Osteoarthritis of the facet joints and its role in low-back pain: evaluation with conventional tomography.

Thirty-seven patients with chronic low-back pain and an atypical irradiation to one or both legs were examined by conventional tomography of the facet joints. A disc herniation was excluded by computed tomography (CT) in 31 patients. The facet joints were considered normal in 4 patients. Four grades of facet joint disease were used to classify the pathological changes. Correlation of the radiological findings with the facet joint block by injection of a local anesthetic was obtained in 12 patients. It appears that conventional tomography is a very sensitive technique as it is possible to detect even discrete abnormalities of the facet joints. However, as it is time consuming and high in radiation dose, the examinations should be reserved for patients with a normal CT examination of the lumbar spine in whom there still remains a high suspicion of facet joint disease.