Abstract
OBJECTIVE
Though the medial wall of orbit is thinnest, the orbital floor is more frequently fractured. However, the frequency of medial wall fracture is also increasing recently, with the development of imaging technology. This study investigates the morphologic properties of orbital wall and ethmoid sinus affecting the site of blow-out fractures.
METHOD
150 patients with periorbital trauma who underwent computed tomography (CT) scans from October 2006 to June 2009 were reviewed. On CT scans, the size of the fracture, the length and height of the lamina papyracea, the number of ethmoid air cell septa, the septal length, the septal angle, and the area of ethmoid sinus were measured. We measured the morphologic parameters from the opposite site in patients with fractures in whom it was difficult to visualize the structures at the fractured site.
RESULTS
In 50 patients without orbital wall fractures, there were no bilateral differences in the measured parameters of lamina papyracea and ethmoid sinus. The number of ethimoid air cell septa (2.640.75 vs 3.180.69) and the septal angle (66.0815.38 vs 75.9610.34) were significantly lower in patients with medial wall fractures. In addition, the lamina papyracea area supported per ethmoid air cell septum (536.66194.90 vs 429.98100.48) and the area of ethmoid sinus (51.0810.71 vs 44.465.94) was significantly higher in patients with medial wall fractures than in those with inferior wall fractures.
CONCLUSION
Patients with fewer ethmoidal bony septa, a larger supporting lamina papyracea per septum, a larger area of ethmoid sinus, and an acute angle of ethmoid bony septa would tend to develop medial wall fractures, rather than inferior wall fractures.