Limits of muscle-to-nerve ratio in functional muscle transplantation

The aim of the present study was to investigate the functional limits of over-dimensioning a free functioning muscle transplant for neuromuscular reconstruction. A part of the rectus femoris muscle, two and three times bigger than a scutuloauricularis muscle, was used to functionally replace the latter after removal. The major finding of these experiments is that both double-sized and triple-sized portions of the rectus femoris muscle developed maximal tetanic tensions during isometric contractions, which were up to 175 percent of the control scutuloauricularis muscle of the unoperated, contralateral side, although the same branch of the facial nerve was used for reinnervation of the grafted muscle. This implies that the supplying branch of the facial nerve has the potency to innervate a muscle much larger than the originally supplied muscle with optimal efficiency. These results underline the usefulness of overdimensioning during functional muscle transplantation, and also in limited neural capacity situations.