Insights into orbital morphological features and fracture patterns in medial and inferior wall fracture: a retrospective cohort study

This study investigated the orbital morphological features that lead to fractures at different sites by comparing patients with isolated inferior wall fracture (IWF) to patients with isolated medial wall fracture (MWF). This study analyzed the orbital morphologic characteristics of all orbital fracture patients who underwent orbital computed tomography (CT) scans between January 2017 and October 2022. On CT scans, the bony structures of the orbit were measured. We investigated the bilateral symmetry of orbital. In addition, orbital morphological differences were compared between patients with fractures of the medial wall and those with fractures of the inferior wall. A total of 135 patients with orbital fractures were included in the study. Of these, 91 were isolated MWFs and 44 were isolated IWF. We confirmed the symmetry of bilateral orbits and measured the orbit of the uninjured side. No differences were found between the MWF group and the IWF group in terms of ocular prominence, horizontal orbital diameter, orbital rim angle, sagittal orbital depth, sagittal orbital depth, and angle of inferior wall inclination. The distance between the infraorbital nerve (ION) entry point and the orbital rim was significantly smaller in the inferior lateral wall fracture group than in the MWF group (11.87 ± 2.54 vs 14.90 ± 4.64, P < 0.001), and the percentage of type 1 ION was significantly lower in the IWF group than in the MWF group (40.9% vs 65.9%, P = 0.012). We demonstrated the symmetry of bilateral orbits and found that when the point where the ION enters the infraorbital canal is near the orbital rim, patients are more prone to suffering a fracture of the inferior wall after orbital trauma. It is less likely for patients with type 1 ION to suffer an IWF following an orbital fracture.