How often is low back pain or sciatica not due to lumbar disc disease?

To determine the percentage of low back pain or sciatica referred for MRI in which the main abnormality was not disc disease.

This is a retrospective study of 634 consecutive lumbar spine MRI`s in patients with low back pain or sciatica performed over 6-month period (January to June 2002). The study was conducted at the University Hospital of King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia. All patients were scanned on a 1.5-T MRI system. The examination included T-1 weighted sagittal images and proton density and T-2 weighted sagittal and axial images. Contrast enhanced images were obtained selectively.

Nine patients were eliminated because they were being followed for a known diagnosis, leaving 625 patients in the study group. Of these, 11 patients (1.7%) had a new diagnosis of metastatic disease to the bony spine, 7 of which (1.1%) had a known primary and 4 of which (0.6%) had no known primary malignancy. Two patients (0.3%) had spinal tumors: one conus ependymoma and one schwannoma. Four patients had non-neoplastic causes of low back pain including syringomyelia, discitis, spondylolisthesis, and an osteoporotic compression fracture. In all, 17 of 625 patients (2.7%) had a new diagnosis of a treatable cause of low back pain or sciatica other than disc disease.

In patients with low back pain or radiculopathy, 2.7% have significant pathologies other than disc disease.