Hands-On Approaches to the Challenges of Back Pain

(NCCAM) "Oh my aching back" is a popular phrase in U.S. culture, and for good reason. Four out of five American adults will experience low-back pain during their lives. For some people, the acute discomfort subsides within a few weeks; for others the pain becomes chronic and debilitating. Unfortunately, far too many patients do not improve, or experience little or no long-term relief, regardless of the treatment approach they choose.

Low-back pain is the most common cause of work-related disability and a leading contributor to missed days of work. It is the number one condition for which U.S. adults turn to complementary medicine approaches. In fact, according to the 2007 National Health Interview Survey, more than 14 million U.S. adults had used CAM for back pain or problems.

"Clearly, this is a symptom that really matters," says NCCAM Director Josephine P. Briggs, M.D. "People want solutions—they want adequate pain control and they want to be able to return to normal activities," she continues. "There is growing evidence that CAM approaches can play a role in relieving back pain. Thus, NCCAM is working with other NIH institutes and centers to strengthen its portfolio of research on back pain, with NCCAM focusing particularly on nonpharmacologic (nondrug) management."

Manipulative and body-based practices, such as spinal manipulation and massage, are the most common nonpharmacologic CAM approaches used for back pain. In spinal manipulation, a clinician such as a chiropractor or an osteopath uses the hands to apply controlled force to a joint, to relieve pain and increase range of motion. Close to 9 percent of adults in the United States used chiropractic or osteopathic manipulation in 2007.

Bringing Back-Pain Researchers to the Table

Researchers studying chronic low-back pain are searching for new and better methods, models, and approaches. A May 2009 NIH Workshop on Back Pain reinforced the notions that:

Chronic back pain is a symptom of multiple conditions requiring better and more specifically targeted management strategies.
To create better and more informative clinical trials, we must know more about the natural history of chronic back pain and its many causes.

To delve more deeply into these issues, NCCAM and a number of other NIH institutes and centers convened a workshop entitled “Deconstructing Back Pain” on May 10 and 11, 2010. The researchers and clinicians who gathered together discussed many topics:

Identifying what types of future studies are needed to better understand chronic back pain
Assessing new interventions and management strategies for back pain as a chronic condition
Evaluating the usefulness of existing datasets and ongoing cohort studies and how they might apply to future studies of chronic back pain
Determining what study designs should be used to look at the natural history of back pain.

The workshop discussion will help inform and guide the further development of NCCAM’s strategic approach to this major public health problem.

Studying Hands-On Therapies for Pain

Just more than 10 years ago, manipulative and body-based procedures were simply not on the research map, according to William Meeker, D.C., M.P.H., president of Palmer College of Chiropractic, West Campus, in San Jose, California. "Compared with some of the other areas of CAM—such as natural products and acupuncture—I think manipulative therapies really came from behind. Chiropractors had been saying 'we need to study manipulative therapies' for decades, as did osteopaths and physical therapists. But it wasn't a research topic."

Dr. Meeker and fellow researcher Daniel Cherkin, Ph.D., senior scientific investigator at the Group Health Center for Health Studies in Seattle, Washington, both feel that NCCAM has played a major role in promoting the development of scientifically rigorous approaches to evaluations of CAM therapies, including manipulative therapies.

More than 14 million American adults use CAM for back pain or problems.

"NCCAM's goal has been to determine the safety and effectiveness of specific manual therapies for specific conditions," says NCCAM program officer Partap S. Khalsa, D.C., Ph.D. "The field's maturity is quite variable," he says. Spinal manipulation is the most studied, whereas fewer studies have been done on massage. And finally, movement therapies—such as tai chi and yoga, Alexander technique, and Feldenkrais—have been explored to varying degrees.

For back pain, research to date shows spinal manipulation can provide mild-to-moderate relief from chronic low-back pain. Gert Bronfort, D.C., Ph.D., vice president of research at Northwestern Health Sciences University in Bloomington, Minnesota, and colleagues published a review of studies on spinal manipulative therapy for chronic low-back pain in 2008, finding moderate evidence that "spinal manipulative therapy with strengthening exercise is similar in effect to prescription nonsteroidal anti-inflammatory drugs with exercise in both the short term and long term." The researchers concluded that "spinal manipulation and spinal mobilization are at least as effective as other efficacious and commonly used interventions."

Additionally, the United Kingdom Back Pain Exercise and Manipulation trial assessed the effectiveness of physical treatments for back pain in primary care. Subjects were randomly assigned to groups receiving usual care, usual care plus exercise, usual care plus manipulation, and usual care plus manipulation and exercise. All groups improved over time, with the largest clinical benefit experienced by the group that had combined manipulation and exercise interventions.

