Experimental study on the influence of tension, immobilisation and denervation on muscle transplantation

To observe the effects of tension and immobilisation on denervated muscle, rats' denervated soleus muscles were transplanted orthotopically at different tensions: high, neutral, moderate and low tension with immobilisation. Results were evaluated by measuring muscle mass, twitch and tetanic tension, and histologically by HE staining. The results showed better preservation of muscle weight in the high tension group. Atrophy and loss of function were rapid during the first 4 weeks and were greatest in the low tension group. Rate of atrophy was slowed and relatively stabilised at the eighth postoperative week. We conclude that increased tension with immobilisation produced slower initial atrophy and loss of function in denervated muscle flaps. Although slower, the atrophy continued during the prolonged immobilisation and there was no significant difference compared with neutral tension at a later period. Moreover, immobilisation produced atrophy and affected function regardless of the amount of tension. Increased tension decelerates and decreased tension accelerates denervation atrophy of muscle. Thus denervation, immobilisation and reduced tension are all detrimental in muscle transplantation.