Fifty-nine patients who had traumatic aortic rupture in the area of the isthmus and were treated less than one week after injury were studied. Most patients (N = 47) underwent repair using pump-oxygenator partial bypass; 7 had simple cross-clamping. Paraplegia developed in 4 during operation. One patient died of a head injury after receiving heparin for bypass. The experience with these patients and a critical review of the literature indicate that the use of extracorporeal circulation and avoidance of hypoxia and hypercapnia may decrease the probability of paraplegia. When laparotomy preceded thoracotomy, there were no clearly deleterious effects of heparinization.