Chiropractic is a complementary and alternative medicine^[1] health care profession and an approach to healing concerned with the diagnosis, treatment and prevention of disorders of the neuromusculoskeletal system and the effects of these disorders on general health.^[2] Chiropractors emphasize manual therapy including joint adjustment and manipulation with particular focus on joint dysfunction/subluxations.^[3][4] Chiropractors practice in over 100 countries in all regions of the world, but they are most prevalent in North America, Australia and parts of Europe.^[2][5] Most people who seek chiropractic care do so for low back pain.^[6]

Chiropractic was founded in 1895 by magnetic healer D.D. Palmer in Davenport, Iowa. Chiropractic theory on spinal joint dysfunction and its putative role in non-musculoskeletal disease has been a source of controversy since its inception in 1895. The controversy is due in part to chiropractic's vitalistic and metaphysical origins, and use of terminology that is not always amenable to scientific investigation.^[7] Far-reaching claims and lack of scientific evidence supporting spinal dysfunction/subluxation as the sole cause of disease^[8][9] has led to a critical evaluation of a central tenet of chiropractic and the appropriateness of the profession's role in treating a broad spectrum of disorders that are unrelated to the neuromusculoskeletal system.^[10] Although there is external and internal debate within the chiropractic profession regarding the clinical significance of joint dysfunction/vertebral subluxation complex,^[11] the manipulable lesion/functional spinal lesion^[12] remains inextricably linked to the profession as the basis for spinal manipulation.^[13]

A critical evaluation found that collectively, spinal manipulation failed to show it is effective for any condition.^[14] The scientific consensus is that chiropractic may be on a par with other manual therapies for some musculoskeletal conditions such as lower back pain, but that there is no credible evidence or mechanism for effects on other conditions, and some evidence of severe adverse effects from cervical vertebral manipulation.^[15] The ideas of innate intelligence and the chiropractic subluxation are regarded as pseudoscience.^[9]

Conceptual basis

For most of its existence, chiropractic has been sustained by pseudoscientific ideas such as subluxation and innate intelligence^[16] which are not based on solid science.^[9] Some chiropractors have been criticized for having an anti-immunization stance, despite the consensus of public health professionals on the benefits of vaccination,^[17] which has led to negative impacts on both public vaccination and mainstream acceptance of chiropractic.^[18] The American Medical Association called chiropractic an "unscientific cult"^[19] and boycotted it until losing an antitrust case in 1987.^[20] Chiropractic is said to have developed a strong political base and to have sustained demand for services; researchers Cooper and McKee report that it has gained more legitimacy and greater acceptance among physicians and health plans in the U.S. for the treatment of some musculoskeletal conditions^[20] and the principles of evidence-based medicine have been used to review research studies and generate practice guidelines.^[21] Traditional (or straight) chiropractic still assumes that a vertebral subluxation interferes with the body's "innate intelligence",^[22] a vitalistic notion ridiculed by the scientific and healthcare communities.^[23] Other chiropractors want to separate themselves from the traditional vitalistic concept of innate intelligence^[24] – John W Reggars wrote in 2011 that chiropractic was at a crossroads, and that in order to progress it would need to embrace science; in his view, the promotion of chiropractic as a cure-all was both "misguided and irrational".^[25]

Chiropractic's early philosophy was rooted in vitalism, spiritual inspiration and rationalism. A philosophy based on deduction from irrefutable doctrine helped distinguish chiropractic from medicine, provided it with legal and political defenses against claims of practicing medicine without a license, and allowed chiropractors to establish themselves as an autonomous profession. This "straight" philosophy, taught to generations of chiropractors, rejects the inferential reasoning of the scientific method,^[7] and relies on deductions from vitalistic first principles rather than on the materialism of science.^[26]

However, most practitioners currently accept the importance of scientific research into chiropractic,^[7] and most practitioners are "mixers" who attempt to combine the materialistic reductionism of science with the metaphysics of their predecessors and with the holistic paradigm of wellness;^[26] a 2008 commentary proposed that chiropractic actively divorce itself from the straight philosophy as part of a campaign to eliminate untestable dogma and engage in critical thinking and evidence-based research.^[10]

Although a wide diversity of ideas currently exists among chiropractors,^[7] they share the belief that the spine and health are related in a fundamental way, and that this relationship is mediated through the nervous system.^[27] Chiropractors examine the biomechanics, structure and function of the spine, along with its effects on the musculoskeletal and nervous systems and what they believe to be its role in health and disease.^[28]

Chiropractic philosophy includes the following perspectives:^[26]

• Reductionism in chiropractic reduces causes and cures of health problems to a single factor, vertebral subluxation.^[10] It stands in contrast to holism, which assumes that health is affected by everything in an individual's environment; some sources also include a spiritual or existential dimension.^[29]
• Conservatism considers the risks of clinical interventions when balancing them against their benefits. It emphasizes noninvasive treatment to minimize risk, and avoids surgery and medication.^[28]
• Homeostasis emphasizes the body's inherent self-healing abilities. Chiropractic's early notion of innate intelligence can be thought of as a metaphor for homeostasis.^[7]
• Straights tend to use an approach that focuses on the chiropractor's perspective and the treatment model, whereas mixers tend to focus on the patient and the patient's situation.^[26]

Straights and mixers

Straight chiropractors adhere to the philosophical principles set forth by D.D. and B.J. Palmer, and retain metaphysical definitions and vitalistic qualities. Straight chiropractors believe that vertebral subluxation leads to interference with an "innate intelligence" exerted via the human nervous system and is a primary underlying risk factor for many diseases. Straights view the medical diagnosis of patient complaints (which they consider to be the "secondary effects" of subluxations) to be unnecessary for chiropractic treatment. Thus, straight chiropractors are concerned primarily with the detection and correction of vertebral subluxation via adjustment and do not "mix" other types of therapies into their practice style.^[30]

Their philosophy and explanations are metaphysical in nature and they prefer to use traditional chiropractic lexicon terminology (i.e. perform spinal analysis, detect subluxation, correct with adjustment, etc.). They prefer to remain separate and distinct from mainstream health care. Although considered the minority group, "they have been able to transform their status as purists and heirs of the lineage into influence dramatically out of proportion to their numbers."^[24]