Meanwhile, joint guidelines from the American College of Physicians and the American Pain Society included spinal manipulation as one of several treatment options, also including acupuncture and massage, for patients with back pain that doesn't improve with self-care. In an accompanying review of the evidence, the authors wrote that they "found good evidence" that spinal manipulation is "moderately effective for chronic or subacute (more than 4 weeks' duration) low-back pain."

"It's fair to say that manipulative therapies have been studied as much as or more than any other conservative treatment for back pain," says Dr. Meeker. "The preponderance of evidence shows a clinically significant benefit for a large proportion of patients who seek those therapies. The effect sizes are not huge. We're not seeing dramatic cures, but we are incrementally making people's lives better when treatment is appropriately applied." He continues, "A number of patients do not benefit, and we want to know why. That's a big research question."

two MRI (magnetic resonance imaging) images depict a region in the spine before (left) and after (right) a spinal manipulation

A Study of Spinal Manipulative Therapy

These two MRI (magnetic resonance imaging) images depict a region in the spine before (left) and after (right) a spinal manipulation, in an NCCAM-funded study. A spinal disc is toward the top of each image (see oval shape), and its two associated vertebral joints are toward the bottom. At left, when spinal segments are hypomobile (i.e., less mobile, whether from disease, lack of exercise, or another cause), connective tissue adhesions—"like small areas of glue," says the lead investigator—may develop in the zygapophyseal (Z) joint space. At right, after manipulation, the left spinal joint is more "open" (at arrow). The small rectangle in each frame depicts the location in the spine.

Study leader Gregory Cramer, D.C., Ph.D., of National University of Health Sciences, Lombard, Illinois, notes that, in theory, manipulation might "unfix" such spinal segments, help break up the adhesions, lead to fewer degenerative changes, and enhance normal motion. Among the study's goals, he says, are a deeper understanding of spinal manipulation; information to help standardize future clinical trials; and insight on which populations may benefit most from manipulation.

Photo reprinted from Journal of Manipulative and Physiological Therapeutics, 23(6), Cramer GD et al., Effects of side-posture positioning and side-posture adjusting on the lumbar zygapophysial joints as evaluated by magnetic resonance imaging: a before and after study with randomization, 380–394, © 2000, with permission from Elsevier.

Next Steps in Research

Both Dr. Meeker and Dr. Bronfort credit NCCAM for supporting training of clinical researchers who can study these modalities. In addition, the chiropractic programs at many institutions have become more evidence-based, says Dr. Bronfort. That's good news, because more work needs to be done.

There are still challenges in designing studies of body-based therapies, since blinding clinical trials (i.e., designing trials so practitioners and/or patients cannot identify the treatments being studied) is generally not practical. The practitioners have to know what treatment they are giving. And patients often are familiar with manipulation or massage, so they can tell what treatment they are receiving. Nonetheless, studies to address practical clinical questions are still feasible and important. Since body-based therapies are widely used, the key questions are generally about effectiveness, and trial designs that assess practical outcomes and permit real-world comparisons are of great value.

But, understanding the mechanisms behind what is happening is also key. Researchers at the University of Iowa have been taking a closer look at the basic biology of the spine, both to understand the underlying mechanisms that cause pain and to explain the impact of manipulative therapies. Studies done in animals suggest that joint manipulation reduces sensitivity to pain by activating specific receptors in the spinal cord that involve serotonin and noradrenaline. Other animal studies by the same research group found that joint mobilization reduces pain induced by chronic inflammation of muscle and joint. Using another animal model, researchers found that mechanical loading altered activation of the sympathetic nervous system, providing support for the notion that spinal manipulation can influence the autonomic, or involuntary, nervous system. A 2009 animal study helped to explain how manual therapies might affect proprioception, or the perception of muscle movement, specifically related to the spinal column. People with chronic back pain have poor proprioception in their backs.

In clinical studies, sophisticated imaging technologies are being used to look at effects of spinal manipulation on neural function, especially in the brain. And state-of-the-art biomechanics devices are measuring the effects of manipulation with a high degree of precision.

What determines whether an individual responds to spinal manipulation?

One of the big unanswered research questions is what determines whether an individual responds to spinal manipulation, says Dr. Khalsa. "If we could answer that question with any sort of strong evidence, it would have an enormous impact on both the public and clinicians who have to decide what to recommend," he says. Scientists are looking at biomarkers (chemicals in the body), inflammatory changes, and effects on cytokines and other immune system markers, to find substances that can be used to identify persons who will respond to manipulation.

NCCAM grantees have a long list of research questions they'd like to address. "We still need to elucidate mechanisms and the role of patient expectations and satisfaction following treatment, and how that relates to biological endpoints," says Dr. Bronfort. "It's unlikely there's any one treatment that is the answer to back pain…. We need to understand more about how individual patients are assessed and how some of these CAM therapies can be integrated into a more comprehensive treatment plan."

"We're still in the throes of trying to sort it all out," Dr. Meeker says.

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