Three-year follow-up of lumbar spine and sacroiliac magnetic resonance imaging changes in early axial spondyloarthritis with consideration of the lumbar facet joints.

OBJECTIVE

To investigate a potentially primary involvement of the facet joints (FJs) in axial spondyloarthritis (axSpA) development, by studying inflammatory and structural magnetic resonance imaging (MRI) and radiographic changes in the sacroiliac joints (SIJs) and lumbar spine, focusing on FJs, in newly diagnosed radiographic axSpA over a 3 year period.

METHOD: Twenty-four patients (14 male, 10 female; mean ± sd age 33.75 ± 8.6 years) with radiologically and MRI-confirmed axSpA according to modified New York and Assessment of SpondyloArthritis international Society criteria, with a symptom duration < 5.5 years at baseline (t0), were followed up after 3 years (t1) by rheumatologists and radiologists with axSpA MRI experience > 15 years. The Berlin MRI score was extended by an inflammation score of the lumbar FJs. Clinical assessments were performed.

RESULTS

Radiographic SIJs and syndesmophyte progression increased significantly between t0 and t1. MRI progression of the SIJs between t0 and t1 showed increasing bone marrow oedema (BME), significant fat lesion progression, and significant increases in sclerosis and erosion. In the lumbar spine, BME and fat lesions decreased while erosions in the vertebral units (VUs) significantly increased. Facet joint inflammation (FJI) in t0 significantly influenced MRI changes in VU bone proliferation at t1. Biologicals had no effect on MRI changes from t0 to t1.

CONCLUSIONS

Structural MRI changes in the SIJs and lumbar VUs, and radiographic axSpA progression, developed significantly within 3 years. MRI-detected lumbar FJI in early disease is associated with MRI signs of VU bone proliferation, indicating a risk of potential ossification.