Evaluation of coronal CT findings of rare cases of isolated medial orbital wall blow-out fractures.

OBJECTIVES: To report rare cases of isolated medial orbital wall blow-out fractures and to evaluate their coronal CT findings.

METHODS: Nine cases of medial orbital wall blow-out fractures, diagnosed by coronal CT in a general medical hospital between 1995 and 1999, were studied. CT was performed using direct coronal acquisition with a slice thickness of 5 mm. Images were obtained at bone window settings. Clinical examination findings from the medical records were used to give information on the cause of injury, ocular symptoms and the days after injury that the CT examination was performed.

RESULTS: Most of the patients (67%) were young male adults. The cause of injury was most frequently the result of fist fighting or athletics (78%). Diplopia and/or limitation of the gaze were the main ocular symptoms (78%). The average time from injury to CT examination was 4 days (range 0-16 days). Seven of the nine patients with medial orbital wall fractures had isolated medial orbital wall blow-out fractures. Herniation of orbital contents toward the ethmoid sinus was observed among all nine fractures. Only three patients (33%) had a swelling and/or medial deviation of the medial rectus muscle, all three having isolated medial orbital wall blow-out fractures.

CONCLUSIONS: Nine cases of medial orbital wall blow-out fractures were examined, seven of which were isolated medial wall blow-out fractures. CT findings of this type of fracture included herniation of the orbital contents toward the ethmoid sinus. However, swelling and/or medial deviation of the medial rectus muscle was also seen.