Mixer chiropractors "mix" diagnostic and treatment approaches from osteopathic, medical, and chiropractic viewpoints. Unlike straight chiropractors, mixers believe subluxation is one of many causes of disease, and they incorporate mainstream medical diagnostics and employ many treatments including conventional techniques of physical therapy such as exercise, massage, ice packs, and moist heat, along with nutritional supplements, acupuncture, homeopathy, herbal remedies, and biofeedback. Mixers tend to be open to mainstream medicine and are the majority group.^[24]

Although mixers are the majority group, many of them retain some belief in vertebral subluxation as shown in a 2003 survey of 1100 North American chiropractors, which found that 88% wanted to retain the term "vertebral subluxation complex", and that when asked to estimate the percent of disorders of internal organs (such as the heart, the lungs, or the stomach) that subluxation significantly contributes to, the mean response was 62%.^[31] Despite this finding, a 2008 survey of 6000 American chiropractors demonstrated that most chiropractors seem to believe that a subluxation-based clinical approach may be of limited utility for addressing visceral disorders, and greatly favored non-subluxation-based clinical approaches for such conditions.^[11][32]

Vertebral subluxation

Palmer hypothesized that vertebral joint misalignments, which he termed vertebral subluxations, interfered with the body's function and its inborn (innate) ability to heal itself.^[22] D.D. Palmer repudiated his earlier theory that vertebral subluxations caused pinched nerves in the intervertebral spaces in favor of subluxations causing altered nerve vibration, either too tense or too slack, affecting the tone (health) of the end organ. D.D. Palmer, using a vitalistic approach, imbued the term subluxation with a metaphysical and philosophical meaning. He qualified this by noting that knowledge of innate intelligence was not essential to the competent practice of chiropractic.^[33] This concept was later expanded upon by his son, B.J. Palmer, and was instrumental in providing the legal basis of differentiating chiropractic medicine from conventional medicine. In 1910, D.D. Palmer theorized that the nervous system controlled health:

"Physiologists divide nerve-fibers, which form the nerves, into two classes, afferent and efferent. Impressions are made on the peripheral afferent fiber-endings; these create sensations that are transmitted to the center of the nervous system. Efferent nerve-fibers carry impulses out from the center to their endings. Most of these go to muscles and are therefore called motor impulses; some are secretory and enter glands; a portion are inhibitory, their function being to restrain secretion. Thus, nerves carry impulses outward and sensations inward. The activity of these nerves, or rather their fibers, may become excited or allayed by impingement, the result being a modification of functionality—too much or not enough action—which is disease."^[34]

Vertebral subluxation, a core concept of traditional chiropractic, remains unsubstantiated and largely untested, and a debate about whether to keep it in the chiropractic paradigm has been ongoing for decades.^[23] In general, critics of traditional subluxation-based chiropractic (including chiropractors) are skeptical of its clinical value, dogmatic beliefs and metaphysical approach. While straight chiropractic still retains the traditional vitalistic construct espoused by the founders, evidence-based chiropractic suggests that a mechanistic view will allow chiropractic care to become integrated into the wider health care community.^[23] This is still a continuing source of debate within the chiropractic profession as well, with some schools of chiropractic still teaching the traditional/straight subluxation-based chiropractic, while others have moved towards an evidence-based chiropractic that rejects metaphysical foundings and limits itself to primarily neuromusculoskeletal conditions.^[35][36]

In 2005, the chiropractic subluxation was defined by the World Health Organization as "a lesion or dysfunction in a joint or motion segment in which alignment, movement integrity and/or physiological function are altered, although contact between joint surfaces remains intact. It is essentially a functional entity, which may influence biomechanical and neural integrity." This differs from the medical definition of subluxation as a significant structural displacement, which can be seen with static imaging techniques such as X-rays.^[2]

The 2008 book Trick or Treatment states "X-rays can reveal neither the subluxations nor the innate intelligence associated with chiropractic philosophy, because they do not exist."^[15] Attorney David Chapman-Smith, Secretary-General of the World Federation of Chiropractic, has stated that "Medical critics have asked how there can be a subluxation if it cannot be seen on x-ray. The answer is that the chiropractic subluxation is essentially a functional entity, not structural, and is therefore no more visible on static x-ray than a limp or headache or any other functional problem."^[37] The General Chiropractic Council, the statutory regulatory body for chiropractors in the United Kingdom, states that the chiropractic vertebral subluxation complex "is not supported by any clinical research evidence that would allow claims to be made that it is the cause of disease."^[38]

Scope of practice

In 2005 the WHO published a document, WHO guidelines on basic training and safety in chiropractic that characterized chiropractic as a health profession which "emphasizes the conservative management of the neuromusculoskeletal system, without the use of medicines and surgery".^[2] Nelson et al wrote, also in 2005, that one characteristic of chiropractic is a particular emphasis on the spine.^[4] In 2011 research by Yvonne Villanueva-Russell found a range of opinions among chiropractors: some believed that treatment should be confined to the spine, or back and neck pain; others vehemently disagreed. For example, while one 2009 survey of American chiropractors had found that 73% classified themselves as "back pain/musculoskeletal specialists", the label "back and neck pain specialists" was regarded by 47% of them as a least desirable description in a 2005 international survey.^[39]

Chiropractic overlaps with several other forms of manual therapy, including massage therapy, osteopathy, physical therapy, and sports medicine.^[40][41] Chiropractic is autonomous from and competitive with mainstream medicine,^[42] and osteopathy outside the US remains primarily a manual medical system;^[43] physical therapists work alongside and cooperate with mainstream medicine, and osteopathic medicine in the U.S. has merged with the medical profession.^[42] Practitioners may distinguish these competing approaches through claims that, compared to other therapists, chiropractors heavily emphasize spinal manipulation, tend to use firmer manipulative techniques, and promote maintenance care; that osteopaths use a wider variety of treatment procedures; and that physical therapists emphasize machinery and exercise.^[40]

