Priyesh N. Patel, Scott R. Owen, Cathey P. Norton, Brandon T. Emerson, Andrea B. Bronaugh, William R. Ries, Scott J. Stephan

The buccinator, despite being a prominent midface muscle, has been previously overlooked as a target in the treatment of facial synkinesis with botulinum toxin. To evaluate outcomes of patients treated with botulinum toxin to the buccinator muscle in the setting of facial synkinesis. Prospective cohort study of patients who underwent treatment for facial synkinesis with botulinum toxin over multiple treatment cycles during a 1-year period was carried out in a tertiary referral center. Botulinum toxin treatment of facial musculature, including treatment cycles with and without buccinator injections. Subjective outcomes were evaluated using the Synkinesis Assessment Questionnaire (SAQ) prior to injection of botulinum toxin and 2 weeks after treatment. Outcomes of SAQ preinjection and postinjection scores were compared in patients who had at least 1 treatment cycle with and without buccinator injections. Subanalysis was performed on SAQ questions specific to buccinator function (facial tightness and lip movement). Of 84 patients who received botulinum toxin injections for facial synkinesis, 33 received injections into the buccinator muscle. Of the 33, 23 met inclusion criteria (19 [82.6%] women; mean [SD] age, 46 [10] years). These patients presented for 82 treatment visits, of which 44 (53.6%) involved buccinator injections and 38 (46.4%) were without buccinator injections. The most common etiology of facial paralysis included vestibular schwannoma (10 [43.5%] participants) and Bell Palsy (9 [39.1%] participants). All patients had improved posttreatment SAQ scores compared with prebotulinum scores regardless of buccinator treatment. Compared with treatment cycles in which the buccinator was not addressed, buccinator injections resulted in lower total postinjection SAQ scores (45.9; 95% CI, 38.8-46.8; vs 42.8; 95% CI, 41.3-50.4; P = .43) and greater differences in prebotox and postbotox injection outcomes (18; 95% CI, 16.2-21.8; vs 19; 95% CI, 14.2-21.8; P = .73). Subanalysis of buccinator-specific scores revealed significantly improved postbotox injection scores with the addition of buccinator injections (5.7; 95% CI, 5.0-6.4; vs 4.1; 95% CI, 3.7-4.6; P = .004) and this corresponded to greater differences between prebotulinum and postbotulinum injection scores (3.3; 95% CI, 2.7-3.9; vs 2.0; 95% CI, 1.4-2.6; P = .02). The duration of botulinum toxin effect was similar both with and without buccinator treatment (66.8; 95% CI, 61.7-69.6; vs 65.7; 95% CI, 62.5-71.1; P = .72). The buccinator is a symptomatic muscle in the facial synkinesis population. Treatment with botulinum toxin is safe, effective and significantly improves patient symptoms. 3.