Author(s): Jennifer J.Mitchell, MD, FAAFP, CAQSM and Kelly T.Mitchell, MD
Description
- Fracture of the osseous walls of the orbit
- Orbital anatomy:
- Bony orbit is a conical structure:
- Base faces anterolaterally.
- Apex originates posteromedially.
- Seven bones: frontal, maxilla, zygoma, ethmoid, lacrimal, palatine, sphenoid
- Orbital roof:
- Forms floor of frontal sinus
- Orbital floor:
- Forms roof of maxillary sinus
- Most commonly fractured area of orbit
- Medial wall:
- Forms walls of ethmoid sinus, sphenoid sinus, and nasal cavity
- Second most frequently fractured area of orbit
- Lateral wall:
- Not bordered by a sinus
- Thickest and strongest of the orbital walls (1)
- Types of orbital fractures:
- Orbital rim: caused by direct blow to bony orbit
- Orbital wall: caused by blunt trauma to globe:
- Blowout fracture: most common; fracture fragment is directed away from the bony orbit.
- Blow-in fracture: trauma typically directed against frontal bone or maxilla; fracture fragment(s) is displaced toward the orbital space, decreasing the orbital volume (2).
- Trapdoor orbital fracture
- Pure orbital floor fracture, typically in pediatric patient
- Bony fragment displaces into maxillary sinus.
- Extraocular muscle(s) can become entrapped (inferior oblique or inferior rectus, most commonly).
- Usually, restriction of upward gaze occurs.
- Also called white-eyed blowout fracture due to minimal outward signs of trauma
- Significant oculocardiac reflex can occur (3,4).
Epidemiology
- ~1/3 of orbital blowout fractures are sustained during sport. Other causes include motor vehicle accidents, assaults, and falls.
- Eye injury is the second leading cause of visual impairment after cataract.
- 40% of monocular blindness is due to eye trauma.
- 57% of eye injuries were sustained by individuals <30 yr of age.
- Males sustain around 80% of eye injuries.
- 13% of serious eye injuries are related to sports and recreation.
- Estimated 1,400 of every 100,000 U.S. citizens will sustain an eye injury in their lives (5).
Incidence
Trauma to the eye represents ~3% of all emergency department (ED) visits in the United States.
Prevalence
- Around 2.5 million new eye injuries occur annually.
- Eye trauma is the cause of 40,000 to 60,000 new cases of blindness each year.
- Annually, ~11,000 eye injuries sustained by children are caused by toys or home playground equipment (5).
Etiology and Pathophysiology
- Blowout fractures:
- Occur along medial wall and/or orbital floor
- Orbital rims are intact.
- Two proposed theories (3):
- Hydraulic theory:
- Blunt object of larger than diameter of the orbital entrance strikes the eye.
- Compresses globe, resulting in sudden increase in intraorbital hydraulic pressure
- Globe does not rupture.
- Increased intraocular pressure dissipates via soft tissues to weakest portions of orbit: posteromedial orbital floor, lamina papyracea of ethmoid bone, or medial orbital wall.
- Buckling theory:
- Fractures occur as a result of direct trauma to the inferior orbital rim.
- Causes buckling of the orbital floor
- Thinnest area fractures
Risk-Factors
- Most common causes of orbital fracture:
- Sporting events/falls/assaults
- Sports most commonly associated with orbital fracture in the United States:
General Prevention
- Use of eye protection for any sport where an object or another participant may impact the globe
- Monocular athlete should always wear polycarbonate eye protection in American Society for Testing and Materials (ASTM)-approved frames (1).
Commonly Associated Conditions
- Ocular injury is associated with blowout fracture 1440% of the time.
- Potential associated injuries:
- Mild ocular injuries:
- Vision-threatening injuries:
- Injuries to ocular adnexa:
- Eyelid contusion ± ecchymosis
- Eyelid laceration ± margin involvement
- Canthal injury, laceration, or avulsion
- Traumatic ptosis
- Intracranial injuries:
- Pneumocephalus
- Cerebral injury
- Cerebrospinal fluid leak
- Delayed complications: