Atlantoaxial Instability Differential Diagnoses

Updated: Jun 06, 2022
  • Author: Daniel P Leas, MD; Chief Editor: Jeffrey A Goldstein, MD  more...
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Diagnostic Considerations

The presence of previously defined radiographic findings (anterior atlantodental interval [AADI] >3 mm in adults or >5 mm in children) is diagnostic of atlantoaxial instability (AAI) or atlantoaxial subluxation (AAS). Patients who present with acute neurologic symptoms that raise concerns for cervical compression or neck pain but are without a known source should undergo a thorough physical examination and radiographic evaluation to determine the source.

Findings are generally nonspecific and can be representative of any number of related conditions, including the following:

  • Cervical strain
  • Cervical trauma or fracture
  • Occipital headaches
  • Degenerative disease of the spine
  • Previously undiagnosed syndrome

Children in particular should be screened for previously undiagnosed syndromes or conditions should they present with AAI or AAS without a definitive source (eg, trauma). Even with a recent history of oropharyngeal infection that could lead to Grisel syndrome, the child should be followed closely to ensure that neurologic symptoms do not develop and that the subluxation resolves.