More MRI machines may mean more back surgeries
A new study suggests that the increasing availability of MRI scanners may be feeding an increase in surgery for lower back pain—despite doubts about the effectiveness of surgery for most people.
Looking at MRI availability in 318 U.S. metropolitan areas, researchers found that Medicare patients with low back pain were more likely to get a scan when they lived in an area with more MRI machines.
Greater MRI availability was also linked to higher odds of getting lower back surgery, the investigators report in the journal Health Affairs.
Surgery can be appropriate for some causes of chronic lower back pain, such as a herniated spinal disk or a narrowing of the spinal canal called spinal stenosis. But for most people with lower back pain, the precise cause is unclear, and the pain often resolves without any extensive therapy.
Because of this, experts generally recommend that people with back pain delay having an MRI for at least a month. And surgery should be considered only when the cause is clear and more conservative treatments fail.
The problem with widespread use of MRI is that the scans—which visualize soft tissue like the spinal discs and muscles—can detect anomalies that may or may not be the cause of a person’s back woes.
So the concern is that some patients may end up getting an invasive treatment that will not help them, say Dr. Laurence C. Baker and Jacqueline D. Baras of Stanford University School of Medicine in California.
“There are some circumstances in which MRI for low back problems is appropriate, and also some circumstances in which surgery can be appropriate,” Baker and Baras told Reuters Health in an email. “There are also other situations where they are not.”
Whether any one person needs an MRI or surgery is something that can only be decided by the doctor and patient, the researchers said.
“If our article encourages doctors and patients to have a conversation about the best tests and treatments in the patient’s specific circumstance,” they added, “we think that would be a good thing.”
The findings are based on Medicare claims data for more than 666,000 cases of lower back pain treated between 1998 and 2005. MRI scans were performed in about 16 percent of cases, and nearly 3 percent of patients underwent surgery within a year of first visiting the doctor.
The likelihood of getting an MRI inched up along with the number of MRI machines in the metropolitan area. For example, people who lived in areas with the highest concentration of scanners had a 7 percent chance of having an MRI within a month of seeing the doctor; those in areas with the fewest machines had a 6 percent chance.
The difference may look small, but on a broader level, the numbers add up. The researchers point out that if all study patients had lived in the areas with the fewest MRI machines, they would have had about 12,000 fewer scans performed over a year—and about 3,500 fewer surgeries.
“It is often the case that patients and doctors automatically think that more care is better care, and this can contribute to overuse of care,” Baker and Baras said.
According to the researchers, “we as a country need to develop a more nuanced view” of high-tech medical services, which includes accepting the fact that they will not always be helpful.
SOURCE: Health Affairs, online October 14, 2009.
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