Journal of vascular surgery
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Spinal cord monitoring during thoracic aneurysmectomy by somatosensory evoked potentials has been criticized for its failure to measure anterior (motor) spinal cord function. We have developed a clinically applicable, noninvasive technique for intraoperative monitoring of motor evoked potentials (MEP), which allows direct functional assessment of spinal cord motor tracts during thoracic aortic occlusion. Twelve dogs underwent continuous intraoperative monitoring of MEP before, during, and after thoracic aortic cross-clamping. ⋯ These data suggest that distinctive changes in MEP indicative of reversible ischemia of spinal cord motor tracts occur after aortic cross-clamping. Such ischemia begins in the most distal cord, exhibits upward progression with time, and can be prevented by maintenance of adequate distal aortic perfusion. Clinical use of MEP monitoring during thoracic aneurysmectomy may provide a method for intraoperative assessment of the adequacy of motor tract perfusion.