Three patients paraplegic following anterior spinal fusion for congenital kyphoscoliosis were noted to have complete somatosensory evoked potential signal loss shortly after segmental arterial ligations at the apex of their respective kyphosis. This has prompted us to use temporary segmental arterial occlusion with somatosensory evoked potential monitoring prior to ligation during anterior spinal fusion. As a result, we have noted seven additional cases, out of a total of 44 cases monitored in this fashion, in which complete loss of somatosensory evoked potential signals, reversible by release of vascular clips, has occurred. For each of these additional cases the critical segmental arteries were identified and were not ligated, usually resulting in some modifications in the planned surgical procedure, and the patients remained neurologically intact. We recommend temporary segmental arterial occlusion with somatosensory evoked potential monitoring during thoracolumbar anterior spinal fusion to potentially avert ischemic neurologic injury. Based on published data and the experience described herein, this technique should be especially important in anterior spinal fusion for congenital kyphoscoliosis.