AN IMMUNOHISTOCHEMICAL STUDY OF INNERVATION OF LUMBAR SPINAL DURA ANDLONGITUDINAL LIGAMENTS

Study Design. An immunocytochemical study of nerve fibers in lumbar sp inal dura and longitudinal ligaments was conducted in New Zealand whit e rabbits. Objectives. To demonstrate the presence of nerve fibers and to establish the presence of nociceptive and sympathetic nerve fibers in lumbar dura and longitudinal ligaments. Summary of Background Data . The role of dura as a source of low back pain is still unclear, and the data present a somewhat conflicting picture of the nature of nocic eptive innervation in this tissue. Methods. An immunocytochemical meth od was used to study dura and longitudinal ligaments from New Zealand White rabbits. Results. Numerous fine nerve fibers and some small bund les were demonstrated in both the dura and the longitudinal ligaments. In dorsal dura, the fibers were seen at lateral margins running towar d midline. In ventral dura and longitudinal ligaments, the fibers were seen throughout the substance of these tissues. A population of subst ance P, calcitonin gene-related peptide, and tyrosine hydroxylase-reac tive nerve fibers were observed in all the tissues. In addition, fiber s exhibiting nicotinamide adenine dinucleotide phosphate diaphorase ac tivity were also observed, indicating the presence of nitric oxide in dura. Conclusions. The results clearly demonstrate an extensive distri bution of nerve fibers in dura and longitudinal ligaments. The presenc e of a significant number of putative nociceptive fibers supports a po ssible role far these structures as a source of low back pain and radi cular pain.