Inflammatory lesions of the spine on magnetic resonance imaging predict the development of new syndesmophytes in ankylosing spondylitis: evidence of a relationship between inflammation and new bone formation

Arthritis Rheum. 2009 Jan;60(1):93-102. doi: 10.1002/art.24132.


Objective: To determine whether a vertebral corner that demonstrates an active corner inflammatory lesion (CIL) on magnetic resonance imaging (MRI) in patients with ankylosing spondylitis (AS) is more likely to evolve into a de novo syndesmophyte visible on plain radiography than is a vertebral corner that demonstrates no active inflammation on MRI.

Methods: MRI scans and plain radiographs were obtained for 29 patients recruited into randomized placebo-controlled trials of anti-tumor necrosis factor alpha (anti-TNFalpha) therapy. MRI was conducted at baseline, 12 or 24 weeks (n=29), and 2 years (n=22), while radiography was conducted at baseline and 2 years. A persistent CIL was defined as a CIL that was found on all available scans. A resolved CIL was defined as having completely disappeared on either the second or third scan. A validation cohort consisted of 41 AS patients followed up prospectively. Anonymized MRIs were assessed independently by 3 readers who were blinded with regard to radiographic findings.

Results: New syndesmophytes developed significantly more frequently in vertebral corners with inflammation (20%) than in those without inflammation (5.1%) seen on baseline MRI (P<or=0.008 for all reader pairs). They also developed more frequently in vertebral corners where inflammation had resolved than in those where inflammation persisted after anti-TNF treatment. This was confirmed in the analysis of the prospective cohort, in which significantly more vertebral corners with inflammation (14.3%) compared with those without inflammation (2.9%) seen on baseline MRI developed new syndesmophytes (P<or=0.003 for all reader pairs).

Conclusion: Our findings indicate that a syndesmophyte is more likely to develop from a prior inflammatory lesion, supporting a relationship between inflammation and ankylosis.

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antibodies, Monoclonal / therapeutic use
  • Antirheumatic Agents / therapeutic use
  • Cervical Vertebrae / immunology
  • Cervical Vertebrae / pathology*
  • Female
  • Humans
  • Infliximab
  • Lumbar Vertebrae / immunology
  • Lumbar Vertebrae / pathology*
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Osteitis / immunology
  • Osteitis / pathology*
  • Osteogenesis / immunology*
  • Spondylitis, Ankylosing / drug therapy
  • Spondylitis, Ankylosing / immunology
  • Spondylitis, Ankylosing / pathology*


  • Antibodies, Monoclonal
  • Antirheumatic Agents
  • Infliximab