Chiropractic diagnosis may involve a range of methods including skeletal imaging, observational and tactile assessments, and orthopedic and neurological evaluation.^[2] A chiropractor may also refer a patient to an appropriate specialist, or co-manage with another health care provider.^[44] Common patient management involves spinal manipulation (SM) and other manual therapies to the joints and soft tissues, rehabilitative exercises, health promotion, electrical modalities, complementary procedures, and lifestyle advice.^[45]

Chiropractors are not normally licensed to write medical prescriptions or perform major surgery in the United States,^[46] (although New Mexico has become the first US state to allow "advanced practice" trained chiropractors to prescribe certain medications.^[47][48]). In the US, their scope of practice varies by state, based on inconsistent views of chiropractic care: some states, such as Iowa, broadly allow treatment of "human ailments"; some, such as Delaware, use vague concepts such as "transition of nerve energy" to define scope of practice; others, such as New Jersey, specify a severely narrowed scope.^[49]

US states also differ over whether chiropractors may conduct laboratory tests or diagnostic procedures, dispense dietary supplements, or use other therapies such as homeopathy and acupuncture; in Oregon they can become certified to perform minor surgery and to deliver children via natural childbirth.^[46] A 2003 survey of North American chiropractors found that a slight majority favored allowing them to write prescriptions for over-the-counter drugs.^[31]

A related field, veterinary chiropractic, applies manual therapies to animals and is recognized in a few US states,^[50] but is not recognized by the American Chiropractic Association as being chiropractic.^[51]

Treatment techniques

Spinal manipulation, which chiropractors call "spinal adjustment" or "chiropractic adjustment", is the most common treatment used in chiropractic care.^[52] Spinal manipulation is a passive manual maneuver during which a three-joint complex is taken past the normal range of movement, but not so far as to dislocate or damage the joint. Its defining factor is a dynamic thrust, which is a sudden force that causes an audible release and attempts to increase a joint's range of motion.^[53]

High-velocity, low-amplitude spinal manipulation (HVLA-SM) thrusts have physiological effects that signal neural discharge from paraspinal muscle tissues, depending on duration and amplitude of the thrust are factors of the degree in paraspinal muscle spindles activation. Clinical skill in employing HVLA-SM thrusts depends on the ability of the practitioner to handle the duration and magnitude of the load.^[54] More generally, spinal manipulative therapy (SMT) describes techniques where the hands are used to manipulate, massage, mobilize, adjust, stimulate, apply traction to, or otherwise influence the spine and related tissues.^[53]

There are several schools of chiropractic adjustive techniques, although most chiropractors mix techniques from several schools. The following adjustive procedures were received by more than 10% of patients of licensed U.S. chiropractors in a 2003 survey:^[52] Diversified technique (full-spine manipulation, employing various techniques), extremity adjusting, Activator technique (which uses a spring-loaded tool to deliver precise adjustments to the spine), Thompson Technique (which relies on a drop table and detailed procedural protocols), Gonstead (which emphasizes evaluating the spine along with specific adjustment that avoids rotational vectors), Cox/flexion-distraction (a gentle, low-force adjusting procedure which mixes chiropractic with osteopathic principles and utilizes specialized adjusting tables with movable parts), adjustive instrument, Sacro-Occipital Technique (which models the spine as a torsion bar), Nimmo Receptor-Tonus Technique, Applied Kinesiology (which emphasises "muscle testing" as a diagnostic tool), and cranial.^[55] Medicine-assisted manipulation, such as manipulation under anesthesia, involves sedation or local anesthetic and is done by a team that includes an anesthesiologist; a 2008 systematic review did not find enough evidence to make recommendations about its use for chronic low back pain.^[56]

Many other procedures are used by chiropractors for treating the spine, other joints and tissues, and general health issues. The following procedures were received by more than one-third of patients of licensed U.S. chiropractors in a 2003 survey: Diversified technique (full-spine manipulation; mentioned in previous paragraph), physical fitness/exercise promotion, corrective or therapeutic exercise, ergonomic/postural advice, self-care strategies, activities of daily living, changing risky/unhealthy behaviors, nutritional/dietary recommendations, relaxation/stress reduction recommendations, ice pack/cryotherapy, extremity adjusting (also mentioned in previous paragraph), trigger point therapy, and disease prevention/early screening advice.^[52]

A 2010 study describing Belgian chiropractors and their patients found chiropractors in Belgium mostly focus on neuromusculoskeletal complaints in adult patients, with emphasis on the spine. The diversified technique is the most often applied technique at 93%, followed by the Activator mechanical-assisted technique at 41%.^[57] A 2009 study assessing chiropractic students giving or receiving spinal manipulations while attending a U.S. chiropractic college found Diversified, Gonstead, and upper cervical manipulations are frequently used methods.^[58]

Practice guidelines

Reviews of research studies within the chiropractic community have been used to generate practice guidelines outlining standards that specify which chiropractic treatments are "legitimate" (i.e., supported by evidence) and conceivably reimbursable under managed care health payment systems.^[21] Evidence-based guidelines are supported by one end of an ideological continuum among chiropractors; the other end employs antiscientific reasoning and makes unsubstantiated claims.^{[4][16][23][59][60]} A 2007 survey of Alberta chiropractors found that they do not consistently apply research in practice, which may have resulted from a lack of research education and skills.^[61]

Education, licensing, regulation

Requirements vary between countries. In the U.S. chiropractors obtain a first professional degree in the field of chiropractic.^[62] The curriculum content of North American chiropractic and medical colleges with regard to basic and clinical sciences has been more similar than not, both in the kinds of subjects offered and in the time assigned to each subject.^[63]

Accredited chiropractic programs in the U.S. require that applicants have 90 semester hours of undergraduate education with a grade point average of at least 3.0 on a 4.0 scale. Many programs require at least three years of undergraduate education, and more are requiring a bachelor's degree.^[64] Canada requires a minimum three years of undergraduate education for applicants, and at least 4200 instructional hours (or the equivalent) of full‐time chiropractic education for matriculation through an accredited chiropractic program.^[65]

