Long-Term 3-D Assessment of Facial Asymmetry After Orthognathic Surgery

Objectives: The objective of this study was to find out if the soft tissue changes after the correction of dentofacial asymmetry with orthognathic surgery will tend to regress to the original deformity. Materials and Methods: A total of 20 patients were recruited in this retrospective study which was performed at Yale New Haven Hospital and University of Connecticut. Patients were divided into two groups: Experimental (8) and Control (12). Stereophotogrammetric Images were obtained for each patient at five timepoints: (T0) Pre-Surgery, (T1) Post-surgery, (T2) 1 month after, (T3) 6 months after, (T4) 1-year after. Fifteen landmarks were identified on faces of each patient at each timepoint. Each landmark had its own of X, Y, and Z coordinates. The coordinates of each timepoint were then compared within each group and between groups. Results: Statistically significant differences were found for points in the lower chin area (Point 10, 11, 12 and 15) in the transverse plane (X-axis) for experimental patients between T0 and T1. Control patients had statistically significant changes in the transverse plane for Points 1 and 15 when comparing T0 and T1. All the bilateral points in our study were separately analyzed for their vertical (Y) and anterior-posterior (Z) changes over time. For vertical changes in the experimental group, Points 13 and 14 had a statistically significant difference before surgery and at 1-month post-surgery when compared to each other. For vertical changes in the Control group, comparison between Points 8 and 9 at 6-month timepoint were statistically significant. When analyzing changes in anterior-posterior direction, we did not see any statistically significant differences in our Experimental group. However, in the Control group, Points 13 and 14 were statistically significant different at Pre-Surgery, 1-month and 6-months for the Z values. Conclusions: Our data suggests that asymmetry improved significantly after surgery for all the lower chin points in the Experimental group after orthognathic surgery when compared to patients in the Control group. Since we did not see any significant changes occurring post-surgery for the lower chin points in the experimental group, we conclude that the asymmetry of the chin does not regress over time back to its original location in asymmetric patients. No other clinically significant results were observed in this study