The vast majority of adults have had a sore back at some point in their lives. If they're lucky, the pain subsides after a few days or weeks. But for some, whose initial injuries appear no different than the fortunate ones, back pain lasts for years. Now, researchers have discovered a difference in brain scans between the two groups of patients that appears early in the course of the pain. The finding could lead to not only ways of identifying patients who are the most at risk for long-term pain but to new treatments or preventions for chronic pain.
"This is the very first time we can say that if we have two subjects who have the same type of injury for the same amount of time, we can predict who will become a chronic pain patient versus who will not," says neuroscientist Vania Apkarian of Northwestern University, Chicago, who led the new work.
Over the past 2 decades, Apkarian's lab has run many studies comparing the brains of patients with chronic back pain with those of healthy people, finding differences in brain anatomy or the function of certain regions. But the study designs made it hard to sort out which brain changes were consequences of the chronic pain—or the patients' painkillers or altered lifestyles—versus those that drove the pain's chronic nature.