The longitudinal assessment of imaging and disability of the back (LAIDBack) study: Baseline data

Study Design. Prospective cohort study of randomly selected Veterans Affairs (VA) outpatients. Objective. To determine the prevalence of magnetic resonance imaging (MRI) findings in the lumbar spine among persons without current low back pain or sciatica and to examine which findings are related to age or previous back symptoms. Summary of Background Information. Previous studies of patients without low back pain have not explored the possible association of various MRI findings to past symptoms. Methods. We randomly selected an age-stratified sample of subjects without low back pain in the past 4 months from clinics at a VA hospital. We collected information on demographics, comorbidity, functional status, and quality of life. MR images were obtained using a standardized protocol through each of the five lumbar disc levels. Results. Of 148 subjects, 69 (46%) had never experienced low back pain. There were 123 subjects (83%) with moderate to severe desiccation of one or more discs, 95 (64%) with one or more bulging discs, and 83 (56%) with loss of disc height. Forty-eight subjects (32%) had at least one disc protrusion and 9 (6%) had one or more disc extrusions. Conclusion. Many MR imaging findings have a high prevalence in subjects without low back pain. These findings are therefore of limited diagnostic use. The less common findings of moderate or severe central stenosis, root compression, and extrusions are likely to be diagnostically and clinically relevant.