Orbital Fractures

Overview

Definition

An orbital fracture is a broken bone involving the eye socket, either in the orbital rim, the orbital floor, or both.

Epidemiology

• Orbital fractures account for approximately 3% of all patients seen in the ED.
• More common in men than in women (4:1)
• More common in adults than in children
• Average age: 30 years

Etiology

• The most common cause of orbital fractures is blunt force trauma to the eye.
• About 85% of traumatic eye injuries (including orbital fractures) are caused by:
  • Auto accidents: most common cause of maxillofacial trauma
  • Contact sports
  • Occupational accidents
  • Home repair projects
• About 15% are due to violent assaults.
• For fractures in adult women, it is important to assess for domestic violence. 

Anatomy and Pathophysiology

To understand the pathophysiology of orbital fractures, it is important to understand the anatomy of the orbit, the clinical presentation, and the potential consequences of fractures.

Anatomy

The 7 bones of the orbit are:

• Maxilla
• Zygomatic
• Frontal
• Ethmoid
• Lacrimal 
• Sphenoid
• Palatine 

The walls of the orbit are: 

• Superior (roof): made up of the orbital part of the frontal bone and the lesser wing of the sphenoid
• Medial: made up of the frontal process of the maxilla, the lacrimal bone, the orbital plate of the ethmoid bone, and the sphenoid body
• Inferior (floor): made up of the maxillary, zygomatic, and palatine bones
• Lateral: made up of the greater wing of the sphenoid, the orbital part of the frontal bone, and the frontal process of the zygomatic bone

Pathophysiology

There are 4 main types of orbital fractures, which are classified on the basis of the anatomy involved.

• Orbital zygomatic fracture: 
  • Zygomatic region of the orbit is the most common location of an orbital rim fracture.
  • Most common cause: a high-impact blow to the lateral orbit
• Nasoethmoid fracture: 
  • Fracture of the medial wall of the orbit
  • Often associated with fractures of the orbital floor
  • Due to direct force applied to the nasal bone
• Orbital roof fracture:
  • Location: frontal bone (roof of the orbit)
  • Frequently associated with intracranial injuries 
• Orbital floor fracture: 
  • “Blowout fracture”
  • Location: maxillary, zygomatic, and palatine bones 
  • Ocular motility may be disrupted, as orbital tissue is commonly involved.

Clinical Presentation

In a patient presenting with possible orbital fractures, it is important to identify life-threatening and/or serious associated injuries, especially intracranial injury and cervical spine fractures.

History and symptoms

• History of blunt (more common) or penetrating trauma
• Diffuse orbital pain 
• Pain on movement of the eyes suggests injury to the extraocular muscles.
• Diplopia on upward gaze suggests injury to the orbital floor.
• Numbness of the forehead suggests injury to the orbital roof.
• Nausea can be caused by entrapment of extraocular muscles.

Physical examination findings

• Periorbital edema
• Ecchymosis 
• Diplopia: due to mechanical entrapment of both inferior oblique and inferior rectus muscles
• Absent pupillary light reflex if damage to the afferent nerves
• Enophthalmos: posterior displacement of the eyeball within the orbit, seen in blowout fractures
• Proptosis: protrusion of the eyeball, seen in orbital zygomatic fractures
• Widened intercanthal distance due to disruption of the medial canthal ligament
• Bradycardia: associated with the “oculocardiac reflex” (a reduction in pulse rate associated with pressure applied over extraocular muscles)

Diagnosis

Ocular injuries are present in up to 29% of patients with orbital fractures. It is imperative that an ocular exam be done as soon as possible to mitigate the risk of vision loss.

Ocular examination

• Visual acuity
• Ocular motility
• Intraocular pressure
• Slit-lamp examination to visualize any retinal damage
• Visual field examination

Imaging

• X-ray:
  • Screening to identify fractures
  • Water’s view (also known as the occipitomental view): X-ray beam is angled at 45 degrees and shows “teardrop sign” in antrum.
• CT scan:
  • Gold standard for detection of orbital fractures
  • Thin slices < 2 mm are preferred. 
  • Coronal and sagittal views differentiate between periorbital edema and entrapment of intraocular structures.
• MRI:
  • Determines the extent of soft tissue injury 
  • Assesses damage to the vessels

Management and Complications

Orbital fractures are facial injuries and should be managed emergently. Delay in diagnosis may lead to complications or postoperative complications.

Management

Supportive management:

• Stabilize airway.
• Ensure hemodynamic stability.
• IV fluids
• Pain and nausea medications
• Elevate head. 
• Evaluate for:
  • Cervical spine integrity
  • Possible head injuries 
  • Soft tissue and bone injuries in the head and neck

Empiric management:

• Antibiotics to cover sinus pathogens
• Advise the patient not to blow the nose, in order to avoid air in the orbital cavity. 
• Reduce periorbital edema:
  • Cold compresses 
  • Oral steroids

Urgent ophthalmology consult if:

• Evidence of globe injury: seen in 30% of orbital fractures
• Decreased visual acuity
• Widened intercanthal distance
• Evidence of orbital compartment syndrome: 
  • Decreased retropulsion
  • “Rock hard” eyelids
• Open globe
• Severe vagal symptoms

Surgery to reduce the fracture and prevent future deformities:

• May be deferred up to 14 days if periorbital edema interferes with visualization and assessment
• Is advised for patients with:
  • Orbital hematoma
  • CSF leakage
  • Globe displacement: exophthalmos or proptosis
  • Entrapment of infraorbital structures leading to the oculocardiac reflex

Commonly used implants for reconstruction are:

• Bone autograft:
  • Provides good strength for reconstruction 
  • Commonly used in children < 7 years of age
• Cartilage: 
  • Most biocompatible
  • Undergoes easy resorption 
  • Most commonly used for small fractures
• Alloplast:
  • Titanium mesh: used for large floor defects
  • Porous polyurethane: used for defects with well-defined edges
  • Resorbable sheeting: used in small gaps with well-defined edges

Complications

Complications arising from orbital fractures can be due to the injury itself or to surgery.

Injury-related complications:

• Ruptured globe
• Orbital hematoma
• Optic nerve sheath hematoma
• Retinal detachment
• Hyphema
• Muscle entrapment
• Orbital compartment syndrome

Surgical complications:

• Intraoperative complications: 
  • Globe and optic nerve injury 
  • Inadequate removal of prolapsed tissue
  • Hemorrhage
• Postoperative complications:
  • Permanent vision loss
  • Persistent diplopia
  • Infection
  • Implant extrusion or malposition