A Double‐Muscle Transfer using a Divided Rectus Femoris Muscle for Facial‐Paralysis Reconstruction

ABSTRACT

There are two types of smiling: without exposure of the teeth (usual smile), and with their exposure (square smile). Performance of the former involves use of the major zygomatic muscle, while the latter is created by the major zygomatic and the depressor labii inferior muscles. The function of the depressor labii inferioris muscle cannot be ignored in facial paralysis reconstruction. A double-muscle transfer using a divided rectus femoris muscle for one-stage reconstruction of both the major zygomatic muscle and the depressor labii inferior muscle is described. The patient suffered facial paralysis caused by an extracranial schwannoma originating from the facial nerve. After the tumor was removed, divided rectus femoris muscle segments were transferred to reconstruct the major zygomatic muscle and the depressor labii inferior muscle. After the pedicle vessel of the muscles was anastomosed to the recipient facial vessel, the long motor nerve of the proximal divided muscle was cross-faced and coapted directly to the prepared contralateral buccal branch. The short motor nerve of the distal muscle segment was sutured to the ipsilateral masseteric nerve.

The advantages of divided rectus femoris muscle transfers are that (1) independent muscle contraction can be reconstructed; (2) no tongue or trapezius muscle atrophy occurs because the masseteric nerve is used as the motor source of the labial depressor; (3) only one muscle is sacrificed for muscle grafts; and (4) it is a one-stage reconstruction.