Facial Muscle Reinnervation: A Comparison of Neuromuscular Pedicle with Direct Nerve Implant

Abstract

Two methods of reinnervation, the neuromuscular pedicle (NMP) and the nerve implant (NI), were compared in a model using the rabbit's denervated mentalis muscle. Results from evoked electromyographic (EMG) and muscle tension studies (twitch and tetanic contraction) provided the basis of comparison. In addition, the timing of denervation was studied (ie, at the time of implantation of the NMP or NI, or 2 weeks following implantation). The NMP achieved more rapid reinnervation and produced stronger contractions than the NI. Demonstrable reinnervation with an NMP was accelerated when the implantation occurred prior to the denervation. This was not the case with the NI. There was poor correlation between the evoked EMG potential and the strength of both twitch and tetanic contraction. It was concluded on the basis of this study that muscle tension provided a more accurate means of assessing reinnervated muscle function. Of the two methods, the NMP would seem, therefore, to be the technique of choice when it is available. The NI is certainly effective and should be used when a satisfactory NMP is not available.