Inflammatory lesions in ankylosing spondylitis predict new syndesmophytes

March 21, 2009

In patients with ankylosing spondylitis (AS), the presence of an active inflammatory lesion at the vertebral corner on MRI is associated with development of new syndesmophytes at the corresponding vertebral corner visible on plain radiography, suggesting a relationship between inflammation and ankylosis. New syndesmophytes will develop from a previous active inflammatory lesion even when the lesion has resolved on follow-up MRI after the start of anti-tumor necrosis factor a (anti–TNF–α) therapy.

In patients with ankylosing spondylitis (AS), the presence of an active inflammatory lesion at the vertebral corner on MRI is associated with development of new syndesmophytes at the corresponding vertebral corner visible on plain radiography, suggesting a relationship between inflammation and ankylosis. New syndesmophytes will develop from a previous active inflammatory lesion even when the lesion has resolved on follow-up MRI after the start of anti-tumor necrosis factor α (anti–TNF-α) therapy.

Maksymowych and associates obtained MRI scans and plain radiographs for 29 patients recruited into randomized placebo-controlled trials of anti–TNF-α therapy. An observational cohort consisted of 41 patients with AS monitored prospectively. Readers blinded to radiographic findings evaluated the MRI scans.

One or more new syndesmophytes developed in 44.4% and 45.5% of patients in the anti–TNF-α therapy and placebo arms of the clinical trial cohort, respectively, and in 27.8% and 34.8% in the anti–TNF-α therapy and standard therapy arms of the observational cohort, respectively. New syndesmophytes developed significantly more frequently in vertebral corners with active inflammation (20%) than in those without inflammation (5.1%).