AUTOLOGOUS NUCLEUS PULPOSUS INDUCES NEUROPHYSIOLOGIC AND HISTOLOGIC-CHANGES IN PORCINE CAUDA-EQUINA NERVE ROOTS

Epidural application of autologous nucleus pulposus in pigs, without m echanical nerve root compression, induced a pronounced reduction in ne rve conduction velocity in the cauda equina nerve roots after 1-7 days , compared to epidural application of retroperitoneal fat in control e xperiments. Histologically, the nerve fiber injury was more pronounced after application of nucleus pulposus than after control tissue appli cation. The results demonstrate that nucleus pulposus may induce nerve tissue injury by mechanisms other than mechanical compression. Such m echanisms may be based on direct biochemical effects of nucleus pulpos us components on nerve fiber structure and function and microvascular changes including inflammatory reactions in the nerve roots.