Clinical and imaging features of spinal fractures in ankylosing spondylitis

  Background  The number of ankylosing spondylitis (AS) patients with spinal fracture is increasing year to year, and it is easy to delay diagnosis and treatment. However, most of the correlative studies are case reports or small sample studies, retrospective studies with relatively large number of patients are still lacking.

  Objective  To investigate the clinical characteristics and imaging features of AS patients with spinal fractures.

  Methods  From January 2008 to December 2020, clinical data about AS patients with spinal fracture admitted to the First Medical Center of Chinese PLA General Hospital were retrospectively analyzed.

  Results  A total of 102 patients were included in our study, with male patients accounted for 83.3%. The average age was (49.6±12.9) years and the average course of disease was (18.7±9.3) years. Forty-three patients (42.2%) had a spontaneous fracture, and thoracic and lumbar vertebra (25 cases, 58.1%) were the most common regions to be involved. Fifty-nine patients (57.8%) had a traumatic fracture, and cervical vertebra (26 cases, 44.1%) was the most common region to be involved. Fourteen patients had inter-vertebral bridge fracture, and lumbar vertebra (11 cases, 78.6%) was the most common regions to be involved. These fractures could only be diagnosed with the help of CT scans with three-dimensional reconstruction. Ten patients had Andersson fractures, imaging examination showed intervertebral disc destruction and visible vacuum sign.

  Conclusion  AS patients with spinal fracture are mostly elderly men with long course of disease. More attention should be paid to the patients presenting with changed pain properties. Patients with inter-vertebral bridge formation in spine are easily to have spontaneous fractures, and they are difficult to be diagnosed correctly on X-ray examinations, therefore, CT with 3D reconstruction are strongly recommended. Andersson fractures often involve three pillars and might be misdiagnosed as tuberculosis or infection, thus we should pay more attention to it.