Thoracolumbar pseudarthrosis in ankylosing spondylitis

Spinal pseudarthrosis (SP) is a well recognized complication in advanced ankylosing spondylitis (AS).1 Such lesion may present with persistent back pain, which is exacerbated by exercise, and sometimes complicated with spinal deformities and neurological deficits.2 On plain film, it usually shows as extensive discovertebral destruction and occurs through the intervertebral disc spaces at the thoracolumar junction. In rare situation, it can be observed through the vertebral body.3 On magnetic resonance image (MRI), it is similar to infective spondylitis, so this may often result in misdiagnosis.4–6 There have been several reports describing the clinical and radiological findings of this condition.1–3,7, 8 However, no reports have analyzed the clinical characteristics combined with a complete set of radiological examination (including plain film, CT with reconstruction and MRI) in a relative large series because of the rarity of this condition. In this report, we respectively reviewed the clinical and radiological features of thoracolumbar pseudarthrosis in AS in a consecutive cohort of patients. A new classification of thoracolumar pseudarthrosis in AS was put forward.