CCEs in the U.S., Canada, Australia and Europe have joined to form CCE-International (CCE-I) as a model of accreditation standards with the goal of having credentials portable internationally.^[66] Today, there are 18 accredited Doctor of Chiropractic programs in the U.S.,^[67] 2 in Canada,^[68] 6 in Australasia,^[69] and 5 in Europe.^[70]

Regulatory colleges and chiropractic boards in the U.S., Canada, Mexico, and Australia are responsible for protecting the public, standards of practice, disciplinary issues, quality assurance and maintenance of competency.^[71][72] There are an estimated 49,000 chiropractors in the U.S. (2008),^[73] 6,500 in Canada (2010),^[74] 2,500 in Australia (2000),^[18] and 1,500 in the UK (2000).^[75]

A 2008 commentary proposed that the chiropractic profession actively regulate itself to combat abuse, fraud and quackery, which are more prevalent in chiropractic than in other health care professions, violating the social contract between patients and physicians.^[10]

The fourth year of chiropractic education persistently showed the highest stress levels. Every student, irrespective of year, experienced different ranges of stress when studying.^[76] The chiropractic leaders and colleges have had internal struggles. Rather than cooperation, there has been infighting between different factions. A number of actions were posturing due to the confidential nature of the chiropractic colleges in an attempt to enroll students.^[77]

Ethics

A study of California disciplinary statistics during 1997–2000 reported 4.5 disciplinary actions per 1000 chiropractors per year, compared to 2.27 for medical doctors, and the incident rate for fraud was nine times greater among chiropractors (1.99 per 1000 chiropractors per year) than among medical doctors (0.20).^[78] According to a 2006 Gallup poll of U.S. adults, when asked how they would "rate the honesty and ethical standards of people in these different fields", chiropractic compared unfavorably with mainstream medicine. When chiropractic was rated, it "rated dead last amongst healthcare professions". While 84% of respondents considered nurses' ethics "very high" or "high," only 36% felt that way about chiropractors. Other healthcare professions ranged from 38% for psychiatrists, to 62% for dentists, 69% for medical doctors, 71% for veterinarians, and 73% for druggists or pharmacists.^{[10][79][80][81]} Similar results were found in the 2003 Gallup Poll.^[82]

Another chiropractic study documented that the largest chiropractic associations in the U.S. and Canada distributed patient brochures which contained unsubstantiated claims.^[83] Chiropractors, especially in America, have a reputation for unnecessarily treating patients.^[15] Sustained chiropractic care is promoted as a preventative tool, but unnecessary manipulation could possibly present a risk to patients. Some chiropractors are concerned by the routine unjustified claims chiropractors have made.^[9] A 2010 analysis of chiropractic websites found the majority of chiropractors and their associations made claims of effectiveness not supported by scientific evidence, including claims about the treatment of asthma, ear infection, earache, otitis media, and neck pain.^[84]

Some New Zealand chiropractors appeared to have used the title 'doctor' in a New Zealand yellow pages telephone directory in a way that implied they are registered medical practitioners, when no evidence was presented it was true.^[85] In New Zealand, chiropractors are allowed to use the title 'doctor' when it is qualified to show that the title refers to their chiropractic role. A representative from the NZ Chiropractic Board states that entries in the yellow pages under the heading of 'Chiropractors' fulfills this obligation when suitably qualified.^[86] If a chiropractor is not a registered medical practitioner, then the misuse of the title 'doctor' while working in healthcare will not comply with the Health Practitioners Competence Assurance Act 2003.^[85]

UK chiropractic organizations and their members make numerous claims which are not supported by scientific evidence. Many chiropractors adhere to ideas which are against science and most seemingly violate important principles of ethical behaviour on a regular basis. The advice chiropractors gave to their patients is often misleading and dangerous.^[87] This situation, coupled with a backlash to the libel suit filed against Simon Singh, has inspired the filing of formal complaints of false advertising against more than 500 individual chiropractors within one 24 hour period,^[88][89] prompting the McTimoney Chiropractic Association to write to its members advising them to remove leaflets that make claims about whiplash and colic from their practice, to be wary of new patients and telephone inquiries, and telling their members: "If you have a website, take it down NOW." and "Finally, we strongly suggest you do NOT discuss this with others, especially patients."^[88]

International reception

Australia

In Australia, most private health insurance funds cover chiropractic care, and the federal government funds chiropractic care when the patient is referred by a medical practitioner.^[90]

United Kingdom

In the United Kingdom chiropractic is available on the National Health Service in some areas, such as Cornwall where the treatment is only available for neck or back pain.^[91] On the NHS Choices website, they make patients aware that there is "no scientific evidence to support the idea that most illness is caused by misalignment of the spine."^[92]

A 2010 questionnaire presented to UK chiropractors indicated only 45% of chiropractors disclosed with patients the serious risk associated with manipulation of the cervical spine as a direct consequence of the fear that the patient would refuse treatment despite knowing the moral responsibility.^[93]

United States and Canada

The percentage of the population that utilizes chiropractic care at any given time generally falls into a range from 6% to 12% in the U.S. and Canada,^[6] with a global high of 20% in Alberta.^[94] Chiropractors are the most common CAM providers for children and adolescents, who consume up to 14% of all visits to chiropractors.^[95] The vast majority who seek chiropractic care do so for relief from back and neck pain and other neuromusculoskeletal complaints;^[96] most do so specifically for low back pain.

