Dual-Innervated Gracilis Free Functional Muscle Transfers in Facial Palsy Patients: Comparing Long-Term Outcomes between One- versus Two-Stage Procedures

Abstract

Abstract Background In facial reanimation, dual-innervated gracilis free functional muscle transfers (FFMTs) may have amalgamated increases in tone, excursion, synchroneity, and potentially spontaneity when compared with single innervation. The ideal staging of dual-innervated gracilis FFMTs has not been investigated. We aim to compare objective long-term outcomes following one- and two-stage dual-innervated gracilis FFMTs. Methods Included were adult patients with facial paralysis who underwent either one- (one-stage group) or two-stage (two-stage group) dual-innervated gracilis FFMT with ≥1 year of postoperative follow-up. Facial measurements were obtained from standardized photographs of patients in repose, closed-mouth smile, and open-mouth smile taken preoperatively, 1 year postoperatively, and 3 years postoperatively. Symmetry was calculated from the absolute difference between the paralyzed and healthy hemiface; a lower value indicates greater symmetry. Results Of 553 facial paralysis patients, 14 were included. Five and nine patients were in the one- and two-stage groups, with mean follow-up time, respectively, being 2.5 and 2.6 years. Within-group analysis of both groups, most paralyzed-side and symmetry measurements significantly improved over time with maintained significance at 3 years postoperatively in closed and open-mouth smile (all p ≤ 0.05). However, only the two-stage group had maintained significance in improvements at 3 years postoperatively in paralyzed-side and symmetry measurements in repose with commissure position (median change [interquartile range, IQR], 7.62 [6.00–10.56] mm), commissure angle (median change [IQR], 8.92 [6.18–13.69] degrees), commissure position symmetry (median change [IQR], −5.18 [−10.48 to −1.80] mm), commissure angle symmetry (median change [IQR], −9.78 [−11.73 to −7.32] degrees), and commissure height deviation (median change [IQR], −5.70 [−7.19 to −1.64] mm; all p ≤ 0.05). In the between-group analysis, all measurements were comparable in repose, closed-mouth smile, and open-mouth smile (all p > 0.05). Conclusion Long-term outcomes demonstrate that both one- and two-stage dual-innervated gracilis FFMTs significantly improve excursion, but only two-stage reconstruction significantly improves resting tone.