Masseteric nerve: a possible donor for facial nerve anastomosis?

In the medical treatment of facial nerve paralysis a large number of different techniques have been developed to restore the function of the facial nerve. These include (a) the ipsilateral nerve grafting (e.g., partial hypoglossal-facial, spinal accessory-facial, partial glossopharyngeal-facial), (b) crossfacial nerve grafting and (c) temporal muscle flaps or even free muscle transfers. None of these techniques uses the masseteric nerve as a graft for reconstruction of the facial nerve. This preliminary report deals with the anatomical basis, which could lead to a new technique. The masseteric nerve leaves the infratemporal fossa through the mandibular notch, accompanied by the masseteric artery. At this level the nerve consists in nine of 36 cases studied of only one branch (25.0%), in 17 cases of two branches (47.0%), in nine cases of three (25.0%), and in the remaining case of four branches (2.8%). There are three main reasons for considering the masseteric nerve as a possible donor for at least the orbicular branch of the facial nerve: (1) The approach to the mandibular notch is quite simple; (2) since the nerve consists of two or more branches in 75.0% of the cases, severe dysfunction of the masseter muscle should not occur; (3) if there is complete denervation of the masseter muscle, its function may be taken over by the temporalis muscle.