OBJECTIVETo review the clinical features of the thoracolumbar fracture with ankylosing spondylitis (AS) in order to avoid delayed or missed diagnosis.

METHODSFive patients of thoracolumbar fracture with AS treated from April 2005 to June 2007 in our department were studied retrospectively, male 4 cases, female 1 case, the age from 26- to 72-years-old with an average of 44.8 years. Analysis including: case history, number of the ankylosed vertebras, characteristic of fracture, active state rheumatism.

RESULTSThe patients had the history of AS for average 22.6 years. The mean number of the ankylosed vertebras was 18.2. Of the 5 cases, 1 case encountered traffic accident, 1case was sprained, and 3 cases without trauma were diagnosed as stress fracture. Two cases were trans-vertebra fracture: the fracture line was through T6, T7, or L1 vertebral body respectively; 3 cases were through the disc space: 2 cases were through L1,2 disc space, 1 case was through L2,3. No compression fracture and neurological injury were found. The acute inflammatory index such as ESR and CRP in 4 cases didn't correlate with the degree of pain. The non-steroidal anti-inflammatory drugs (NSAIDs) hadn't significant effectiveness in relieving pain. The patients were diagnosed as 'relapse' of AS in other hospital, and had been misdiagnosed for average 1.51 months.

CONCLUSION1) the fracture is prevalent at the middle or late period of AS when extensive ankylosis has been existed at the thoracolumbar region; 2) the fracture is common at the lower thoracal spine and the upper lumbar spine, and the majority is the stress fracture; 3) the fracture line may be through the vertebral body, but more often through the disc space; 4) it is like an exacerbation of AS and therefore to be missed diagnosis; 5) when the back pain exacerbated suddenly in the middle or late period of AS, the degree of pain not correlating with acute inflammatory index, and the NSAIDs ineffective, the thoracolumbar fracture should be considered.