A Comparative Study of Nerve Regeneration on End-to-Side and End-to-End Neurorrhaphy in Rats

Hwang, So Min; Yoon, Dong Ju; Bae, Yong Chan; Lee, Chang Hun; Ko, Hyun Yoon; Kim, Dong Il

Abstract

The surgical methods of injured peripheral nerve were limited to end-to-end neurorrhaphy, nerve graft, neurotization, etc. Recently, Several studies were executed about end-to-side neurorrhaphy in peripheral nerve injury. The purpose of this study is to investigate the axonal regeneration of end-to-side neurorrhaphy in rats, as alternative surgical method for peripheral nerve injury comparing with the state of normal, denervated, and end-to-end neurorrhaphy. Sixty female Sprague-Dawley rats were divided into four groups; group I as normal control group, group II as denervated control group, group III as end-to-end neurorrhaphy group, group IV as end-to-side neurorrhaphy group. At postoperative 4, 8, 12, 16, 20 and 24 week, nerve regeneration was assessed through electrophysiologic and histological studies. The results obtained were as follows: 1. In electrophysiologic test, the mean amplitude was higher in normal control group(group I) than either in end-to-end neurorrhaphy group(group III) or in end- to- side neurorrhaphy group(group IV)(p < 0.05). But there is no significant difference between group III and group IV. 2. The mean number of regenerating myelinated nerve fibers was higher in group I than either in group III or in group IV(p < 0.05). But there is no significant difference between group III and group IV, except at postoperative 16 week. 3. The mean number of motor end-plates at postoperative 24 week was 20.5 in group III and 18.2 in group IV, but there is no significant difference between group III and group IV. In conclusion, end-to-side neurorrhaphy through an epineural window could induce distal nerve regeneration by collateral sprouting of main peripheral nerve and positively reflected in functional improvement of the target muscle.