Comparative Study of 2 Different Innervation Techniques in Facial Reanimation Cross-face Nerve Graft-Innervated Versus Double-Innervated Free Gracilis Muscle Transfer

Recently, 1-stage double innervation with the masseter nerve and the cross-face nerve graft (CFNG) has gained popularity owing to its outcomes of powerful and synchronous muscle contraction. In this study, we compared CFNG- and double-innervated free gracilis muscle transfer (FGMT) for facial palsy reconstruction. A total of 49 patients with facial palsy who underwent facial reanimation surgery from August 2013 to January 2017 were enrolled. The CFNG group (18 patients) underwent 2-stage CFNG innervation, whereas the double-innervated FGMT group (31 patients) underwent dual coaptation with end-to-end masseter nerve and end-to-side CFNG. The FACEgram software was used for evaluating smile excursion, symmetry index, spontaneous smile occurrence, Terzis' score including palsy pathogenesis, and clinical progress. In the CFNG group, the smile excursion at rest increased (P = 0.000); however, there was increased smile excursion both at rest and during smiling in the double-innervated FMGT group (rest P = 0.002, smile P = 0.028). Improvement of the symmetry index was observed only in the FMGT group (rest P = 0.001, smile P = 0.000). There was no significant difference in Terzis' scores. The average time to the first visible muscle contracture was statistically significantly shorter in the double-innervated FGMT group (P = 0.035). With respect to spontaneous smile achievement, the double-innervated FGMT group (25.8%) showed a satisfactory outcome. Cross-face nerve graft-innervated FGMT improved only smile excursion at rest, whereas double-innervated FGMT provided improvement in both the resting and smiling postures. Furthermore, the double-innervated FGMT group showed a higher symmetry index. However, the 2 operations did not show a significant difference in functional aspects.