Computed tomographic assessment of orbital and maxillary dysmorphology in craniofacial microsomia

Mandibular dysmorphology is well-documented in craniofacial microsomia (CFM), but data on midface abnormalities remain limited. This study aimed to compare orbital and maxillary dimensions between the affected and unaffected sides in patients with CFM.

The retrospective cross-sectional study conducted in South Australia comprised 31 patients with CFM and 31 age- and sex-matched control patients (median age 13.2 years; range 0.3-48.4 years; 80.6% children and 19.4% adults; 51.6% males and 48.4% females). Computed tomography reconstructions were assessed bilaterally for 4 orbital and 6 maxillary dimensions in mild, moderate, and severe subgroups, as well as in the control group. Linear mixed-effects models, adjusted for age and sex, were performed to assess whether there were significant differences in the measured dimensions between the sides and groups.

Midface asymmetries in patients with CFM were generally commensurate with their severity. In moderate CFM, the affected side showed hypoplastic orbits and maxillae compared with the unaffected side (orbital height: -4.9%; P = 0.018; maxillary middle height: -10.3%; P <0.001). In severe CFM, the reduced maxillary middle height on the affected side (-18.5%; P <0.001) was compensated by increases in the orbital height (+7.0%) and maxillary depth (+6.8%; P = 0.014) (all data adjusted for covariates).

CFM is a bilateral condition characterized by orbital and maxillary asymmetries, primarily because of hypoplasia but occasionally involving hyperplasia on the affected side. In severe CFM, compensatory increases in maxillary depth and orbital height often offset midmaxillary height deficiencies.