The prevalence of the term subluxation in North American English-Language Doctor of chiropractic programs

The subluxation construct in the DCP curriculum

Murphy et al [7] noted nine areas of reform that were essential to the mainstreaming of the chiropractic profession. One of these areas included educational reform, in particular the need to discontinue the perpetuation of dogma and unfounded claims. The most frequently encountered unsubstantiated claim related to the putative clinical meaningfulness of subluxation [8]. Keating et al have found that the subluxation construct lacks adequate evidence as a theoretical construct and appears to be more of a dogma [3]. Our study found that 50% of English-language doctor of chiropractic educational programs in Canada and the United States continue to teach this dogma. This contrasts with the chiropractic programs in the United Kingdom which do not teach about the subluxation or only do in a historical context [9].

One might argue that a historical presentation of the subluxation may be all we are finding references to in our search of the DCP curricula. This would be a reasonable argument if the subluxation was mentioned in only one course in a DCP program or if it was only in what was described as a philosophy course. This, in fact, only occurred at two colleges (Texas Chiropractic College and the University of Bridgeport College of Chiropractic), however, with an aggregate average of 13.5 appearances and many of those in technique classes. It seems unlikely that this is purely to explain the history of term in the chiropractic profession.

Faculty and alumni resistance may play a part in the continued teaching about the subluxation. Lawrence [10] noted that getting faculty to change is akin to trying to move an iceberg with a toothpick. The recent uproar about the U.S. Council on Chiropractic Education's new accreditation standards [11, 12] and General Chiropractic Council of the UK's position on the subluxation [13, 14] shows how much resistance there is to dropping the term. However, other facts such as the committee structure and internal academic policy regarding course modification may be factors as well. The input of the alumni of a college may also prevent change. Many alumni continue to use the term [15, 16] and thus might desire future generations of chiropractors to be trained as they were.

Evidence-based medicine

Since the concept of subluxation lacks a sufficient evidence base to support it as a real clinical entity, [3] continuing to teach this is in conflict with the need for the DCPs to be evidence-based [5, 17, 18].

While this study did not delve into the concept of evidence-based practice, some schools have devoted coursework to the concept. An interesting finding not related to the study design was that one particular college catalog appears to teach evidence-based concepts yet continues to teach the subluxation construct. This dichotomy is worth further examination in future studies. Palmer-West presented one course entitled "Evidence-based chiropractic I" with a course description similar to what one would expect in such a course i.e. development of skills in critical thinking, literature search, critical evaluation and integration of evidence [19]. However, this same curriculum offered in its "Chiropractic Philosophy & Practice II" course a description denoting concepts of subluxation and its mechanism of production and dysfunction [19].

Four chiropractic programs studied have received grants from the National Center for Complimentary and Alternative Medicine (a part of the U.S. National Institutes of Health) to improve the teaching of evidence base practice in their respective chiropractic curricula. Only one of those four does not include the subluxation in their curriculum (National University of Health Sciences). Future research should determine what affect, if any, these research grants have on the prevalence of the subluxation construct in these DCPs.

We believe that for the chiropractic education curriculum to become truly evidence-based it will have to make changes that reflect a current state of the knowledge base. This means that a certain number of unsupported beliefs and theories of the past will, of necessity, have to be abandoned. This will be the hallmark of a profession prepared to change as science and evidence changes and not of a craft group that follows an ideology espoused by its founder or guru.

McDonald et al [16] reported that over 88% of chiropractors surveyed favored retaining the term vertebral subluxation complex. Smith and Carber [15] found that over 70% of chiropractors reported that subluxation is important to their clinical decisions and guides their clinical care of patients. McDonald et al [16] reported that a strong majority (over 75%) of their surveyed chiropractors believed that subluxation was a significant contributing factor to 50% or more of visceral disorders. Despite this finding, Smith and Carber's research [15] demonstrated that most of their surveyed chiropractors seemed 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. The findings of McDonald et al [16]and Smith and Carber's [15] support the notion that the chiropractic curriculum may be producing graduates who are using the subluxation construct as fact or readily accept the notion after course completion. Until and unless sound research published in credible journals demonstrates the existence and reliable identification of vertebral subluxation, and vertebral subluxation is found to be an important public health problem, society at large will be skeptical and not care about its correction [5].

There is an obvious disconnect between those who are skeptical and critical of the subluxation and those practicing in the field who adhere to it. The few in academic circles that may be highly critical of the subluxation construct appear to have had little influence on curtailing its use both inside and outside the chiropractic academy. Alumni who favor the term may be influential in this matter. This should not be surprising given that field practitioners hold in much disdain those who dedicate themselves to an academic career [10]. Nonetheless, faculties do have influence on curricular matters and the failure to curtail the use of subluxation in the chiropractic curriculum would undoubtedly indicate to critics that the faculty of chiropractic colleges is more than willing to embrace an unscientific concept such as subluxation. Such failure of faculty to be instrumental in curricular changes indicates that they themselves are not scientifically-minded or that college administration is unwilling to allow faculty the necessary steps to make progress in matters related to the curriculum. No matter who may be at fault in the curricular propagation of the subluxation construct, the lack of change may indicate that chiropractic, as an academic enterprise is willing to embrace scientifically unsubstantiated concepts. Using the slippery slope argument, if one area of the curriculum or even mission of the institution has one unsubstantiated construct such as subluxation, how many more unsubstantiated ideas, concepts, constructs are being perpetuated?

The accreditation process

College catalogs are the one of the first lines of evidence to accreditation agencies. Three chiropractic schools made the decision to not make mention of the subluxation construct. What is perplexing about this aspect is found in the documents of the Council of Chiropractic Education (CCE) itself. The new CCE Accreditation Standards do not mention subluxation at all [20] and the new Manual of Policies only mentions the term one time in the meta-competencies:

Performing case-appropriate physical examinations that include evaluations of body regions and organ systems, including the spine and any subluxation/neuro-biomechanical dysfunction, that assist the clinician in developing the clinical diagnosis(es)[21].

The older Standards for Chiropractic Programs and Requirements for Institutional Status mentioned the term six times [22]. We wonder if this change in the accrediting agency's use of the term will result in a corresponding change at the DCP level. Thus, we anticipate replicating this study in a few years to determine what changes in DCP programs maybe seen after implementation of these changes in 2012.

Chiropractic philosophy in the DCP curriculum

The philosophical basis of chiropractic is another topic of considerable importance. At the root of the chiropractic philosophical system and the connection to subluxation is the nervous system. One of the colleges' examined noted: "Our purpose as Doctor's of Chiropractic is to locate and correct any interference to the system in the body that controls and coordinates all functions--the nervous system"[23]. This same school utilized the subluxation term in two of its biochemistry courses. Since there is no scientific evidence to support subluxation at the biochemical level why is such a connection made in a biochemistry course? The reason this is relevant is that some chiropractors have compared chiropractic education to medical education. When an entity such as subluxation which has such little evidence to support its existence is portrayed as having an effect upon human biochemistry it gives the appearance that the dogmatic character of subluxation beliefs [3] has permeated into core scientific courses in the chiropractic program.