Assessment of spinal cord ischemia by means of evoked potential monitoring during thoracoabdominal aortic surgery.

Besides renal failure and mesenteric infarction, spinal cord ischemia is the most dreaded complication after thoracoabdominal aortic surgery. Several techniques have been developed to improve neurologic outcome of these massive surgical procedures, including pharmacologic adjuncts, epidural cooling, distal aortic perfusion, cerebrospinal fluid drainage, and reattachment of segmental arteries. The authors developed a technique to assess spinal cord integrity as part of the surgical protocol, dictating operative strategies to restore blood supply to the endangered grey matter. Monitoring motor evoked potentials (MEPs) was performed in experimental studies and in 170 patients with a thoracoabdominal aortic aneurysm. The surgical protocol included left heart bypass and cerebrospinal fluid drainage, and MEP monitoring was applied to identify critical intercostal and lumbar arteries. Based on MEPs, the aggressive surgical approach resulted in a significant reduction of neurologic complications (2.3%).