Retrospective Cohort Study of Frequency and Patterns of Orbital Injuries on Whole-Body CT with Maxillofacial Multi-Slice CT

Abstract

Background: High-impact trauma frequently leads to injuries of the orbit, but literature focusing on the viscerocranium rather than the neurocranium is underrepresented. Methods: Retrospective cohort study (2006-2014) at an urban level 1 trauma center assessing the frequency and typical patterns of orbital injuries on whole-body computed tomography (WBCT) with maxillofacial multi-slice CT (MSCT) after severe trauma. (1) Screening of consecutive WBCT cases for dedicated maxillofacial MSCT. (2) Examination by two independent experts' radiologists for (peri-/)orbital injuries. (3) Case review for trauma mechanisms. Results: 1061 WBCT were included revealing 250 (23.6%) patients with orbital injuries. Less than one-quarter (23.3%) of patients showed osseous and 9.5% showed soft tissue injuries. Combined osseous and soft tissue lesions were present in 39.2% of orbital injuries, isolated soft tissue injuries were rare. Single- or two-wall fractures of the orbit were prevalent, and the orbital floor was affected in 67% of fractures. Dislocated extraocular muscles (44.6%), deformation of the ocular globe (23.8%), and elongation of the optic nerve (12.9%) were the most frequently soft tissue findings. Vascular trauma was suspected in 15.8% of patients. Conclusions: Orbital trauma was confirmed in 23.6% of cases with suspected facial injuries after severe trauma. Concomitant soft tissue injuries should be excluded explicitly in cases with orbital fractures to prevent loss of vision or ocular motility.

Keywords: emergency imaging; maxillofacial; orbital soft tissue injury; orbital trauma; polytrauma.

Figure 1

Study protocol visualizing the workflow according to the recommendations of the STROBE—Strengthening the Reporting of Observational Studies in Epidemiology Initiative [19] showing patient screening, inclusion, exclusion, and the results of analysis by two neuroradiologists (WBCT = whole-body CT, MSCT = multi-slice CT).

Figure 2

(a–c) Dislocated extraocular muscles. CE-MSCT, soft tissue window, coronal reformations. (a) Dislocation of the left inferior rectus muscle (white solid arrow) due to orbital floor fracture. Asterisk indicates orbital emphysema. (b) Displacement of the right superior rectus muscle (solid white arrow) with orbital roof fracture (white outlined arrow) and intraorbital hemorrhage (asterisk). Concomitant left hematosinus maxillaris due to midface fractures. (c) Right inferior rectus muscle (white solid arrow) incarcerated in a so-called “trapdoor fracture” of the orbital floor. (d,e) Extraocular muscles pierced by bone fragments. CE-MSCT, soft tissue window. (a) Axial reformation. Left lateral rectus muscle pierced by a fragment of the greater sphenoid wing (white arrow). (b) Sagittal reformation. Right superior rectus muscle pierced by a frontal bone fragment (white arrow), which also displaces the optic nerve (CE-MSCT = contrast-enhanced multi-slice CT).

Figure 3

(a,b) Orbital compartment syndrome after blow-in fracture of the left orbital floor. NE-MSCT (a) Soft tissue window, axial reformation. Mass effect of a dislocated orbital floor fragment leading to left-sided exophthalmos with elongation of the optic nerve and deformation of the ocular bulb (globe tenting, indicated by hollow arrow). The posterior globe angle is reduced to 117° in the left globe, compared to 139° on the right side. Asterisk indicates intraconal air bubbles. (b) Bone kernel, coronal reformation. Solid arrow indicates the orbital floor fragment which is dislocated upwards into the orbital cavity. (c,d) Complete rupture of the left globe with irregular shape, volume loss, and air bubbles in the anterior chamber. NE-MSCT, soft tissue window in (a) Axial and (b) coronal reformation (NE-MSCT = non-contrast-enhanced multi-slice CT).

Figure 4

Dislocated left lens (indicated by arrow) and lateral rotation of about 70 degrees. Asterisk (*) indicates periorbital soft tissue emphysema due to a concomitant orbital floor fracture. NE-MSCT, soft tissue window, axial reformation (NE-MSCT = non-contrast-enhanced multi-slice CT).

Figure 5

Elongated optic nerves associated with traction trauma. NE-MSCT, soft tissue window, axial plane. (a) The left optic nerve (white arrow) appears elongated and hyperdense due to intraneural bleeding. (b) Swelling and deformation of the right optic nerve (white arrow) and retrobulbar hematoma (asterisk) in a complex midface fracture involving all orbital walls (NE-MSCT = non-contrast-enhanced multi-slice CT).

Figure 6

Prominent right ophthalmic vein (white arrows). Compared to the contralateral vein, the vessel appears engorged. CE-MSCT, soft tissue window. (a) Axial reformation. (b) Engorged superior ophthalmic vein and exophthalmos of the right globe hinting at post-traumatic CCF (CE-MSCT = contrast-enhanced multi-slice CT, CCF = carotis-cavernous fistula).

Figure 7

Intraorbital foreign bodies. NE-MSCT, bone window, axial reformation. (a) Metallic foreign body (white arrow) within the right lateral rectus muscle. (b,c) Multiple metallic foreign bodies in one patient (b) near the left optic nerve (white arrow) and (c) within the rear wall of the ocular globe (white arrow). (d,e) Wooden foreign body in the right orbit (white arrows) piercing through the orbital floor into the right maxillary sinus. Concomitant hematosinus and pronounced proptosis due to retrobulbar hematoma and swelling. Hypodense air bubbles entrapped within the otherwise undetectable dry wood. NE-MSCT, bone window and bone kernel in (d) sagittal and, (e) axial reformation (NE-MSCT = non-contrast-enhanced multi-slice CT).

Figure 8

Exemplary protocol for diagnosis and treatment of orbital injuries. The figure highlights the importance of thorough initial clinical and radiological examinations and of an ongoing surveillance for delayed clinical sings of orbital injuries to allow for prompt or early imaging via CT, MRI, or cerebral angiography in the acute and subacute phase after severe trauma (WBCT = whole-body CT, CSF = cerebrospinal fluid, CCF = carotid-cavernous fistula).