In April of 2013, two related studies caused a media frenzy in the world of back pain that has yet to let up. Headlines have since been proclaiming that antibiotics may be able to cure as many as 40% of chronic back pain patients.
Since back pain is one of the leading causes of disability in the industrialized world, it’s not surprising that such “news” would cause a lot of excitement. However, it’s likely that the promise in these studies has been exaggerated. First, we’ll review the findings; then, we’ll take a look at why, though promising for some, antibiotics may have nothing to offer for the majority of people with back pain.
The potential promise in the two studies revolves around “modic changes” in the vertebrae. Modic changes are instances of bone swelling, or edema, on a vertebral endplate (the top and bottom of a vertebra that contact intervertebral discs) that can cause chronic back pain. Researchers in the first study theorized that bacterial infection from a nearby herniated disc may cause modic changes to vertebrae, and sought to test this theory on 61 patients with herniated discs and modic changes. Discs that were found to be infected with bacteria (43%) corresponded positively to increased modic changes in surrounding vertebrae. See link.springer.com for more on this study.
A second study was done to see if antibiotics can be used to treat back pain. Researchers treated 144 patients with previous herniated disc and demonstrated modic changes with either antibiotics or placebo for 100 days. Researchers took scores for disability, leg pain and back pain before and after treatment. The placebo group showed no improvement, but the antibiotic group showed progressive, notable improvement throughout the course of treatment, with the best results at a one-year follow-up. More on this study can be found at link.springer.com.
So, what’s not to love here? For starters, most people with chronic back pain – 85-90% — have what is called idiopathic back pain, meaning no cause is found, meaning a herniated disc isn’t a likely cause. Still, the researchers of the above study note that modic changes are found to be present in around 40% of people with back pain, even those without a herniated disc. Authors of the exciting headlines seem to interpret this to mean that antibiotics may be a treatment for all people with modic changes.
However, there are other potential causes of these changes, particularly when a herniated disc is lacking. Researchers found that, in people with degenerated discs, biomechanical force changes may lead to modic changes, and that, even in people with herniated discs, inflammatory rather than bacterial causes of such changes may be present. See more on this at www.ncbi.nlm.nih.gov. For people with idiopathic back pain, similar causes may be present.
For people with disc herniation and modic changes, antibiotics may be a valuable resource. However, we must remember that less than half of patients in the first study above were found to have bacteria in their herniated discs. This suggests that antibiotics are not even the answer for everyone with a herniated disc. For now, it’s too early to proclaim that antibiotics for back pain is the key for 40% of those affected.