Repair of the sciatic nerve defect with a direct gradual lengthening of proximal and distal nerve stumps in rabbits.

BACKGROUND The current clinical repair method used for the segmental peripheral nerve defect is autogenous nerve grafting. However, this method has several inherent disadvantages. Therefore, the authors have invented an alternative method for repairing the segmental peripheral nerve defect with a direct gradual lengthening of nerve stumps. In this study, for the clinical application, the authors developed a new external nerve-lengthening device for lengthening peripheral nerve stumps daily without anesthesia. METHODS In this study, a nerve segment 20 mm in length was resected from the rabbit sciatic nerve. In the nerve-lengthening group, direct nerve lengthening was performed in the proximal and distal nerve stumps at a rate of 1 mm/day without anesthesia. After being lengthened for 22 days, both proximal and distal nerve stumps were evaluated by immunohistochemical analysis. When confirming that both nerve stumps were successfully lengthened, a direct end-to-end neurorrhaphy was performed. As a control, 20-mm-long autografting was performed immediately after nerve resection. Nerve regeneration was evaluated by electrophysiologic and histologic examination at 16 weeks after the first operation in both the nerve-lengthening and the control groups. RESULTS The results of both electrophysiologic evaluation and histologic examination showed that the nerve-lengthening group performed significantly better than the autografting group. CONCLUSION The gradual nerve-lengthening procedure can be used as an alternative therapeutic method for repairing segmental peripheral nerve defects, which proved to be advantageous over widely adopted autogenous nerve grafting.