Paraplegia after thoracic aortic occlusion: influence of cerebrospinal fluid drainage. Experimental and early clinical results.

Paraplegia occurs in 6.5% to 40% of patients after repair of extensive thoracoabdominal aortic aneurysms requiring aortic clamping. This study aimed to determine whether drainage of cerebrospinal fluid (CSF) done before aortic cross-clamping could decrease the incidence of paraplegia in dogs. The descending thoracic aorta was clamped distal to the left subclavian artery for either 40 minutes (group I) or 60 minutes (group II). All control animals in group I (10) and group II (10) showed evidence of spinal cord injury with paraparesis or paraplegia. In contrast, 9 of 10 animals (90%) in group I and 7 of 10 animals (70%) in group II that had CSF drainage before aortic cross-clamping were neurologically normal (p less than 0.001 and p less than 0.01, respectively). Aortic pressure distal to the aortic cross clamp was the same in all groups; however, spinal cord perfusion pressure (distal aortic pressure minus CSF pressure) was significantly higher in neurologically normal animals (34 +/- 5 mm Hg, n = 15) compared with those with paraparesis (26 +/- 4 mm Hg, n = 8) or paraplegia (19 +/- 5 mm Hg, n = 8) (r = 0.871, p less than 0.001). This study demonstrates that drainage of CSF before thoracic aortic occlusion significantly increases spinal cord perfusion pressure and decreases the incidence of paraplegia. Limited early clinical experience suggests that CSF drainage may be a useful adjunct to prevent paraplegia in patients who are having repair of thoracoabdominal aortic aneurysms.