Comparison of preoperative selective spinal angiography and somatosensory-evoked potential monitoring with temporary occlusion of segmental vessels during anterior spinal surgery

Study Design. The results of preoperative selective spinal angiography were compared with intraoperative occlusion of segmental arteries and somatosensory-evoked potential monitoring during anterior spinal surgery. Objectives. To determine if temporary occlusion of major radicular vessels supplying the spinal cord would result in intraoperative somatosensory-evoked potential changes. Summary of Background Data. Temporary occlusion of segmental spinal arteries with concomitant somatosensory-evoked potential monitoring has been used during anterior spinal surgery to avoid intraoperative vascular paraplegias caused by permanent ligations of vessels critical to the blood supply of the spinal cord. Methods. Preoperative selective spinal angiography was performed in 16 patients to identify important radicular arteries supplying the spinal cord. At the time of anterior spinal surgery, temporary occlusion of segmental vessels was accomplished with somatosensory-evoked potential monitoring. Results. Thirty-two radicular arteries were identified by arteriography in 16 patients. Temporary occlusion of nine segmental arteries in the surgical field supplying these radicular vessels resulted in no somatosensory-evoked potential changes. Conclusions. The lack of somatosensory-evoked potential changes after temporary occlusion of segmental arteries from which radicular arteries supply the spinal cord demonstrates sufficient perimedullary collateral circulation in that area of the spinal cord.