Background The morphologic characteristics of atlantoaxial ankylosis in AS patient and suggests different pathways of involvement resulting in atlantoaxial subluxation in AS patients
Objectives To evaluate morphologic characteristics of AAA in AS patient and classify them into categories which reflects the end-stage manifestations of two differents disease pathways.
Methods Plain radiographs of cervical spine in 62 AS patients with AAA were reviewed. We classified AAA in AS patients into three subtypes: loss of atlantodental interval (type I), ankylosis of facet joint (type II) and ankylosis of anterior longitudinal ligament or anterior atlantooccipital membrane with cervical spine (type III).
And then, we categorized 62 AS patients with AAA into two subgroups: group A (21 patients) with only synovial joint involvement of AS (type I or type II or both) and group B (41 patients) with enthesis involvement of AS with additional synovial joint involvement (type III plus type I or type II or both).
We compared the results of mSASSS and disease duration between group A and B.
Results The mean cervical mSASSS of patients in group A and B were 27.3 and 16.0 each (p value, 0.196). The mean duration of AS patients in group A and B were 23.7 and 23.6 years each. There was no siginificant differences in cervical, lumbar and total mSASSS or disease duration between the two groups.
Conclusions We propose that atlantoaxial joint involvement in the AS patients is not chronological changes that occur with disease progression, but rather it is end-stage manifestation of two different pathways: one only involving synovial joint and the other one involving both synovial joint and enthesis.
Martel W. The occipito-atlanto-axial joints in rheumatoid arthritis and ankylosing spondylitis. Am J Roentgenol Radium Ther Nucl Med 1961;86:223–240
Meijers KA, van Voss SF, Francois RJ. Radiological changes in the cervical spine in ankylosing spondylitis. Ann Rheum Dis1968;27:333–338
Lee HS, Kim TH, Yun HR, Park YW, Jung SS, Bae SC, et al. Radiologic changes of cervical spine in ankylosing spondylitis.Clin Rheumatol 2001;20:262–266
Laiho K, Kauppi M. The cervical spine in patients with ankylosing spondylitis. Clin Exp Rheumatol 2002;20:738
Disclosure of Interest None declared