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

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

METHODS: 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.

RESULTS: 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.

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