The Evaluation of Neurotoxicity after Intrathecal Restorative Fluid Injection in the Rat

ABSTRACT

OBJECTIVE: To assess neurotoxicity of intrathecal restorative fluid leakage in the course of the intradiscal restorative fluid injection. METHOD: Twenty male Sprague-Dawley rats, body weight range of 300~350 gm, were divided randomly into four groups. Control group, group A (mixed solution of glucosamine hydrochloride 5%, chondroitin sulfate 5%, and bupivacaine hydrochloride 2%), group B (glucosamine hydrochloride 8%, chondroitin sulfate 2%, and bupivacaine hydrochloride 2%) and group C (glucosamine hydrochloride 16%, chondroitin sulfate 2%, and bupivacaine hydrochloride 2%). The behavioral test for cold allodynia (tail flick test) was conducted 1 day prior to the injection and 7 days postoperatively. Histopathologic evaluation was performed using light microscopy by a neuropathologist. The severity of nerve and cord injury were graded according to injury scoring system. RESULTS: Each group showed no significant difference in sensory function test using tail flick test before and after intrathecal restorative fluid injection. Cold allodynia was not showed statistically significant difference among the group. Histological examination showed statistically significant difference between control group and group B, group C, and between group A and group B, C in both cord and root. CONCLUSION: Intrathecal injection of restorative fluid shows neurotoxic changes in roots and spinal cord in histopathologic studies. Although same ingredients of restorative solution, the different concentration of the ingredients revealed different neurotoxicity.