In 2001, the highly respected Annals of Internal Medicine began publishing a long series of invited papers to inform physicians about "complementary and alternative medicine" ("CAM") The series editor is David Eisenberg, M.D., whose current professional career depends upon his ability to promote interest in "CAM" methods.
"Chiropractic: A Profession at the Crossroads of Mainstream and Alternative Medicine," which the Annals published on February 5, 2002, is a one-sided puff piece written by two prominent chiropractors. Dr. Meeker is director of research at Palmer College of Chiropractic. Dr. Haldeman is a third-generation chiropractor who is associate clinical professor of neurology at the University of California-Irvine and an adjunct professor at Los Angeles Chiropractic College.
Imagine for a moment that you were asked to write an article about a city. You walk down the main street and notice that the buildings on one side of the street are attractive and well maintained, but the buildings on the other side look like they are falling apart. Instead of giving the whole picture, you write only about the attractive side. Suppose further that you realize that half of the buildings on the attractive side are made of cardboard. But instead of commenting on their construction, you report that they look attractive. Even if every word you write is true, the report does not really describe the city.
Meeker and Haldeman have done something similar in writing their article about chiropractic. Although most of what they say is "factual," they either ignore or attempt to obfuscate information about chiropractic's shortcomings. To highlight their deception, I have inserted comments in bold-faced red text.
Chiropractic is a large and well-established health care profession in the United States. In this overview, we briefly examine the development of chiropractic from humble and contentious beginnings to its current state at the crossroads of alternative and mainstream medicine. [Chiropractic is not like a freely moving car whose driver can decide which of two roads to take by merely turning the steering wheel a few degrees. Chiropractic is chained to its past by a preposterous basic theory that is an integral part of its identity, and its practitioners cannot agree among themselves about what they are doing or should be doing. Moreover, its road to mainstream care is blocked by the mainstream requirement that practitioners follow science-based standards.] Chiropractic has taken on many of the attributes of an established profession, improving its educational and licensing systems and substantially increasing its market share in the past two decades. [Data from three major studies suggest that the percentage of Americans using chiropractors has changed little during the past ten years. Telephone surveys reported by Eisenberg found that 10% of respondents said they had used a chiropractor in 1991 and 11% said they had used a chiropractor in 1997. But a more comprehensive survey estimated that only 3% of Americans had used chiropractors during the previous year.] The public increasingly uses chiropractic largely for spinal pain syndromes and appears to be highly satisfied with the results. Of all the so-called alternative professions, chiropractic has made the largest inroads into private and public health care financing systems and is increasingly viewed as an effective specialty by many in the medical profession. [The authors provide no data on how medical doctors regard chiropractors. Most medical doctors regard manipulation as a potentially useful option for treating acute low-back pain but still regard chiropractors generally as quacks.]
Much of the positive evolution of chiropractic can be ascribed to a quarter century-long research effort focused on the core chiropractic procedure of spinal manipulation. [This statement is true but neglects to discuss the negative views based on chiropractic quackery or the fact that most of the research was not done by chiropractors.]
This effort has helped bring spinal manipulation out of the investigational category to become one of the most studied forms of conservative treatment for spinal pain. Chiropractic theory is still controversial, but recent expansion in federal support of chiropractic research bodes well for further scientific development. [Chiropractic theory -- the idea that spinal misalignments ("subluxations") are the primary or underlying cause of ill health -- is controversial only among chiropractors. The scientific community regards it as a delusion.] The medical establishment has not yet fully accepted chiropractic as a mainstream form of care. ["Not yet"? It never will fully accept the quackery that is integral to chiropractic theory and practice.] The next decade should determine whether chiropractic maintains the trappings of an alternative health care profession or becomes fully integrated into all health care systems. [Chiropractic cannot become "fully integrated" because its basis is delusional.]
