By Dr. Craig F. Nelson
Posted: Thursday, April 1, 1999
ARTICLES
Publication Date: April 1, 1999
The chiropractic profession has crusaded against one of the most effective public health measures of all time¬vaccination¬and many of its members publicly scoff at the germ theory of disease. Even today some chiropractors are openly opposed to vaccination. Some practice "muscle testing"¬for example, manually, subjectively appraising the muscle strength of a patient with a vitamin pill in his or her hand as a means of diagnosing nutritional deficiencies.
Thus, it may seem at first glance that, for the scientist or skeptic, the only fitting posture toward chiropractic is adversarial. The chiropractic situation, however, is far more complex than the facts provided above suggest. While knowledge of those facts can contribute to insight regarding the profession, it may also tend to obscure both real-life benefits to patients and potential contributions to the health of the public. Indeed, there are good reasons for scientists and skeptics to support the maturation of chiropractic¬along scientific lines.
Chiropractic Theory
Chiropractic originally had four basic assumptions: (1) that a force animates and regulates the human body; (2) that this force, which chiropractors call "Innate Intelligence," flows through the body via the nervous system; (3) that vertebral misalignments, or "subluxations," hinder Innate Intelligence; and (4) that such hindrance is the cause of disease. The corollary of these principles is that correcting "subluxations" cures disease. Traditional chiropractors try to correct these alleged misalignments only manually. Critical thinkers, of course, do not consider the notions outlined above a compelling basis for a healthcare profession.
Some chiropractors believe that Innate Intelligence is a physiologic entity; some consider it an embarrassing anachronism . . . .
Nearly every mode or system of alternative medicine has a theory that posits something vitalistic, supernatural, and/or mystical. But explaining how such a method might have a specific effect on a disease does not unexceptionally entail recourse to such concepts. Pain reduction from acupuncture, for example, is explainable without reference to the concepts of chi and invisible carriers thereof. [See "Horsefeathers: Acu-puncture from a Veterinary Perspective," page 14] Similarly, how spinal manipulation (also called "spinal manipulation therapy")¬manual thrusting that induces the momentary separation of joint surfaces¬can reduce back and neck pain is explainable without reference to the concept of Innate Intelligence or to a vitalistic subluxation theory. In contrast, it is impossible to explain in naturalistic, nonvitalistic terms how a "high-potency" homeopathic "remedy"¬a preparation without even one molecule of the "active ingredient"¬might have a specific health effect.
Whether the healthful results of spinal manipulation are biomechanical effects or nonspecific (placebo) effects has not been determined.
The hypothesis that manually moving a joint near a locus of physical pain might diminish that pain is reasonable and testable; accepting this hypothesis does not require suspension of critical thinking. It is also plausible, or at least not inconsistent with what is known about human physiology, that spinal manipulation therapy (SMT) might have other healthful physical effects, though no such effects have been demonstrated.
Some chiropractors believe that Innate Intel-ligence is a physiologic entity; some consider it an embarrassing anachronism; most regard it as a useful metaphor for the human body's self-healing mech-anisms. But whether a chiropractor regards Innate Intelligence as objective, usefully symbolic, or simply nonexistent probably has little or no effect on how he or she performs SMT.
Scientists have found no specific effects of spinal manipulation on hypertension or on adult or childhood asthma.
Yale anatomy professor Edmund S. Crelin, Ph.D., D.Sc., tested chiropractic's basic subluxation theory in 1973. He subjected the spines of six human cadavers to a series of mechanical forces and measured the effects of these forces on the sizes and shapes of the intervertebral foramina¬the openings through which spinal nerves pass and where, according to chiropractic theory, vertebral subluxations induce the pinching of nerves and thereby destabilize the flow of Innate Intelligence. Crelin found that no force short of that which broke the spine deformed the openings so that their walls contacted the nerves. Publication of his findings cast enormous doubt on chiropractic's "pinched nerve" theory.
Healthful Effects of Spinal Manipulation
Crelin showed that one of the bedrock principles of chiropractic¬the hypothesis that the vertebral pinching of spinal nerves impairs nerve functioning¬is almost certainly invalid. Chiro-practic without this principle is analogous to meridianless acu-puncture.
The most serious condition associated as a side effect with spinal manipulation is stroke subsequent to treatment of the cervical (neck) portion of the spine.
But the consensus of researchers, clinicians, and health policy analysts is that SMT is an effective modality for the most common forms of low back pain. This conclusion¬reached in several systematic reviews and in a study from the Agency for Health Care Policy and Research¬is based on the findings of numerous randomized clinical trials of SMT, most of which were conducted in the last ten years. Doubts were expressed in the re-views, and questions were raised, such as: Is SMT effective against both acute and chronic low back pain? Is it relatively cost-effective? Is it effective against sciatica? But such doubts and questions stem less from conflicting experimental findings than from a lack of data.
Somewhat less certain is the utility of SMT for headaches and neck pain; studies on SMT and such discomfort have been far fewer than those on SMT and low back pain.
Whether the healthful results of SMT are biomechanical effects or nonspecific (placebo) effects has not been determined. Nearly all trials of SMT have been pragmatic studies¬studies in which researchers compare two or more "active" (nonplacebo) treatments (e.g., SMT and a medication)¬rather than placebo-controlled trials¬studies in which researchers compare an "active" treatment and a sham treatment. The problem here is largely methodological: How can one nontherapeutically manipulate the spine in a manner that appears therapeutic to the patient?
That some chiropractors steadfastly promote absurd beliefs about health and disease complicates the question of chiropractic-treatment risks.
This description of the status of SMT, which may seem damning with faint praise, should be considered in relation to how little is known about back pain¬low back pain and neck pain¬and its treatment. A considerable research effort over the last two decades by the medical and chiropractic professions has failed to provide answers to the most basic questions about low back pain: What causes it? What can prevent it? Who are likeliest to develop it? What is the best remedy for any individual with back pain? The experts have agreed on only two points: (1) that persons with low back pain should avoid prolonged bed rest and inactivity, and (2) that surgery for low back pain is appropriate only in rare circumstances and only if conservative measures have failed.
Which of the many nonsurgical treatments for low back pain is most effective has not been determined; and such a determination does not, to say the least, seem imminent. In terms of safety and efficacy, the most that can judiciously be said about any treatment for back pain is whether or not it is a reasonable therapeutic option. SMT is among the more tested and better understood of such options.
That the profession has an autonomous scientific research community that upholds skepticism and disinterested inquiry distinguishes chiropractic from other modes of alternative medicine.
Much of the controversy over chiropractic and SMT regards ap-plying the latter to nonmusculo-skeletal conditions. This has been the focus of very few studies, and these have not justified such use of SMT. Scientists have found no specific effects of SMT on hypertension or on adult or childhood asthma. But the application of SMT to nonmusculoskeletal conditions may be a moot issue, for¬contrary to the wishes of some chiropractors and the insinuations of some critics¬instances of such appear rare. According to the most comprehensive study of chiropractic usage in the United States, published in 1998, chiropractors treat less than one percent of their patients for visceral (e.g., cardiovascular, gastrointestinal, and respiratory) problems. The belief that SMT is effective against various nonmusculoskeletal conditions has been strong in the profession, but, without scientific grounds, it is unlikely that the application of SMT to nonmusculoskeletal conditions will increase.
Risks of Spinal Manipulation
The most serious condition associated as a side effect with SMT is stroke subsequent to treatment of the cervical (neck) portion of the spine. A stroke can result in permanent impairment of the central nervous system and even death. But stroke subsequent to spinal manipulation at the neck is rare and, thus, scientifically re-searching such events is very difficult. The nature and incidence of these events can be studied only retrospectively and through subjective accounts¬therefore, only unreliably. The best estimate concerning strokes associated with SMT is that a stroke will ensue in 5 to 10, and death in 3, of every 10 million cervical spinal manipulations. Some professionals have argued that such treatment should be prohibited because the conditions against which it is used (headaches and neck pain, for instance) are virtually never deadly. But this line of reasoning doesn't hold water. For example, on its basis the most common means of relieving pain¬aspirin and other NSAIDs (non-steroidal anti-inflammatory drugs)¬should be prohibited, for NSAIDs can cause fatal gastrointestinal bleeding. Indeed, on this basis all treatments for nonpernicious conditions should be prohibited.
Chiropractic has thrived . . . because American physicians as a whole have nearly abandoned a large segment of the patient population.
