Orbital roof fracture

Orbital roof fractures may be blow-in or blow-out. In a blow-out fracture of the orbital roof, the fracture fragment is displaced into the anterior cranial fossa. A dural tear resulting in a CSF leak may be present in either type of orbital roof fracture. Most orbital roof fractures are blow-in fractures (displacement of the bone is towards the orbit), frequently causing downward and forward globe displacement.

Clinical diagnosis is based on a meticulous examination of the eye, including the patient's vision and palpation of the orbital rims. Since the advent of CT imaging, the surgeon can better define fractures, the degree of fracture displacement, and the necessity for fracture reduction. CTs should be obtained in the axial coronal planes and sagittal views such as those obtained in the longitudinal axis of the optic nerve.

The complexity of an orbital fracture is defined by the combination of its anterior-posterior and mediolateral extensions. This complexity is not visible on plain films. Therefore, proper diagnosis and treatment should be based on voxel-based datasets (CT, cone beam).

Intra-/periorbital air is a common feature of an orbital wall fracture, which appears clinically as emphysema (independent of whether the injury was penetrating or nonpenetrating).

The most widely available technology is CT scanning, which has the advantage of combined hard- and soft-tissue visualization. Cone beam technology is becoming increasingly popular, although only hard tissues can be reliably assessed. MRI is limited to soft-tissue visualization and provides only indirect information on hard tissues. It is rarely obtained for specialized evaluation of orbital soft tissue.

In some cases, it is difficult to appreciate the fracture's full extent, morphology, and quality from the CT scan alone. In very complex cases, a complete understanding of the fracture is obtained only after surgical exposure.

The following diagnostic procedures can be performed if there is a suspected CSF leak (clinical sign: straw-colored nasal drainage):

• Application of fluorescent dyes
• Comparison of the concentration of glucose between fluid and patient’s serum
• Laboratory analysis for beta-2 transferrin
• Specialized neuroradiological imaging with intrathecal contrast medium

Sagittal slices (hard-tissue window) of an isolated right orbital roof fracture demonstrating displacement of the bone towards the orbit causing downward and forward globe displacement.

Coronal slices (hard-tissue window) of the same isolated right orbital roof fracture.

Coronal view of an orbital roof fracture.

Muscle entrapment can occur between bone fragments.

In orbital roof fractures displaced bone fragments may damage extraocular muscles.

Orbital roof fractures are commonly part of an extensive frontal bone fracture such as the one shown in this image.