An 80-year-old woman falls at home and presents with neck pain. CT demonstrates a fracture through the base of the odontoid process, separate from the body of the axis, with 4 mm of displacement. This fracture pattern is associated with which well-known problem?

• A High incidence of associated vertebral artery transection at the foramen transversarium of C1
• B Uniformly excellent union with collar immobilisation alone
• C High rate of nonunion due to a tenuous retrograde blood supply ✓
• D Inevitable progression to basilar invagination regardless of treatment

Explanation

Anderson and D'Alonzo type II odontoid fractures occur at the junction of the dens with the body of the axis and carry the highest nonunion rate of cervical spine fractures because the blood supply reaches the dens retrogradely from its base, which the fracture disrupts. Displacement worsens the outlook, so displaced fractures in the elderly are frequently managed with posterior A1-A2 fusion rather than halo immobilisation. Type III fractures, through the axis body, unite reliably.

Reference: Apley's System of Orthopaedics and Fractures, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.