The incidence of fatal NSAID side effects is much greater than that of fatal SMT side effects. And, of course, surgical interventions are several thousand times riskier than SMT. Dying as a result of undergoing cervical SMT is about as likely as dying during a 20-mile round-trip drive to a chiropractic office.
The evidence concerning side effects of SMT that are less serious than a stroke also suggests consistent safety. In a study of 1,058 patients who had undergone a total of 4,712 SMT treatments, research-ers found that in no case had SMT caused severe or permanent physical harm. Although undergoing SMT had apparently caused "unbearable" discomfort in 14 cases, in no case had such discomfort lasted for more than three days. Fifty-five percent of the patients in the study group evidently had had "mild to moderate" discomfort during treatment, but this discomfort had abated within three days, in most instances within 24 hours.
. . . [T]here is a throwback movement within [the profession], fighting for the return of chiropractic's metaphysical roots.
That some chiropractors steadfastly promote absurd beliefs about health and disease complicates the question of chiropractic-treatment risks. For example, a well-known chiropractor wrote recently of his supposed ability to identify criminal tendencies from radiographs of the spine. Furthermore, the prescribing and selling of dietary supplements by chiropractors is commonplace. These supplements range from unremarkable multivitamins to glandular-extract concoctions whose nutritional characteristics are unknown (or at least unreported publicly). Evidence that chiropractors' promotion of health-related misconceptions and prescribing of supplements cause harm consists of anecdotes. Evidence that widespread harm has resulted is absent. But so long as the profession tolerates such practices, chiropractic will continue to be an appropriate object of harsh criticism.
Scientific Research
For much of the history of their profession chiropractors have shown little interest in scientific inquiry and have regarded their principles and practices as self-evidently valid, or at least as provable from basic anatomic and physiologic principles alone. They held, in effect: "If Gray's Anatomy is correct, chiropractic is correct." What sustained whatever urges toward scientific inquiry there were, was the hope that a grand, global experiment or other study would materialize and vindicate the whole of chiropractic dogma.
In the mid 1970s, the spines of guinea pigs were variously assaulted in an animal lab at the chiropractic college I attended, and their internal organs were examined for evidence that the spinal insults had triggered disease. Of course, such research has never yielded anything valuable. Less than 20 years have passed since the chiropractic profession began to understand that, to vindicate SMT, what was necessary was not research to define the physiologic mechanisms whereby SMT has healthful effects, but rather, research to measure its clinical results in patients¬i.e., randomized clinical trials. Moreover, the profession has come to understand that, for the time being at least, it must pay for such trials itself. The costs of a randomized clinical trial are considerable. A medium-sized one¬say, one with 200 subjects¬would be a bargain at half a million dollars. Furthermore, a research department is prerequisite to the execution of such a study. Ten years ago the chiropractic college at which I teach spent $3.5 million to build and staff a clinical research department. This expenditure did not cover the performance of any study; it simply equipped the college for seeking research funds.
Other chiropractic institutions have made similar investments. Five of the 16 chiropractic colleges in the U.S. and several in other countries have productive research departments. Thus, there has been a growing stream of published studies on chiropractic treatments. Some of the findings from such studies have not been favorable to chiropractic. For example, in a study funded and conducted by chiropractors and published in an October 1998 issue of The New England Journal of Medicine, researchers found that SMT had not been effective against childhood asthma.
Such investments in science have created a chiropractic research culture whose dedications and values derive largely from its membership in the scientific community rather than from its membership in the chiropractic profession. That the profession has an autonomous scientific researchcommunity that upholds skepticism and disinterested inquiry distinguishes chiropractic from other modes of alternative medicine.
The Need for SMT
Chiropractic has thrived¬despite its self-destructiveness and despite vigorous opposition from the medical establishment in the U.S.¬because American physicians as a whole have nearly abandoned a large segment of the patient population. In terms of frequency of patient reporting to physicians, musculo-skeletal pain is second only to respiratory infections. The best treatment by far for most cases of musculo-skeletal pain is conservative¬more specifically, outpatient treatment that features physiotherapy (physical exercise and noninvasive manual and related methods). Musculoskeletal complaints have never had prestige in the medical sphere. Primary care physicians often respond to patients' reporting of back pain, for example, not with curiosity and concern but rather with annoyance or frustration¬at worst, with disdain.
