Deep hypothermic cardiopulmonary bypass with intervals of circulatory arrest has been used for protection of the spinal cord during operations for thoracoabdominal aortic aneurysm (TAAA) in our hospital. We examined the effect of this adjunct this time. We studied 15 patients who were operated using deep hypothermic cardiopulmonary bypass with intervals of circulatory arrest among 19 patients with the TAAA who we performed the operations from 1995 through 2003. The patients ranged in age from 21 to 80 (an average of 65 +/- 14 SD) years. We used deep hypothermic cardiopulmonary bypass with intervals of circulatory arrest between 16 and 20 degrees C for the adjunct but did not use a monitor of evoked spinal cord potentials or cerebrospinal fluid drainage. Operation time was an average of 805 +/- 168 minutes. Cardiopulmonary bypass time was an average of 403 +/- 73 minutes. Deep hypothermic cardiopulmonary bypass time was an average of 215 +/- 67.5 SD minutes. Duration of spinal cord ischemia to the intercostal arteries were reconstructed was from 25 to 104 (50.5 +/- 24) minutes. We recognized nerve disorder in 6 cases in progress after operation, and respiratory organs management period and a hospitalization period became long, but the hospitalization death was 3 cases, and, as for the paraplegia was no case, 12 patients were discharged in good condition. The deep hypothermic cardiopulmonary bypass with intervals of circulatory arrest was regarded as a useful adjunct for prevention of the paraplegia.