Chiropractic is the largest, most regulated, and best recognized of the professions that have traditionally functioned outside of mainstream medical institutions and, in the new lexicon, have fallen into the category of "complementary and alternative medicine." It is unique in the United States as the most widely disseminated indigenous U.S. system of healing. Its steadily increasing acceptance and use by the public and payers indicate that chiropractic is no longer the "marginal" or "deviant" profession it was once considered to be (1). [Data on public acceptance are very sparse. Insurance coverage is largely the result of laws that force third-party payers to pay even though they would prefer not to do so.] According to surveys of patients seeking alternative care, chiropractors are used more often than any other alternative provider group (2), and the satisfaction with chiropractic care is very high (3, 4). The number of chiropractors is growing: The current number of 60 000 is expected to reach 100 000 by 2010 (5). [The market appears to be saturated. Chiropractic incomes appear to have been falling steadily for more than ten years.]
Although some observers suggest that the profession may be entering the health care mainstream (6, 7), chiropractic remains a young profession; in 1995, it celebrated its 100th anniversary. Until the mid-1970s, chiropractic was considered to be outside mainstream medicine, often an outcast, and most chiropractors viewed themselves as differing in philosophy and practice from other health care practitioners (8). During the past two decades, there has been a marked change in the manner in which chiropractic is viewed, not only by mainstream medical practitioners (9) and institutions (10, 11) but also by members of the profession itself (12). [Reference 9, which summarizes various surveys, is a very peculiar report. Most of the surveys were done in foreign countries, and not enough were done to establish any trend. Moreover, although these surveys supposedly measured physician attitudes, many of the surveyed practitioners said they practiced chiropractic, which suggests that they were chiropractors rather than medical doctors.] Examining the factors that led to this change in attitude and the legitimization of chiropractic as a method of treatment and as a profession, as well as the conflicting emotional discussion that has accompanied these changes, is an interesting and informative exercise in health care sociology (13). [The data in references 9-11 do not necessarily support the assertion that chiropractic has been legitimized.] The changes in the chiropractic (and medical) profession are, however, still in the transitional phase, and the acceptance and even the future role of chiropractic in the overall health care system remain controversial (14, 15).
Chiropractors have designated 18 September 1895, when Daniel David Palmer reportedly gave his first spinal adjustment, as the origin of the chiropractic profession; however, spinal manipulation is one of the oldest and most widely practiced healing methods. References to spinal manipulation, and even the term subluxation, can be traced back as far as Hippocrates and Galen (16), and manual and manipulative procedures have been depicted in the art and writings of most ancient cultures. [Neither Hippocrates or Galen used the word "subluxation" the way chiropractors do.] Although manipulation has been part of orthopedic medical practice for centuries, most nonmedical practitioners of spinal manipulation in the 19th century were "bonesetters" who had learned their skills primarily by apprenticeship and observation (17).
The early and middle years of chiropractic were dominated by charismatic and authoritarian figures who often disagreed with one another. Many of the early schisms around the theory and scope of practice from this period still exist in some form (9, 17). Daniel David Palmer, who originally practiced as a lay magnetic healer, is credited with professionalizing the practice of spinal manipulation. He integrated popular natural health and scientific models of the day to present a unique theory of chiropractic. [This statement is pure baloney. There was nothing scientific about what he did. His theory was more akin to religion than to science.] He did this by incorporating the concept of an inherent healing ability of the body, which he named "innate intelligence," into concepts drawn from contemporary knowledge about anatomy and physiology. He eschewed the use of drugs and surgery as unnatural invasions to the body and focused on what he perceived as normalizing the function of the nervous system as the key to health (17).
From the beginning, chiropractors understood that professional self-regulation and independent legal status were crucial to survival. [Translation: Chiropractors realized that they could not survive if they were held to science-based standards. So their only hope for survival was to free themselves from outside regulation.] This stormy history of the first century of chiropractic includes many milestones on the march to professionalization. ["Professionalism" usually implies something about standards. Chiropractic is not noted for high standards.] Although chiropractic originated in the United States (the primary training ground and theoretical inspirational source for chiropractors), it took less than 10 years for chiropractors to immigrate and begin practice in other countries. In 1923, the province of Alberta in Canada became the first jurisdiction to license chiropractic outside of the United States; in 1939, the canton of Zurich in Switzerland was the first to license the profession outside of North America. Today, chiropractors are licensed and regulated in many countries throughout the world (18) and are permitted to practice in most countries, pursuant to general law.
