Cross-Facial Nerve Graft Viability in the Setting of Delayed Free Functional Muscle Transfer for Facial Reanimation

Introduction: Cross-facial nerve graft with free functional muscle transfer (FFMT) is a mainstay approach for facial reanimation. However, the effect of delay between cross-facial nerve graft and FFMT procedures is unknown. Objective: To measure the effect of delay between cross-facial nerve graft and FFMT among patients with facial nerve paralysis, as measured by clinician-graded assessments longitudinally. Methods: Patients who underwent both cross-facial nerve graft and gracilis FFMT, which was performed from 2016 to 2023, were retrospectively reviewed. Primary outcomes were time to first facial movement and time to spontaneous smile. Results: This study included 31 patients with cross-facial nerve graft and FFMT. Time between procedures did not adversely impact reinnervation. Between single and dual innervation patients, there was no difference in time to first facial movement (198, interquartile [IQR: 152.5-290 days] vs. [146, IQR: 116-196 days] [p = 0.089]) and time to spontaneous smile ([297.5, IQR: 200.25-409 days] vs. [282, IQR: 202-464 days] [p = 0.779]). Conclusion: Delays between cross-facial nerve graft and FFMT do not adversely impact time to first facial movement or spontaneous smile. Mature grafts may potentially remain viable for prolonged periods of time and thereby create opportunities for patients.