Purpose: To evaluate morphologic differences in isolated inferior medial orbital wall fractures (OWF) based on computed tomography scans.
Methods: This was a retrospective observational case study of 22 patients with an isolated inferior OWF and 32 patients with an isolated medial fracture between January 2008 and August 2010. We analyzed patient demographics and bony radiologic characteristics on CT scans, including the length and height of the lamina papyracea, the number of ethmoid air cell septa, the length of the anterior and posterior border of the orbital floor, the thickness of the orbital floor maxillary bone, and the axial length of the eyeball.
Results: There were no significant differences in sex, laterality, or concomitant intraocular injury between the two groups. The anteroposterior length (p = 0.391), the number of ethmoid septa (p = 0.869), and the thickness of the orbital floor (p = 0.419) did not differ significantly. The anterior (p < 0.001) or posterior (p = 0.014) height of the lamina papyracea, the lamina papyracea area (p < 0.001), and the lamina papyracea area/ethmoid air cell septa (p = 0.024) were significantly higher in the medial OWF group, while the anterior (p = 0.026) or posterior (p < 0.001) border length of the orbital floor and the axial length (p = 0.047) and volume (p = 0.034) of the eyeball were longer and smaller, respectively, in the inferior OWF group.
Conclusions: Patients with a longer anterior or posterior border of the orbital floor, a shorter axial length, and a smaller eyeball volume are more likely to incur an isolated inferior OWF than an isolated medial OWF.
Keywords: Axial length; blow-out fracture; ocular trauma; orbit; orbital wall fracture.