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Low Back Pain MRIs, Surgery Rates Higher in Areas with More Units


doi: 10.1097/01.NT.0000365684.86799.6c
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Investigators reported a 1.23-fold increase in the likelihood of surgery for nonspecific low back pain if patients lived in areas with the greatest concentrations of MRI scanners, compared to places with the fewest units.

Patients with nonspecific low back pain have significantly greater odds of having an MRI and undergoing subsequent surgery within the first year if they live in an area with an abundance of MRIs, according to a new study.

Despite questions about the efficacy of imaging or surgery for low back pain within the first year, and a number of professional clinical guidelines advising against either, researchers at Stanford University reported a 1.23-fold increase in the likelihood of surgery for nonspecific low back pain if patients lived in areas with the greatest concentrations of MRI scanners, compared to places with the fewest units.



About two-thirds of the scans occurred within the first month of pain onset, despite clinical guidelines that recommend waiting at least four weeks to see if patients recover on their own, as many do.

In 2004 alone, there would have been 5.4 percent fewer low-back MRIs and 9 percent fewer surgerical procedures if all patients had lived in areas with the fewest MRIs.

The findings were reported online Oct. 14 ahead of the print edition of the journal Health Affairs, a public policy research publication.

Senior author Lawrence Baker, PhD, professor of health research and policy, and Jacqueline Baras, a Stanford medical student with a master's degree in health services research, assessed the number of scans and surgical claims in a 20 percent sample of Medicare patients living in 318 metropolitan areas. They then compared the data with the number of MRI units in each area.

The final sample included claims for 666,455 episodes of low back pain, of which 15.6 percent resulted in an MRI and 2.7 percent resulted in surgery within one year.

Extrapolated to the entire Medicare population in 2004, 456,250 patients in the highest MRI-availability areas had a 17.2 percent chance of receiving an MRI within one year. If all patients lived in the lowest availability areas there would have been 6,388 fewer scans, according to the study.

“Not only are patients in high-availability areas getting more MRIs, but they are getting them earlier,” the authors noted.

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Practice guidelines issued in 2007 by the American College of Physicians and the American Pain Society “strongly” advise against imaging in patients with nonspecific low back pain within the first six weeks unless severe or progressive neurologic deficits are present, or serious underlying conditions are suspected.

The Agency for Healthcare Policy and Research recommends waiting at least three months before referring patients for surgery, while a European working group has advised waiting two years. According to a literature review published in the February 2009 issue of the Journal of the Academy of Orthopedic Surgeons, 90 percent of low back pain symptoms resolve within three months.

Nonetheless, the number of MRI units in the United States more than tripled between 2000 and 2005, from 7.6 to 26.6 per million individuals, according to the Organization for Economic Cooperation and Development. MRI was among the fastest-growing service paid for under the Medicare Part B physician fee schedule during the same period.

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High-end scanners can cost upward of $2 million per unit, but many of them are far less expensive, older, and their usefulness is questionable, said Gary M. Franklin, MD, research professor of environmental and occupational health sciences (neurology) at the University of Washington in Seattle.

Dr. Franklin studies the impact managed care delivery systems have on cost and outcome in neurological injuries.

“A lot of the increase in MRI availability has not been in high quality scanners but in lower quality equipment, but they charge the same amount for their services,” he said. “What is clear from this paper is that there are too many MRIs being done too early in low back pain patients, and I know many of these are being done on lower-quality CT equipment.”

Addressing excessive imaging and surgeries for low back pain should be considered an important part of health care reform, he noted.



“The paper is very well done, and confirms what a number of other researchers have reported. It is pretty clever that they matched Medicare data with other sources of MRI availability data. What they found is not especially surprising, but it is important,” he said. “I think whoever buys a unit feels they have to use it.”

He noted that Washington State recently passed the nation's first law mandating prospective review of MRI requests for Medicaid patients, using evidence-based standards.

“When it comes to Medicaid claims that need to be reviewed, MRIs for low back pain are at the top of the list. Within six months, Washingon's Medicaid and worker's compensation agencies will require prospective review of all imaging claims,” he said.

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Richard Deyo, MD, the Kaiser Permanente Professor of Evidence-Based Family Medicine at Oregon Health and Science University in Portland, noted that the bulk of evidence has shown MRIs and surgery to be unnecessary for such patients early on.

“Unfortunately, this study confirms what others have found — the more hardware there is out there, the more MRIs, and more surgeries,” he told Neurology Today in a telephone interview.

“Excessive imaging is driving up the surgery rate for these patients — the more scans you do, the more surgeries — but it remains unclear whether any of it improves outcomes. There is a lot of evidence that it does not.”

He noted that study conducted by James N. Weinstein, MD, at Dartmouth Medical School, compared one-year outcomes in 400 low back pain patients following either an X-ray or MRI. “ Although twice as many MRI patients had surgery, there was little difference in outcomes,” Dr. Deyo said.

Professional guidelines, he added, offer little help. The American College of Radiology, the North American Spine Society, the American Pain Society, and the American College of Physicians have all weighed in with recommendations against surgery for most patients, but the criteria for selection “is ambiguous,” he said. “There are too many conflicts and too much uncertainty. Patients and physicians need to understand that there are many people with abnormalities on their MRI that have never had any back pain or sciatica.”

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• Baras J, Baker L. Magnetic resonance imaging and low back pain care for Medicare patients. Health Affairs 2009;28:1133–1140; E-pub 2009 Oct. 14.
    • Chou R, Qaseem A, Snow V, et al. Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Ann Intern Med 2007;147:478–491.
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            • Weinstein JN, et al. Surgical vs. nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. JAMA 2006;296:2441–2450.
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                ©2009 American Academy of Neurology