Three-dimensional facial morphology in patients with craniofacial microsomia and microtia

Introduction: Craniofacial microsomia (CFM) is classified using the subjective Orbit, Mandible, Ear, Nerve and Soft tissue (OMENS) tool. Digital stereophotogrammetry (i.e. three-dimensional [3D] photography) can be used to capture facial shape objectively. This case-control study assessed the applicability of 3D photography in distinguishing between patients with CFM and individuals without craniofacial conditions, as well as classifying the severity of facial involvement. Methods: 3D photographs of patients with CFM and/or microtia from the Amsterdam UMC, Radboudumc and the Great Ormond Street Hospital and of individuals without craniofacial conditions were assessed. Differences between patients and controls were explored through asymmetry index (ASI) and facial signature (FS) scores, as well as a principal components (PC) analysis of FS scores and logistic regression. Correlations between OMENS scores and ASI, FS and PC scores were evaluated. Results: A total of 179 patients and 210 controls were analyzed. ASI and FS scores differed significantly between patients and controls (p<0.001), and were correlated with several OMENS subscales. The logistic regression model distinguishing between patients and controls showed increasing asymmetry of the mandible and orbits with increasing Pruzansky-Kaban score. Patients with isolated microtia deviated from controls in the midface. Conclusion: Clinically significant differences in the facial morphology of patients with CFM and microtia were found compared to controls, suggesting that 3D photography can be used to assess the severity of facial involvement in a novel, objective and safe way in these patients.