Functional Outcome of Dual Reinnervation with Cross-Facial Nerve Graft and Masseteric Nerve Transfer for Facial Paralysis

Abstract

Background: The combination of cross-facial nerve graft (CFNG) and masseteric nerve transfer (MNT) for reinnervation of facial paralysis may provide advantages of both neural sources. However, quantitative functional outcome reports with a larger number of patients are lacking in the literature. Here we describe our 8-year experience with this surgical technique. Methods: Twenty patients that presented with a complete facial paralysis (duration <12 months) received dual reinnervation with CFNG and MNT. The functional outcome of the procedure was evaluated with the physician-graded outcome metric eFACE. The objective artificial intelligence-driven software Emotrics and FaceReader were used for oral commissure measurements and emotional expression assessment, respectively. Results: The mean follow-up was 31.75±23.32 months. In the eFACE score, the nasolabial fold depth and oral commissure at rest improved significantly (p<0.05) towards a more balanced state after the surgery. Postoperatively, there was a significant decrease in oral commissure asymmetry while smiling (19.22±6.1mm to 12.19±7.52mm). For the emotionality expression, the median intensity score of happiness, as measured by the FaceReader software, increased significantly while smiling (0.28, IQR 0.13-0.64). In 5 (25%) patients, a secondary static midface suspension with fascia lata strip had to be performed due to an unsatisfactory resting symmetry. Older patients and patients with greater preoperative resting asymmetry were more likely to receive static midface suspension. Conclusions: Our results suggest that the combination of MNT and CFNG for reinnervation of facial paralysis provides good voluntary motion and may lessen the use of static midface suspension in the majority of patients.