During aneurysm repair of the descending thoracic or thoracoabdominal aorta, the likelihood of neurological complications increases greatly after only 30 minutes of spinal cord ischemia. However, the manifestation of paraplegia or paraparesis relates not only to aortic cross-clamping time, but to multiple factors that may include aortic dissection, previous aortic surgery, advanced age, preoperative renal insufficiency, rupture, and most significantly, aneurysm extent. At greatest risk is the patient with type II thoracoabdominal aortic aneurysm. For this patient the simple cross-clamp technique, which uses no protective surgical adjuncts, heightens the threat of neurological deficit. With the surgical adjuncts of cerebrospinal fluid drainage and distal aortic perfusion, the probability of neurological deficit is appreciably lowered.