Review the pathophysiology, anatomy and biomechanics of the ankylosed spine (AS) Review the key imaging findings Review cases from our institution demonstrating delayed or missed spinal injury in AS Propose a diagnostic pathway that aims to overcome the dangers associated with AS

Ankylosing spondylitis (AS) is a well recognised clinical entity. It was previously thought of as a variant of rheumatoid arthritis (RA) until around 1960 and termed ‘rheumatoid spondylitis’. In 1973, the association with human leukocyte antigen (HLA)-B27 gene was discovered, thus establishing the genetic background of AS, and in 1976 a unifying concept for the ‘seronegative spondylarthritides’ was proposed. The prevalence today is 0.5 – 1.9%. Bone formation is typical for AS and distinguishes AS from RA in which bone destruction prevails. The radiographic findings...

Diagnosis of spinal fractures in AS can be challenging. Two thirds of patients present in an atypical fashion or are unaware of their AS. The diagnosis is often overruled by attributing symptoms to chronic back pain even in the presence of acute symptoms. Fractures are often overlooked even when the radiographs are available due ankylosed soft tissues and pseuodoathroses. Fractures of the posterior elements are difficult to diagnose because of their location. This can be exacerbated by poor radiograph quality of thoracic spine due to...

Recognition of AS and an understanding the biomechanics is key to both physician and radiologist. The presence of ankylosed segments may herald an unstable spinal fracture in every trauma patient regardless of the mechanism of injury We advocate first line CT (rather than plain radiography) in all patients with AS with unexplained or ongoing back pain following any trauma thus avoiding delayed diagnosis, secondary neurological deterioration and high mortality.

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