Association of spinal ankylosis with spinal mobility and functional impairment in radiographic axial spondyloarthritis: A computed tomography study.

Objective: This study aimed to examine relationships of the degree and level of spinal ankylosis with spinal mobility and functional impairment in patients with radiographic axial spondyloarthritis (r-axSpA) using computed tomography (CT).

Methods: This retrospective study involving 27 patients examined the number of fused intervertebral segments in the whole, cervical, thoracic, and lumbar spine using CT as a measure of spinal ankylosis, Bath Ankylosing Spondylitis Metrology Index (BASMI) as a measure of spinal mobility, and Bath Ankylosing Spondylitis Functional Index (BASFI) as a measure of functional impairment.

Results: Significant positive correlations were found between both BASMI and BASFI and the number of fused intervertebral segments in the whole, cervical, thoracic, and lumbar spine. 'Tragus to wall distance', a BASMI item, was significantly positively correlated with the number of intervertebral segments in the lumbar spine (r = 0.46, P = .02). 'Looking over your shoulder', a BASFI item, was strongly negatively correlated with the number of fused intervertebral segments in the cervical spine (r = 0.804, P < .01).

Conclusions: The number of fused intervertebral segments was associated with impaired spinal mobility and functional impairment. Impaired spinal motion and functional impairment in daily living varied depending on the level of spinal ankylosis.