Selective Myectomies Alone versus Selective Myectomies Combined with Neurectomies in Postparetic Synkinesis: Comparing Outcomes.

BACKGROUND

In postparetic synkinesis, muscle tone imbalance between upper and lower lip depressors and elevators results in the inability to produce an effective smile. Surgical treatments to improve smile focus on restoring tonicity balance between perioral muscles by weakening hypertoned muscles through selective myectomies or selective neurectomies. The goal of this study was to compare objective outcomes between selective myectomies alone with those of selective myectomies combined with selective neurectomies.

METHODS

A retrospective cohort study was performed on postparetic synkinesis patients who underwent depressor anguli oris (DAO) myectomies or DAO and platysma myectomies with selective neurectomies. Objective outcomes included preoperative and postoperative analyses of smile measures (excursion, angle, and dental show) and botulinum toxin type A administration (periorbital and platysmal).

RESULTS

Thirty-seven patients underwent DAO myectomies only (myectomy group), and 18 patients underwent DAO and platysma myectomies with selective neurectomies (myectomy-neurectomy group). Within-group analyses showed significant angle improvement in both groups ( P < 0.05) and improved smile excursion in the myectomy-neurectomy group ( P < 0.05). Between-group comparisons showed significant closed mouth smile excursion improvement (difference in means, -1.14 mm; 95% CI, -2.19 to -0.09 mm; P = 0.034) and a significant decrease in platysmal botulinum toxin type A administration (difference in means, 27.36 units; 95% CI, 18.72 to 36.00 units; P < 0.001) in the myectomy-neurectomy group compared with the myectomy group.

CONCLUSIONS

This study suggests that selective myectomies and selective myectomies with selective neurectomies provide overlapping and differing benefits to perioral synkinesis. Selective neurectomies and platysma myectomy provided slightly improved excursion and significantly decreased botulinum injections to the platysma.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.