The incidence of postoperative paralysis after thoracic and thoracoabdominal aortic operations has decreased, but is still high in comparison with other operations. The analysis of the mechanism involved in the ischemic tolerance of the spinal cord could contribute to the protection of the spinal cord from ischemia. The identification of the Adamkiewicz artery and the predictive factors for postoperative paralysis in the preoperative period, the use of motor evoked potential, several adjuncts to keep the spinal cord circulation, the stabilization of the hemodynamics with good oxygenation, and hypothermia contribute to the prevention of the spinal cord ischemia. The anesthetics appropriate for the monitoring of the motor-evoked potential are propofol and fentanyl with or without ketamine. Among the anesthetic drugs, narcotics might exacerbate the motor function after the spinal cord ischemia. The analgesic drugs which do not aggravate the spinal cord dysfunction would be expected. Good cooperation of surgeons and anesthesiologists greatly contributes to the finding of the spinal cord ischemia during this operation.