Surgical treatment of ankylosing spondylitis with Andersson lesion in the thoracic spine: a case report and review of the literature.

Andersson lesion (AL) is a complication of ankylosing spondylitis (AS), characterized by non-neoplastic destruction of the intervertebral disc and adjacent vertebral bodies. Typically involving the anterior spinal column, AL may be accompanied by posterior column fracture or unfused facet joints abnormalities. We report a case of a young male patient with a long-standing history of AS complicated by AL and ossification of the posterior longitudinal ligament and ligamentum flavum in thoracic spine at the T9 to T10 level. The patient underwent posterior surgical intervention. At a 4-month post-operative follow-up, significant pain relief and marked improvement in lower limb motor function were observed.