Double innervation in free-flap surgery for long-standing facial paralysis

Abstract

One-stage free-flap facial reanimation may be accomplished by using a gracilis transfer innervated by the masseteric nerve, but this technique does not restore the patient's ability to smile spontaneously. By contrast, the transfer of the latissimus dorsi innervated by the contralateral facial nerve provides the correct nerve stimulus but is limited by variation in the quantity of contraction. The authors propose a new one-stage facial reanimation technique using dual innervation; a gracilis muscle flap is innervated by the masseteric nerve, and supplementary nerve input is provided by a cross-face sural nerve graft anastomosed to the contralateral facial nerve branch. Between October 2009 and March 2010, four patients affected by long-standing unilateral facial paralysis received gracilis muscle transfers innervated by both the masseteric nerve and the contralateral facial nerve. All patients recovered voluntary and spontaneous smiling abilities. The recovery time to voluntary flap contraction was 3.8 months, and spontaneous flap contraction was achieved within 7.2 months after surgery. According to Terzis and Noah's five-stage classification of reanimation outcomes, two patients had excellent outcomes and two had good outcomes. In this preliminary study, the devised double-innervation technique allows to achieve a good grade of flap contraction as well as emotional smiling ability. A wider number of operated patients are needed to confirm those initial findings.