Odontoid fracture

Background

• Also known as dens fracture
• Only stable if fracture confined to avulsion of the tip (superior to transverse ligament)
• Bimodal distribution
  • Young - blunt trauma to head, flexion/extension injury
  • Elderly - fall, with higher morbidity/mortality
• False positives
  • Dens and vertebral body are connected by cartilage at young age, and do not fuse until 3-6 yoa (up to 11 yoa)
  • Os odontoideum - normal variant

Clinical Features

• Frequently involves other cervical spine injuries
• 25% associated with neurologic injury

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

Diagnosis

• Imaging
  • Xray: AP, lateral, open-mouth odontoid view of cervical spine
  • CT for further assessment if fracture identified

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

Management

• Observation for:
  • Os odontoideum
  • No neuro deficits
• Hard C-collar for 6-12 wks for:
  • Type 1 and 2 non-surgical candidates
  • Partial fibrous union
• Prehospital Immobilization see NAEMSP National Guidelines for Spinal Immobilization
• Consult ortho/neurosurgery/trauma

See Also

• Cervical spine injuries