Reduction of epidural scar adhesion by topical application of simvastatin after laminectomy in rats.

OBJECTIVE Epidural scar adhesion is one of the major causes of the failed back surgery syndrome after laminectomy. Recent studies have shown that simvastatin has potent anti-fibrotic and anti-inflammatory properties. This study evaluates the effect of the topical application of simvastatin on reducing epidural scar adhesion after laminectomy in rats. MATERIALS AND METHODS Thirty-six male Sprague-Dawley rats were randomly divided into three groups: control, chitosan and simvastatin group. After laminectomy was performed at L1 level, simvastatin and chitosan were applied to the laminectomy sites. The control group received no additional treatment. Four weeks later, the rats were killed and the epidural adhesion was evaluated by macroscopic assessment, hydroxyproline content analysis and histological analysis. The number of fibroblasts and the optical density of the collagen were also determined. RESULTS The results showed that simvastatin could reduce epidural scar adhesion in rats. Little epidural adhesions were seen in the laminectomy sites treated with simvastatin. The hydroxyproline content, the number of fibroblasts and the optical density of the collagen in the simvastatin group were significantly less than those of the chitosan and control group. However, dense epidural adhesion was found in control group. CONCLUSIONS Topical application of simvastatin could reduce epidural scar adhesion after laminectomy in rats. Further research is necessary to determine the optimal dosage and the safety of simvastatin.