The radiology of low back pain associated with posterior element lesions of the lumbar spine.

Chronic low back pain is frequent, ubiquitous, intermittent and usually difficult to categorize. Aside from the minority of cases with specific inflammatory or neoplastic causes, its etiology is usually vague and its radiographic evaluation obscure on routine films of the lumbar spine. For almost 50 years it has been known that disc disease was a significant etiologic factor. More recently, abnormal zygapophyseal joints have been pinpointed as specific areas of causation of low back pain. Other posterior element lesions associated with low back pain include facet fractures, interarticular isthmus defects, and laminar and pedicular fracture deformities. The radiographic demonstration of these lesions may require axially angled oblique views, vertebral arch views, and motion studies added to the standard projections. CT and apohyseal joint arthrography have been especially helpful.