1. Radiologic Assessment of Orbital Trauma
Lani Hoang, MS IV
Radiology
February 23, 2007

2. Orbital Trauma Commonly associated with craniofacial trauma
Mechanism: MVA, violence, falls
Predominantly affects young adult males

3. Assessment of Orbital Trauma
Check ABC’s
History of mechanism of injury
Signs & Symptoms:
Varies but look for s/s suggestive of severe injury, including diplopia, visual loss, ptosis, lid laceration, subconjunctival hemorrhage, periorbital ecchymosis or infraorbital anesthesia
Ophthalmologic examination:
visual acuity, pupil reaction, motility, sensation, globe position, lid function, integrity of globe and fundoscopy
Imaging…

4. Important Considerations during assessment of Orbital Trauma
Open Globe
Retrobulbar hemorrhage or compartment syndrome
Foregin Body
Other Significant Head/Neck Injuries

5. Indications for further Imaging
Significant blunt or penetrating trauma
Suspected Orbital Fractures
Suspected Foreign Bodies
Suspected Open Globe
X-ray vs CT vs MRI????

6. (Obtain CT with ≤3mm axial cuts & with coronal images)
Imaging
CT: #1 choice for acute orbital trauma
(Obtain CT with ≤3mm axial cuts & with coronal images)
MRI: complementary role to CT in the evaluation of subacute orbital trauma
Plain film: no primary role

7. CT in Acute Orbital Trauma
Advantages:
Relatively fast
No contraindications for metallic foreign body
Excellent bony detail to identify fractures
Hemorrhages easily identified
Visualization of globe injuries, such as lens dislocation
Able to monitor unstable patients during CT
Disadvantages:
May require hyperextension of the head for coronal images (however this may be obtained by reconstructed images)

8. MRI in Subacute Orbital Trauma
Advantages:
Images in multiple planes (good for surgical planning)
Detection of fat herniations into the paranasal sinus
Distortion, avulsion or herniation of extraocular muscles are well demonstrated by MR
MR is best for evaluating chronic orbital soft tissue trauma and chronic hemorrhage
Disadvantages:
Poor detection of focal acute hemorrhage in orbit
Poor depiction of subtle bony detail
Contraindicated if metallic foreign body in orbit

9. (Caldwell, Waters, optic canal, lateral and basal)
Plain x-ray films
Not recommended for primary investigation of acute orbital trauma
May miss 5 to 10% of orbital wall fractures
Images inferior to CT
If only X-ray is available, request standard plain film views of the orbit
(Caldwell, Waters, optic canal, lateral and basal)

10. Type of Orbital Injury Depends on site of impact
Depends on nature of Injury:
- blunt injury
- pentrating/lacerating/sharp injury
- chemical/burn injury
+/- propagation of injury
Can result in orbital wall fracture and/or soft tissue injury to the globe, optic nerve and orbital soft tissues

11. Orbital Foreign Body
CT may miss nonmetallic foreign bodies, such as wood or plastics
CT should be performed in at least 1.5-mm thin axial cuts to detect small foreign bodies reliably
Additional planes of imaging are also helpful, particularly oblique sagittal views oriented along the optic nerve.
Intraocular air seen on CT should cause suspicion of penetrating injury with a potential foreign body

12. Open Globe Globe injury can manifest as penetrating or blunt injury.
“Flat-tire” appearance of a shrunken and irregular contoured globe is classic appearance on CT
A normal-appearing CT scan does not rule out an open globe

13. Orbital Fracture in Detail
Blow-out Fracture – medial wall and floor
Lateral Wall Fracture
Roof Fracture
Combined Fractures – tripod, nasoorbital and LeFort I-III

14. Blow-out Fracture Most common orbital fracture
Mechanism: blunt trauma compresses orbital contents, raising intraorbital pressure, which then fractures weakest region of orbit: medial wall and/or floor
Coronal CT demonstrates blow-out fracture involving inferiororbital wall

15. Coronal CT demonstrating tripod fracture of the lateral wall
Lateral Wall Fracture
Rare since lateral wall is thick and strong
Mechanism: direct lateral blow, also known as “blow-in” fracture when displaced toward orbital space
Commonly associated with diastasis of the frontozygomatic suture and displacement or fracture of the zygomatic arch
Coronal CT demonstrating tripod fracture of the lateral wall

16. Coronal CT demonstrating orbital roof fracture
Rare since superior orbital rim is strong & well-supported
Mechanism: severe blunt trauma (ie MVA)
Potential communication between the orbit and anterior cranial fossa - consult neurosurgery
Coronal CT demonstrating orbital roof fracture

17. Combined Fractures
Tripod Fracture: force to malar eminence results in separation of the zygoma from its maxillary, frontal and temporal attachments
LeFort Types II & III: symmetric orbitomaxillary fractures that extend posteriorly, typically involving the pterygoid plates and pterygomaxillary fossa
Nasoorbital Fractures: Ant  Post force (dashboard injury) pushes medial wall posteriorly

18. LeFort Type II & III Fractures
LeFort II LeFort III

19. Other Complications to Consider
Entrapment of soft tissue
Intraocular injury – hyphema, angle recession, retinal detachment, iris disruption, lens dislocation, glaucoma, cataract, etc…
Traumatic optic neuropathy
Enophthalmos of the globe – may occur immediate from herniation of orbital fat or subacutely after atrophy/scarring of the soft tissue
Diplopia – can be caused by direct neuromuscular damage, entrapment of extraocular muscles or swelling of orbital contents
Retrobulbar Hemorrhage
Arteriovenous fistula

20. Conclusion
Orbital trauma commonly occurs in association with craniofacial trauma
Perform ophthalmologic exam
CT is modality of choice for imaging acute orbital trauma
Consider consultation if suspect ocular or brain injury

21. References
Green, AD. Maxillofacial trauma. Imaging of Head Trauma. New York, Raven Press, 1994, pp
Kousobris, PD & Rosman, DA. Radiologic Evaluation of lacrimal and orbital disease. Otolaryngolgic clinics of North America 39, 2006.
Mauriello, JA, Gonzalez, CF, Grossman CB et al. Orbital trauma. Diagnostic Imaging in Ophthalmology. New York, Springer-Verlag, 1986, pp
Mazock, JB, Schow, SR, Triplett RG. Evaluation of ocular changes secondary to blowout fractures. Journal of Oral and Maxillofacial Surgery 62: , 2004.
Pelletier, CR, Jordan, DR, Braga, R, McDonald, H. Assessment of ocular trauma associated with head and neck injuries. The Journal of Trauma – Injury, Infection & Critical Care 44: , 1998.
Vaughan, DG, Asbury, T, Riordan-Eva, P. General Ophthalmology. Norwalk, Appleton & Lange, 1992.