Abstract: Both interposition nerve grafts and masseter nerve transfers have been successfully used for facial reanimation after irreversible injuries to the cranial portion of the facial nerve. However, no comparative study of these two procedures has yet been reported. In this two-site, two-arm, retrospective case review study, 32 patients were included. Of these, 17 patients (eight men and nine women, mean age 42.1 years) underwent interposition nerve graft after tumor extirpation or trauma between 2003 and 2006 in the Ear Institute, School of Medicine, Shanghai Jiao Tong University, China, and 15 patients (six men and nine women, mean age 40.6 years) underwent masseter-to-facial nerve transfer after tumor extirpation or trauma between November 2010 and February 2016 in Shanghai Ninth People’s Hospital, China. More patients achieved House-Brackmann III recovery after masseter nerve repair than interposition nerve graft repair (15/15 vs. 12/17). The mean oral commissure excursion ratio was also higher in patients who underwent masseter nerve transfer than in patients subjected to an interposition nerve graft. These findings suggest that masseter nerve transfer results in strong oral commissure excursion, avoiding obvious synkinesis, while an interposition nerve graft provides better resting symmetry. This study was approved by the Institutional Ethics Committee, Shanghai Ninth People’s Hospital, China (approval No. SH9H-2019-T332-1) on December 12, 2019. 

Key words: facial palsy, facial reanimation, facial symmetry, House-Brackmann score, interposition, masseter nerve, nerve graft, oral commissure excursion, resting symmetry, synkinesis