The largest chiropractic associations in the U.S. and Canada distributed patient brochures which contained unsubstantiated claims.^[83]

In the U.S., chiropractic was reported in 1992 as being the largest alternative medical profession, with chiropractors performing over 90% of all manipulative treatments, although "serious complications of lumbar manipulation, including paraplegia and death" were also reported.^[97] In studies examining back pain treatments, satisfaction rates among chiropractic patients are typically higher than among medical patients.^{[98][99][100]} Treatment outcomes are not necessarily better for chiropractic patients than for medical patients;^[100] the higher satisfaction among chiropractic patients is typically attributed to better communication of advice and information.^{[98][99][100]} Practitioners such as chiropractors are often used as a complementary form of care to primary medical intervention.^[6]

Chiropractic is viewed as a marginal healthcare profession.^[39] Public perception of chiropractic compares unfavorably with mainstream medicine with regard to ethics and honesty: in a 2006 Gallup Poll of U.S. adults, chiropractors rated last among seven health care professions for level of honesty and ethical standards, with 36% of poll respondents rating chiropractors very high or high; the corresponding ratings for the other professions ranged from 62% for dentists to 84% for nurses.^{[10][101][102]}

Utilization of chiropractic care is sensitive to the costs incurred by the co-payment by the patient.^[1] The use of chiropractic declined from 9.9% of U.S. adults in 1997 to 7.4% in 2002; this was the largest relative decrease among CAM professions, which overall had a stable use rate.^[103] As of 2007 only 7% of the U.S. population is being reached by chiropractic.^[104] Employment of U.S. chiropractors is expected to increase 14% between 2006 and 2016, faster than the average for all occupations.^[73]

In the U.S., most states require insurers to cover chiropractic care, and most HMOs cover these services.^[95] In Canada, there is lack of coverage under the universal public health insurance system.^[105]

History

Chiropractic was founded in 1895 by Daniel David (D.D.) Palmer in Davenport, Iowa. Palmer, a magnetic healer, hypothesized that manual manipulation of the spine could cure disease.^[106] Although initially keeping chiropractic a family secret, in 1898 Palmer began teaching it to a few students at his new Palmer School of Chiropractic. One student, his son Bartlett Joshua (B.J.) Palmer, became committed to promoting chiropractic, took over the Palmer School in 1906, and rapidly expanded its enrollment.^[107]

Early chiropractors believed that all disease was caused by interruptions in the flow of innate intelligence, a vital nervous energy or life force that represented God's presence in man; chiropractic leaders often invoked religious imagery and moral traditions. D.D. and B.J. both seriously considered declaring chiropractic a religion, which might have provided legal protection under the U.S. constitution, but decided against it partly to avoid confusion with Christian Science.^[107][108] Early chiropractors also tapped into the Populist movement, emphasizing craft, hard work, competition, and advertisement, aligning themselves with the common man against intellectuals and trusts, among which they included the American Medical Association (AMA).^[107]

Palmer defined chiropractic as "a science of healing without drugs" and considered establishing chiropractic as a religion. Chiropractic included vitalistic ideas of Innate Intelligence with religious attributes of Universal Intelligence to substitute science.^[9] Evidence suggests that D.D. Palmer had acquired knowledge of manipulative techniques from Andrew Taylor Still, the founder of osteopathy.^[9] Although D.D. Palmer combined bonesetting to give chiropractic its method, and "magnetic healing" for the purported theory.^[24] According to D.D. Palmer, subluxation was the sole cause of disease and manipulation was the cure for all diseases.^[8][9]

A longstanding feud between chiropractors and medical doctors continued for decades. The AMA labeled chiropractic an "unscientific cult" in 1966,^[19] and until 1980 advised its members that it was unethical for medical doctors to associate with "unscientific practitioners".^[109] This culminated in a landmark 1987 decision, Wilk v. AMA, in which the court found that the AMA had engaged in unreasonable restraint of trade and conspiracy, and which ended the AMA's de facto boycott of chiropractic.^[20]

In 2008 and 2009, chiropractors, including the British Chiropractic Association, used libel lawsuits and threats of lawsuits against their critics.^[110] However, a libel case against science writer Simon Singh ended with the BCA withdrawing its suit in 2010.^[111][112] Simon Singh was sued for libel by the British Chiropractic Association (BCA) for criticizing their activities in a column in The Guardian.^[113] A preliminary hearing took place at the Royal Courts of Justice in front of Justice David Eady. The judge held that merely using the phrase "happily promotes bogus treatments" meant that he was stating, as a matter of fact, that the British Chiropractic Association was being consciously dishonest in promoting chiropractic for treating the children's ailments in question.^[114] An editorial in Nature has suggested that the BCA may be trying to suppress debate and that this use of British libel law is a burden on the right to freedom of expression, which is protected by the European Convention on Human Rights.^[115] The libel case ended with the BCA withdrawing its suit in 2010.^[111][112]

Chiropractic has had a strong salesmanship element since it was started by D.D. Palmer. His son, B.J. Palmer, asserted that their chiropractic school was founded on "…a business, not a professional basis. We manufacture chiropractors. We teach them the idea and then we show them how to sell it".^[116] D.D. Palmer established a magnetic healing facility in Davenport, Iowa, styling himself ‘doctor’. Not everyone was convinced, as a local paper in 1894 wrote about him: "A crank on magnetism has a crazy notion hat he can cure the sick and crippled with his magnetic hands. His victims are the weak-minded, ignorant and superstitious, those foolish people who have been sick for years and have become tired of the regular physician and want health by the short-cut method…he has certainly profited by the ignorance of his victims…His increase in business shows what can be done in Davenport, even by a quack."^[116] D.D. Palmer remarked that "Give me a simple mind that thinks along single tracts, give me 30 days to instruct him, and that individual can go forth on the highways and byways and get more sick people well than the best, most complete, all around, unlimited medical education of any medical man who ever lived."^[9]

In recent decades chiropractic gained legitimacy and greater acceptance by medical physicians and health plans, and enjoyed a strong political base and sustained demand for services. However, its future seemed uncertain: as the number of practitioners grew, evidence-based medicine insisted on treatments with demonstrated value, managed care restricted payment, and competition grew from massage therapists and other health professions. The profession responded by marketing natural products and devices more aggressively, and by reaching deeper into alternative medicine and primary care.^[20]

Effectiveness

Unsubstantiated claims about the efficacy of chiropractic have continued to be made by individual chiropractors and chiropractic associations.^[9] Many studies of treatments used by chiropractors have been conducted, often with conflicting results.^[9][117] Manual therapies commonly used by chiropractors are as effective as other manual therapies for the treatment of low back pain,^[118][119] and might also be effective for the treatment of lumbar disc herniation with radiculopathy,^[120][121] neck pain,^[122] some forms of headache,^[123][124] and some extremity joint conditions.^[125][126] While guidelines issued by the WHO state that chiropractic care may be considered safe when employed skillfully and appropriately,^[2] chiropractic spinal manipulation is frequently associated with mild to moderate adverse effects, and with serious or fatal complications in rare cases.^{[127][128][129]} The efficacy and cost-effectiveness of maintenance chiropractic care are unproven.^[130]

