Lumbar spine films in primary care: current use and effects of selective ordering criteria.

Low back pain (LBP) often prompts radiography, although the diagnostic yield of lumbar spine films is low, and many radiographic abnormalities are unrelated to symptoms. Criteria have been proposed for selective x-ray use, but their value and safety are uncertain. To evaluate these criteria, the authors prospectively studied 621 walk-in patients with LBP. The yield of explanatory x-ray findings was over three times greater among patients with indications for radiography than among those without. Furthermore, an indication for x-rays existed for all patients found to have a malignancy, and for 13 of 14 patients with an identified fracture. Actual physician ordering, however, did not correspond well with the recommended indications. Application of selective criteria appears safe and may improve the yield of useful findings. It may not, however, reduce x-ray utilization from current levels without further refinement in the criteria.