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

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.