Botulinum toxin A in patients with oromandibular dystonia: long-term follow-up.

OBJECTIVE: To study the safety and efficacy of botulinum toxin A (BTX) in patients with oromandibular dystonia (OMD) and to compare the treatment results of the various subtypes of OMD.

BACKGROUND: OMD is one of the most challenging forms of dystonia to treat. Pharmacologic therapies are generally not effective, and there are no surgical alternatives.

METHODS: Of 202 patients diagnosed clinically to have OMD in a movement disorders clinic over a period of 10 years, 162 patients satisfied the study inclusion criteria. The masseters and submentalis complex were the only two muscle groups injected with BTX in this group of patients.

RESULTS: The mean age was 57.9+/-15.3 years and the mean follow-up period was 4.4+/-3.8 years. More than half the patients had jaw-closing (JC) dystonia. A total of 2,529 BTX treatments were administered into the masseter muscles, submentalis complex, or both during a total of 1,213 treatment visits. The mean doses of BTX (per side) were 54.2+/-15.2 U for the masseters and 28.6+/-16.7 U for the submentalis complex. The mean total duration of response was 16.4+/-7.1 weeks. The mean global effect of BTX was 3.1+/-1.0 (range, 0 to 4, where 4 equals the complete abolition of the dystonia), with the JC dystonia patients responding best. Fifty-one patients (31.5%) reported adverse effects with BTX in at least one visit. Complications such as dysphagia and dysarthria were reported in 135 (11.1%) of all treatment visits.

CONCLUSIONS: BTX is a safe and effective long-term treatment for OMD. JC dystonia responds better than jaw-opening or mixed dystonias, and the treatment of the latter types of OMD are more likely associated with dysphagia and dysarthria. Jaw-opening dystonia can be treated successfully by injecting the submentalis complex.