Characteristics and diagnosis of spinal fractures in the patients with ankylosing spondylitis / 中华骨科杂志

ABSTRACT

Objective To study the characteristics of spinal fractures in ankylosing spondylitis(AS) in order to provide data in its diagnosis and treatment. Methods 19 cases of concomitant spinal fractures following AS, admitted in our hospital between January 1994 and October 2001, were studied retrospectively. Examination of AS, including A-P and lateral X-ray films of bilateral sacroiliac joint, HLA-B27, rheumatoid test and ESR were accomplished in all patients. MRI and CT scan were taken in 12 cases. 4 cases of thoracolumbar stress fracture treated surgically were conformed to pathological examination. 2 cases received preoperative puncture biopsy under CT guidance. In the group, there were 18 males and 1 female aging from 31 to 69 years with an average of 52.6 years. Results All of 19 cases were consistent with the diagnostic standards of AS. 17 of the patients prior to spinal fracture had a history of AS with duration of mean 20.6 years ranging from 8 to 37 years. All of 19 patients had round-backed deformity of different extent. Of 19 patients, 15 cases had a traumatic history. Falls while standing and walking were the cause of injury in 9 patients. The mechanism of injury appeared to be hyperextension in 7. 11 patients had the cervical fracture, and 8 had the thoracolumbar fracture. Of the patients with cervical fracture, 10 patients were due to shearing force, 9 of whom were located at C5-C7. In patients with thoracolumbar injury, stress fractures were seen in 7 patients, all of seven fractures occurred at T10-L2. Fracture through ankylosed disc was seen in 12 and vertebral body in 7. 16 of the 19 patients sustained fractures through three columns of the spine. 5 patients were associated with dislocation. 9 patients had spinal cord injury, 8 of whom were cervical fracture. The period from the injury to the diagnosis ranged from 10 hours to 7 months (mean 29.6 days). Conclusion Spinal fractures in AS can result from a mild trauma, and are associated with a high rate of neurological injury. Most frequent mechanism of the injury is hyperextension. Shearing fracture usually occurs at the lower cervical spine and stress fracture at thoracolumbar spine. Most of the fractures involve three columns of spine; and corresponding dislocation is common. The common fracture line is through the disc space. Delay in diagnosis is not rare.