(HealthDay News)  Nearly half of all patients with rheumatoid arthritis (RA) initially without any cervical spine instabilities will develop some type of instability within about five years, according to research published in the Dec. 15 issue of Spine.

Takashi Yurube, MD, of the Kobe University Graduate School of Medicine in Japan, and colleagues conducted a prospective, minimum five-year follow-up study of 140 patients with RA and no cervical involvement to assess the incidence and aggravation of cervical spine instabilities.

During approximately six years of follow-up, the researchers found that 43.6% of RA patients developed some type of cervical instability. Of these, 32.1% developed atlantoaxial subluxation (AAS), 11.4% developed vertical subluxation (VS), and 16.4% developed subaxial subluxation (SAS). Severe cervical instability was noted in 12.9% of all patients (AAS in 3.6%, VS in 6.4%, and SAS in 5%), and 4.3% developed canal stenosis, defined as space available for the spinal cord of ≤13mm. Corticosteroid administration, mutilating changes at baseline, and development of non-mutilating into mutilating changes correlated significantly with severe instabilities.

“In conclusion, our prospective follow-up study describes the detailed incidence and predictors of cervical spine instabilities, providing useful information for clinical follow-up in patients with RA,” the authors write. “Established mutilating changes and progressive development of non-mutilating into mutilating changes indicate poor prognosis of the cervical spine in patients with RA. Intensive corticosteroid treatment also correlates with the aggravation of cervical spine instabilities in RA; however, its clinical significance needs to be carefully examined.”

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