title: Post-traumatic severe trismus caused by impairment of the masticatory muscle.
abstract: Restriction of the mouth opening from a pathologic condition outside the temporomandibular joint is called a pseudo- or extra-articular ankylosis. The authors report two cases of severe post-traumatic pseudoankylosis. One case showed fibrous degeneration of the bilateral masseter muscles without a facial bone fracture, which caused severe trismus, a mouth opening of less than 2 mm, and gradually appeared after blunt injuries to the face. The other was a rare case accompanied with the bone formation in the masseter muscle and was diagnosed as myositis ossificans traumatica, which also presented as severe trismus, with a maximal mouth opening of 5 mm after facial violence. Both were surgically treated with dissection of the affected muscles. In addition, a hemicoronoidotomy was performed in the case of myositis ossificans traumatica. Although a conservative therapy with physical rehabilitation is the basic policy for the management of pseudoankylosis of the temporomandibular joint, a surgical treatment should be considered when the origin of the problems is an osteogenic character or severe extra-articular ankylosis resistant to conservative therapy before completion of true temporomandibular joint ankylosis.
authors.affiliation: Department of Plastic & Reconstructive Surgery, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan. h-yano@net.nagasaki-u.ac.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yano
authors.forename: Hidenaga
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Reijiro
authors.initials: R
authors.lastname: Hirata
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Hirano
mesh_terms: D000293:Adolescent; D000328:Adult; D005151:Facial Injuries / Q000150:complications; D005355:Fibrosis; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000293:injuries* / Q000473:pathology; D009135:Muscular Diseases / Q000209:etiology; D009221:Myositis Ossificans / Q000209:etiology; D014313:Trismus / Q000209:etiology*; D014949:Wounds, Nonpenetrating / Q000150:complications