Evaluation of Postoperative Facial Asymmetry Index Following Mandibular Reconstruction Using Free Fibular Flap With Condylar Involvement

Background: Loss of the temporomandibular joint (TMJ) following mandibulectomy disrupts maxillomandibular continuity and occlusion, potentially resulting in facial asymmetry with functional, structural, and aesthetic consequences. The free fibular flap remains the gold standard for mandibular reconstruction. However, the impact of condylar involvement on postoperative facial asymmetry remains poorly studied. Methods: A retrospective cohort study was conducted on patients undergoing free fibular flap mandibular reconstruction at Cipto Mangunkusumo Hospital (RSCM) between 2023 and 2025. Subjects were stratified based on the presence or absence of condylar involvement. Postoperative facial asymmetry was quantified using a 3D-derived asymmetry index (AI) based on predefined anatomic landmarks at the TMJ, mandibular angle, and mental region across the transverse (X), vertical (Y), and sagittal (Z) axes. Measurements were obtained using Autodesk Meshmixer and statistically analyzed to compare outcomes. Result: A total of 20 subjects were included, with comparable baseline demographics and mean evaluation periods of 23.20 and 23.80 months, respectively. At the mandibular angle, the condyle-involved group showed significantly greater asymmetry along the vertical ( P =0.043) and sagittal axes ( P =0.006). At the mental region, significant differences between the 2 groups were observed along the transverse ( P =0.002) and sagittal axes ( P =0.015). Notably, no significant asymmetry was observed at the TMJ region across any axis ( P >0.05). Conclusion: Condylar involvement is a key determinant of postoperative mandibular asymmetry, particularly affecting vertical and sagittal alignment. These findings highlight the importance of incorporating condylar status into preoperative planning to optimize long-term facial symmetry outcomes.