Sciatic nerve autografts were performed on 20 wistar rats as two experimental groups, with 10 animals receiving 3600 rads of postoperative irradiation over 6 weeks.
Through the electrophysiologic tests including nerve-muscle twitch-tetany measurement, direct muscle twitch-tetany measurement, and histologic analysis we surveyed to determine the effect a tumorcidal dose of radiation would have on the return of function of autogenous nerve graft as compared to the return of function with non-irradiated grafts.
Control group composed of 10 whistar rats without surgical intervention nor irradiation were also evaluated.
Results of the experiments are as follows;
1. When electrical stimuli of supramaximal voltage were delivered to the proximal sciatic nerve, the mean twitching and tetanic force per gram of the
gastrocnemius-soleus muscle was 72%(33.8±10.7g G) and 85%(79.8±15.4g G) of control value respectively in the operated only group; in the case of the operated plus irradiated group, 68%(31.6±9.7g G) and 83%(77.6±9.7g G) of control value respectively. The statistical differences between two experimental groups were not significant in both twitching and tetanic force measurements.
2. When electrical stimuli of supramaximal voltage were delivered to the gastrocnemius-soleus muscle, their mean twitching and tetanic force per gram of the muscle was 73%(26.4±5.8g G) and 82%(66.3±12.4g G) of control value respectively in the operated only group; in the case of the operated plus irradiated group, 68%(24.4±7.9g G) and 79%(64.0±23.3g G) of control value respectively. The statistical differences between two experimental groups were not significant in both twitching and tetanic force measurements.
3. On the histologic examination, the regenerating axons have grown up well through the nerve graft in both experimental groups, and more mature-myelinated axons were observed in the operated plus irradiation does not give an adverse effect on the nerve regeneration.
4. Electrophysiologic test and histologic examination revealed that postoperative irradiation itself was not a significant deterrent to nerve regeneration.
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