Fractures of the spine in ankylosing spondylitis.

Fractures through the disc or the vertebral body as well as the posterior elements are typically seen in ankylosing spondylitis. The fractures can be compared to the fractures of long bones and are often unstable. These fractures are usually associated with increasing pain and may be the result of minor traumas. The radiographic appearance may be discrete, but overlooking the fracture may have disastrous consequences. The characteristic features and the biomechanical pathogenesis of these fractures are reviewed.