One indicator of chiropractic mainstreaming is the steadily increasing use by patients in the United States, which has tripled in the past two decades from about 3.6% according to a 1980 survey (19) to an estimated 11% according to a 1997 national random telephone survey (2). This translates to an estimated 190 million patient visits to chiropractors in a year, or about 30% of visits to all complementary and alternative practitioners (2). One recent survey of family physicians and chiropractors in North Carolina (20) found that two thirds of the medical physicians felt "moderately" or "very" informed about chiropractic. Furthermore, 65% admitted referring patients to chiropractors, and 98% of chiropractors made routine referrals to physicians. [The meaning of the 98% figure is not clear. The chiropractors surveyed were members of the American Chiropractic Association. Nonmembers may have very different referral patterns.]
Payments for chiropractic care historically came directly from patients' pockets until chiropractic services were included in Medicare in the 1970s. In the past few decades, chiropractic has been included in a substantial proportion of private and public insurance plans, all state workers-compensation systems, and all forms of managed care (including health maintenance organizations). More than 50% of health maintenance organizations and more than 75% of private health insurance plans now offer chiropractic services (21). Under order of the U.S. Congress, the military health care system has initiated a series of demonstration projects to investigate the feasibility of providing chiropractic care to military personnel.
From many proprietary schools hastily established during the first part of the 20th century, a stable number of chiropractic training institutions have emerged in the United States. Unlike in the United States, where all but one college are privately funded, chiropractic education in Australia, South Africa, Denmark, one college in Canada, and two in Great Britain is provided at established government-sponsored universities and colleges. Most colleges in the United States are accredited by the Council on Chiropractic Education, an agency certified by the U.S. Department of Education. Each college requires at least 4 academic years of professional education before students can qualify for licensure examinations. A minimum of 60 units of prescribed college-level courses (increasing to 90 units by 2002), mostly in the sciences, is required before admission to chiropractic college. Approximately 50% of students enter chiropractic training with a baccalaureate degree.
A recent study described U.S. chiropractic curricula as an average of 4820 classroom and clinical hours, with about 30% spent in the basic sciences and 70% in clinical sciences and internship (22). Medical school curricula average about 4670 hours with a similar breakdown. Compared with medical students, chiropractic students spend more hours in anatomy and physiology but fewer in public health. Both programs have similar hours in biochemistry, microbiology, and pathology. Chiropractic curricula provide relatively little instruction in pharmacology, critical care, and surgery but emphasize biomechanics, musculoskeletal function, and manual treatment methods. Medical education has more than twice as many hours in actual clinical experience but 1000 fewer hours in didactic and workshop-like clinical courses. [Translation: Whereas medical students see large numbers of sick patients, chiropractors covering many of the same subjects attend lectures and read about medical care. Moreover, chiropractor typically enter practice after four years of coursework in which they have limited or no exposure to problems outside of their limited scope. Most medical doctors have 3-4 more years of additional specialty training before entering practice.] All chiropractic colleges maintain busy training clinics that deliver chiropractic care in settings similar to typical chiropractic practice. [This statement is misleading. In many schools, lack of real patients forces students to recruit healthy people as patients in order to meet minimal accreditation standards. Moreover, in the largest chiropractic college (Life Chiropractic College), students were taught to avoid differential diagnosis and to diagnose "subluxations" in every patient.] Specialty training is available in 2- to 3-year postgraduate residency programs in radiology, orthopedics, neurology, sports, rehabilitation, and pediatrics. [The paragraph falsely implies that medical and chiropractic educational programs are similar in depth and quality.] Coursework leads to eligibility for accredited specialty board competency examinations, which confer "diplomate" or "certified" status. [The required coursework is not compatible to medical specialty training either in depth or in scope. Chiropractic pediatrics is completely illegitimate.] Forty-six states either recognize or require passage of examinations administered by the National Board of Chiropractic Examiners in the areas of basic science, clinical science, and clinical competency before granting a graduate a license to practice. Most states also require annual proof of continuing education credits for ongoing license renewal. [The CME course approval standards are very low.]
