Effectiveness of Human Amniotic Fluid and Amniotic Membrane in Preventing Spinal Epidural Fibrosis in An Experimental Rat Model

Background: Our study aimed to investigate the effectiveness of human amniotic fluid and amniotic membrane in preventing postlaminectomy spinal epidural fibrosis in an experimental rat model. Material and Methods: Twenty-seven Sprague-Dawley male rats were used in this study. Rats were divided into 3 groups to undergo laminectomy at 2 levels (L1 and L4) with an undamaged area between levels: (1) control group (laminectomy only, n = 5), (2) laminectomy + amniotic membrane (the amniotic membrane was wrapped around the L4 level, n = 9), (3) laminectomy + human amniotic fluid (the amniotic fluid was administrated topically on the L4 level, n = 7). All the rats were sacrified after 6 weeks, and their vertebral colon was removed en bloc. The groups were evaluated according to the histological criterias, and the results were compared statistically. Results: No significant differences were observed between the groups (p = 1.0) with regard to epidural scar formation and mean fibroblast count. However, excessive scar tissue was seen in the amniotic membrane group. When compared with the other groups, the mean fibroblast level was reduced. However, significant amount of inflammatory cells were seen in this group. Conclusion: Our study suggests that the human amniotic fluid and amniotic membrane have an effect but not significant on preventing epidural scar tissue formation. Although fibroblast levels were lower in the amniotic membrane group, the existence of epidural scar tissue is thought to be the result of scar formation by intensive inflammatory reaction against the amniotic membrane.