Rheumatoid arthritis: epidural enhancement as an underestimated cause of subaxial cervical spinal stenosis.

PURPOSE: To assess the frequency and site of subaxial spinal canal stenosis due to enhancing tissue in patients with rheumatoid arthritis.

MATERIALS AND

METHODS

Data from 33 consecutive patients with rheumatoid arthritis were evaluated; these patients had undergone 1.5-T magnetic resonance imaging following gadolinium chelate administration, in combination with a frequency selective fat-suppression technique. Stenosis and enhancement were scored for each of six cervical spinal levels and were compared with results in a control population consisting of 16 patients with degenerative disease. Enhancement was scored as superficial or deep on the anterior and posterior sides from the cervical spinal cord. Differences between patient groups were tested by using the chi(2) test for trend and the Fisher exact test.

RESULTS

No significant difference was found in the frequency or severity of subaxial stenosis between rheumatoid arthritis and degenerative disease. Deep epidural enhancement was observed more often with rheumatoid arthritis than with degenerative disease both anterior (25 of 33 patients vs seven of 16 patients, respectively; P <.001) and posterior (24 of 33 patients vs two of 16 patients, respectively; P =.001) to the spinal cord. Enhancing stenosing tissue in rheumatoid arthritis frequently occurred anterior and posterior at the same time and at the same level, with segmental cufflike extension of enhancing tissue around the dural sac. Stenosing tissue enhanced more frequently with rheumatoid arthritis than with degenerative disease (22 of 33 vs four of 16 patients, respectively; P =.008).

CONCLUSION

In patients with rheumatoid arthritis, subaxial stenosis is frequently caused by enhancing epidural tissue. This enhancing tissue presumably represents pannus.