Buccinator synkinesis treated by botulinum toxin in facial palsy and hemifacial spasms.

OBJECTIVE: To assess botulinum toxin treatment for buccinator muscle synkinesis including: how often the synkinesis was troublesome; who benefitted and how from the treatment; and what were the adverse effects, ideal dosage, and injection site. SUBJECTS AND METHODS: Facial palsy (FP) patients and patients with hemifacial spasms who were attending for multiple site botulinum-toxin treatment for facial sequelae were assessed for buccinator synkinesis. The study group comprises those experiencing buccinator synkinesis with associated bothering symptoms who were willing to try injection also to the buccinator muscle. RESULTS: During 9/2017-12/2019, 126 different patients with facial sequelae were treated with multiple-site botulin-toxin injections by the author. Of them, 83 (66%) received injection also for buccinator synkinesis and 66/82 (80%) wanted to continue with the buccinator injections. The most remarkable results were seen with FP patients biting the mucus membrane of their cheek: usually the biting ceased totally. Patients with powerful hemifacial cheek spasms also experienced cessation of the spasms, contrasting any previous treatments. Adverse effects were mostly mild: slight weakness of the corner of the mouth or additional leakage of saliva or liquids. Only a few patients experienced more pronounced adverse effects. The most posterior contracting part of the buccinator muscle proved to be the best site for the injection. CONCLUSIONS: Buccinator synkinesis was very common and its treatment gave many patients additional relief from facial sequelae symptoms. Professionals treating patients with synkinesis and hemifacial spasms should add well-tolerated buccinator injections to their repertoire of injection sites.