Correlations between the Pterygomaxillary Junction and Appropriate Osteotome Placement Angles during Junction Separation in le Fort i Osteotomy

Purpose: The authors evaluated pterygomaxillary junction angles across malocclusion patterns and identified the optimal technique for effective pterygomaxillary junction separation during Le Fort I osteotomy, focusing on appropriate osteotome angles and clinical applications. Methods: This retrospective study included 211 patients with malocclusion who had undergone Le Fort I osteotomy at Chang Gung Craniofacial Center between December 2015 and September 2023. The patients were stratified by sex and malocclusion class (class I, II, or III). Preoperative cone-beam computed tomography was performed to measure pterygomaxillary junction angles at 2 axial levels: the posterior nasal spine level and the lower border level corresponding to the maxillary tuberosity. Le Fort I osteotomy involving an angle oscillating saw, and a curved-tip Dautrey osteotome was performed, ensuring the precise placement of the osteotome and tilting of the osteotome handle during pterygomaxillary junction separation. The correlations between the pterygomaxillary junction and appropriate osteotome placement angles were investigated. Results: Among the 211 patients, 5%, 15%, and 80% had class I, class II, and class III malocclusion, respectively. At the posterior nasal spine level, the average angles of the pterygomaxillary junction relative to the coronal plane were 16.76, 19.16, and 17.82 degrees in class I, class II, and class III groups, respectively; the corresponding angles at the lower border level were 27.29, 27.80, and 25.91 degrees. No significant between-class or between-sex differences were observed in pterygomaxillary junction angles; however, significant differences were noted between the 2 levels. Conclusion: Our surgical technique was both safe and effective for pterygomaxillary junction separation.