End-to-side neurorrhaphy: the mechanism of nerve regeneration

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 11671788
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Plastic surgery
• Research Institution: JUNTENDO UNIVERSITY
• Principal Investigator: YANAI Akira Juntendo University, Plastic Surg, Professor, 医学部, 教授 (80114495)
• Co-Investigator(Kenkyū-buntansha): TAKIGAWA Junko Juntendo University, Phsiology, Assistant Doctor, 医学部, 助手 (90053339) ; ARAI Hajime Juntendo University, Neurosurgery, Associate Professor, 医学部, 助教授 (70167229)
• Project Period (FY): 1999 – 2001
• Keywords: end-to-side neurorrhaphy / neurorrhaphy / nerve regeneration / end-to-side / nerve graft

Research Abstract

The mechanism of nerve regeneration after the end-to-side neurorrhaphy is yet to be studied. There are three kind of possibilities of nerve regenerating after the procedure. First, the nerve which was damaged through the procedure regenerates to the transplanted nerve. Second, recipient nerve sprouts collaterally. Third, after the collateral sprouting, the regenerated nerves were pruned gradually to avoid double domination. Some suggested the possibility of collateral sprouting from the donor nerve by the double-labelling technique or the gap model using the Y-shaped silicone tube. With the complete non-injury rat model, we proved that the axonal sprouting originates from the intact donor nerve collaterally. The sciatic nerve of adult wistar rat was dissected and transplanted between the left and right median nerve. In group A, recipient nerve was neurorrhaphied end- to-side with the divided donor nerve by non-injury technique. In group B, these nerves were wrapped in the faascia and neurorrhaphied non-injuriously. In group C, the epineurium was removed at the suture site and then neurorrhaphied. Thirty and sixty days after the operation, we evaluated nerve regeneration with electromyography of bilateral flexor muscle at the forearm. For morphometric evaluation, coaptatoin site was dissected out and fluorescent dye(DiI) crystal was attached to the proximal side of the harvested donor nerve. It was then incubated in 37 degree for 3 weeks. We observed cross section of this specimen under a confocal microscope. Even in a complete non-injury model, nerve regenerated electrophysically. Fluorescent dye(Dil) stained the regenerated nerve beyond the coaptation site. These results supported that in the end-to-side neurorrhaphy the nerve regenerated by the collateral sprouting from the donor nerve.