Found this in an interesting article from Jonah Lehrer (jonahlehrer.com):
"Back pain is an epidemic. The numbers are sobering: There’s an 80 percent chance that, at some point in your life, you’ll suffer from it. At any given time, about 10 percent of Americans are completely incapacitated by their lumbar regions, which is why back pain is the second most frequent reason people seek medical care, after general checkups. And all this treatment is expensive: According to a recent study in The Journal of the American Medical Association, Americans spend nearly $90 billion every year treating back pain, which is roughly equivalent to what we spend on cancer.
When doctors began encountering a surge in patients with lower back pain in the mid-20th century, they had few explanations. The lower back is an exquisitely complicated area of the body, full of small bones, ligaments, spinal discs, and minor muscles. Then there’s the spinal cord itself, a thick cable of nerves that can be easily disturbed. There are so many moving parts in the back that doctors had difficulty figuring out what, exactly, was causing a person’s pain. As a result, patients were typically sent home with a prescription for bed rest.
This treatment plan, though simple, was still extremely effective. Even when nothing was done to the lower back, about 90 percent of people with back pain got better within six weeks. The body healed itself, the inflammation subsided, the nerve relaxed.
Over the next few decades, this hands-off approach to back pain remained the standard medical treatment. That all changed, however, with the introduction of magnetic resonance imaging in the late 1970s. These diagnostic machines use powerful magnets to generate stunningly detailed images of the body’s interior. Within a few years, the MRI machine became a crucial diagnostic tool.
The view afforded by MRI led to a new causal story: Back pain was the result of abnormalities in the spinal discs, those supple buffers between the vertebrae. The MRIs certainly supplied bleak evidence: Back pain was strongly correlated with seriously degenerated discs, which were in turn thought to cause inflammation of the local nerves. Consequently, doctors began administering epidurals to quiet the pain, and if it persisted they would surgically remove the damaged disc tissue.
But the vivid images were misleading. It turns out that disc abnormalities are typically not the cause of chronic back pain. The presence of such abnormalities is just as likely to be correlated with the absence of back problems, as a 1994 study published in The New England Journal of Medicine showed. The researchers imaged the spinal regions of 98 people with no back pain. The results were shocking: Two-thirds of normal patients exhibited “serious problems” like bulging or protruding tissue. In 38 percent of these patients, the MRI revealed multiple damaged discs. Nevertheless, none of these people were in pain. The study concluded that, in most cases, “the discovery of a bulge or protrusion on an MRI scan in a patient with low back pain may frequently be coincidental.”
Similar patterns appear in a new study by James Andrews, a sports medicine orthopedist. He scanned the shoulders of 31 professional baseball pitchers. Their MRIs showed that 90 percent of them had abnormal cartilage, a sign of damage that would typically lead to surgery. Yet they were all in perfect health.
This is not the way things are supposed to work. We assume that more information will make it easier to find the cause, that seeing the soft tissue of the back will reveal the source of the pain, or at least some useful correlations. Unfortunately, that often doesn’t happen. Our habits of visual conclusion-jumping take over. All those extra details end up confusing us; the more we know, the less we seem to understand.
The only solution for this mental flaw is to deliberately ignore a wealth of facts, even when the facts seem relevant. This is what’s happening with the treatment of back pain: Doctors are now encouraged to not order MRIs when making diagnoses. The latest clinical guidelines issued by the American College of Physicians and the American Pain Society strongly recommended that doctors “not routinely obtain imaging or other diagnostic tests in patients with nonspecific low back pain.”
(However, most GPs and even specialists in the UK dont seem to know this!)
Chronic back pain remains a mystery. While doctors have long assumed that there’s a valid correlation between pain and physical artifacts—a herniated disc, a sheared muscle, a pinched nerve—there’s a growing body of evidence suggesting the role of seemingly unrelated factors. For instance, a recent study published in the journal Spine concluded that minor physical trauma had virtually no relationship with disabling pain. Instead, the researchers found that a small subset of “nonspinal factors,” such as depression and smoking, were most closely associated with episodes of serious pain. We keep trying to fix the back, but perhaps the back isn’t what needs fixing. Perhaps we’re searching for causes in the wrong place.
The same confusion afflicts so many of our most advanced causal stories. Hormone replacement therapy was supposed to reduce the risk of heart attack in postmenopausal women—estrogen prevents inflammation in blood vessels—but a series of recent clinical trials found that it did the opposite, at least among older women. (Estrogen therapy was also supposed to ward off Alzheimer’s, but that doesn’t seem to work, either.) We were told that vitamin D supplements prevented bone loss in people with multiple sclerosis and that vitamin E supplements reduced cardiovascular disease—neither turns out to be true."
Contributing editor Jonah Lehrer (jonahlehrer.com) is the author of the forthcoming book Imagine: How Creativity Works.
