gms | German Medical Science

Background: Despite the differences in pathogenesis, neck pain associated with functional limitation and impaired mobility of the cervical spine is a frequent clinical symptom of patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). We here directly compare inflammatory and structural findings obtained by magnetic resonance imaging (MRI) in patients with RA and AS who present with chronic neck pain, and to correlate MRI findings with clinical measurements.

Methods: A total of 120 patients (60 RA and 60 AS) were consecutively included in the study if they had chronic neck pain (duration >3 months). All patients had clinical examinations for neck function and mobility and were asked to fill in disease specific questionnaires. They also had laboratory examinations (CRP, ESR) and MRI of the cervical spine (CS) using contrast-enhanced MRI sequences (T1 pre- and post-Gadolinium, sagittal and axial images). A total of 107 patients (59 RA with 295 and 48 AS with 240 vertebral segments) could be finally evaluated. An experienced rheumatologist examined all patients blinded to diagnosis and MR images. In addition, two experienced readers blinded to patients’ diagnosis and clinical assessments evaluated the MRIs by describing the anatomical structures of the CS (vertebral body, intervertebral disc, facet joints) and the pattern of inflammatory activity in the bone marrow (vertebral edges vs. vertebral endplates).

Results: The RA group included more females (66.1%) and older patients (58.6±11.4 years) in comparison to AS (68.8% males, mean age 47.9±13.1 years), while there were no differences in the duration of neck pain. AS patients reported higher mean levels of neck pain on a 0–10 numerical rating scale (5.0±3.6) as compared to RA patients (3.0±3,1) (p=0.003), while the Northwick pain questionnaire didn’t reveal any differences. There were numerically more patients with AS (n=11, 22.9%) than RA (n=9, 15.3%) (p=0.166) with bone marrow edema (BME) at the vertebral edges. The majority of lesions was located in the lower CS. In contrast, more patients with RA (n=18, 30.5%) than AS (n=3, 6.3%) had erosive osteochondrosis with endplate BME (p=0.002). Atlantoaxial synovitis was found in only 1 patient with RA (1.7%), while inflammatory changes around the dens axis were found in 2 (3.4%) and atlantodental synovitis in 5 (8.5%) RA patients but not in AS patients. In comparison, erosive changes in the dens axis region were found in 3 RA (5.1%) vs. 2 AS (4.1%) patients.

No major differences related to the presence of facet joint osteoarthritis was found (78% in RA vs. 65% in AS). The prevalence of facet joint osteoarthritis was the only imaging finding correlating with clinical symptoms: r=0.259 (p=0.049) for RA and r=0.416 (p=0.003) for AS, respectively. Similarly, only facet joint osteoarthritis correlated with restriction of cervical rotation in patients with AS (r=0.471, p=0.001).

Conclusion: Both BME and chronic changes of the lower part of the CS but not of the atlantoaxial region are seen in patients with RA and AS who present with chronic neck pain. The pattern of BME involvement in patients with RA vs. AS was different. Facet joint osteoarthritis was the only imaging finding that correlated with the magnitude of neck pain, in AS it also correlated with impaired cervical rotation.