Trismus Due to Hyperplastic Coronoid Process: Series of Five Cases and Review of Literature

Hyperplasia of the coronoid process is a rare condition, potentially leading to a mechanical mouth opening restriction. Diagnostic workup and treatment will be discussed based on 5 cases. This article presents 5 cases of true coronoid process hyperplasia. In addition, we reviewed accessible literature on the topic with special attention to pathophysiologic theories, surgical approach, and postoperative physiotherapy. The improvement in the maximal intercuspidal opening ranged from 4 and 31 mm. Greater maximal intercuspidal opening improvement was connected to compliant patients, while poor outcome occurred in the case of a patient that neither followed the recommendations for physical therapy nor showed up for his follow up appointments. The success of the therapy is defined by a long-lasting and stable improvement of the mouth opening compared to the preoperative situation. In the presented cases, the outcome was strongly dependent on the patients' postoperative compliance. Based on the cases described, we conclude that a good outcome is accomplishable for patients using the methods presented, as long as patients cooperate well after surgery.Diagnostic workup in patients with trismus should be thorough to correctly diagnose rare entities such as coronoid hyperplasia. If treated correctly this condition has a good outcome, as long as the compliance of the patient is adequate.