Thoracoabdominal aneurysm surgery and the risk of paraplegia: contemporary practice and future directions.

Thoracoabdominal aneurysm surgery is associated with a high incidence of morbidity and mortality. Spinal cord ischemia and the risks of paraparesis or paraplegia remain devastating complications. The mechanisms of spinal cord injury involve both acute ischemic injury and delayed reperfusion injury. Blood flow to the spinal cord frequently arises in the segment of the aorta requiring aortic cross clamping. As such, there is an obligate period of blood flow disruption. Multiple strategies have evolved to reduce the ischemic interval and to provide adjunct interventions to reduce the impact of the ischemia. Despite a multidisciplinary approach, a spinal cord ischemia is present in approximately 4 to 16% of patients, depending on the type of aneurysm and other comorbid diseases. Cerebral spinal fluid drainage, distal perfusion techniques, intercostal artery anastomosis, hypothermia techniques, and mechanisms of ischemic preconditioning are interventions employed to reduce the risk of paraplegia after thoracal-abdominal aortic surgery. Surgeons, anesthesiologists, and perfusionist are intimately involved in the decision making as to which interventions will be employed in a given case. Although these adjuncts have been evaluated in multiple animal and human protocols, the efficacy of each intervention when looked at in isolation remains difficult to determine fully. This is attributable, in part, to the complex mechanisms of the patient injury, the inherint risks of the surgical procedure, and the confounding effects of comorbid disease states. Nonetheless, clinicians must have comprehensive understanding of these various interventions and their application. This review serves as an overview of these various interventions with special emphasis on outcome data.