Chiropractic is an evolving health profession with functions, values, traditions, and training institutions similar to those of other professions. [Similar in form, perhaps, but very different in substance and validity.] As envisioned by its founder, chiropractic was to be a revolutionary system of healing based on the premise that neurologic dysfunction caused by "impinged" nerves at the spinal level was the cause of most "dis-ease" and that spinal manipulation (adjustment) removed the interference to a full and healthy expression of life. Modern chiropractic theory and practice have moved away from the original monocausal theory, and research is gradually redefining the nature of the discipline and its education. ["Modern chiropractic theory," if it exists, is double-talk that attempts to cling to "subluxation" theory while pretending to have abandoned it. The actual reality is that chiropractors cannot agree among themselves about what they believe or should believe.] Many still think "chiropractic" is synonymous with "spinal manipulation," but as described below, this is only partially accurate. [Many chiropractors are engaged in homeopathy, bogus muscle-testing procedures, hair analysis, inappropriate recommendations for dietary supplements, and other forms of quackery.] With the advent of the category "complementary and alternative medicine" (CAM), chiropractors themselves are divided about how to define the profession; many do not want to be termed CAM practitioners (23). Chiropractors have many of the attributes of primary care providers and often describe themselves as such (24). [In so doing, they use a definition that differs from that of other health-care disciplines. Chiropractors who do this use the term "primary care provider" when they mean portal of entry practitioner.] Others point out that chiropractic has more of the attributes of a limited medical profession or specialty, akin to dentistry or podiatry (1). [This is the correct viewpoint, but chiropractic leaders are afraid that if they cannot have primary-care status, patients in managed care programs will not be able to see them without referral from a medical doctor.] This is an ongoing internal and external debate affected by dynamic health industry forces.
The core clinical action that all chiropractors agree upon is spinal manipulation. Chiropractors much prefer the term spinal "adjustment," reflecting their belief in the therapeutic and health-enhancing effect of correcting spinal joint abnormalities. [This passage refers to the belief that spinal manipulation can enhance general health. This belief is false. Why don't Meeker and Haldeman note that?] Dozens of adjusting "techniques" exist, and discussions about their relative merits make up much chiropractic academic discourse (25, 26). The procedure in its broadest definition describes application of a load (force) to specific body tissues with therapeutic intent. This load, which has traditionally been delivered by hand, can vary in its velocity, amplitude, duration, and frequency, as well as anatomic location, choice of levers, and direction of force. [The variation is enormous. What Meeker and Haldeman refer to as variation in "anatomic location" includes systems, for example, whose practitioners adjust the upper neck vertebrae no matter where in the body the patient's problem is located.]
Although "spinal manipulation" is traditionally associated with "chiropractic" (chiropractors deliver >90% of the manipulations in the United States ), chiropractors also provide many other treatments and counseling services. Physical therapies such as heat, cold, electrical methods, and rehabilitation methods are common (28, 29). Chiropractors usually suggest therapeutic exercises and general fitness recommendations to most patients, and give advice to many patients about nutrition, vitamins, weight loss, smoking cessation, and relaxation techniques (30). [Meeker and Haldeman fail to mention that the vast majority of chiropractors who give "nutrition advice" make inappropriate recommendations for dietary supplements.] Many chiropractors use other forms of CAM, with emphasis on massage, acupressure, and mineral and herb supplements (23). [The supplement and herb recommendations are almost always inappropriate.]
Studies confirm that most patients go to chiropractors for musculoskeletal problems: about 60% with low-back pain, and the remainder with head, neck, and extremity symptoms (28, 31). Approximately one third of all patients who seek professional care for low-back pain consult chiropractors in a primary health care role (32-34). Furthermore, about half of the patients seeking chiropractic care have chronic symptoms (31, 35). Only a small number, typically fewer than 2% to 5%, seek care for other conditions. Recent studies have also documented that a minor proportion of patients visit chiropractors for general health concerns, prevention, and a feeling of well-being; they often receive standard health advice, most often with regard to physical fitness and nutrition (35-37). [The idea that chiropractors routinely give standard health advice is preposterous. One third strongly oppose immunization, chiropractors receive very little training in science-based nutrition, and the majority who give nutrition advice engage in inappropriate testing (such as hair analysis) and/or make inappropriate supplement recommendations. Reference 36 states that 97% of patients coming for "maintenance care" received "adjustments/manipulation," the average number of recommended visits for maintenance care was 14.4 visits per year, and the total revenue represented an estimated 23% of practice income. Recommendations for periodic spinal examinations and adjustments are not "standard health advice." ]
The approach used in chiropractic training and practice for clinical diagnosis is similar to that of all health care disciplines: a history, physical examination, and specialty-specific assessments (25, 38). [The scope and quality of training varies considerably from one chiropractic school to another, but the average quality is far below that of medical schools.] The Council on Chiropractic Education specifies that these basic clinical competencies must be taught in all accredited institutions, and chiropractors are expected to differentiate mechanical musculoskeletal problems from visceral abnormalities that may present with a similar clinical picture (29). Chiropractic practice guidelines developed by the profession rate history taking, physical examination, and periodic reassessments of progress as "necessary" attributes of good practice (39). [Large percentages of chiropractors engage in diagnostic practices that have no scientific validity. Implying otherwise is downright dishonest.]
