End‐to‐side neurorrhaphy

End-to-side neurorrhaphy, a possible strategy for treating nerve lesions without useable proximal nerve stumps, has been experimentally and clinically investigated. In end-to-side neurorrhaphy, three main elements should be considered: 1) the induction of axonal collateral sprouting in the donor nerve; 2) the ability of the collateral axons to pierce the different conjunctival layers, including the ability the donor nerve basal laminae, to reinnervate the recipient nerve; and 3) the functional plasticity and behavioral readjustment of single motoneurons that have eventually adopted new motor units. This article reviews the following areas of research and clinical investigation: animal models, axonal collateral sprouting from end-to-side neurorrhaphy, effect of epineurotomy and perineurotomy on axon regeneration, motor reinnervation, and clinical trials.