Spondylodiscitis (SD) is a destructive discovertebral lesion which is uncommon, but well recognised as a complication of Ankylosing Spondylitis (AS), and also called the Andersso  lesion. This prospective study described 24 cases of AS, 12 of them with SD with variable clinical presentation and radiological appearance (SD). Two had multiple lesions, in one patient
spondylodiscitis was the presenting symptom of AS. None had a history of even a minor trauma and radiological appearance of Andersson lesion in AS. In a prospective analysis of 24 patients with ankylosing spondylitis (AS) with multiple nationalities, 12 individuals (50%) had spondylodiscitis, affecting the spine at various levels, we
described the demographic data, full medical history, clinical examination and radiological findings including thoracolumbar spinal magnetic resonance imaging (MRI) in all patients diagnosed as SD with AS admitted to our department. All patients were fulfilling the modified New York criteria and ASAS criteria for AS. The results showed that the mean age of patients was 43 ± 10.8 yrs, 16 (66.667%) were males. Half of the 12 patients had multiple lesions (between two and six levels). Mean disease duration were 11±8.7. The most common site of lesion was the thoracic spine The prognosis was good with conservative treatment including NSAID's, rest, and physiotherapy. The literature was reviewed regarding the mechanisms that may contribute to these lesions: mainly inflammatory like increasing enthesopathy or mainly mechanical like pseudoarthrosis about a fracture site. It might be that both mechanisms could result in similar destructive
intervertebral disc lesions.