Physicians are not well trained in the management of common musculoskeletal complaints. In a study published in The Journal of Bone and Joint Surgery in 1998, researchers found that 82 percent of new medical residents had failed what was considered a basic competency examination in musculoskeletal medicine. The researchers concluded that medical-school preparation in such medicine was inadequate. The specialists who have been adequately trained in musculoskeletal medicine¬neurologists, orthopedists, physiatrists, and rheumatologists¬are relatively scarce and inaccessible, can be expensive, focus on cases more exotic than those of ordinary aches, and tend to treat musculoskeletal problems aggressively.
Some physical therapists have most of the skills necessary for treating musculoskeletal problems, but physical therapists are not "portal of entry" practitioners (i.e., they can lawfully treat only patients whom physicians have referred to them) and are not adequately trained to serve as such.
It is the important niche described above that chiropractors have filled. A consistent finding from re-search on chiropractic is that, even when the objective results of nonchiropractic medical treatment and those of SMT are identical, chiropractic patients appear more satisfied than do the patients of medical doctors.
The Future of Chiropractic
In terms of scientific integrity and sophistication, chiropractic's history has been one of incremental improvement punctuated by retrogression. Despite recent scientific progress in the profession, there is a throwback movement within it, fighting for the return of chiropractic's metaphysical roots. The participants in this movement hold that, without these roots, chiropractic has no raison d'?tre. Sid E. Williams, D.C., the president of Life University, personifies chiropractic's "back to basics" movement. Williams evidently imagines chiropractic as locked in an apocalyptic battle with the medical establishment. The June 1994 issue of Consumer Reports quoted him:
Let's suppose the world realizes that subluxations are really the problem. The first thing you notice, you need fewer drugs, less surgery, fewer hospitals. This must really frighten medical doctors, but they're going to have to swallow their cud [sic] on this one. Who would have thought the Berlin Wall would come down? Well, medicine will be recognized as a failed theory, too.
In many ways chiropractic is two professions: one that accepts the validity of scientific inquiry and one that considers scientific inquiry extraneous or even unfavorable to the aims of chiropractic. This schism is profound. How it will be resolved is unclear.
Craig F. Nelson, D.C., is a graduate of, and an Associate Professor at, Northwestern College of Chiropractic. He is a researcher at the Wolfe-Harris Center for Clinical Studies, in Bloomington, Minnesota, and the author of numerous articles on chiropractic and alternative healthcare.
Charles E. DuVall, Jr., D.C., and ACSH scientific advisors Stephen Barrett, M.D., and William Jarvis, Ph.D. operate Chirobase (http://www.chirobase.org/), an engaging website that focuses (skeptically) on chiropractic.
ACSH member Donald Paulin heads Victims of Chiropractic, a clearinghouse founded in 1991: P.O. Box 3962, Huntington Beach, CA 92605; (714) 962-8683.
¬J.R.
One Profession, Two Worldviews
That chiropractic encompasses beliefs and aims that are contradictory to one another is a grand understatement. The doctrinal differences among chiropractors are deep-rooted and amount to something unique in the range of healthcare professions: a full-blown schism. Occasionally, chiropractors have even formally discussed codifying differences in principles and practices so as to split chiropractic into two professions. Below I outline the differences that define this schism.
Fundamentalist chiropractors:
* regard biomedicine and chiropractic as incompatible opponents
* reject standard diagnostic principles
* limit treatment to spinal manipulation (which they refer to as "chiropractic adjustment")
* have as their treatment goal the improvement of overall health through the removal of "subluxations"
* regard chiropractic's original principles as epochal insights concerning health and disease
* derive standards of care from chiropractic's original principles
Progressive chiropractors:
* view chiropractic as integral to the healthcare system in the U.S. and Canada and promote clinical, educational, and research ties between chiropractic and medicine
* use diagnostic procedures and principles that satisfy biomedical standards
* apply various modes of physiotherapy
* have as their treatment goal the conservative managing of neuro-musculoskeletal disorders
* regard chiropractic's original principles as of little clinical importance
* derive standards of care from scientific research
¬C.F.N.
(From Priorities, Vol. 11, No. 2)
