Atlantoaxial subluxation/dislocation

• Pain, neurological deficit, deformity

  A. Mechanical compression

  B. Instability – microtrauma

  C. Changes in vascular and CSF Dynamics

  

• Aetiologies of IAAD and its related issues
  • Congenital IAAD
    • Osseous
    • Neural
    • Vascular

  – Missing bone / Abn. alignment

  – Abn. Assimilation – Neu. Comp.

  • Acquired pathologies
    • Trauma – malunited fracture
    • Infection – healed T.B in deformed position
    • Degenerative – Arthritis (O–C1–C2) ankylosed in malposition

Analyse →

– Neural compression & instability

– Issues of implant purchase

– Available bone for fusion

• Irreducible AAD
  • It fails to get reduced radiologically by
    • Positional manoeuver
    • Traction
    • Under anaesthesia
  • Tight and contracted soft tissue, anomalous bony block
  • Akin to long standing neglected dislocation of peripheral joints

• Srivastava et al 2016
  • All irreducible AADs can be converted to reducible AAD by anterior release
  • There is no difference in reducibility of AAD whether anterior release is done by trans-oral or extra-pharyngeal approach
• General
  • Lower morbidity and mortality than atlanto-occipital dislocation
  • C1- C2 instability (atlantoaxial subluxation) results from destruction of the transverse, apical, and alar ligaments
  • 3 types
    • Rotatory: usually seen in children after a fall or minor trauma
    • Anterior: more ominous
    • Posterior: rare. Usually from erosion of odontoid. Unstable. Requires fusion