Background Lumber lesions associated with rheumatoid arthritis (RA) are defined as radiologic changes such as scoliosis, spondylolisthesis, or disc space narrowing. Recently, studies demonstrated that lumbar lesions might be more common than previously thought, affecting 45-57% of patients with RA1,2. The pathologies of lumbar lesions are speculated to follow endplate or facet erosion. However, few reports have examined lumbar endplate or facet erosion among patients with RA.
Objectives We aimed to quantify the extent of lumbar endplate and facet joint erosion in patients with RA using magnetic resonance imaging (MRI), to calculate the prevalence of erosion, and to identify correlated factors.
Methods A total of 201 RA patients without prior spinal surgery were included. We obtained plain standing X-ray and MRI of the lumbar spine for all patients. Erosion was defined as irregularities or changes toward low-intensity signals on MRI T1-weighted images and graded applying a concept of the Rheumatoid Arthritis Magnetic Resonance Imaging Score. Endplate erosion was evaluated by sagittal plane and graded as 0 (none) – 3 (severe), depending on the eroded area at each lumbar intervertebral disc. Facet erosion was evaluated by axial plane and graded as 0–2 in the same way. The correlations of MRI findings (≥Grade 2 of endplate erosion and ≥Grade 1 of facet erosion) with lumbar level, RA-related factors, X-ray findings, and disc degeneration were investigated using multiple logistic regression analysis.
Results Of 1005 intervertebral levels, 340 exhibited endplate erosion (Grade 1, 191; Grade 2, 73; Grade 3, 76) and 389 exhibited facet erosion (Grade 1, 322; Grade 2, 67). Multivariate analysis indicated correlated factors for endplate erosion included L3-4 and L4-5 lumbar level (odds ratio [OR] 2.1, 2.3), Steinbrocker’s stage IV (OR 2.4), moderate and high disease activity by disease activity score of 28 joints and the erythrocyte sedimentation rate (DAS28-ESR) (OR 1.8, 2.1), adjustment vertebral fracture (OR 2.9), coronal disc wedging (OR 2.2), decrease of disc height (OR 4.2), and disc degeneration (OR 3.8). Correlated factors for facet erosion were L3-4, L4-5, and L5-S1 of lumbar level (OR 2.6, 3.7, 2.1), high age (OR 1.4), high disease activity by DAS28-ESR (OR 1.8), spondylolisthesis (OR 9.5), coronal disc wedging (OR 1.6), and decrease of disc height (OR 2.2).
Conclusions MRI evaluation showed that both endplate and facet erosion were correlated with mid-lower lumbar level, RA disease activity, and lumbar degeneration. Furthermore, endplate erosion was strongly correlated with a decrease of disc height and disc degeneration, and facet erosion was strongly correlated with spondylolisthesis.
Kawaguchi Y, Matsuno H, Kanamori M, et al. Radiologic findings of the lumbar spine in patients with rheumatoid arthritis and a review of pathologic mechanisms. J Spinal Disord Tech 2003;16:38-43.
Sakai T, Sairyo K, Hamada D, et al. Radiological features of lumbar spinal lesions in patients with rheumatoid arthritis with special reference to the changes around intervertebral discs. Spine J 2008;8:605-11.
Disclosure of Interest K. Yamada: None Declared, T. Koike Grant/research support from: Takeda Pharmaceutical, Mitsubishi Tanabe Pharma Corporation, Chugai Pharmaceutical, Eisai, Abbott Japan, Teijin Pharma, Banyu Pharmaceutical, Ono Pharmaceutical, A. Suzuki: None Declared, S. Takahashi: None Declared, H. Yasuda: None Declared, K. Inui: None Declared, M. Tada: None Declared, Y. Sugioka: None Declared, T. Okano: None Declared, H. Nakamura: None Declared