1988 Volume 34 Issue 7 Pages 1255-1274
Experiment was conducted on 96 Wistar rats to estimate the clinical utility of the lyophilized nerve which has advantages of being enduring of and easy for long-term storage. After implanting to the unilateral sciatic nerve trunk a piece of lyophilized homograft of the sciatic nerve of 10mm in length, the nerve and the muscles (soleus, extensor digitorum longus and gastrocnemius) were examined from different aspects and were compared with the results after fresh nerve homografting.
The results were as follows:
1. Macroscopic observations;
i) In both the lyophilized and fresh homografts the initial form was well maintained during the observation period of up to 48 weeks. The fresh homografts tended to show stronger adhesion to the surrounding tissues due to intense proliferation of the connective tissue.
ii) The muscles were atrophic and pale. Recovery started around the 8th postoperative week, and was almost complete within 48 weeks.
2. From the 8th postoperative week electromyographic responses could be evoked by stimulating the sciatic nerve trunk. The latency of the evoked EMG became progressively shorter at a similar pace in both the lyophilized and fresh nerve-grafted groups.
3. The wet weight of the muscles in the operated side was lowest on 4th week and showed a gradual recovery to reach a level of 65-83% of the contralateral homonymous muscles. No marked difference was found between the lyophilized and fresh nerve-grafted groups.
4. Histological observation revealed no significant difference between the lyophilized and fresh nerve grafts in terms of the overall time course of the progressive regenerated axons entering into the graft. The inflammatory response was more intense in and around the fresh nerve grafts. The number of regenerated axons of the fresh nerve grafts increased more than the lyophilized nerve grafts.
5. The degree and the time course of the change in the concentration of the nerve and muscle-related proteins were not much different between the both groups.
It can be concluded that the homograft of the lyophilized nerve can be substituted for the fresh nerve homografting for restoration of the nervous and muscular functions, and is even superior to the latter in that it can be easily stored for a long time and causes less inflammatory responses.