Many controlled clinical studies of spinal manipulation have been conducted, but their results often disagree^[131] and they are typically of low methodological quality.^[132] A 2010 report found that manual therapies commonly used by chiropractors are effective for the treatment of low back pain, neck pain, some kinds of headaches and a number of extremity joint conditions.^[117]

A 2011 systematic review of systematic reviews found that collectively, spinal manipulation failed to show it is effective for any condition.^[14] A 2008 critical review found that with the possible exception of back pain, chiropractic manipulation has not been shown to be effective for any medical condition.^[9] Health claims made by chiropractors regarding use of manipulation for pediatric health conditions are supported by only low levels of scientific evidence^[95][133] that does not demonstrate clinically relevant benefits.^[134]

Most research has focused on spinal manipulation in general,^[135] rather than solely on chiropractic manipulation.^[21] A 2002 review of randomized clinical trials of spinal manipulation^[44] was criticized for not making this distinction;^[135] however, the review's authors stated that they did not consider this difference to be a significant point as research on spinal manipulation is equally useful regardless of which practitioner provides it.^[135]

There is a wide range of ways to measure treatment outcomes.^[136] Chiropractic care, like all medical treatment, benefits from the placebo response.^[137] It is difficult to construct a trustworthy placebo for clinical trials of spinal manipulative therapy (SMT), as experts often disagree about whether a proposed placebo actually has no effect.^[138] The efficacy of maintenance care in chiropractic is unknown.^[130]

Available evidence covers the following conditions:

• Low back pain. Specific guidelines concerning the treatment of nonspecific (i.e., unknown cause) low back pain remain inconsistent between countries.^[139] A 2012 overview of systematic reviews found that collectively, spinal manipulation failed to show it is an effective intervention for pain.^[140] A 2011 Cochrane review found strong evidence that there is no clinically meaningful difference between spinal manipulation and other treatments for reducing pain and improving function for chronic low back pain.^[118] A 2010 Cochrane review found no current evidence to support or refute a clinically significant difference between the effects of combined chiropractic interventions and other interventions for chronic or mixed duration low back pain.^[141] A 2010 systematic review found that most studies suggest spinal manipulation achieves equivalent or superior improvement in pain and function when compared with other commonly used interventions for short, intermediate, and long-term follow-up.^[119] A 2008 review found strong evidence that SM is similar in effect to medical care with exercise.^[142] A 2008 literature synthesis found good evidence supporting SM for low back pain regardless of duration.^[143] A 2007 review found good evidence that SM is moderately effective for low back pain lasting more than 4 weeks.^[144] In 2007 the American College of Physicians and the American Pain Society recommended that clinicians consider the addition of spinal manipulation for patients who do not improve with self care options.^[145] Methods for formulating treatment guidelines for low back pain differ significantly between countries, casting some doubt on their reliability.^[139]

• Radiculopathy. There is no consensus on the effectiveness of manual therapies for radiculopathies. There is moderate quality evidence to support the use of spinal manipulation for the treatment of acute lumbar radiculopathy^[120] and acute lumbar disc herniation with associated radiculopathy.^[121] The evidence for chronic lumbar spine-related extremity symptoms and cervical spine-related extremity symptoms of any duration is low or very low and no evidence exists for the treatment of thoracic radiculopathy.^[120]

• Whiplash and other neck pain. There is no consensus on the effectiveness of manual therapies for neck pain.^[146] Systematic reviews have concluded that thoracic spine manipulation may provide short-term improvement in patients with acute or subacute mechanical neck pain; although the body of literature is still weak.^[147][148] A 2010 Cochrane review found low evidence that manipulation was more effective than a control for neck pain, and moderate evidence that cervical manipulation and mobilisation produced similar effects on pain, function and patient satisfaction.^[122] A 2010 systematic review found low level evidence that suggests chiropractic care improves cervical range of motion and pain in the management of whiplash.^[149] A 2009 systematic review of controlled clinical trials found no evidence that chiropractic spinal manipulation is effective for whiplash injury.^[150] A 2008 review found evidence that suggests that manual therapy and exercise are more effective than alternative strategies for patients with neck pain.^[151] A 2007 review found that spinal manipulation and mobilization are effective for neck pain.^[146] A 2005 review found evidence supporting spinal mobilization, and limited evidence supporting spinal manipulation for whiplash.^[152]

• Headache. There is no consensus on the effectiveness of manual therapies for headaches. Of two systematic reviews published in 2011, one found evidence that spinal manipulation might be as effective as propranolol or topiramate in the prevention of migraine headaches,^[123] but the other concluded that evidence does not support the use of spinal manipulation for the treatment of migraine headaches.^[153] A 2004 Cochrane review found evidence that suggests spinal manipulation may be effective for migraine, tension headache and cervicogenic headache.^[124] A 2006 review found inconclusive evidence supporting manual therapies for tension headache.^[154] A 2005 review found that spinal manipulation showed a trend toward benefit in the treatment of tension headache, but the evidence was weak.^[155]

• Extremity conditions. A 2011 systematic review and meta-analysis concluded that the addition of manual mobilizations to an exercise program for the treatment of knee osteoarthritis resulted in better pain relief then a supervised exercise program alone and suggested that manual therapists consider adding manual mobilisation to optimise supervised active exercise programs.^[156] There is silver level evidence that manual therapy is more effective than exercise for the treatment of hip osteoarthritis, however this evidence could be considered to be inconclusive.^[157] A 2008 systematic review found that the addition of cervical spine mobilization to a treatment regimen for lateral epicondylosis (tennis elbow) resulted in significantly better pain relief and functional improvements in both the short and long-term.^[158] There is a small amount of research into the efficacy of chiropractic treatment for upper limbs,^[159] limited to low level evidence supporting chiropractic management of shoulder pain^[126] and limited or fair evidence supporting chiropractic management of leg conditions.^[125]

