A case of acquired Brown syndrome after surgical repair of a medial orbital wall fracture

Abstract

A case of acquired Brown syndrome caused by surgical repair of medial orbital wall fracture is reported in the present paper. A 23-year-old man presented at the hospital with right periorbital trauma. Although the patient did not complain of any diplopia, the imaging study revealed a blow-out fracture of the medial orbital wall. Surgical repair with a calvarial bone autograft was performed at the department of plastic surgery. The patient was referred to the ophthalmologic department due to diplopia that newly developed after surgery. The prism cover test at distant fixation showed hypotropia of the right eye, which was 4 prism diopters (PD) in primary gaze, 20 PD in left gaze, while orthophoric in right gaze. Eye movement of the right eye was markedly limited on elevation in adduction with normal elevation in abduction with intorsion in the right eye present. Forced duction test of the right eye showed restricted elevation in adduction. Computerized tomography scan of the orbits showed the right superior oblique muscle was entrapped between the autografted bone fragment and posterior margin of the fracture. When repairing medial orbital wall fracture that causes Brown syndrome, surgeons should always be careful of entrapment of the superior oblique muscle if the implant is inserted without identifying the superior and posterior margin of the orbital fracture site.

Keywords: Acquired Brown syndrome; Blow-out fracture; Ocular motility disorders; Orbital fractures; Superior oblique muscle entrapment.

Fig. 1

A computerized tomography scan was performed before surgery and showed a medial orbital wall fracture (arrow).

Fig. 2

Postoperative computerized tomography scan of the orbits showed the right superior oblique muscle was entrapped between the autografted bone fragment and posterior margin of the fracture (arrow).

Fig. 3

After repair of the blow-out fracture, limitation of elevation in adduction of the right eye developed (arrow) while elevation in abduction was normal.

Fig. 4

Fundus examination showed intorsion of the right eye.