Evaluation of soft tissue asymmetry using cone-beam computed tomography after open reduction and internal fixation of zygomaticomaxillary complex fracture

Objectives: In this study, we assessed soft tissue asymmetry that occurred after open reduction of unilateral zygomaticomaxillary complex (ZMC) fractures. We proposed a simple method to assess soft tissue asymmetry after reduction surgery by evaluating the symmetry between the affected and the unaffected sides. The factors affecting soft tissue contour after surgery were also analyzed. Materials and Methods: Subjects included patients admitted to Wonkwang University Dental Hospital from 2008 to 2013. Cone-beam computed tomography (CBCT) images of asymmetric patients who underwent open reduction at least 3 months prior were compared with healthy patients. Results: The degree of asymmetry was measured in both the open reduction and control groups. Landmarks that showed a statistically significant difference between the two groups were zygion ($1.73{\pm}0.24mm$), bucclae ($1.08{\pm}0.26mm$), point of cheek ($2.05{\pm}0.33mm$) and frontozygomatic point ($1.30{\pm}0.31mm$). Conclusion: When compared with the normal group, asymmetry can occur in the affected side, which usually shows depression of overlying soft tissue and is statistically significantly different. Evaluation of soft tissue asymmetry with CBCT images after open reduction of ZMC fracture is useful.