By using job analysis concepts, the National Board of Chiropractic Examiners has provided the most thorough description of chiropractic practice (28). Chiropractors rated "extremely important" the knowledge needed to arrive at a diagnosis on the basis of information gathered from a patient's history and physical, neurologic, and orthopedic examinations. [Yes, and 43% use applied kinesiology, in which problems throughout the body are diagnosed by placing substances in the patient's mouth (or elsewhere) and testing the strength of patients' muscles. And the vast majority of diagnostic tests that are unique to chiropractic are either unsubstantiated or have been studied and found to be invalid.] In most states, chiropractors have the statutory right and obligation to render a medical diagnosis, especially within their scope of customary and legal practice. Patients with diagnoses not amenable to chiropractic care are routinely referred (20). [The extent to which this is done has not been extensively studied.]
Chiropractors' use of advanced diagnostic tests is generally low, reflecting the typical nature of the musculoskeletal caseload (29). The main exception is plain-film radiography, which has been traditional in chiropractic ever since its development at the beginning of the 20th century. Much training time is spent on the technique and interpretation of musculoskeletal radiographs (22, 40, 41). In regard to radiographic examination, the job analysis survey indicated that chiropractors "frequently" obtain radiographs for new patients to determine abnormality; they "sometimes" obtain radiographs to determine instability or joint dysfunction; they "frequently" determine the possible site and nature of a manipulable subluxation; they "frequently" perform radiography on a patient whose condition is deteriorating or who is not responding to care; and they "rarely" obtain radiographs to monitor a patient's progress. [The authors neglect to mention how often chiropractors do inappropriate x-ray examinations.] Chiropractors consider knowledge of normal radiographic anatomy and of radiographic interpretation and diagnosis to be "extremely important" (28).
Indications for radiography are hotly debated in chiropractic circles, but use appears to be declining over time (42). The use of radiography may also vary substantially by geographic region. A practice-based study comparing chiropractic and physician practices for patients with back pain in Oregon found that 26% of patients of both provider groups had radiography (43). [The study did not indicate why the x-rays were obtained, what x-rays were obtained, or whether obtaining them was appropriate. ] Carey and colleagues (4) found higher rates of use in North Carolina: 67% for chiropractors and 72% for orthopedists. Of note, since the inception of Medicare 30 years ago, chiropractors had been mandated to obtain radiographs in order to be reimbursed for care. Only after persistent legislative activity has this provision finally been changed (44).
Chiropractors use the information from the case history and examination to ascertain the patient's state of health and to form a diagnostic impression, with additional studies obtained as needed. [A substantial minority of chiropractors pay very little attention to the patient's history or standard physical findings. Rather, they rely on bogus tests to find "subluxations."] Focal joint, muscle, and soft tissue examinations are usually performed to determine the potential utility of spinal manipulation and other interventions. These usually include palpation, assessing the range and quality of joint motion, and probing for tenderness and inflammation. On the basis of the findings, the chiropractor chooses a treatment plan and estimates prognosis. Essentially, patients may receive a trial of chiropractic care, be referred for co-management, or be referred to an appropriate specialist. The profession has developed detailed consensus guidelines for quality for most aspects of case management (39), and these are didactically and clinically modeled in accredited chiropractic institutions. [The guidelines are not as well developed as the authors imply, and many chiropractors flatly reject them anyway. Moreover, this paragraph deliberately omits mention that many chiropractors recommend lifelong periodic care from birth onward to detect and correct "subluxations.]
