IMPORTANCE A multivector functional muscle flap that closely simulates the biomechanical effects of facial muscle groups is essential for complete smile restoration after facial paralysis. OBJECTIVE To determine the feasibility of a multivector gracilis muscle flap design for reanimation after facial paralysis and to analyze the effect on the smile display zone. DESIGN, SETTING, AND PARTICIPANTS Prospective analysis of patients who underwent a double paddle multivector gracilis flap for complete facial paralysis between June 2015 and December 2016 was carried out in a tertiary hospital. INTERVENTIONS The gracilis muscle was harvested as a double paddle flap and inserted along 2 vectors for facial reanimation. MAIN OUTCOMES AND MEASURES The primary outcome measures were: (1) dental display (the number of maxillary teeth displayed on paralyzed vs normal sides), (2) exposed maxillary gingival scaffold width, (3) interlabial gap at midline and canine, (4) facial asymmetry index (FAI), and (5) dynamic periorbital wrinkling. RESULTS There were 10 women and 2 men between ages 20 and 64 years (mean [SD], 46  years). Five flaps were reinnervated with facial and masseteric nerves, 5 with masseteric nerve only, and 2 with crossfacial nerve only. There was functional muscle recovery in all cases. On average there was additional 3.1 maxillary teeth exposed posttreatment when smiling (5.5 vs 8.6; CI, 7.9 to 16.6; P < .001). The mean exposed maxillary gingival scaffold width improved from 31.5 mm to 43.7 mm (95% CI, 1.9 to 4.3; P < .001). There was no significant difference in interlabial exposure at midline (7.1 mm vs 7.7 mm; CI, −1.5 to 2.7; P = .56) but a 56.4% improvement at the level of the canines (3.9 vs 6.1; CI, 0.1 to 4.3; P = .04). The mean FAI when smiling was reduced from 9.1 mm to 4.5 mm (CI, −8.0 to −1.2; P = .01). Dynamic wrinkling of the periorbital area with smiling was noted in 4 patients. CONCLUSIONS AND RELEVANCE The gracilis flap can be reliably designed as a functional double paddle muscle flap for a multivector facial reanimation. The multivector gracilis flap design is effective in improving all components of the smile display zone and has the potential for producing periorbital-wrinkling characteristic of a Duchenne smile.
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