[Sliding of the distal epineural sheath to cover nerve defects]

Autologous nerve grafting is the most referred technique for bridging neural gaps. The aim of this study was to evaluate the effects of distally sliding the epineurial sheath to cover a defect created in the left sciatic nerve of the rat. Twenty male Wistar rats were divided into three groups: sham (n=6), in which the sciatic nerve was dissected but left intact; conventional suture (CS, n=7), in which a transverse section of the sciatic nerve was followed by an epineurial suture; sliding of the distal epineurial sheath (SDES, n=7), in which a 5 mm resection of the nerve was conducted, followed by a circumferential cut in the distal epineurium, and the epineurial sheath was slid down and sutured into the distal end of the epineurium of the proximal stump. After 12 weeks, histomorphometric analyses of the number of myelinated nerve fibers, mean cross-sectional axonal area and total fiber diameter (G-ratio) were carried out. There was no statistical differences between CS and SDES (p > 0.05, ANOVA). However, an increase in the number of myelinated nerve fibres (p < 0.001, ANOVA) and decreases in the mean axonal area (p < 0.001, ANOVA) and in the G-ratio were observed in SDES or SC groups when compared to sham, although with no statistical differences between the SDES and SC. It could be suggested this technique is efficient to cover nerve gaps in rats.