• Other. A 2012 systematic review found insufficient low bias evidence to support the use of spinal manipulation as a therapy for the treatment of hypertension.^[160] A systematic review in 2011 found moderate evidence to support the use of manual therapy for cervicogenic dizziness.^[161] There is very weak evidence for chiropractic care for adult scoliosis (curved or rotated spine)^[162] and no scientific data for idiopathic adolescent scoliosis.^[163] A 2007 systematic review found that few studies of chiropractic care for nonmusculoskeletal conditions are available, and they are typically not of high quality; it also found that the entire clinical encounter of chiropractic care (as opposed to just SM) provides benefit to patients with cervicogenic dizziness, and that the evidence from reviews is negative, or too weak to draw conclusions, for a wide variety of other nonmusculoskeletal conditions, including ADHD/learning disabilities, dizziness, high blood pressure, and vision conditions.^[164] Other reviews have found no evidence of significant benefit for asthma,^{[165][166][167]} baby colic,^[133][168] bedwetting,^[169] carpal tunnel syndrome,^[170] fibromyalgia,^[171] gastrointestinal disorders,^[172] kinetic imbalance due to suboccipital strain (KISS) in infants,^[133][173] menstrual cramps,^[174] or pelvic and back pain during pregnancy.^[175]

Safety

Chiropractic care in general is safe when employed skillfully and appropriately. Manipulation is regarded as relatively safe, but as with all therapeutic interventions, complications can arise, and it has known adverse effects, risks and contraindications. Absolute contraindications to spinal manipulative therapy are conditions that should not be manipulated; these contraindications include rheumatoid arthritis and conditions known to result in unstable joints.^[2]

Sustained chiropractic care is promoted as a preventative tool, but unnecessary manipulation could present a risk to patients. Some chiropractors are concerned by the routine unjustified claims chiropractors have made.^[9]

Relative contraindications are conditions where increased risk is acceptable in some situations and where low-force and soft-tissue techniques are treatments of choice; these contraindications include osteoporosis.^[2] Although most contraindications apply only to manipulation of the affected region, some neurological signs indicate referral to emergency medical services; these include sudden and severe headache or neck pain unlike that previously experienced.^[128]

Spinal manipulation is associated with frequent, mild and temporary adverse effects,^[127][128] including new or worsening pain or stiffness in the affected region.^[176] They have been estimated to occur in 33% to 61% of patients, and frequently occur within an hour of treatment and disappear within 24 to 48 hours;^[177] adverse reactions appear to be more common following manipulation than mobilization.^[178] Chiropractors are more commonly associated with serious manipulation related adverse effects than other professionals.^[129]

Rarely,^[2] spinal manipulation, particularly on the upper spine, can also result in complications that can lead to permanent disability or death; these can occur in adults^[127] and children.^[179] Estimates vary widely for the incidence of these complications,^[177] and the actual incidence is unknown, due to high levels of underreporting and to the difficulty of linking manipulation to adverse effects such as stroke.^[127] Adverse effects are poorly reported in recent studies investigating chiropractic manipulations.^[180]

The study reported frequency of serious adverse effect as between strokes 50 per 100,000, 1.46 per 10 million serious adverse events and death rate of 2.68 per 10 million, though it was determined that there was inadequate data to be conclusive.^[177]

Several case reports show temporal associations between interventions and potentially serious complications.^[151] The published medical literature contains reports of 26 deaths since 1934 following chiropractic manipulations and many more seem to remain unpublished.^[129] Vertebrobasilar artery stroke is statistically associated with chiropractic services in persons under 45 years of age,^[181] but it is similarly associated with general practitioner services, suggesting that these associations are likely explained by preexisting conditions.^[151][182] Weak to moderately strong evidence supports causation (as opposed to statistical association) between cervical manipulative therapy and vertebrobasilar artery stroke.^[183] A 2012 systematic review determined that there is insufficient evidence to support a strong association or no association between cervical manipulation and stroke.^[184]

Chiropractors, like other primary care providers, sometimes employ diagnostic imaging techniques such as X-rays and CT scans that rely on ionizing radiation.^[185] Although there is no clear evidence for the practice, some chiropractors may still X-ray a patient several times a year.^[15] Research suggests that most chiropractors in Canada are taught and follow stringent radiography guidelines,^[186] which were developed to reduce unnecessary radiography.^[185]

Risk-benefit

A 2012 systematic review concluded that no accurate assessment of risk-benefit exists for cervical manipulation.^[184] A 2010 systematic review stated that there is no good evidence to assume that neck manipulation is an effective treatment for any medical condition and suggested a precautionary principle in healthcare for chiropractic intervention even if a causality with vertebral artery dissection after neck manipulation were merely a remote possibility.^[129] The same review concluded that the risk of death from manipulations to the neck outweighs the benefits.^[129] Chiropractors have criticized this conclusion, claiming that the author did not evaluate the potential benefits of spinal manipulation.^[187] Edzard Ernst stated "This detail was not the subject of my review. I do, however, refer to such evaluations and should add that a report recently commissioned by the General Chiropractic Council did not support many of the outlandish claims made by many chiropractors across the world."^[187]

A 2009 review evaluating maintenance chiropractic care found that spinal manipulation is routinely associated with considerable harm and no compelling evidence exists to indicate that it adequately prevents symptoms or diseases, thus the risk-benefit is not evidently favorable.^[188]

A 2008 summary found that the best evidence suggests that chiropractic care is a useful therapy for subjects with neck or low-back pain for which the risks of serious adverse events should be considered negligible.^[189] A 2007 systematic review found that with uncertain efficacy and definite risks, the risk-benefit balance of spinal manipulation can't be positive.^[127] A 2006 systematic review of systematic reviews found the risk-benefit balance does not favor spinal manipulation over other treatments like physical therapy.^[131]

