Odontoid fracture

Background

The three types of odontoid fracture. Type II and type III are unstable fractures.

• Fracture of C2 (dens)
• Bimodal age distribution
  • Young - injury secondary to blunt trauma to head or flexion/extension injury
  • Elderly - injury secondary to fall, higher morbidity/mortality than young patients
    • Increased risk of fracture due to bone loss, which is disproportionate at C2 relative to rest of skeleton
• Frequently associated with other cervical spine injuries
• 25% associated with neurologic injury/deficit
• Os odontoideum (normal variant) can look like a Type II odontoid fracture on imaging, causing false postive

Types

• Type I: Oblique avulsion fracture of tip of odontoid; alar ligament avulsion
  • Stable fracture
• Type II: Fracture at base of odontoid where it meets C2 body
  • Unstable fracture
  • High risk of nonunion (30%) due to interruption of blood supply
• Type III: Extension of the fracture through upper portion of body of C2
  • Unstable fracture

Vertebral fractures and dislocations types

Vertebral anatomy.

Numbering order of vertebrae.

• Cervical fractures and dislocations
  • Atlanto-occipital dissociation
  • C1
    • Jefferson fracture
    • C1 isolated anterior arch fracture
    • C1 isolated posterior arch fracture
  • C2
    • Odontoid fracture
    • Hangman's fracture
  • C3-C7
    • Cervical burst fracture
    • Cervical spinous process fracture
    • Extension cervical teardrop fracture
    • Flexion cervical teardrop fracture
    • Anterior cervical wedge fracture
  • Cervical facet dislocation
  • Isolated transverse process fracture
• Thoracic and lumbar fractures and dislocations
  • Chance fracture
  • Thoracic burst fracture
  • Lumbar burst fracture
  • Isolated transverse process fracture
  • Thoracic and lumbar compression fractures

Clinical Features

• Neck pain
• May have neurologic deficit

Differential Diagnosis

Neck Trauma

• Penetrating neck trauma
• Blunt neck trauma
  • Vertebral and carotid artery dissection
  • Strangulation
  • Whiplash injury
• Cervical injury
  • Cervical fractures and dislocations
  • Cervical injury (peds)
  • Cervical spine clearance
• Neurogenic shock
• Spinal cord injury

Evaluation

• CT is the imaging study of choice
• Cervical spine x-ray may be performed if CT unavailable
  • Must include open-mouth odontoid view

Management

• Cervical spine motion restriction via hard cervical collar
• Consult spine surgery

Disposition

• Admit
• May consider discharge with hard cervical collar for Type I fracture (stable)
  • Consider only in consultation with spine surgery service

See Also

• Cervical spine fractures and dislocations