PT - JOURNAL ARTICLE AU - Sovira Tan AU - Lawrence Yao AU - Michael M. Ward TI - Thoracic Syndesmophytes Commonly Occur in the Absence of Lumbar Syndesmophytes in Ankylosing Spondylitis: A Computed Tomography Study AID - 10.3899/jrheum.170340 DP - 2017 Dec 01 TA - The Journal of Rheumatology PG - 1828--1832 VI - 44 IP - 12 4099 - http://www.jrheum.org/content/44/12/1828.short 4100 - http://www.jrheum.org/content/44/12/1828.full SO - J Rheumatol2017 Dec 01; 44 AB - Objective. To determine the extent of thoracic involvement with syndesmophytes in ankylosing spondylitis (AS) relative to lumbar involvement.Methods. We performed thoracolumbar spine computed tomography (CT) and lumbar radiography on 18 patients. We quantitated syndesmophytes in 11 intervertebral disc spaces and related these to the presence of syndesmophytes on lumbar radiographs.Results. Syndesmophytes were slightly more common in the thoracic than in the lumbar spine and bridging was significantly more common. Thoracic syndesmophytes were universally present in patients without visible lumbar syndesmophytes on either radiographs or CT.Conclusion. Syndesmophytes predominate in the thoracic spine. Lumbar radiographs underestimate the degree of thoracic involvement.