Abstract
Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a disease that presents as a hard trismus due to hyperplasia of the masseter and temporalis aponeurosis. Standard surgical methods for MMTAH include masseter resection, temporalis aponeurosis, and coronoidectomy. The operation of resecting the tendon aponeurosis attached to the posterior surface of the coronoid process carries the risk of bleeding and nerve damage because it cannot be observed directly. Therefore, the authors introduce a safer method by using an ultrasonic bone scalpel for this procedure. The authors used an ultrasonic bone scalpel with a long neck blade to scrape the posterior side of the coronoid process from the bottom to the top. The authors have treated 4 cases using this technique, and in all cases, the surgical procedure was performed safely and easily. In conclusion, ultrasonic bone scalpels are effective in MMTAH surgery for removing the attachment of the stiffened temporalis muscle tendon and aponeurosis.