End-to-Side Nerve Coaptation: Benefits and Problems

When Fausto Viterbo drew attention to the possibility of neurotizing a denervated nerve just by end-to-side coaptation, a new approach to peripheral nerve surgery emerged. Sufficient collateral sprouting was easily proven, but the functional value is still controversial.

Over the years, the authors have utilized end-to-side coaptation in brachial plexus surgery and in high lesions of the median nerve. In brachial plexus surgery, they used the ventral rami of the spinal nerves or divisions, the accessory nerve, the phrenic nerve, and the long thoracic nerve as donors. In high median nerve lesions, they utilized the motor fibers of the deep branch of the ulnar nerve to neurotize the thenar branch of the median nerve.

Poor results were obtained if the donor was a major nerve containing fibers of different qualities. Results were excellent if donor and recipient were small mono-functional nerves, even if nerve fiber transfer was achieved by long nerve grafts. In high median nerve lesions, functional and useful reinnervation of the thenar muscles occurred.

The major problem in end-to-side coaptation is the fact that there is no way to influence the sprouting of nerve fibers of the desired quality. This is solved by electing mono-functional nerves as donors and recipients. The major benefit is the full functional preservation of the donor nerve. This may cause problems if the donor nerve supplies muscles of antagonistic functions. This problem can be solved by election of synergistic donors and recipients, as demonstrated with abduction and adduction of the thumb.