Surgery
If long-term extremely forceful dystonic elevator muscle contraction results in masticatory muscle tendon-aponeurosis hyperplasia or hyperplasia of the coronoid process (Fig. 9), surgery, e.g., coronoidotomy, might be required (Fig. 10) (22,25,26). We approach, and all incisions are made in the mouth, so no surgical scars remain on the face. The operation takes 1.5-2 hours. As postoperative mouth opening training is important, the patient has to remain in hospital for about two weeks.
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Fig. 9. A case of hyperplasia of the coronoid process. Note the enlargement of the bilateral coronoid process and the hypertrophy of the mandibular angle (a). The enlargement impinges on the zygomatic arch during mouth opening. The maximal extent of mouth opening was only 17 mm (b). After bilateral coronoidotomy (c), the maximal extent of mouth opening increased to over 40 mm (d).
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Fig. 10. This patient could not open her mouth at all due to involuntary contracture of the bilateral temporalis and masseter muscles (a). Radiographs of the temporomandibular joints showed normal findings. Bilateral coronoidotomy via the intraoral approach was performed under general anesthesia. Just after the operation, the patient was able to open her mouth by 50 mm (b).
Video 6. Jaw closing dystonia before and after coronoidotomy