Most patients with acute low back pain (LBP), with or without radiculopathy, have substantial improvements in pain and function in the first 4 weeks, and they do not require routine imaging. Imaging is considered in those patients who have had up to 6 weeks of medical management and physical therapy that resulted in little or no improvement in their LBP. It is also considered for those patients presenting with suspicion for serious underlying conditions, such as cauda equina syndrome, malignancy, fracture and infection. In western country primary care settings, the prevalence has been suggested to be 0.7% for metastatic cancer, 0.01% for spinal infection and 0.04% for cauda equina syndrome. Of the small proportion of patients with any of these conditions, almost all have an identifiable risk factor. Osteoporotic vertebral compression fractures (4%) and inflammatory spine disease (<5%) may cause LBP, but these conditions typically carry lower diagnostic urgency. Imaging is an important driver of LBP care costs, not only because of the direct costs of the test procedures but also because of the downstream effects. Unnecessary imaging can lead to additional tests, follow-up, referrals and may result in an invasive procedure of limited or questionable benefit. Imaging should be delayed for 6 weeks in patients with nonspecific LBP without reasonable suspicion for serious disease.
The translational potential of this article: Diagnostic imaging studies should be performed only in patients who have severe or progressive neurologic deficits or are suspected of having a serious or specific underlying condition. Radiologists can play a critical role in decision support related to appropriateness of imaging requests, and accurately reporting the potential clinical significance or insignificance of imaging findings.