Predictive Risk Factors of Cervical Spine Instabilities in Rheumatoid Arthritis: A Prospective Multicenter Over 10-Year Cohort Study

• Published in: Spine (Philadelphia, Pa. 1976) Pa. 1976), 2017-04, Vol.42 (8), p.556-564
• Main Authors: Terashima, Yoshiki, Yurube, Takashi, Hirata, Hiroaki, Sugiyama, Daisuke, Sumi, Masatoshi
• Format: Article
• Language: English
• Subjects: Aged; Arthritis, Rheumatoid - complications; Atlanto-Axial Joint - diagnostic imaging; Cervical Vertebrae - diagnostic imaging; Disease Progression; Female; Humans; Joint Dislocations - diagnostic imaging; Joint Dislocations - etiology; Joint Instability - diagnostic imaging; Joint Instability - etiology; Male; Middle Aged; Prognosis; Prospective Studies; Risk Factors; Spinal Cord Compression - diagnostic imaging; Spinal Cord Compression - etiology
• ISSN: 0362-2436; 1528-1159
• DOI: 10.1097/BRS.0000000000001853

A prospective multicenter cohort study for more than 10 years of outpatients with rheumatoid arthritis (RA). To identify predictive risk factors of cervical spine instabilities, which may induce compression myelopathy in patients with RA. Many reports described the natural course of cervical spine involvement in RA. Only a few studies, however, conducted comprehensive evaluation of its prognostic factors. Cervical spine instability was radiographically defined as atlantoaxial subluxation with the atlantodental interval greater than 3 mm, vertical subluxation (VS) with the Ranawat value less than 13 mm, and subaxial subluxation with irreducible translation of 2 mm or higher. The "severe" category of instability was defined as atlantoaxial subluxation with the atlantodental interval of 10 mm or lower, vertical subluxation with the Ranawat value of 10 mm or higher, and subaxial subluxation with translation of 4 mm or higher or at multiple levels. Of 503 "definite" or "classical" patients with RA without baseline "severe" instability, 143 were prospectively followed throughout for more than 10 years. The Cox proportional hazards regression analysis was performed to determine predictors for the development of "severe" instabilities. To exclude biases from the low follow-up rate, similar assessments were performed in 223 patients followed for more than 5 years from baseline. The incidence of cervical spine instabilities and "severe" instabilities significantly increased during more than 10 years in both 143 and 223 cohorts (all P