Association of lumbosacral transitional vertebra and sacroiliitis in patients with inflammatory back pain suggesting axial spondyloarthritis.

OBJECTIVE: Lumbosacral transitional vertebras (LSTVs) are common in the general population, but their potential impact on the sacroiliac joints is unclear. We aimed to determine the prevalence of LSTVs and to assess their associations with sacroiliitis by standard radiography and MRI in a population with suspected axial spondyloarthritis. METHODS: The data were from the DESIR cohort of 688 patients aged 18-50 years with inflammatory low back pain for ⩾3 months but <3 years suggesting axial spondyloarthritis. The baseline pelvic radiographs were read by two blinded readers for the presence and type (Castellvi classification) of LSTVs. Associations between LSTVs and other variables collected at baseline and at the diagnosis were assessed using the χ2 test (or Fisher's exact test) or the Mann-Whitney test. RESULTS: LSTV was found in 200/688 (29.1%) patients. Castellvi type was Ia in 54 (7.8%), Ib in 76 (11.0%), IIa in 20 (2.9%), IIb in 12 (1.7%), IIIa in 7 (1.0%), IIIb in 21 (3.0%) and IV in 10 (1.4%) patients. Compared with the group without LSTVs, the group with LSTVs had higher proportions of patients meeting modified New York criteria for radiographic sacroiliitis (19% vs 27%, respectively; P = 0.013) and Assessment of SpondyloArthritis international Society MRI criteria for sacroiliitis (29% vs 39%, respectively; P = 0.019). CONCLUSION: In patients with inflammatory back pain suggesting axial spondyloarthritis, LSTVs are associated with both radiographic and MRI sacroiliitis.

Associations of lumbar scoliosis with presentation of suspected early axial spondyloarthritis.

OBJECTIVE: Scoliosis may impact the mechanical loading and cause secondary changes of the sacroiliac joints and lumbar spine. Our goal was to look how lumbar scoliosis modify the clinical and imaging-study in patients with recent-onset inflammatory back pain (IBP) suggesting axial spondyloarthritis (axSpA). METHODS: Baseline weight-bearing lumbar-spine radiographs obtained in the DESIR cohort of patients aged 18-50 years and having IBP for at least 3 months but less than 3 years suggesting axSpA were studied. After training on scoliosis detection based on Cobb's angle>10° plus Nash-Moe grade≥1, readers blinded to patient data measured spine lumbar scoliosis, sacral horizontal angle, lumbosacral angle and lumbar lordosis on the radiograph of the lumbar and scored sacroiliitis on the radiograph of the pelvis. Baseline MRIs T1 and STIR of the lumbar spine and sacroiliac joints were evaluated for respectively degenerative changes and signs of axSpA. RESULTS: Of the 360 patients (50.8% females) 88.7% had lumbar pain and 69.3% met ASAS criteria for axSpA. Mean Cobb's angle was 3.2°±5.0° and 28 (7.7%) patients had lumbar scoliosis. No statistical differences were observed for radiographic sacroiliitis, MRI sacroiliitis, modified Stoke Ankylosing Spondylitis Spinal Score, Pfirmmann score, high-intensity zone, protrusion, extrusion, MODIC score between patients with and without scoliosis. In both groups, degenerative changes by MRI were rare and predominated at L4-L5 and L5-S1. CONCLUSION: In patients with early IBP suggesting axSpA, lumbar scoliosis was not associated with inflammatory or degenerative changes.