title: Are syndesmophytes most prevalent in the lumbar or in the cervical spine in patients with ankylosing spondylitis and do they develop in a specific direction?
abstract: OBJECTIVE
  To describe the distribution of prevalent syndesmophytes and bridges, and the occurrence of new ones in a prevalence cohort of patients with AS.
  
  
  METHODS
  Clinical and radiological data from 132 patients from the Outcome in Ankylosing Spondylitis International Study of which complete sets of radiographs were available at baseline and at 2- and 4-year follow-up were used.
  
  
  RESULTS
  At baseline, 81 (61%) patients, of which 17 (45%) were females and 64 (65%) males (P = 0.03), had prevalent (bridging) syndesmophytes. Both syndesmophytes and bridges were found at all vertebral levels. Syndesmophytes were more frequently seen in the cervical spine compared with the lumbar spine (mean per vertebral level 17.5 vs 11.2%, respectively, P = 0.01). Bridges were more frequently seen in the lumbar spine compared with the cervical spine (mean per vertebral level 16.9% vs 12.1%, P = 0.02). With increasing disease duration more (bridging) syndesmophytes were found, occurring similarly at the lumbar and cervical spines. After 2- and 4-years of follow-up, new (bridging) syndesmophytes developed throughout the entire cervical and lumbar spines.
  
  
  CONCLUSIONS
  In general, syndesmophytes occur more frequently in the cervical spine and bridges more frequently in the lumbar spine, but neither a specific predilection site nor any particular order for occurrence and development of syndesmophytes could be detected.
authors.affiliation: Department of Medicine, Division of Rheumatology, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands. a.van.tubergen@mumc.nl
authors.forename: Astrid
authors.initials: A
authors.lastname: van Tubergen
authors.forename: Désirée
authors.initials: D
authors.lastname: van der Heijde
authors.forename: Maxime
authors.initials: M
authors.lastname: Dougados
authors.forename: Herman
authors.initials: H
authors.lastname: Mielants
authors.forename: Robert
authors.initials: R
authors.lastname: Landewé
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008022:Ligaments / Q000000981:diagnostic imaging / Q000473:pathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D054850:Osteophyte / Q000000981:diagnostic imaging / Q000209:etiology*; D015995:Prevalence; D011859:Radiography; D013167:Spondylitis, Ankylosing / Q000150:complications* / Q000000981:diagnostic imaging