No Benefit to Routine Imaging for Low Back Pain Without “Red Flags”

Susan Jeffrey – Medscape Medical News 2009. © 2009 Medscape

A new meta-analysis of randomized trials finds no benefit to routine lumbar imaging for low back pain without indications of serious underlying conditions.
The researchers conclude that clinicians should refrain from routine use of imaging in these patients, although they acknowledge that patient expectations will also have to be managed to accomplish this.
“We need to identify back-pain assessment and educational strategies to meet patient expectations and increase satisfaction, while avoiding unnecessary imaging,” Roger Chou, MD, from Oregon Health and Science University, in Portland, and colleagues conclude.
Their study, funded by the American Pain Society, is published in the February 7 issue of the Lancet.

Use of Imaging Increasing

In 1994, the Agency for Healthcare Policy and Research released a guideline that recommended against lumbar imaging in the first month of acute low back pain, based on observations of a low frequency of serious conditions, a high likelihood the back pain will improve on its own, and a weak correlation between the findings on imaging studies and treatment decisions. The exception to this recommendation was in patients with “red flags,” the authors note; that is, historical or clinical features suggestive of serious underlying conditions, such as cancer, infection, or cauda equina syndrome.

Guidelines published since then have consistently recommended a similar approach, some even in chronic back pain. However, some clinicians still do routine imaging, they note, possibly to reassure the patient as well as themselves or because certain reimbursement structures provide financial incentives. Nevertheless, imaging has risks, including radiation exposure or turning up anatomic problems that are not the actual cause of the back pain, and raises both direct and indirect costs.

In this study, Dr. Chou and colleagues conducted a meta-analysis of randomized controlled trials comparing immediate lumbar imaging using radiography, magnetic resonance imaging (MRI), or computed tomography (CT) scanning with usual clinical care without immediate imaging in terms of clinical outcomes. Patients all had low back pain without any of the red flags indicative of a serious underlying condition.

Six trials, including 1804 patients, met their inclusion criteria; all reported pain or function, the primary outcomes of interest, as well as quality of life, mental health, overall patient-reported improvement using a variety of scales, and patient satisfaction with the care received.

They found no difference on either primary outcome with immediate imaging vs usual care without immediate imaging, either in the short term, up to 3 months, or in the long term, from 6 to 12 months. Nor were there significant differences in the other outcomes.

Short- and Long-Term Outcomes with Immediate Imaging vs Usual Care without Immediate Imaging

*Negative values favor imaging

Trial quality, the use of different imaging methods, and the duration of low back pain did not affect the results, the authors note.

“Lumbar imaging for low back pain without indications of serious underlying conditions does not improve clinical outcomes,” they conclude. “Therefore, clinicians should refrain from routine, immediate lumbar imaging in patients with acute or subacute low back pain and without features suggesting a serious underlying condition.”

Changing Clinical Behavior

In a Comment accompanying the paper, Michael W. Kochen, Eva Blozik, Martin Scherer, and Jean-François Chenot, all from the University of Goettingen, in Germany, write that the findings by Chou and colleagues support guideline recommendations made on the basis of high-quality randomized trials and focus on clinically relevant outcomes, including pain or function, quality of life, and patient satisfaction rather than “mere markers of diagnostic accuracy.”

But, they ask, will the findings be enough to change clinician behavior? “At first glance there seem to be grounds for pessimism,” they write. Among these is the fact that doctors are “inundated” with guidelines, “and there is no compelling reason why more attention should be paid to low back pain than to any other prevalent condition.” Other factors include patient expectations about diagnostic testing, reimbursement structures that provide incentives for imaging, and the fear of missing relevant pathology, the editorialists add.

Worse, patients with low back pain are an “interesting market” for poorly evaluated spinal interventions, including implantation of intervertebral devices or “so-called” dynamic stabilization systems, they point out.

A “promising approach,” Dr. Kochen and colleagues conclude, is educating patients both inside and outside of general practitioners’ offices. A previous study of public education about the limited value of imaging reduced the pressure on physicians to order imaging and changed physicians’ reported management of back pain for 4 to 5 years afterward, they point out (Buchbinder R et al. Spine 2007;32:E156-E162).

“Thus, all has not been said and done,” they conclude.

The study was funded by the American Pain Society. Dr. Chou and colleagues report they have no conflict of interest. The editorialists declare they have no conflict of interest.

Lancet. 2009;373:463-472, 436-437.

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