Is Your Back Pain Caused By OA?
Osteoarthritis of the spine is more common than you think.
Studies show that four out of five adults have back pain at some time in their lives. With an aging U.S. population, back pain may be a growing problem, since osteoarthritis (OA) typically emerges in people over age 40, and the spine is a prime target for this common joint condition. But just how much of our nation’s back pain is caused by OA? “That’s the $64,000 question,” says University of Pittsburgh pain specialist Debra K. Weiner, MD. Back pain is a complex condition, and OA is often just one piece of the puzzle.
OA and the Spine
Osteoarthritis is a disease of the joints, and your back has plenty. The spine is a column of 33 bones called vertebrae. Five of the lower vertebrae are fused into the sacrum; another four combine to form the tailbone. The rest of the vertebrae are connected by facet joints. Tucked between each vertebra are cushion-like pads called disks, which protect the spine and give it flexibility. Resting within the column of vertebrae lies the spinal cord.
Viewed from the side, the spine forms a graceful S shape. Yet this elegant structure is vulnerable to OA—especially in the lower, or lumbar, region—thanks in large part to the fact that we walk on two legs. “That produces a constant loading on the spine,” says Michael Marks, MD, a spokesperson for the American Academy of Orthopedic Surgeons. As we age, the cartilage lining the facet joints wears away. Meanwhile, disks in the spine narrow due to water loss, adding pressure on the facet joints (and subtracting from your overall height). As a result of these changes, says Dr. Marks, the facet joints can develop inflammation.
Osteoarthritis can make the spine unstable, explains Dr. Marks. In response, growths called osteophytes, or bone spurs, can form. While bone spurs appear to be the body’s attempt to restore stability, they can cause the spine to stiffen. As OA worsens, bone spurs can narrow the “frames” where nerves exit the spinal cord. This condition, called spinal stenosis, can pinch nerves and cause numbness and weakness in the legs.
Not Just Joints
Trauma to the spine increases your chances of having spinal OA. “If you were a football lineman with constant impact, you’re more likely to have it [spinal OA] than someone who was a swimmer,” says Dr. Marks. However, genetics plays a role too; if one or both of your parents had OA in the spine, your odds rise. Dr. Marks estimates that OA is the likely culprit in about 20% of 40-year-old men and women who develop back pain, a figure he says rises to as much as 75% among people over age 60.
However, some doctors who treat back pain feel that OA gets too much of the blame. X-rays reveal that the vast majority of middle-aged and older men and women have OA and disk degeneration in their spinal joints, yet many have no symptoms. “They’re walking around on the street, pain free,” says Norman Marcus, MD, director of the division of muscle pain research in the department of anesthesiology at the New York University School of Medicine.
Dr. Marcus argues that weak, stiff or damaged muscles are responsible for three out of four bad backs, regardless of age. Dr. Marcus believes that doctors who target OA of the spine as a significant contributor to this common problem are misguided.
Dr. Weiner feels that while there’s “definitely too much focus” on OA as a source of back pain, she says it can be part of the problem. “Back pain is usually multifactorial,” she says. For instance, studies show that 7% of women over 60 have fibromyalgia, a condition of unknown origin that can cause back pain. OA is also linked to scoliosis, or abnormal curvature of the spine. Depression and anxiety, or even having mismatched leg lengths can contribute, too, says Dr. Weiner.
Exercise is a Must
Given that back pain has many causes beyond OA, it’s no surprise experts say there’s no one-size-fits-all treatment. Some patients respond well to simple over-the-counter pain relievers such as ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs). For severe inflammation, cortisone injections can provide relief, although it’s often temporary.
When nothing else helps, surgery is a last resort. According to Dr. Marks, many patients with OA of the spine respond well to a procedure called laminectomy, in which a surgeon removes a portion of bone from vertebrae to relieve pressure on the spinal cord and nerves.
Regardless what’s causing your back pain, all doctors agree that getting it under control requires exercise to increase the strength and flexibility of muscles that support the spine. But for some, that means overcoming tension in the muscle between their ears.
“People often believe their pain is unsafe,” says Carol Hartigan, MD, a spine physician at New England Baptist Hospital in Boston. “They become fearful of moving, and start to anticipate pain and avoid activities. That makes your muscles weak and tight, which makes you more sensitive to pain.” Once Dr. Hartigan and her colleagues rule out potentially serious causes of back pain, they start educating patients. “We tell them: It’s safe to move, even if you initially experience some pain,” says Dr. Hartigan. Exercising increases blood flow to the back, which nourishes joints and muscles while clearing away destructive inflammatory waste products.
Just as importantly, a patient’s fear gradually clears away too. For many, realizing they can once again unload the dishwasher or take out the trash without wincing is a revelation. “They feel less afraid to move,” says Dr. Hartigan. “They say: Oh my gosh, I actually did that—and it was okay.”
Updated June 26, 2015