Impairment of motor recovery after late nerve suture: experimental study in the rabbit. Part 1: functional and electromyographic findings.

To study the motor recovery after increasingly late nerve suture, we severed 75 rabbit peroneal nerves and reanastomosed them by microsurgical epineural technique after a delay of up to 12 months. Functional, electromyographic, and morphological parameters were used to evaluate the quality of motor function 6 months after suture. This first part of the study deals with the functional (toe-spreading reflex) and electromyographic findings. With increasing denervation intervals before the nerve suture, significant (p less than 0.01) changes were observed 6 months later. Spontaneous electromyographic activity was seen more frequently, and the strength of toe spreading decreased. The amplitude of the muscle action potential, which became polyphasic, also decreased. The latency and duration of the muscle action potential did not change significantly with an increasing denervation interval before nerve suture.