An aching back -- a dull twinge or a stabbing pain, lasting days or years -- is a source of annoyance, misery or even disability for millions of sufferers.
Eighty percent of the population will experience back pain at some point in their lives, and while the majority of cases resolve quickly, 30% recur, according to the North American Spine Society, an association of spinal health professionals based in Burr Ridge, Ill.
Those aching backs, in turn, cost Americans more than $80 billion in healthcare costs, time off from work and other expenses, the spine society says. There is evidence that the suffering is rising slightly -- perhaps because people spend more time hunched over computer keyboards. A 2008 study, published in the Journal of the American Medical Assn., found that the percentage of U.S. adults seeking medical help for spine problems rose from 12% in 2000 to 15% in 2005.
Rising significantly, meanwhile, are expensive treatments and surgeries that may not help patients much. The same study found that patients are spending more money on back pain treatment -- an average of $6,096 per patient in 2005, up from $4,695 in 1997 -- without seeing corresponding improvements in how they feel.
The research implies that expensive treatments with glossy advertising may not be as good as they sound, says study author Brook Martin, a health services researcher at the University of Washington in Seattle.
Surgery rates, in particular, are going up. More professionals now argue that doctors need to think more before they resort to the knife. They note that the U.S. has, by far, the highest frequency of back surgeries among developed nations: There are approximately 1.2 million spinal surgeries in the U.S. each year, double the rate in those other countries. Yet there is no evidence that Americans have a higher rate of back pain or injury.
"I don't think you want to take the surgical option lightly," says Dr. Gunnar Andersson, an orthopedic surgeon at the Rush University Medical Center in Chicago.
For the lucky ones who benefit from surgery, it's certainly worth the risk and costs, he says. Others may not get the results they anticipate.
Spine sets squeezed
The spine is a stack of bony vertebrae separated by gel-filled discs that act as shock absorbers. "It's one of the major ways the human body fails," says Dr. Aaron Filler, a spinal surgeon in Santa Monica. In part, back pain is the price mankind pays to stand upright. When the spine is horizontal, as it is in a four-legged animal, additional weight causes the vertebrae to spread out. But in people, more weight pushes the vertebrae and discs together -- and there is only so far the structure can compress.
Over time the effects of aging, use and gravity wear on the spine, making the 40-plus crowd most susceptible to back pain, though injury or stress can occur at any age.
Back pain is a symptom with many possible causes. Sprains, muscle tears and spasms are common. The discs, which cushion the vertebrae, can also suffer injury. In a herniated disc, the gel inside leaks out and irritates nearby nerves. Or the disc's outer layer merely thins, allowing the gel inside to form a bulge, which may also poke a nerve.
The joints between vertebrae, called facet joints, are susceptible to wear and tear, particularly in people with arthritis. The joint's cushioning cartilage can wear thin and the bone can jut out, causing pain in the back and thighs.
And as discs or bone protrude past their normal locations, the interior of the spine can narrow, putting pressure on nerves in a condition called stenosis.
Older people are more susceptible to back pain as are pregnant women, who carry added weight on the spine. Children, however, are not likely to suffer back pain without an obvious injury as the cause. "If I see a teenager with back pain, it really raises red flags," says chiropractor Robert Hayden of Griffin, Ga.
Hayden believes part of the rise in back pain patients has to do with the personal computer. Leaning over to type or peer at the screen strains the extensor muscles in the neck and the trapezius and rhomboid muscles that hold up the shoulders. The extensors, in particular, are small, thin muscles, and with too much use they can run out of oxygen, causing irritation or spasms.
The postural muscles in the lower spine, such as the quadratus lumborum, can also get sore if a person leans forward or slumps for a long time.
Being inactive can contribute to back problems because the body's core muscles -- the back and abdominal muscles that hold up the torso -- weaken and become more susceptible to tears or pulls. Weak muscles can also cause problems by forcing the spine to support extra weight -- as does obesity.
The good news is that most back pain goes away on its own. For minor complaints such as muscle strains, most doctors recommend over-the-counter painkillers, heat to relax the muscles, or ice to reduce swelling and numb pain.