[Muscular neurotization in the field of reconstructive surgery (author's transl)].
Attention is drawn in a short historical review to muscular neurotization, a surgical procedure described at the turn of the century. This term is applied to the reinnervation of paralyzed muscles by the proliferation of collateral neural axons arising in an adjacent muscle possessing normal function. The physiological basis for this procedure was expounded by eminent muscle physiologists following extensive research. The present experimental investigations on 20 Vietnamese pigs demonstrated that a defective anal sphincter muscle could be rectified by a muscle graft. This spindle-shaped muscle graft became incorporated into the anal and rectosphincteric reflex mechanism by muscular neurotization. Complete--or even parts of--muscles with parallel fibres are better suited for transplantation purposes than entire spindle-shaped or feather-like muscles. Once the edge of the muscle has been reached by the proliferating axons all the cells can be simultaneously supplied with motor end plates in the case of muscles with parallel fibres. On the other hand, the use of spindle-shaped or feather-like muscles with a diagonal arrangement of the fibres entails axon proliferation over relatively large distances to achieve reinnervation of the more distal parts of the muscle with an attendant prolongation of the reinnervation procedure and, frequently, partial loss of muscle viability. In another experiment on Vietnamese pigs the total anal sphincter was excised and replaced by the denervated, but vascular semitendinosus muscle of the right hind limb. When transposed to the pelvic floor musculature the denervated muscle becomes adequately reinnervated by muscular neurotization and at the same time adopts all the properties typical of a sphincteric muscle. The newly-formed sphincter displays changes in its enzyme pattern and becomes capable of continuous tonus; the spinal reflex arc is set up and the transplanted muscle develops characteristic metabolic and contractile properties. In another experimental series the reinnervation of paralyzed extraocular muscles by muscular neurotization was investigated in 10 rabbits. The denervated but still vascular inferior oblique muscle was successfully grafted onto the inferior rectus muscle, with obvious clinical application in future. The clinical application of muscular neurotization in surgical reconstruction is demonstrated in 4 cases, the first being one of facial palsy and the second one of blepharoptosis, whilst muscular neurotization was used in the two last cases to treat anal incontinence due to partial destruction and absence of the sphincter, respectively. In the one case a muscle graft was taken to reconstruct the anal sphincter and in the other case a new sphincter was reconstructed by transposing the denervated gracilis muscle onto the pelvic floor muscle. Both cases were eminently successful with restoration of anal continence and the rectosphincteric reflex mechanisms.