Accelerated Development of Cervical Spine Instabilities in Rheumatoid Arthritis: A Prospective Minimum 5-Year Cohort Study

Abstract

ObjectiveTo clarify the incidence and predictive risk factors of cervical spine instabilities which may induce compression myelopathy in patients with rheumatoid arthritis (RA).MethodsThree types of cervical spine instability were radiographically categorized into “moderate” and “severe” based on atlantoaxial subluxation (AAS: atlantodental interval >3 mm versus ≥10 mm), vertical subluxation (VS: Ranawat value <13 mm versus ≤10 mm), and subaxial subluxation (SAS: irreducible translation ≥2 mm versus ≥4 mm or at multiple). 228 “definite” or “classical” RA patients (140 without instability and 88 with “moderate” instability) were prospectively followed for >5 years. The endpoint incidence of “severe” instabilities and predictors for “severe” instability were determined.ResultsPatients with baseline “moderate” instability, including all sub-groups (AAS+ [VS− SAS−], VS+ [SAS− AAS±], and SAS+ [AAS± VS±]), developed “severe” instabilities more frequently (33.3% with AAS+, 75.0% with VS+, and 42.9% with SAS+) than those initially without instability (12.9%; p<0.003, p<0.003, and p = 0.061, respectively). The incidence of cervical canal stenosis and/or basilar invagination was also higher in patients with initial instability (17.5% with AAS+, 37.5% with VS+, and 14.3% with SAS+) than in those without instability (7.1%; p = 0.028, p<0.003, and p = 0.427, respectively). Multivariable logistic regression analysis identified corticosteroid administration, Steinbrocker stage III or IV at baseline, mutilating changes at baseline, and the development of mutilans during the follow-up period correlated with the progression to “severe” instability (p<0.05).ConclusionsThis prospective cohort study demonstrates accelerated development of cervical spine involvement in RA patients with pre-existing instability—especially VS. Advanced peripheral erosiveness and concomitant corticosteroid treatment are indicators for poor prognosis of the cervical spine in RA.

Risk Factors for the Development and Progression of Atlantoaxial Subluxation in Surgically Treated Rheumatoid Arthritis Patients, Considering the Time Interval between Rheumatoid Arthritis Diagnosis and Surgery

“…The prevalence of cervical spine involvement has been shown to range from 16% to 70.4%, and AAS has been reported to be the most common abnormal finding1424). The risk factors for cervical involvement have been shown to be peripheral hand or foot joint erosion1424), disease-modifying antirheumatic drug (DMARD) failure4), corticosteroid use24), and age at RA diagnosis1). Additionally, our study found that the CRP level and time interval between RA diagnosis and radiographic hand joint erosion were risk factors for surgically treated AAS development.…”

“…Previous studies have shown that radiographic hand and foot joint erosion in radiographs was the most common risk factor for cervical involvement in RA patients141024). Proliferative and erosive synovitis progresses to destruction of the articular cartilage, especially in metatarsophalangeal joints, which are the most commonly involved joints10), and the cervical spine is the second most commonly involved region.…”

“…A previous study reported that adequate treatment with DMARDs and biological agents (BAs) prevented the development of cervical spine disease, but probably did not prevent the progression of pre-existing injury10). Additionally, another study reported that among patients who were administered MTX, only 8.3% without baseline instability developed instability, while 80% with baseline instability showed progression of instability1124). Therefore, MTX can protect against the new onset of erosive synovitis; however, MTX cannot delay the progression of instability once destruction has started.…”

“…SAS was diagnosed if a vertebra had moved more than 2 mm in relation to the next vertebra, when measured from the posterior line of the vertebral bodies. Radiological cervical findings for diagnosis were as follows : 1) AAS : ADI >3 mm2024); 2) VS : Ranawat value <13 mm16); and 3) SAS : irreducible translation ≥2 mm9). Additionally, radiological cervical findings for the diagnosis of severe conditions were as follows : 1) severe AAS : ADI ≥10 mm1524); 2) severe VS : Ranawat value ≤10 mm16); and 3) severe SAS : translation ≥4 mm or translation at multiple levels9).…”

“…Anterior AAS is the most common subtype, with a prevalence of 10–55%7817). Many studies have reported the prevalence of cervical spine involvement and the predictive risk factors for rheumatoid cervical spine involvement, such as erosion at the peripheral joints, corticosteroid administration, early diagnosis of RA at <45 years of age, and presence of rheumatoid factor (RF)110232426). Because subluxation could result in irreversible neural impairment, non-ambulation, respiratory dysfunction, and consequent death5), its early diagnosis and treatment should be a priority in patients with RA.…”