Effect on Nerve Regeneration after End-to-Side Neurorrhaphy with Epineurium Removal in Rats

ABSTRACT

End-to-side neurorrhaphy had been firstly reported at the beginning of this century, but no further clinical reports have been released. In some cases of end-to-end neurorrhaphy, donor nerve incision or even sacrification is inevitably necessary. In doing end-to-side neurorrhaphy, has not been widely accepted because previous results were not satisfactory. The purpose of this study is to evaluate the applicability of end-to-side neurorrhaphy in rats. Twenty female Sprague-Dawley rats, weighing approximately 200-250 g(232.50+/-12.6g) were used. In 10 rats, their right and left peroneal nerves were cut and the distal end of peroneal nerves were end-to-side neurorrhaphied to the tibial nerve. On the right side, the epineurium was left intact and on the left side, it was removed. The proximal end of peroneal nerves were imbedded in the thigh muscle. After 6 months, eletrophysiologic tests, including nerve conduction velocity, the amplitude and the areas of action potential of the tibial cranial muscle were done and then all rats were sacrificed for histologic analysis. The other 10 offspring rats were raised and used for control group. The mean weight of the tibial cranial muscle was 1.74(+/-0.30)g on the right side, 1.54(+/-0.31)g on the left side and 1.97(+/-0.28)g in the control group, which was statistically not significant. The number of muscle fibers in x 100 magnification was 106.10(+/-4.28) on the right side, 109.67(+/-4.69) on the left side and 107.80(+/-4.64) in the control group, which was also not significant. The amplitude and width of muscle action potential were not statistically different among the right side, the left side and in the control group. However, the nerve conduction velocity was bilaterally delayed if compared to control group. In histologic analysis, the presence of epineurium did not impact the results and end-to-side neurorrhaphy were successfully regenerated in all rats. End-to-side neurorrhaphy seem to be a functionally and histologically tolerable alternative when end-to-end neurorrhaphy is not available.