, prevention of the nerve injury, and prediction of postoperative prognosis. In other countries, intraoperative electrophysiologic monitorings are commonly done in various cases such as selective posterior rhizotomy, scoliosis, sponlylolisthesis, lipomeningocele, and spinal cord tumor, but it is not a common procedure in Korea except for the selective posterior rhizotomy. We report 3 cases of electrophysiologic monitoring during sugery for the spinal cord tumor at lower thoracic level. Using multichannel EMG machine, we recorded free-run EMG, somatosensory evoked potential(SSEP) of tibial nerve, and compound motor unit action potential (CMAP) of various regions such as abdomen, lower extremity, and anus, stimulating nerve roots at the lower thoracic level. We identified CMAP from rectus abdominis muscles only in the first case, but in the second case, we identified CMAP from tibialis anterior and gastrocnemius muscles which avoided the injury to lumbosacral roots. In the third case, SSEP improved immediately after we removed the mass at lower thoracic level. We concluded that intraoperative electrophysiologic monitoring combined with recording CMAP is a useful procedure to minimize neural tissue damage during surgery for the spinal cord tumor at lower thoracic level.