Extent of fiber regeneration after peripheral nerve repair: silicone splint vs. suture, gap repair vs. graft.

The degree of regeneration in surgically repaired sciatic nerves in rats was measured using a simple new electrophysiologic method: comparison of the size of nerve responses evoked by stimulation distal and proximal to the anastomosis. Five different repair procedures were evaluated. After simple end-to-end suture anastomosis, about 40% of the severed parent fibers regenerated past the suture line. The result was substantially improved when the anastomosis was covered with a newly designed thinwall silicone sheath which incorporated a narrow longitudinal slit. The presence of suture material at the point of anastomosis had no effect. Finally, regeneration across a 5-mm gap ensheathed in silicone (67%) was better than regeneration through a 5-mm autograft (45%).