While the prevalence of anterior atlantoaxial subluxations has decreased in patients with rheumatoid arthritis, aAAs remain twice as common as other cervical problems.
With advances in treatment, spinal complications in rheumatoid arthritis (RA) seem less common these days and may receive less attention-- but patients with RA are still at risk.
While the prevalence of one problem -- anterior atlantoaxial subluxations (aAASs), shifting of the first two spinal vertebrae –- may have decreased, it remains twice as common as other cervical problems. The result is severe pain, deformities and potentially dangerous neurological complications for RA patients, say Canadian researchers.
An extensive literature search reveals that the prevalence of aAAs has decreased by a third since the 1960s. However, aAAs still affects one quarter of RA patients in North America, 27% in Europe, and almost a third of Asian patients.
The condition is caused by erosive pannus formation at the axis and atlas (C-1 and C-2) that leads to bony destruction and loosening of ligaments that keep the cervical spine in alignment, shifting the vertebrae in the neck and those just below it.
These neck subluxations can develop as RA progresses; they cancause vertigo, visual changes, brainstem compression and -- in rare cases -- severe neurological complications, such as paraplegia.
In severe cases of myelopathy, the prognosis can be grave: 1-year mortality can be as high as 50% if aAAs is left untreated, the researchers note.
The decrease in aAAs can be attributed to better treatment of RA in recent years. In the 1970s and earlier, the prevalence of aAAS was 36%, dropping to 24% by the 2000s, with the advent of biological disease modifying anti-rheumatic drugs (DMARDs).
However, the study does not assess specific treatments and the rate of progression of cervical lesions does not appear to be affected by DMARDs. And, the researchers stress, cervical spine complications in RA take years to develop and the actual effect of modern DMARDs remains to be seen.
The literature search, from 1960 to 2014, shows a similar decline in the prevalence of other cervical spine problems in RA, which remain relatively uncommon.
Zhang T, Pope J. Cervical spine involvement in rheumatoid arthritis over time: results from a meta-analysis. Arthritis Research & Therapy. 2015;17:148 doi:10.1186/s13075-015-0643-0. PDF (open access)