m REVIEW ARTICLES

POSTOPERATIVE paraplegia resulting from spinal cord ischemia is a devastating complication of thoracic aneurysm (TA) or thoracoabdominal aortic aneurysm (TAAA) surgery. Permanent neurologic deficits are a major cause of morbidity and may shorten long-term survival. Factors that are associated with the development of paraplegia are previous aortic surgery, preoperative renal function, age, aortic cross-clamp time, and emergency repair. The risk of injury also is significantly greater after repair of more extensive aneurysms. Aneurysms traditionally are classified by their extent and location (table 1). At greatest risk is the patient with an aneurysm involving most or all of the thoracic and abdominal aorta (Crawford type II). Strategies proposed to protect the spinal cord during TAAA repair aim to maintain spinal cord perfusion. Aortic occlusion increases cerebrospinal fluid pressure (CSFP) and decreases distal aortic systolic pressure, thereby decreasing perfusion of the spinal cord. Theoretically, decreasing CSFP by cerebrospinal fluid drainage (CSFD) should improve spinal cord blood flow and decrease the risk of spinal cord ischemic injury. Indirect evidence from canine models showing improved neurologic outcome using CSFD in spinal cord ischemia was first reported by Blaisdell and Cooley. Despite improvements in neurologic outcome in other animal models, no prospective, randomized trial has demonstrated any benefit of CSFD alone in humans undergoing aortic aneurysm repair. The purpose of this article is to provide a systematic review of the literature on the use of CSFD in humans undergoing surgical repair of the TAAA. Methods