MEDICATIONS: MRIS VS. X-RAYS LEAD TO SIMILAR OUTCOMES FOR PATIENTS WITH LOW BACK PAIN

June 3, 2003 — Although many physicians and patients prefer a rapid MRI than an X-ray for the evaluation of low back pain, there is no significant difference at one year later in pain, disability or general health status between the two imaging procedures, and MRIs appear to increase the number of spine operations and increase costs, according to a study in the June 4 issue of The Journal of the American Medical Association (JAMA).

According to background information in the article, rapid magnetic resonance imaging (MRI) scanning has made MRI a potential cost-effective replacement for radiographs (X-rays) for patients with low back pain. But whether rapid MRI scanning results in cost effectiveness or better patient outcome than radiographic evaluation has been unknown.

Jeffrey G. Jarvik, M.D., M.P.H., of the Department of Radiology, University of Washington, Seattle, and colleagues conducted a study to determine the clinical and economic consequences of replacing spine radiographs with rapid MRI for primary care patients. The study was a randomized controlled trial of 380 patients aged 18 years or older whose primary physicians had ordered that their low back pain be evaluated by X-rays.

The patients were recruited between November 1998 and June 2000 from one of four imaging centers in the Seattle area, including a university-based teaching program, a nonuniversity-based teaching program, and two private clinics. Patients were randomly assigned to receive lumbar spine evaluation by rapid MRI or by radiograph. At 12 months, primary outcomes of functional disability were obtained from 337 (89 percent) of the 380 patients enrolled.

The average back-related disability modified Roland score (based on a questionnaire about back pain disability and how back pain affects common daily activities; higher scores indicate worse function) for the 170 patients assigned to the radiograph evaluation group was 8.75 vs. 9.34 for the 167 patients assigned the rapid MRI evaluation group. The mean difference between the two groups in the secondary outcomes concerning pain bothersomeness, pain frequency, subscales of bodily pain and physical functioning were not statistically significant.

Ten patients in the rapid MRI group vs. four in the radiograph group had lumbar spine operations. The rapid MRI strategy had a mean cost of $2,380 vs. $2,059 for the radiograph strategy.

"A major impetus for this work was the concern that substituting radiographs with rapid MRI scans would result in worse patient outcomes because incidental abnormalities would foster increased interventions and unnecessary morbidity. Our study suggests that substituting rapid MRI scan for radiographs is likely safe but may in fact result in more specialist consultations and operations. Despite the higher rate of surgery, average outcomes were not better among those in the rapid MRI group," the authors write.

"Given the current evidence, it is difficult to make strong recommendations regarding the use of rapid MRI for patients with low back pain," they add. "Rapid MRI has the potential to increase the number of back operations without an apparent benefit to patients and perhaps to increase costs. If the use of rapid MRI scans disseminates widely and surgical complications are more common than we observed, the consequences could be detrimental. In this setting, a cautious approach is probably most prudent, and we recommend that rapid MRI not become the first imaging test for primary care patients with back pain until its consequences for surgical rates and costs are better defined."

Editorial: MRI For Regional Back Pain — Need for Less Imaging, Better Understanding

In an accompanying editorial, Nortin M. Hadler, M.D., of the University of North Carolina, Chapel Hill, writes that "as a result of this randomized controlled trial, rapid MRI joins the ranks of appealing innovations that have proved illusory. Modern medicine is conditioned to be swayed by such a deduction, as is society at large, and is less conditioned to question the reasoning that generated the experiment in the first place. The results reported by Jarvik et al demand careful reflection before anyone rushes to develop a more rapid MRI. Why is it so important to define the anatomy of the lumbosacral spines of patients with regional back pain?"

"As Jarvik et al point out ..., low specificity limits the diagnostic utility of MRI scans as much as it limits that of radiographs. Magnetic resonance imaging cannot be used to predict back pain. Magnetic resonance imaging is not even sensitive to anatomical changes that might correlate with new symptoms. Cost has little to do with cost-effectiveness if imaging is ineffective," writes Dr. Hadler.