Cost-effectiveness

A 2012 systematic review suggested that the use of spine manipulation in clinical practice is a cost-effective treatment when used alone or in combination with other treatment approaches.^[190] A 2011 systematic review found evidence supporting the cost-effectiveness of using spinal manipulation for the treatment of sub-acute or chronic low back pain; the results for acute low back pain were inconsistent.^[191] A 2006 qualitative review found that the research literature suggests that chiropractic obtains at least comparable outcomes to alternatives with potential cost savings.^[192]

A 2006 systematic cost-effectiveness review found that the reported cost-effectiveness of chiropractic manipulation in the United Kingdom compared favorably with other treatments for back pain, but that reports were based on data from clinical trials without sham controls and that the specific cost-effectiveness of the treatment (as opposed to non-specific effects) remains uncertain.^[193] A 2005 American systematic review of economic evaluations of conservative treatments for low back pain found that significant quality problems in available studies meant that definite conclusions could not be drawn about the most cost-effective intervention.^[194] The cost-effectiveness of maintenance chiropractic care is unknown.^[130]

Analysis of a clinical and cost utilization data from the years 2003 to 2005 by an integrative medicine independent physician association (IPA) which looked the chiropractic services utilization found that the clinical and cost utilization of chiropractic services based on 70,274 member-months over a 7-year period decreased patient costs associate with the following use of services by 60.2% for in-hospital admissions, 59.0% for hospital days, 62.0% for outpatient surgeries and procedures, and 85% forpharmaceutical costs when compared with conventional medicine (visit to a medical doctor primary care provider) IPA performance for the same health maintenance organization product in the same geography and time frame.^[195]

Gleberzon et al. identify "deliberate fraud" as a notably harmful element of the chiropractic profession, finding that dubious practice techniques can translate into "outlandish billing and utilization rates". Those at the "fringe of ethical behavior" present the profession with a challenge, they believe, and must be weeded out.^[196]

Public health

Some chiropractors oppose vaccination and water fluoridation, which are common public health practices.^[10] Within the chiropractic community there are significant disagreements about vaccination,^[17][18] one of the most cost-effective public health interventions available.^[197] Most chiropractic writings on vaccination focus on its negative aspects,^[17] claiming that it is hazardous, ineffective, and unnecessary. Some chiropractors have embraced vaccination, but a significant portion of the profession rejects it, as original chiropractic philosophy traces diseases to causes in the spine and states that vaccines interfere with healing.^[18]

The extent to which anti-vaccination views sustain the current chiropractic profession is uncertain.^[17] The American Chiropractic Association and the International Chiropractors Association support individual exemptions to compulsory vaccination laws, and a 1995 survey of U.S. chiropractors found that about a third believed there was no scientific proof that immunization prevents disease.^[18] The Canadian Chiropractic Association supports vaccination;^[17] a survey in Alberta in 2002 found that 25% of chiropractors advised patients for, and 27% against, vaccinating themselves or their children.^[198]

Early opposition to water fluoridation included chiropractors, some of whom continue to oppose it as being incompatible with chiropractic philosophy and an infringement of personal freedom. Other chiropractors have actively promoted fluoridation, and several chiropractic organizations have endorsed scientific principles of public health.^[199]

In addition to traditional chiropractic opposition to water fluoridation and vaccination, chiropractors' attempts to establish a positive reputation for their public health role are also compromised by their reputation for recommending repetitive lifelong chiropractic treatment.^[10]

Controversy and criticism

Throughout its history chiropractic has been the subject of internal and external controversy and criticism.^[24][200] According to Daniel D. Palmer, the founder of chiropractic, subluxation is the sole cause of disease and manipulation is the cure for all diseases of the human race.^[8][9] A critical evaluation stated "Chiropractic is rooted in mystical concepts. This led to an internal conflict within the chiropractic profession, which continues today."^[9] Chiropractors, including D.D. Palmer, were jailed for practicing medicine without a license.^[9] For most of its existence, chiropractic has battled with mainstream medicine, sustained by antiscientific and pseudoscientific ideas such as subluxation.^[30] Chiropractic has been controversial, though to a lesser extent than in past years.^[201] The American Medical Association has long been particularly critical, as indicated by a 1966 targeting of chiropractors described as a "national campaign against medical quackery."^[202]

Chiropractic authors have stated that fraud, abuse and quackery are more prevalent in chiropractic than in other health care professions.^[203] The core concept of traditional chiropractic, vertebral subluxation, is not based on sound science. The biomechanical listing systems taught in chiropractic college technique offerings have been criticized as inaccurate, inadequate and invalid.^[204] A critical evaluation found that research has not demonstrated that spinal manipulation, the main treatment method employed by chiropractors, is effective for any medical condition, with the possible exception of treatment for back pain,^[9] whereas another review found manual therapies in general to be effective for back pain, neck pain, some forms of headaches and some extremity joint conditions.^[117] Although rare,^[2] spinal manipulation, particularly on the upper spine, can also result in complications that can lead to permanent disability or death; these can occur in adults^[127] and children.^[179]

In an article on quackery, W.T. Jarvis has stated that "Non-scientific health care (e.g., acupuncture, ayurvedic medicine, chiropractic, homeopathy, naturopathy) is licensed by individual states. Practitioners use unscientific practices and deception on a public who, lacking complex health-care knowledge, must rely upon the trustworthiness of providers. Quackery not only harms people, it undermines the scientific enterprise and should be actively opposed by every scientist."^[205]

No single profession "owns" spinal manipulation and there is little consensus as to which profession should administer SM, raising concerns by chiropractors that other medical physicians could "steal" SM procedures from chiropractors. A focus on evidence-based SM research has also raised concerns that the resulting practice guidelines could limit the scope of chiropractic practice to treating backs and necks.^[21] Two U.S. states (Washington and Arkansas) prohibit physical therapists from performing SM,^[206] some states allow them to do it only if they have completed advanced training in SM, and some states allow only chiropractors to perform SM, or only chiropractors and physicians. Bills to further prohibit non-chiropractors from performing SM are regularly introduced into state legislatures and are opposed by physical therapist organizations.^[207]

References

External links

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• Chiropractic at Curlie