Low Back Pain and X-rays -(un)Neccesary Radiation?
A lot of people are concerned about exposure to radiation from x-ray studies. But many back pain patients feel that their conditions have not been properly evaluated unless x-rays or other imaging studies such as CT or MRI have been performed. A recent guideline from the American College of Physicians (ACP)1 has clarified when imaging2 is and is not indicated. In the vast majority of cases it is not necessary.
The chiropractors at Root Whole Body rarely rely on imaging to make a diagnosis and provide treatment. The effects of radiation from imaging studies are cumulative, that is, the consequences can add up throughout your life.3 If you are concerned about the amount of radiation you may be exposed to, but also want to be sure your back pain is properly evaluated, here is a summary of the reasoning behind the ACP guideline.
1. The value of a diagnostic test is in its ability to improve the results of treatment. If someone has pneumonia, for example, testing to identify the pathogen that is causing the disease may result in prescribing the correct antibiotic, thus increasing the likelihood of recovery. For low back pain the opposite is true. A study of over 1800 patients with low back pain found no differences in those who had imaging and those who did not in terms of pain, function, quality of life, and overall improvement. In the first 3 months, the trend favored those who did not undergo imaging. The most important point of this finding is that many abnormalities seen on imaging are commonly found in people without back pain as well as those with back pain. These abnormal findings — osteoarthritis, for example, or a bulging disc — are not necessarily the cause of the symptoms. Thus, there is a high false positive rate.4
2. Only a very small percentage of back pain patients have serious conditions for which imaging is necessary. The following list shows some common serious conditions which can cause back pain and the frequency with which they occur.
Metastatic cancer 0.70%
Spinal infection 0.01%
Cauda equina syndrome5 0.04%
Compression fractures 4.00%
Three of the 4 conditions listed occur less than 1% of the time, and all can be spotted with a thorough medical history and identifying risk factors. When imaging is thus indicated the results can lead to an accurate diagnosis and more favorable treatment outcomes. In several clinical trials no serious conditions were missed when patients without risk factors for serious disease went without imaging.
3. Imaging results rarely affect treatment plans. In 2 studies of 100 patients each, the results of low back x-rays influenced the management of only 1 or 2 patients. Another randomized trial of imaging versus no imaging found no differences in diagnosis or treatment plans. Selecting therapies based on the results of imaging does not improve outcomes.
4. Risks of radiation exposure may far outweigh any benefits. X-rays and CT scans contribute to cumulative radiation exposure which can be carcinogenic. Of the 2.2 million lumbar (low back) CT scans performed in the US in 2007, one study estimated 1200 additional future cases of cancer. Low back x-rays are taken much more frequently than CTs. They comprise 3.3% of the total radiation dose from medical imaging procedures in the US. The average exposure from low back x-rays is 75 times higher than for chest x-rays. Because the ovaries are within the field of exposure and are difficult to shield effectively, the amount of radiation to a woman’s gonads has been estimated to be the equivalent of one chest x-ray every day for several years.
3. False positives lead to unintended harm. The common abnormalities seen on imaging, which may be unrelated to the back pain itself, can result in “labeling,” where the patient is stigmatized by the diagnosis, thus interfering with recovery by causing more worry, focusing excessively on minor back symptoms, and avoiding exercise and other activities because of the fear of further damage. In one trial of lumbar MRI, those who were given the results of their study reported smaller improvements than those who were unaware of the findings. Another study looked at back pain patients who had routine x-rays. They reported more pain and worse overall health after 3 months than those who did not have x-rays. Perhaps the most serious concern is that false positives can lead to unnecessary and sometimes risky procedures. In a study of work-related low back pain, MRI within the first month was associated with an 8-fold increase in surgery rates and a 5-fold increase in total medical expenses compared to controls.
The guideline discussed in the ACP paper has been in place since 2007, and similar guidelines preceded it. However, a survey published in 2009 found that 40% of family practice physicians and 13% of internal medicine specialists routinely ordered diagnostic imaging for low back pain. In another study, 62% of physicians said they would order lumbar x-rays for low back patients who had sciatica.6 Actual practice results bear out the survey findings. Out of 35,000 Medicare patients with acute low back pain and no serious underlying condition, nearly 30% had x-rays within the first 28 days.
Chiropractors have traditionally relied on x-rays to determine where to adjust the spine and if manipulation is safe for a patient. However, the utilization rate of x-ray by chiropractors is difficult to determine. (Information in this paragraph was not discussed in the ACP paper.) A 2002 study of chiropractors in an Ontario, Canada community found that 63% would take x-rays if the patient had back pain lasting one week, and 68% thought x-rays were useful in diagnosing low back pain of less than one month. None of the reasons given for taking x-rays was supported by evidence.7 Unfortunately, fewer than 26 chiropractors responded to the survey. A 2012 study of workers’ compensation claimants in Washington state found that seeing a chiropractor first resulted in a lower rate of MRI in the first 6 weeks following injury, but it said nothing about chiropractors’ rates of x-ray utilization.8
At Root we are concerned about the excessive and unnecessary use of x-rays and other imaging as well as determining the most appropriate diagnosis and treatment. We strive to adhere to evidence-based guidelines in our care of patients. Please don’t hesitate to contact Dr. Ku firstname.lastname@example.org or Dr. Burke email@example.com if you have concerns. Schedule an appointment here.
1 Diagnostic Imaging for Low Back Pain: Advice for High-Value Health Care From the American College of Physicians. Chou R; Qaseem A; Owens DK; Shekelle P. Ann Intern Med. 2011;154:181-189.
2 The term imaging includes x-rays, computerized tomography (CT), and magnetic resonance imaging (MRI).
3 MRI uses a magnetic field to obtain images, not radiation, but there are other negative effects common to all forms of imaging.
4 A false positive is a normal or harmless finding mistakenly interpreted as abnormal.
5 Pinching of the lower portion of the spinal cord, usually a surgical emergency.
6 The presence of sciatica (radiating leg pain), like back pain itself, is not an indication for imaging.
7 Views on Radiography Use For Patients With Acute Low Back Pain Among Chiropractors In an Ontario Community. Ammendolia C; Bombardier C; Hogg-Johnson S; Glazier R. J Manipulative Physiol Ther 2002;25:511-20.
8 Factors Associated With Early Magnetic Resonance Imaging Utilization for Acute Occupational Low Back Pain: A Population-Based Study From Washington State Workers' Compensation
Graves JM; Fulton-Kehoe D; Martin DP; Jarvik JG Franklin GM. Spine,September 01, 2012 - Volume 37 - Issue 19.
This article was written by Dr. Michael Burke.