Analysis of different manifestations in the cervical spine involvement of longstanding ankylosing spondylitis : atlantoaxial ankylosis and atlantoaxial subluxation

Abstract

Abstract

Purpose To analyze radiologic findings of cervical involvement in ankylosing spondylitis (AS) patients and to determine their correlations with structural severity and clinical variables, and to classify atlantoaxial ankylosis (AAA) in AS patients into subcomponents

Materials and Method

A total of 150 AS patients (145 men, 5 women, mean age, 36.8 years) who had AAA (60 men and 2 women, mean age, 42.7 years) or atlantoaxial subluxation (AAS, 85 men and 3 women, mean age, 34 years) were randomly selected from January, 2002 through February, 2014 and underwent at least two lateral plain radiographs of cervical spine on flexion. The medical records were retrospectively reviewed and the lateral plain radiographs of cervical spine were analyzed by a musculoskeletal radiologist. We compared the results of modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) between AAS and AAA to see if mSASSS was related to severity or duration of AS.

Result

The mean mSASSS of AS patients with AAA and AAS were 40.1 and 16.5, respectively, and the mean duration of AS patients with AAA and AAS were 19.3 and 13.7 years respectively. There was a significantly (p<0.05) higher total mSASSS, especially cervical spine mSASSS, for AS patients with AAA than those with AAS. But, age and disease duration were not significantly related with the development of AAA compared with that of AAS.

Conclusion

Although AAA has infrequently been described, it has incidence as high as AAS and both are similar in that they are late presentation of AS and occur in patient with long duration. We found that AAA is another manifestation of cervical spine involvement in longstanding AS and is related to severity of the AS reflected by higher cervical mSASSS. We also found that AS patients with AAA have more stable atlantoaxial joint than AS patients with AAS.