Dynamic Instability of Lumbar Spine without Spondylolisthesis

Kang, Ki Ser; Lee, Eun Woo; Kang, Soo Yong; Jung, Ho Joong

Abstract

Although flexion and extension lateral views were known the most preferable diagnostic method of instability of lumbar spine, many authors had reported that there were some findings which suggested instability of lumbar spine in plain films. This study was undertaken to analyze clinical aspect and plain film findings of dynamic instability of lumbar spine and to suggest indication of dynamic X-ray to find out the causes of low back pain. A retrospective analsysis was perfomed on 30 patients who had dynamic instability of lumbar spine without spondylolithesis between January 1996 and March 1997. They were reviewed in sex, age, symptom duration and instability level, etiologic factor etc. And then their plain films and flexion and extension lateral views were reviewed. Following results were obtained. Dynamic instability was more frequent in women than in man and occured younger age in women. The mean symptom duration was 5 years and 10 months and simple degenerative change was the most common etiologic factor. In plain films, traction spur and dome shaped end plate were common findings and the L4-5 intervertebral disc space was most frequently involved(23/30 cases). Translation was occured more frequently in flexion position(23/30 cases). The mean dynamic translation distance was 4.7mm, the mean sagittal rotational angle was 16.2degreesand the mean angular displacement was 3.2degrees. Conclusively, among the diagnostic criteria af instability of lumbar spine, translational distance was the most common finding. Flexion and extension lateral views have diagnostic value in patients who complaint back pain from unknown origin, in old age, for prolonged symptom duration, or those who have findings associated with instability in plain films.