How are subaxial vertebral subluxations assessed in rheumatoid arthritis (RA) of the cervical spine?

Updated: Aug 13, 2019
  • Author: Steven R Garfin, MD; Chief Editor: Jeffrey A Goldstein, MD  more...
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Plain radiographs are also useful in detecting subaxial vertebral subluxations. Historically, these subluxations have been quantitated on lateral cervical radiographs as translation forward in millimeters or as a percentage slip of the total anteroposterior diameter of the inferior vertebral body. More recently, however, the sagittal diameter of the subaxial canal has been shown to correlate with the presence and degree of paralysis more often than does the percentage of vertebral slip. Patients with canal diameters of 13 mm or less are at higher risk for neurologic involvement.

The following image depicts a cervical radiograph from a patient with combined SMO and subaxial subluxation who underwent occipitocervical fusion and lateral mass plating.

Rheumatoid spondylitis. Occipitocervical fusion co Rheumatoid spondylitis. Occipitocervical fusion combined with lateral mass plating for a patient with combined superior migration of the odontoid and subaxial subluxation. Courtesy of Steven R. Garfin.

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