MRI evaluation of lumbar endplate and facet erosion in rheumatoid arthritis.

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

This study was aimed to quantify the extent of lumbar endplate and facet joint erosion in patients with rheumatoid arthritis (RA) using magnetic resonance imaging, to calculate the prevalence of erosion, and sought correlated factors.

SUMMARY OF BACKGROUND DATA

Few studies have examined the lumbar spine in RA, especially the relationship between endplate and facet joint erosions and lumbar lesions induced by RA.

METHODS

A total of 201 patients with RA were enrolled. Lumbar endplate and facet joint erosion were defined as irregularities and low-intensity change on magnetic resonance imaging, and graded utilizing the Rheumatoid Arthritis Magnetic Resonance Imaging Score. Lumbar lesions were defined as scoliosis, spondylolisthesis, and vertebral fracture on plain x-ray. Multivariable logistic regression analysis was used to seek correlations between the erosion and spinal level, RA-related factors and x-ray findings.

RESULTS

Lumbar endplate and facet erosion were detected in 70.6% and 76.6% of individuals, respectively, and at 33.8% and 38.7% of lumbar intervertebral levels, respectively. The severity of erosion in individual patients correlated with lumbar lesions. Endplate and facet erosion at each level correlated with high disease activity, and were most common at mid-lumbar and lower-lumbar levels. Strong correlations were observed between endplate erosion and adjacent vertebral body fracture or disk degeneration, and between facet erosion and spondylolisthesis.

CONCLUSIONS

Lumbar endplate and facet erosion are common in RA, and are observed more frequently at mid-low levels and when RA is poorly controlled. This pattern of erosion may play a crucial role in the generation of lumbar lesions in RA.