Natural variation of the zygomaticomaxillary complex symmetry in normal individuals

Objective: The study aim was to investigate variations in the symmetry of the zygomaticomaxillary complex (ZMC) in normal individuals. Method: Computed tomography datasets of 200 individuals without facial fractures were analyzed using a validated three-dimensional analysis technique. The absolute average distance (AD) and 90th percentile distance (NPD) were calculated, representing respectively the overall and maximum symmetry between bilateral ZMCs. Results: The mean AD and NPD of the total study group was 0.9 +/- 0.3 mm(95% CI 0.3-2.3) and 1.7 +/- 0.5 mm (95% CI 0.5-3.9), respectively. The mean AD and NPD in males were 1.0 +/- 0.3 mm (95% CI 0.28-2.34) and 1.9 +/- 0.5 mm (95% CI 0.5-3.9) versus 0.8 +/- 0.3 mm (95% CI 0.4-1.7) and 1.6 +/- 0.5 mm (95% CI 0.8-2.9), respectively, for females. A statistically significant difference between male and female was found for both AD and NPD (p 40 years. Conclusion: The naturally occurring anatomic variation in ZMC symmetry described in this study is proposed as a benchmark for evaluating the amount of preoperative displacement and postoperative reduction of ZMC in trauma cases. (C) 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved