Facial animation with free-muscle transfer innervated by the masseter motor nerve in unilateral facial paralysis

Abstract

Purpose: Facial paralysis is a congenital or acquired disorder of varying severity leading to an asymmetric or absent facial expression. It represents an important debilitation from both esthetic and functional points of view. In this article we report our experience with patients treated with gracilis muscle transplantation innervated by the motor nerve to the masseter muscle. We discuss the surgical technique and the functional and esthetic results and evaluate the effectiveness of this donor nerve in providing adequate innervation to the muscle transfer for lower facial reanimation.

Materials and methods: Fifteen patients with unilateral facial paralysis were seen and surgically treated at the Department of Maxillofacial Surgery, University of Parma, Parma, Italy, between 2003 and 2007. In this study we report on 8 cases treated with gracilis muscle transfer reinnervated by the motor nerve to the masseter muscle.

Results: In this series all free-muscle transplantations survived transfer, and no flap was lost. Facial symmetry at rest and while smiling was excellent or good in all patients, and we observed a significant improvement in speech and oral competence. With practice, the majority of patients developed the ability to smile spontaneously and without jaw movement.

Conclusions: We consider the masseter motor nerve a powerful and reliable donor nerve, allowing us to obtain a commissure and upper lip movement similar to those of the normal site for amount and direction. This is why we think that there may be a larger role for the masseter motor nerve for innervation of patients with unilateral facial paralysis who would otherwise have been considered candidates for cross-facial nerve graft innervation of the muscle transfer.