Surgical treatment of spondylodiscitis in ankylosing spondylitis. Two cases report

Introduction. Spondylodiscitis in ankylosing spondylitis has a prevalence of 5%. Mechanical and inflammatory factors are involved in its pathogenesis. Neurosurgical operation is required when neurological complications orvertebral instability occur. Surgery is complicated by the increased fragility of the vertebral column, advanced stage of the disease in many patients, and serious pulmonary complications. Clinical cases. We report two patients who had had ankylosing spondylitis for over 20 years. Both presented complaining of symptoms for several months with lumbarpain and signs of spinal cord lesions. There were signs of discitis and destruction of the adjacent vertebral bodies at Tl 1-T12 and T12-L1 on imaging investigations ofthe first and second patient respectively. In both cases an anterior approach was used for discectomay and resection ofthe adjacent vertebral plates. Then an autologous rib graft was done, and anterolateral fixation with plate and screws to the adjacent vertebral bodies. The patients' condition improved. Their pain and previous clinical neurological disorder had disappeared by 5 and 1 year later. Discussion and conclusions. The prevalence of patients operated on for spondylodiscitis in the context of ankylosing spondylitis is not known. Dorsolumbar pain with inflammatory characteristics of recent onset in patients with chronic ankylosing spondylitis shouldleadto suspicion ofspondylodiscitis. Although it may be related to previous trauma, discitis is the fundamental mechanism. MR is the most sensitive imaging technique. There may be marked osteoporosis and stenosis of the vertebral canal together with marked ossification of all the paraspinal ligaments. This hinders the approach to the vertebral bodies and their subsequent fixation. Decompression of the vertebral canal using an anterior approach (thoracotomy or thoraco-phreno-laparotomy) and anterior spinal fixation is the treatment of choice in cases with neurological involvement or involvement of the anterior and medial columns of Denis.