Analysis of Dynamic Mandibular Movement of Patients With Condylar Hyperplasia Treated With Orthognathic Surgery and Condylectomy

Objective: To assess the dynamic mandibular movement of patients with condylar hyperplasia before and after simultaneous orthognathic surgery and condylectomy through an intraoral approach. Methods: Two groups of patients diagnosed with unilateral condylar hyperplasia were studied: the preoperative group consisted of 23 patients and the postoperative group consisted of 13 patients who had undergone simultaneous orthognathic surgery and condylectomy through an intraoral approach with follow-up for more than 1 year. The normal reference value was obtained from 11 individuals without oral and maxillofacial diseases. Three-dimensional mandibular movement trajectories and electromyography of masticatory muscles were recorded. Results: Patients showed no limitation in mandibular border movement before surgery, but the average amplitude of electromyography of the lower head of lateral pterygoid muscle on the affected side was lower than normal reference value. After condylectomy, the maximum mouth opening decreased [32.00 (26.55, 36.20) mm], mandibular movement deviated to the affected side, and the maximum distance in protrusive movement of the mandibular incisal point and the movement to the normal side were both significantly lowered. Amplitude of electromyography of the lateral pterygoid muscle on the normal side increased in the postoperative group compared with the preoperative group. Conclusions: Patients with condylar hyperplasia had a restriction in protrusive and to the normal side movement, and mandibular movement deflected to the affected side after condylectomy, which indicates the necessity of postoperative individualized rehabilitation training.