End-to-side neurorrhaphy of motor nerves: reinnervation of free muscle transplants—first clinical application

Abstract

End-to-side neurorrhaphy may offer a practical solution in limited cases of nerve reconstruction when no donor nerve or nerve transfer is available for direct end-to-end nerve suture, or when extremely long distances for nerve regeneration cause irreversible atrophy of the targets. We report our experience with the successful clinical use of a completely new technique of end-to-side neurorrhaphy for motor reinnervation of free functional muscle transplants. Since 1995 we have used end-to-side nerve repair for motor or sensory reinnervation in 13 cases. A free functional muscle graft was reinnervated by an end-to-side neurorrhaphy in four patients after tumor resection (two myocutaneous latissimus dorsi flaps), Volkmann's contracture (one myocutaneous latissimus dorsi flap), and in a long-standing brachial plexus lesion (one gracilis muscle flap). All four patients showed reinnervation of their muscle graft through the end-to-side nerve suture site. Two functional muscle grafts to the upper extremity had positive outcome of M3–M4 for elbow and finger extension in one case, and M4 for finger flexion in one case more than 2 years after transplantation. The transplant in the brachial plexus lesion is too early for a final functional result. One patient had a M3 for knee extension 8 months postoperatively. In the clinical cases there was no downgrading of the muscle functions supplied by the "donor" nerve. Good and clinically relevant reinnervation of a functional muscle graft is possible through an end-to-side nerve suture. Proximal avulsion, missing proximal nerve stumps, partial recovery, shortening of long distances for nerve regeneration, and prevention of long nerve grafts in proximal lesions are good indications for reinnervation of a functional muscle transplant by end-to-side neurorrhaphy without harm to the donor nerve. Donor nerves supplying synergists should be preferred.