gms | German Medical Science

Introduction: In axial spondyloarthritis (ax SpA, AS), the development of ossification and loss of function is still unclear or at least discussed controversially. Are there differences in the progression of imaging in the sacroiliac joints (SIJs) compared to the lumbar spine? Are active inflammatory lesions in the lumbar facet joints and posterior segments of prognostic significance? We analyse the disease course of newly diagnosed ax SpA patients clinically, radiographically and by magnetic resonance imaging (MRI) over a three years period.

Methods: 24 patients (14 male, 58.3%, 10 female, 41.7%), (mean age at baseline (t0): 33.75 years) with radiologically and MRI confirmed axial spondyloarthritis and a duration of symptoms <5.5 years and diagnosis <2,5 years at t0 were followed up after 3 years (t1). X-rays of the lumbar spine and SIJs were performed, the latter using the modified New York criteria (mNY criteria), MRI of the lumbar spine and SIJs (T1, T2, Stir, Vibe sequences) according to the Berlin MRI score. In addition to the Berlin criteria and the posterior segments recorded there, an osteitis/synovitis score of the lumbar facet joints was also integrated. Demographic data and assessments (BASDAI, CRP-ASDAS, BASFI, BASMI, FFbH) as well as CRP were collected at t0 and t1, HLA-B 27 at t0.

Results: Complete data sets were available for all 24 patients. At t0, all patients were treated according to the AS/ax SpA guidelines. There was no difference in CRP-ASDAS and BASDAI between t0 and t1. In the three years period the radiographic progression of the SIJs and the formation of syndesmophytes differed significantly between t0 and t1. MRI progression of the SIJs between t0 and t1 showed increasing bone marrow oedema (BME), significant progression of fatty lesions, sclerosis and erosions. In the MRI of the lumbar spine, BME and fatty lesions decreased. Osteitis/synovitis of the facet joints and inflammation of the posterior segments had an significant influence in X-ray and MRI changes of SIJs. There was no difference between patients with (t0: 11, 45.8%; T1: 13 54.2%) or without biological treatment.

Conclusion: Radiological progression in the SIJs and lumbar spine as well as MRI changes in the SIJs and lumbar spine develop faster than previously assumed. This appears to be independent of treatment with biologics. The involvement of the lumbar facet joints could be a possible prognostic indicator for the radiographic progression of axial SpA.

Disclosures: Nothing to declare.