Treating Buccinator With Botulinum Toxin in Patients With Facial Synkinesis: A Previously Overlooked Target

Objective: Synkinesis after facial nerve injury produces functional and cosmetic concerns for patients. The purpose of this study was to review the authors' experience of treating buccinator synkinesis with botulinum toxin. Methods: This was a retrospective medical records review. All patients seen at the University of Wisconsin Neuromuscular Retraining Clinic who were treated with botulinum injections to the buccinator muscle were included. After a period of neuromuscular retraining lasting 6 to 12 months, botulinum injections were administered to the anterior, middle, and/or posterior aspect of buccinator by the senior author via an intraoral approach. The sites and dosage of the injections depended substantially on input from the therapist overseeing the patient's neuromuscular retraining therapy. Data on patient age, gender, indication for treatment, location and dose of botulinum administration, and outcome were collected. The Synkinesis Assessment Questionnaire (SAQ) was used as a patient-reported outcome measure. Descriptive statistics were computed for all recorded variables. Results: A total of 42 patients with synkinesis involving the buccinator were treated. Female-to-male ratio was 9:1, and follow up ranged from 5 months to 18 years. The indications for treatment included significant retraction and immobility of the affected oral commissure at rest and during volitional and spontaneous facial expressions, difficulty manipulating food during mastication, and biting the inside of the affected cheek. Mean total dose of botulinum administered to buccinator per session was 2.0 units (range, 0.6-2.5 units). SAQ scores improved from a mean of 66.6 preinjection to 45.0 postinjection. In general, patient satisfaction with the procedure was high, and there were no serious complications. Conclusions: To the authors' knowledge, this is the first report of a cohort of patients with buccinator synkinesis treated with botulinum toxin. This treatment has become a valuable adjunct in the comprehensive management of patients with facial synkinesis.