End-to-side nerve repair: review of the literature and clinical indications.

End-to-side (ETS) nerve repair, in which the distal stump of a transected nerve is coapted to the side of an uninjured donor nerve, has been suggested as a technique for repair of peripheral nerve injuries where the proximal nerve stump is unavailable or a significant nerve gap exists. Full review of the ETS literature suggests that sensory recovery after ETS repair results in some, but not robust, regeneration. Sensory axons will sprout without deliberate injury. However, motor axons only regenerate after deliberate nerve injury. Experimental and clinical experience with ETS neurorrhaphy has rendered mixed results. Continued research into ETS nerve repair is warranted. ETS techniques should not yet replace safer and more reliable techniques of nerve repair except when some, but not good, sensory recovery is appropriate and a deliberate injury to the donor motor nerve is made.