The clinical encounter tends toward a high-touch, low-technology health model with more concern for the person than the disease. [No well-designed study has demonstrated that chiropractors focus on the person rather than the ailment. The authors fail to mention that many chiropractors focus on the spine rather than the person.] Chiropractors believe in the inherent healing ability of the body and communicate the hope of healing to patients. [The "inherent healing power of the body" includes homeostasis, immune responses, and various other mechanisms that medical science has elucidated. Nothing chiropractors do has been shown to enhance the body's "inherent healing power."] Spinal manipulation and other forms of touching care require that a level of trust develop between the patient and the chiropractor. Repeated visits allow a relationship to flourish that is often used to communicate on a social and psychological level as well as about biological implications of care (45). [The relationship can also be used to brainwash patients into coming for periodic care that has no proven value.]
One recent essay opined that much of chiropractic's success and perhaps its most important contribution to health care might concern this patient-physician relationship (7). [Chiropractors have contributed nothing.] Analyses from anthropologic and sociologic perspectives have suggested that treatment by a chiropractor, especially for many patients with chronic pain, can generate a sense of understanding and meaning, an experience of comfort, an expectation of change, and a feeling of empowerment (46, 47). The hands-on and compassionate "can do" clinical behavior of the typical chiropractor seems to be concrete, reassuring, and immediately satisfying. Observational studies (3, 4) and randomized trials (48) leave little doubt that chiropractic patients are very satisfied with their management. [Satisfaction is not the same thing as effectiveness.]
Throughout the short history of chiropractic, the profession has had the difficult task of justifying a treatment partially rooted in quasi-mystical concepts to a skeptical mainstream medical and scientific community. Confounding this problem has been the fact that pain, especially chronic musculoskeletal pain, remains something of a scientific enigma (49). A 1975 National Institute of Neurological Diseases and Stroke conference, "Research Status of Spinal Manipulative Therapy," pointed out the lack of any substantial research to justify claims made by chiropractors or any other practitioner of manipulation (50); by doing so the conference galvanized a quarter century-long research effort. [Research has increased, but I don't know of any evidence that the conference -- which I attended -- was responsible. It might also be pointed out that chiropractic research appears to have very little effect on chiropractic practice.]
Two broad categories of research have been pursued: 1) clinical outcomes in randomized clinical trials and observational studies and 2) basic science efforts attempting to understand the biological mechanisms of spinal manipulation. For this report, we supplemented our own exhaustive reference collections of randomized clinical trials of spinal manipulation with additional searches of MEDLINE, MANTIS, CHIROLARS, and the Cochrane Collaboration Library. We tracked citations and manually searched relevant journals to verify that the list was as complete as possible. We made no attempt to find finished unpublished clinical trials or review non-English-language reports.
To date, at least 73 randomized clinical trials of a broadly defined spinal manipulation procedure can be found in the English-language literature. Most trials have been published in general medical and orthopedic journals (for example, British Medical Journal, Journal of the American Medical Association, Spine). Nineteen papers were published in the chiropractic peer-reviewed literature (for example, Journal of Manipulative and Physiological Therapeutics). Most first authors have medical degrees, and 23 papers were written by chiropractors. Authors did not necessarily publish in the literature of their profession. While publication bias cannot be ruled out, there is no evidence of it in this information.
Most of these studies have been conducted on patients with low-back, neck, and head pain, and a few have examined other conditions. The clinical trials include placebo-controlled comparisons, comparisons with other treatments, and pragmatic comparisons of chiropractic management with common medical management.
Forty-three randomized trials of spinal manipulation for treatment of acute, subacute, and chronic low-back pain have been published. Thirty favored manipulation over the comparison treatments in at least a subgroup of patients, and the other 13 found no significant differences. No trial to date has found manipulation to be statistically or clinically less effective than the comparison treatment. Eleven of the low-back pain trials included a placebo group; 8 of them showed an advantage to manipulation (125). Eleven randomized, controlled trials of spinal manipulation for neck pain have been conducted; 4 had positive findings and 7 were equivocal. Seven of 9 randomized trials of manipulation for various forms of headache were positive.
