Clinical and instrumental diagnostics of early changes in the atlantoaxial area in ankylosing spondylitis

The purpose — to assess the early imaging changes in the atlantoaxial area and to compare them with clinical and laboratory characteristics in patients with ankylosing spondylitis (AS). Material and methods. 20 patients with AS were examined, the average age is 44.2 ± 12.66 y. o. Activity (ASDAS(CRP)): very high — 85%, high — 5%, low — 10%. X-ray stage of sacroiliitis: 2 — 60%, 3 — 15%, 4 — 25%. Functional deficiency (FD): 3 — 55%, 2 — 20%, 1 — 25%. The duration of illness was 176 [2; 360] months. The extended clinical examination included: assessment of neurological status, presence of components of neuropathic pain (NP) and central sensitization (CS), assessment of quality of life, degree of functional disorders. Magnetic resonance imaging (MRI) of the craniovertebral junction was performed with the measurement of 5 craniometric parameters (CMP) for the presence of translocation of the dens axis. Results. Neck pain syndrome — 75%: inflammatory — 95%, non-inflammatory — 80% (NP — 65%, CS — 50%). VAS: 5.75 ± 2.09. FD: BASMI — 3.86 [2; 7], BASFI — 4,84 [0,7; 8,7]. 75% — limitation of neck rotation, 65% — increase in the distance of the trestle-wall. CMP: 100% — decrease in the retroflex angle, 20% — increase in the anterior atlantodental index, 15% — translocation relative to the Chamberlain line, 10% increase in pB-C2, 5% — decrease in the posterior atlantodental index. A correlation was revealed between the CMP with the X-ray stage (rSp = 0.629; p = 0.021), BASMI (rSp = 0.575; p = 0.04) and the psychological component SF-36 (rSp = 0.570; p = 0.042). The angle of retroflexion with the duration of the disease (rSp = -0.580; p = 0.038), CRP (rSp = 0.624; p = 0.023). Conclusions. All patients with AS had pathological MRI changes in the form of initial manifestations of translocation of the dens, which had nonspecific clinical manifestations. Changes in craniovertebral transition to MRI did not correlate with disease activity (ASDAS (CRP)), but were associated with the level of CRP, duration of the disease, X-ray stage of sacroiliitis and functional indices (BASMI).