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What’s the deal with chiropractic? Real, or quackery? —Scott S.

The short answer: It depends on who’s doing it and what kind of results you expect.

Chiropractic was dreamed up in Davenport, Iowa, in 1895 by a guy named Daniel David Palmer. Unburdened by any formal medical training (not that medical training circa 1895 was always so great), Palmer was a devotee of phrenology, magnetic therapy, and other metaphysically inclined notions of the era, and he conceived of chiropractic as a “philosophy, art, and science” of healing. Its core premises: (1) The body is possessed of an “innate intelligence” that permits it, under ordinary circumstances, to repair itself as needed; (2) this innate intelligence is transmitted through the nervous system, and disease is usually caused by disruptions in the “nerve flow” resulting from “subluxation,” or misalignment, of the vertebrae; therefore (3) pretty much any ailment—deafness, heart trouble, you name it—can be treated by manual adjustments to the spine. Such an adjustment would typically consist of an abrupt push or pull on the back or neck, involving about the same range of movement as cracking your knuckles.

OK, so Palmer was in no small part a wacko, but this hardly differentiated him from many other quasimedical pioneers of the era—back then it was something of a seller’s market for zany ideas about health. What’s alarming is that there are many chiropractors working today who haven’t progressed much beyond Palmer’s initial precepts. These old-school types, known as traditional or philosophy-based chiropractors, still insist that spinal manipulation improves health by restoring the body’s “neural homeostasis.” Generally, such chiropractors don’t bother with clinical diagnosis or medical examination; adjustments aren’t necessarily a cure for what ails you but often a means of managing it long-term, meaning patients come in for multiple treatments over an extended period of time. Is this quackery? The continued existence of philosophy-based chiropractic suggests that some patients at least are experiencing results they’re OK with. Let’s just say I’ve got my doubts about any theory of medicine whose tenets were largely in place before the role of germs was widely understood.

On the other side you’ve got a significant number of chiropractors who’ve been more receptive to medical insights gleaned over the past century. Such new-breed chiropractors are often affiliated with hospitals or doctors’ practices and typically conduct thorough intake exams (including X-rays, MRIs, etc.) as a matter of course. They’ll use spinal manipulation to treat non-disease-related back disorders, but they’re willing to break out some other tools in the therapeutic toolbox as well, which may include ultrasound, electric muscle stimulation, rehab exercises, and the like; they’ll also provide suggestions about lifting and bending techniques, diet, and ergonomics. Science-friendly chiropractors tend to have good success rates in combating lower back pain and tension headaches.

As you might imagine, scientific studies haven’t turned up much in support of the traditional chiropractic worldview. Ignoring dodgy research conducted by chiropractic true believers, there’s nothing out there to suggest that the disruption of nerve impulses causes disease. Thus, tweaking the vertebrae in the neck probably isn’t going to help anyone’s ear infection. There is clear evidence, though, that spinal adjustment can provide relief for acute back troubles, widening range of motion, improving function, and decreasing pain.

Then, of course, there are findings that you just don’t see coming. Writing last year in the Journal of Human Hypertension, a team of medical researchers reported on a placebo-controlled study in which people suffering from high blood pressure received a particular chiropractic adjustment to the C-1 or Atlas vertebra, which holds up the head. What happened? The procedure did in fact realign the vertebra with the rest of the spinal column, and the patients who underwent it showed significantly lower blood pressure for a sustained period afterward. It’s not clear why this should be, and the authors caution that it probably wouldn’t work for everyone, but still.

So if you’re suffering from lower back pain, is chiropractic worth a shot? Yeah, maybe. First see a doctor and rule out any underlying disease—if you’ve got osteoporosis, for example, you’re not a good candidate. Keep in mind that if spinal adjustment is going to help, you should see real improvement within a few weeks. And make sure to find a chiropractor who’s operating on a 21st-century scientific model; if you hear “subluxation,” just keep walking.

Is there something you need to get straight? Take it up with Cecil on the Straight Dope message board, straightdope.com.