In most of the randomized, controlled trials of manipulation for musculoskeletal pain, the positive effect sizes appear to be clinically and statistically significant but not dramatic, leaving room for various interpretations. Systematic reviews and meta-analyses conducted in the early to mid-1990s made cautiously positive or equivocal statements about the effectiveness of manipulation for low-back pain, neck pain, and headache, and called for higher-quality studies (27, 125-129).
Using formal consensus processes, in 1995 the Quebec Task Force on Whiplash-Associated Disorders concluded that spinal manipulation had at least "weak cumulative evidence," and recommended that a short regimen of spinal manipulation may be used as a therapeutic trial for neck pain (130). In 1994, the U.S. Agency for Health Care Policy and Research similarly concluded that spinal manipulation was safe and effective for acute low-back pain, with a strength of evidence level of "B." This agency reviewed all clinical trials available at the time and found no other treatment to have stronger evidence, although nonsteroidal anti-inflammatory drugs received the same "B" rating (131).
A 1997 systematic review of manipulation for low-back pain concluded (132), in contrast to previous opinions (27, 128, 131), that evidence was sufficient to recommend manipulation for chronic back pain but that the evidence for acute back pain was weak. The most recent systematic review (133) used a slightly different method of analysis, taking into account study design, quality, and strength of evidence; these authors concluded that there was moderately strong evidence of a short-term benefit of manipulation for both acute and chronic back pain. They found insufficient evidence for or against the effectiveness of manipulation for sciatica. However, a recent trial found that manipulation for patients with sciatica related to disc herniation was better than chemonucleolysis in the short term and equivalent to that therapy at 12 months (95). A recent quantitative review found only equivocal evidence for the benefit of traction, exercise, and drug therapies for sciatica (134).
The heterogeneity of patients with spinal pain, the lack of definitive diagnoses, and the indications in some trials that subgroups of patients appear to respond better to manipulation than others have further highlighted the need to understand the underlying physiologic and psychological mechanisms of pain and disability. The design of rigorous clinical experiments of treatment efficacy for approaches that include strong physician-patient interactions and "hands-on" therapy has been challenging, posing the question of a strong psychological effect of chiropractic treatment. Surprisingly, spinal manipulation is one of the most studied treatments for back pain (56, 132). All manipulation trials, however, have had to contend with design and execution weaknesses that need to be addressed in future studies.
The treatment of disorders not directly related to the musculoskeletal system by manipulation has been supported mainly by clinical experience and case reports. In the past few years, randomized clinical trials for primary dysmenorrhea (115, 116), hypertension (123, 124), chronic asthma (119, 120), enuresis (118), infantile colic (117), and premenstrual syndrome (121) have been completed, with variable results. Two systematic reviews, one on extant trials at the time (135) and a recent one on asthma sponsored by the Cochrane Collaboration (136), concluded that the results do not argue convincingly for or against the utility of spinal manipulation for these kinds of conditions. [Meeker and Haldeman fail to note that there is no scientifically plausible reason to believe that manipulation is effective for treating any non-musculoskeletal problem.]
Chiropractors direct spinal manipulation to a dysfunctional joint "lesion" known as a subluxation. This is characterized as a form of joint strain or sprain with clinically associated hypomobility, malalignment, local and referred pain, inflammation, and muscle tension (137). [Chiropractors cannot agree among themselves what a "subluxation" is. Many chiropractors regard it as a something that interferes with the body's "vital force."] Subluxation in the chiropractic context primarily connotes a functional and not necessarily an anatomic entity. ["Subluxation in the chiropractic context" also includes a "spiritual entity." The phrase "functional and not necessarily anatomic" means that some chiropractors think subluxations are visible on x-rays and others think they are not.] At least five mechanical and neurologic mechanisms have been proposed. [It is completely senseless to propose neurologic mechanisms to explain an entity that has not been defined.]
Chiropractic theory has held that subluxation and manipulation can have important physiologic effects: increased range of joint motion (147, 148), changes in facet joint kinematics (149), increased pain tolerance (150), increased muscle strength (151), attenuation of motoneuron activity (152), enhanced proprioceptive behavior (153), and changes in -endorphins (154) and substance P (155). A biomechanical picture of manipulation is beginning to emerge from studies on the forces involved and the resultant kinetics and kinematics (156, 157). [This again ignores how subluxation-based chiropractors view what they are doing.]
