Analysis of Craniofacial Microsomia and Facial Asymmetry: Approaches in Facial Feminization Surgery

Background Comprehensive facial analysis among transgender and gender-diverse (TGD) individuals undergoing facial feminization surgery (FFS) has created new opportunities to investigate facial asymmetry in adults. Although craniofacial microsomia (CFM) is typically identified in infancy, milder forms may go unrecognized, leaving gaps in diagnosis and treatment. Objectives The authors of this study examine facial asymmetry, including CFM, among TGD patients undergoing FFS and discuss appropriate surgical strategies. Methods Adults registered male at birth undergoing de novo FFS from 2020 to 2024 were retrospectively reviewed. CFM was diagnosed in patients with same-sided hypoplasia in multiple features, including skeletal structures, malar soft tissue, nerves, and the external ear. The OMENS classification characterized facial morphology. Descriptive statistics, Fisher's exact tests, and Mann–Whitney U tests were performed. Results Among 175 patients with a median age of 28.0 years (interquartile range [IQR], 24.0-34.0 years), 11 (6.3%) were diagnosed with unilateral CFM and demonstrated greater orbital asymmetry, mandibular hypoplasia, ear anomaly, nerve impairment, and soft tissue deficiency compared with their non-CFM counterparts (total OMENS of 5.0 [IQR, 4.0-6.0] vs 0.0 [IQR, 0.0-1.0], respectively, P < .001). Asymmetry in at least 1 facial feature was observed throughout the entire cohort (83.4%). As for surgical maneuvers, to correct chin cants, patients with CFM often underwent osseous genioplasties involving asymmetrical vertical lengthening, whereas patients without CFM underwent symmetrical repositioning (3.3 mm [IQR, 0.0-4.1 mm] vs 0.0 mm [IQR: 0.0 mm], respectively, P < .001). Conclusions CFM may be more common than previously estimated. For individuals with CFM seeking FFS, greater vertical chin manipulation with osseous genioplasty may improve symmetry and feminization.