SPINAL-CORD PROTECTION IN THE ABSENCE OF COLLATERAL CIRCULATION - METAANALYSIS OF MORTALITY AND PARAPLEGIA

A meta-analysis of paraplegia complicating aortic surgery on patients having neither intercostal nor spinal collaterals, epitomized by patie nts with acute traumatic aortic rupture, was done. Index Medicus and M edline were searched for all suitable English publications between 197 2 and 1992. New paraplegia occurred in 9.9% of 1492 patients who under went surgery. However, 19.2% of patients undergoing surgery with only simple aortic cross-clamping developed paraplegia, in contrast to 6.1% if distal aortic perfusion was augmented by either ''passive'' or ''a ctive'' methods (p < 0.00001). The risk of paraplegia increased progre ssively as cross-clamp times lengthened if simple aortic cross-clampin g was used (p < 0.00001), but only once did the cross-clamp time excee d 30 minutes (p < 0.05). Paraplegia occurred in 8.2% of patients with ''passive'' shunts from the ascending aorta (p < 0.001 vs simple cross -clamping). Shunts from the left ventricular apex, however, had an inc idence of paraplegia of 26.1% and, therefore, did not decrease the ris k of paraplegia. ''Active'' augmentation of distal perfusion had the l owest risk of paraplegia: 2.3% (p < 0.00001 vs simple cross-clamping o r ''passive'' shunts). Mortality, however, was higher in these potenti ally polytraumatized patients when they were perfused distally using m ethods requiring full systemic heparinization (18.2%), compared to mor tality with methods not requiring heparin (11.9%; p < 0.01). In conclu sion, simple aortic cross-clamping has a high risk of paraplegia if th e cross-clamp time extends beyond 30 minutes. ''Active'' modalities of augmenting distal perfusion provide optimal spinal protection.