The topic of complications from spinal manipulation has been controversial (126, 158, 159). Nonserious side effects of manipulation may consist of localized discomfort, headache, or fatigue that resolves within 24 to 48 hours (160). The more serious reported complications are the cauda equina syndrome from lumbar manipulation and cerebrovascular artery dissection from cervical manipulation. The apparent rarity of these accidental events has made it difficult to assess the magnitude of the complication risk. No serious complication has been noted in more than 73 controlled clinical trials or in any prospectively evaluated case series to date. [One reason for this may be that the type of neck manipulation that poses the greatest cerebrovascular risk may not be used by the practitioners who are most interested in participating in research.]
Serious complications from lumbar spinal manipulation are extremely rare, estimated to be 1 case per 100 million manipulations (27). For cervical manipulation, the risk for a cerebrovascular accident has been calculated by various authors to range from 1 in 400 000 (161) to between 3 and 6 per 10 million manipulations (126). The figures have been primarily based on retrospectively collected single case reports (126, 158) and unsubstantiated practitioner surveys (161, 162). One retrospective cohort study examined the incidence of cerebrovascular accidents after manipulation (163). It covered the experience of 99% of the practicing chiropractors in Denmark from 1978 to 1988. During this 10-year period, five cases and one death were identified, representing approximately one serious complication for every 1 million cervical manipulations. Unfortunately, there do not appear to be any specific risk factors for vertebrobasilar artery dissection after manipulation, and the cases might represent idiosyncratic events or the aggravation of arterial dissections in progress (159). [The chiropractic profession has not made a serious effort to study the incidence of cerebrovascular complications of neck adjustment.]
Significant challenges for conducting high-quality studies in the chiropractic profession continue to exist, but this is changing. The U.S. Health Resources and Services Administration's Chiropractic Demonstration Program was the first federal effort to facilitate collaborative research between chiropractic and medical institutions in 1994, and it continues to sponsor annual conferences designed to set research agenda (164). In 1997, the National Center for Complementary and Alternative Medicine initiated a research center, the Consortial Center for Chiropractic Research, at Palmer College of Chiropractic in Davenport, Iowa. It represents a collaboration of six chiropractic colleges and four state-supported universities.
Chiropractic has survived, and it has begun to embrace the values and behaviors of a mainstream health profession. [One thing that is missing is a systematic effort to identify and discard ineffective practices.] In the past few decades, chiropractic has strengthened its educational system; initiated research that has validated spinal manipulation; increased its market share of satisfied patients; initiated collaborations with other disciplines in practice, research, and professional settings; and effectively used political, legislative, and legal measures to secure a role. Nevertheless, significant attitudinal and structural barriers to mainstream status still hinder chiropractic, and the advances of recent years may not be enough to ensure continuing progress in this direction. [The main "mainstream barrier" is the fact that the majority of chiropractors engages in improper practices.]
Chiropractic still maintains some vestiges of an alternative health care profession in image, attitude, and practice. [Vestiges? What gall! Data from the 1998 National Board of Chiropractic Examiners' job analysis survey indicate that the majority of chiropractors engage in unscientific practices and that the percentage is higher than it was in the previous (1991) survey.] The profession has not resolved questions of professional and social identity, and it has not come to a consensus on the implications of integration into mainstream health care delivery systems and processes. In today's dynamic health care milieu, chiropractic stands at the crossroads of mainstream and alternative medicine. Its future role will probably be determined by its commitment to interdisciplinary cooperation and science-based practice.
Acknowledgments: The authors thank Ted Kaptchuk, OMD, and David Eisenberg, MD, for encouraging them to write this paper; Cheryl Hawk, DC, PhD, for her incisive criticism and excellent advice; and the experts who reviewed the manuscript, to its great benefit.
Grant Support: In part by grant U24 AR45166, "Establishing the Consortial Center for Chiropractic Research," from the National Institutes of Health, National Center for Complementary and Alternative Medicine; and the Palmer Center for Chiropractic Research, Davenport, Iowa.