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
• 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
  • Atlanto-occipital instability (AAI) should be ruled out with flexion and extension films
  • AAI requires surgical management
• Type II: Fracture at base of odontoid process where it attaches to C2; Fracture through waist
  • Unstable
  • High nonunion rate due to interruption of blood supply
    • Young: Halo if no risk factors for nonunion, Surgery if risk factors for nonunion
    • Elderly: Collar if not surgical candidates, Surgery if surgical candidates
• Type III: Extension of the fracture through upper portion of body of C2
  • Unstable

Clinical Features

• Neck pain
• May have neurologic deficit

Differential Diagnosis

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

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). Must be done in consultation with spine surgery.

See Also

• Cervical spine injuries