Sensitivity of lateral view cervical spine radiographs taken in the neutral position in atlantoaxial subluxation in rheumatic diseases

The value of lateral view cervical spine radiography in various positions of the neck was assessed in patients with rheumatoid atlantoaxial subluxation (AAS). We wanted to find out how much information is lost if only neutral position radiographs are used. The series consisted of 65 rheumatoid patients with unstable AAS. Lateral view cervical spine radiographs were taken in the neutral position and during flexion and extension. Neutral position radiographs would have failed to confirm the diagnosis of AAS in 31 cases (48%) and would have failed to record its true severity in 43 cases (66%); their diagnostic sensitivity was 52%. The sensitivity of the neutral radiographs in showing the reversibility of AAS was 48%. Routine cervical spine radiography of rheumatoid patients should include lateral view radiographs taken during flexion and extension. The result may be applied to magnetic resonance imaging, which is usually performed in the neutral position.