Prevention of spinal cord injury during thoracic and thoracoabdominal aortic repairs

Spinal cord injury is the most dreaded, unpredictable complication following repair of the descending thoracic and thoracoabdominal aorta. In this study, based on our experimental results in dogs and early clinical results we reviewed the incidence of paraplegia and the perioperative detection of spinal cord injury. Between October 1, 1985 and June 31, 1999 a total of 73 patients who underwent elective surgical repair of the descending thoracic and thoracoabdominal aorta entered the study. Somatosensory evoked potentials (SEPs) were monitored, and the mean distal aortic pressure (MDAP) and cerebrospinal fluid pressure (CSFP) were measured perioperatively. No patients developed paraplegia in this study, although one patient with significant changes in SEP, whose spinal cord perfusion pressure (SCPP) was 60mmHg, developed delayed paraplegia. Another 20 of the remaining 72 patients showed significant ischemic changes in the SEP; in 13 of these 20 patients the SEP gradually recovered by increasing the SCPP up to more than 40 mmHg. In 51 of the other 53 patients without ischemic SEP changes, the SCPP was kept at more than 40 mmHg; the other two patients did not develop paraplegia. These results strongly suggest that SEP, MDAP, and CSFP should be monitored during aortic repairs. Moreover, maintaining the SCPP at more than 40 mmHg by increasing the MDAP, withdrawing cerebrospinal fluid, or both valuable for preventing paraplegia.