Effect of epidural block on tissue structure of prolapsed intervertebral disc and yellow ligament / 中国组织工程研究

ABSTRACT

BACKGROUND: Epidural block(EB) is one of the effective and widely used remedies for lumbar disc herniation(LDH) . Animal experiments have been conducted to study the changes in the local tissue structure in the spinal canel after several treatments with EB.OBJECTIVE: To study the effect of EB for LDH on the local tissue structures in the spinal canel.DESIGN: A non-randomized and controlled clinical observation.PARTICIPANTS: Department of Pathology and Laboratory of Electron Microscope of an Affiliated Hospital of a University.SUBJECTS: Forty patients with LDP, who failed to respond to EB treatment and subsequently received discectomy in the Department of Orthopaedics,First Affiliated Hospital of Sun Yat-sen University from May 1992 to December 1997, were enrolled in this study, with 20 patients receiving discectomy but not EB treatment serving as the control group.METHODS: From the 60 cases, totally 120 specimens of yellow ligament and the disc tissues were obtained during discectomy for optical microscopical examination. A portion of the yellow ligament and the lumbar disc tissues were chosen from EB group(12 cases) and non-EB group(10 cases), respectively, for electron microscope examination(involving altogether 44specimens) . The changes in histology and ultrastructnres in the specimens were compared between the two groups.MAIN OUTCOME MEASURES: ① Main results: the reactive proliferation of the tunica adventitia and inflammatory reaction of the intervertebral disc and yellow ligament; ② Secondary results: changes in the ultrastructure of the anulus fibrosus, nucleus pulposus and yellow ligament.RESULTS: No significant difference was found between the two groups either in light microscopy or electron microscopy in the degree of smoothness and the inflammatory reaction of the cavosurface of the yellow ligament and the disc tissues, nor in the cellular ultrastructures and fibrous arrangement.CONCLUSION: There is no direct relationship between lumbar EB and epidural scar adhesion formation. EB does not affect the ultrastructures of the local tissues in the spinal canal, but care must be taken of the sterilization in the surgical procedure, as chronic inflammatory reaction in the yellow ligament and disc tissues can be present in some patients.