Muscle transplantation for reconstruction of a smile after facial paralysis past, present, and future.

Reconstruction of a natural, spontaneous, symmetrical smile remains the ultimate goal of reanimation of the mid-face after facial paralysis. Recently the one-stage mini-gracilis muscle transplantation, innervated by the contralateral facial nerve, has been introduced to solve this difficult problem. This paper illustrates by means of a historical review the numerous procedures which have led to the development of this intervention. Moreover, it addresses relevant differences between the classical two-stage procedure using a cross-facial nerve graft and the recently advocated one-stage procedure. The underlying neurophysiological mechanism and determination of the final functional outcome of the neurovascular muscle transfer to the face are discussed, and areas which deserve future research are mentioned.