Unusual Causes of Trismus: Three Case Reports and Literature Review

Objectives:

Restricted mouth opening is a commonly encountered problem in oral and maxillofacial surgical practice. Different cut- off values have been used, but an interincisal distance of 35 mm or less best relates to the perception of functional impairment. Affected patients have difficulties in eating, speaking, and maintaining oral hygiene, and it can have a severe impact on psychosocial wellbeing and quality of life. The major causes of inability to open mouth are articular and sometimes the aetiology may be extra-articular. Because of their rarity, the extra-articular causes of trismus, pose a challenge for accurate diagnosis.

Methods:

In this paper we describe three patients, a female and two males, with limited mouth opening. In all cases the aetiology of trismus were extra-articular. In the first case the cause was osteoma of coronoid process, in the second case traumatic myositis ossificans of the masseter muscle and in the third case bilateral hypertrophy of the mandibular coronoid process

Results:

All three patients were managed with surgery and had adequate mouth opening intraoperatively and at long term follow up.

Conclusion:

Trismus is a fairly common presenting complaint amongst patients seen by oral and maxillofacial surgeons, but long standing limitation of jaw opening due to causes other than TMJ ankylosis is unusual. An accurate diagnosis of these causative factors is necessary for appropriate management of the condition, and provides the patient their best possible chance of overcoming their disability.