Zygomatico-Orbital Fracture-Dislocation in Surgical Treatment: Novel 3-Dimensional Software Automated Analysis

Purpose: The human capability to detect the degree of zygomatico-orbital (ZMO) fracture-dislocation in surgical treatment is unknown. The aim of this study was to examine the association between ZMO fracture-dislocation and injury etiology and treatment. Materials and Methods: We implemented a retrospective cross-sectional study, enrolled a sample composed of patients with an isolated unilateral ZMO fracture, and analyzed fracture-dislocation from computed tomography images with an automatic algorithm. The primary predictor variable was mean surface point-to-point dislocation (the mean distance of dislocation for all surface points in isolated ZMO fracture segments between the original position and after virtual repositioning). The primary outcome was the treatment choice (operative vs nonoperative). Other studied variables were gender, age group, injury mechanism, clinical asymmetry, and human-evaluated dislocation on computed tomography images. Descriptive and bivariate statistics were computed, and the threshold for statistical significance was set at P < .05. Results: The sample consisted of 115 patients with a mean age of 66.3 years, 66.1% of whom were male patients, and the most common cause of injury was falling on the ground (49.6%). Operative treatment was required in 58 patients (50.4%). A significant association was found between mean dislocation and operative treatment. Mean dislocation of operatively versus nonoperatively treated fractures was 2.39 mm versus 1.05 mm (P < .001). Mean fracture-dislocation was greatest in injuries caused by assault (2.41 mm) and smallest in motor vehicle accidents (1.08 mm) and ground-level falls (1.25 mm). The threshold of human-eye detection for ZMO fracture-dislocation was 1.97 mm. Conclusions: The results of this study demonstrate that the threshold for operative treatment of ZMO fracture-dislocation is over 2 mm, which the human eye is able to detect. True dislocation is greater in younger patients than elderly patients and in injuries caused by assault compared with falling. (C) 2020 American Association of Oral and Maxillofacial Surgeons