Quantitative determination of zygomaticomaxillary complex position based on computed tomographic imaging

Background: The zygomaticomaxillary complex (ZMC) is frequently involved in craniofacial fractures. We propose an objective approach for defining the ZMC position on skeletal and soft tissue by using Amira to process 3-dimensional (3D) facial computed tomography (CT) images. Aim and Objectives: In this study, we aim to propose 1 anthropometric system, facilitated based on CT images, which can be used in quantitative analysis of ZMC position and examine the symmetry of skeletal and soft tissue of the ZMC with high reliability and validity. Methods: Twenty Taiwanese trauma patients with pure mandibular fracture but bilateral intact ZMCswere recruited to participate in this study. The head position was adjusted in 3D planes during the examinations. The distances between the zygion and nasion and maxillozygion and nasion were defined as the x plane. The y plane was defined as the distance between the maxillozygion to the vertex and orbitale to the vertex. The distance between themaxillozygion and opisthocranion was defined as the z plane. Results: The results indicated that the intrasubject variability was 0.7 to 1.6 and 0.1 to 1.8 mm in skeletal and soft tissue, respectively. The intersubject variability ranged from 3.1 to 9.2 and 1.8 to 9.3 mm in skeletal and soft tissue, respectively. The proposed anthropometric systemdemonstrated high validity and reliability in ZMCmeasurements. No significant differencewas observed among bilateral ZMCs, indicating the feasibility of the mirroring technique during surgical processes. Conclusions:We conclude that the anthropometric system for processing 3D facial CT images facilitated by Amira has potential implication in the assessment and reconstruction of the ZMC in both skeletal and soft tissue.