Circulation of the spinal cord: an important consideration for thoracic surgeons.

The spinal cord has significant thoracic arterial watershed areas rendering it vulnerable to intraoperative ischemic damage, clearly mandating a need for postoperative neurologic monitoring. Mechanisms of hypoperfusion include aortic cross-clamping, rib retraction, intercostal artery interruption, and costovertebral junction bleeding. We report cases of primary lung cancer resection, resection of pulmonary metastasis adherent to the thoracic aorta, resection of cartilaginous tumor with chest wall invasion, and esophagomyotomy for achalasia-all complicated by postoperative paraplegia. We review spinal cord circulation, describe mechanisms and patterns of neurologic dysfunction of susceptible watershed areas, and outline roles of preoperative spinal angiography and intraoperative evoked potentials.