Transposition of the Intratemporal Facial to Hypoglossal Nerve for Reanimation of the Paralyzed Face: The VII to XII TranspositionTechnique.

Abstract

The hypoglossal nerve has long been an axonal source for reinnervation of the paralyzed face. In this study, we report our experience with transposition of the intratemporal facial nerve to the hypoglossal nerve for facial reanimation. To determine the feasibility and outcomes of the transposition of the infratemeporal facial nerve for end-to-side coaptation to the hypoglossal nerve for facial reanimation. A case series of 20 patients with facial paralysis who underwent mobilization and transposition of the intratemporal segment of the facial nerve for an end-to-side coaptation to the hypoglossal nerve (the VII to XII technique). Participants were treated between January 2007 and December 2014 at a tertiary care center. Outcome measures include paralysis duration, facial tone, facial symmetry at rest, and with smile, oral commissure excursion, post-reanimation volitional smile, and synkinesis. Demographic data, the effects of this technique on facial tone, symmetry, oral commissure excursion and smile recovery were evaluated. Preoperative and postoperative photography and videography were reviewed. Facial symmetry was assessed with a facial asymmetry index. Smile outcomes were evaluated with a visual smile recovery scale, and lip excursion was assessed with the MEEI-SMILE system. All 20 patients had adequate length of facial nerve mobilized for direct end-to-side coaptation to the hypoglossal nerve. The median duration of facial paralysis prior to treatment was 11.4 months. Median follow-up time was 29 months. Three patients were excluded from functional analysis due to lack of follow-up. Facial symmetry at rest and during animation improved in 16 of 17 patients. The median (range) time for return of facial muscle tone was 7.3 (2.0-12.0) months. A significant reduction in facial asymmetry index occurred at rest and with movement. The MEEI FACE-gram software detected a significant increase in horizontal, vertical, overall lip excursion and smile angle. No patient developed significant tongue atrophy, impaired tongue mobility, or speech or swallow dysfunction. Mobilization of the intratemporal segment of the facial nerve provides adequate length for direct end-to-end coaptation to the hypoglossal nerve and is effective in restoring facial tone and symmetry after facial paralysis. The resulting smile is symmetric or nearly symmetric in the majority of patients with varying degree of dental show. The additional length provided by utilizing the intratemporal segment of the facial nerve reduces the deficits associated with complete hypoglossal division/splitting, and avoids the need for interposition grafts and multiple coaptation sites. 4.