Back Pain Due to Fracture of a Sacral Syndesmophyte in Ankylosing Spondylitis.
A 52 year old man with long standing ankylosing spondylitis (AS) presented with a sudden worsening of lower back pain. The symptoms had started after immoderate exercise. Imaging studies with conventional radiographs (Figure, A) and computed tomography scan (Figure, B) showed coronal fractures of a syndesmophyte involving the sacral promontory (Figure, A [black arrow] B [white arrow] Neurologic symptoms or deficits were absent, and the patient was treated with conservative management with pain control, bed rest, and physical therapy. Increased vulnerability of fracture in AS is believed to be caused by the rigidity of the spine and bone loss due to inflammation. Prevalence of vertebral fracture in patients with AS has been highly variable, but the majority of fractures were located in the cervical spine and were rarely recognized in the sacrum. The classification of sacral fracture is based on the involvement of ala and central sacral canal; however, syndesmophyte fracture of sacral promontory is not included in this classification. This case emphasizes the characteristics of ankylosed spine fractures at an unusual location.
Journal of clinical rheumatology practical reports on rheumatic musculoskeletal diseases