| Research Abstract |
This study was undertaken to investigate the influence of the subject age to histopathological changes of the intervertebral discs after intradiscal therapy.
MATERIALS AND METHODS: Fifteen young monkeys and seven aged monkeys were used. Under general anesthesia, lumbar spine was exposed through transperitoneal approach. Chymopapain(500u/0.1ml) or Chondroitinase-ABC (2u/0.1ml) was injected into each disc. Two other discs were treated by CO2 laser discectomy or nucleotomy. After treatment, the animals were sacrificed at prescribed intervals of up to 96 weeks, and lumbar vertebral columns were obtained. T2-weighted MR(2.0Tesla) images of the specimen was taken to evaluate water content. Safranin-O stainability was also compared.
RESULTS: All discs showed decreased signal intensity on T2- weighted MR images two days after treatment. Forty-eight weeks after treatment, all discs showed similar to those of the normal control in the young monkeys. However, in aged monkeys, all discs demonstrated decreased signal 48 and even 96 weeks after treatment. Safranin-O staining revealed the disappearance of proteoglycan from the nucleus pulposus, inner annulus fibrosus, and cartilagenous endplates of the treated discs. These changes predominated in the aged group. Although Safranin-O stainability was recovered within 48 weeks in the young group, which was remained lost in the aged group.
CONCLUSION: This study suggests that laser discectomy offers unique advantages in the treatment of disc herniation, but also demonstrated that the disc degeneration after treatment correlated with the subject age.
|
