RESUMO
<p><b>OBJECTIVE</b>To evaluate the ability of a polycaprolactone/polylactic acid (PCL/PLA) membrane to inhibit epidural scar adhesion after laminectomy, and observe the responsive changes of the pain media in the spinal cord.</p><p><b>METHODS</b>L(1), L(3) laminectomies were performed on 96 Wistar rats. The rats were divided into 3 groups: None-implant Control Group (NC), Autologous free fat graft group (AFFG) and PCL/PLA membrane group (PCL/PLAm). The rats were killed at 1, 3, 6, and 12 weeks postoperatively. Epidural scar formation and adhesion were observed grossly and histologically. Reverse transcription polymerase chain reaction (RT-PCR) were used to analyses the expression of Transforming growth factor beta (TGF-beta) in the epidural scar. Immunohistochemistry stain and RT-PCR were performed to evaluate the expression of the substance P and the c-fos gene in the relevant spinal cord, and the results were analyzed statistically.</p><p><b>RESULTS</b>Gross evaluation and histological evaluation showed that in the NC lamina defect site had much scar tissue and had wide and tight adhesions to the dura; in the AFFG, with the fat degrading gradually, the adhesions were increased; whereas in the PCL/PLAm group, there were slightly adhesions to the dura. RT-PCR showed that the expression of the TGF-beta was much less in the PCL/PLAm group than in the NC group. The insertion of the PCL/PLA membrane and the fat patch reduced the expression of the substance P and the c-fos gene in the spinal cord.</p><p><b>CONCLUSION</b>The insertion of the PCL/PLA membrane reduces scar formation and separates fibrosis tissue from the dura, the results indicate that PCL/PLA membrane is an effective way of reducing peridural scar formation and preventing the failed back surgery syndrome.</p>