Background: Masseter-to-facial nerve transfer is a new procedure for patients who acquire a proximal injury to the facial nerve. This article reports that this procedure is effective and associated with minimal morbidities.
Methods: From November 2010 to February 2013, 16 patients underwent a masseter-to-facial nerve transfer. Their denervation periods varied from 2 to 18 months, with an average of 10.1±4.1 months. Their ages varied from 22 to 70 years, with an average of 34.7±15.4 years. The etiology of denervation was tumor resection in the cerebellopontine angle in all cases. All of the patients were followed up several times. The outcomes of the first follow-up at 3 months postoperatively and the last follow-up at a minimum 12 months postoperatively were documented. Using Terzis' and Metha's scales, the smile outcomes and synkinetic movements as visualized using standardized videos were graded preoperatively and postoperatively. The periods between the operation and the onset of mimetic muscle contraction were documented. A questionnaire was administered to evaluate the donor-site morbidity and the ability to smile without biting.
Results: The final outcomes for smile function were as follows: 9 patients (56.3%) had excellent or good function, 5 patients (31.3%) had moderate function, and 2 patients (12.5%) had poor function. There was significant improvement between the preoperative and postoperative time points and between the outcomes at the first and last follow-ups (P<0.05). Additionally, 13 (81.3%) patients had the ability to smile without biting 12 months postoperatively. The onset of muscle motion varied from 56 to 365 days and was positively correlated with age in the group of patients older than 40 years and negatively correlated with the outcome of the first follow-up. Four (25%) patients complained of concavity at the parotideomasseteric region, but none complained of disturbance in food intake. Synkinetic movements were observed in all patients and were rated as mild.
Conclusions: The masseter-facial nerve transfer effectively reanimated the paralytic muscle in patients who acquired an intracranial facial nerve injury with minimal deficits at the donor site. After continued physical therapy, some patients were able to regain a symmetrical and effortless smile with mild synkinetic movements.