Imaging the Tight Orbit: Radiologic Manifestations of Orbital Compartment Syndrome.

background and purposeOrbital compartment syndrome is a sight-threatening emergency caused by rising pressure inside the orbit. It is usually diagnosed clinically, but imaging might help when clinical findings are inconclusive. This study aimed to systematically evaluate imaging features of orbital compartment syndrome. MATERIALS AND

methodsThis retrospective study included patients from 2 trauma centers. Proptosis, optic nerve length, posterior globe angle, morphology of the extraocular muscles, fracture patterns, active bleeding, and superior ophthalmic vein caliber were assessed on pretreatment CT. Etiology, clinical findings, and visual outcome were obtained from patient records.

resultsTwenty-nine cases of orbital compartment syndrome were included; most were secondary to traumatic hematoma. Pathologies occurred in the extraconal space in all patients, whereas intraconal abnormalities occurred in 59% (17/29), and subperiosteal hematoma in 34% (10/29). We observed proptosis (affected orbit: mean, 24.4 [SD, 3.1] mm versus contralateral: 17.7 [SD, 3.1] mm;

conclusionsOrbital compartment syndrome is characterized by proptosis and optic nerve stretching. In some cases, the posterior globe is deformed. Orbital compartment syndrome can be caused by an expanding pathology anywhere within the orbit with or without direct contact to the optic nerve, confirming the pathophysiologic concept of a compartment mechanism.