Coronoidotomy as treatment for trismus due to jaw-closing oromandibular dystonia.

Oromandibular dystonia is a focal dystonia involving the masticatory and/or tongue muscles. This report describes 2 female patients with jaw-closing dystonia treated by surgical resection of the coronoid process. The patients could not open their mouths due to involuntary jaw-closing muscle contraction. We first treated them by injecting lidocaine and alcohol (muscle afferent block) into the masseter and temporal muscles and then botulinum toxin. However, the trismus improved mildly and transitorily. Therefore, coronoidotomy was done under general anesthesia. The jaw opening increased to 50 mm. Coronoidotomy is useful for patients with jaw-closing dystonia in whom other therapies are ineffective.