The defining characteristic of pseudoscience is an idea which sounds scientific, which claims to be scientific, but which isn’t actually based on legitimate scientific research or is theoretically inconsistent which established scientific knowledge. There can be some subjectivity in the characterization of something as pseudoscience, and of course no one promoting an idea would ever accept the label for their own beliefs. However, an article I recently read concerning veterinary chiropractic exemplifies many key features of a pseudoscientific idea.
Maler, MM. Overview of veterinary chiropractic and its use in pediatric exotic patients. Vet Clin Exot Anim. 2012;15:299-310
The article spends a great deal of time describing the Vertebral Subluxation (VS), which the author states “is at the core of chiropractic theory, and it’s detection and correction are central to chiropractic practice.” The only problem with this claim is that the vertebral subluxation, as defined by chiropractic theory doesn’t exist. (1, 2, 3)
Historically, chiropractors defined the VS as a misalignment of bones in the spine, leading to interruption in the flow of “innate intelligence,” a magical spiritual force responsible for normal health. Of course, no scientific evaluation of such a supernatural force is possible, and to gain the appearance of scientific legitimacy, most chiropractors gradually moved away from this concept and argued that the misalignment of vertebrae damaged health by impinging on nerves leaving the spine. This theory makes some sense when used to explain musculoskeletal pain, though it doesn’t make any sense when used to justify chiropractic as a treatment for ear infections, asthma, allergies, or other such complaints.
As it turned out, however, chiropractors have never been able to demonstrate that the bones they are supposedly adjusting into proper position were ever out of position. In other words, they have never been able to show any misalignment in the spine treatable by their form of manipulation. Studies involving imaging, such as x-rays, don’t show the misalignments, and when radiologists or chiropractors look at x–rays of patients diagnosed with a VS on physical examination, they can’t consistently find a lesion in the area identified as abnormal during the exam.
In response to this failure, chiropractors have once again modified the definition of the VS, this time describing the subluxation not as a misalignment of bones but a “a complex of functional and/or structural and/or pathological articular changes that compromise neural integrity and may influence organ function and general health.” How’s that for a definition vague enough to qualify as a horoscope? Basically, chiropractors are now saying that a VS cannot be seen or measured or identified in any way other than the subjective impression of a chiropractor during an examination, yet it is still an appropriate basis for an entire approach to maintaining health and treating innumerable diseases.
But the situation is even worse than it sounds. When chiropractors examine the same patient multiple times, they cannot consistently locate a VS in the same location each time. And when multiple chiropractors examine the same patient, they all claim to find abnormalities in different places. So they can’t even agree with themselves or each other on where a VS is in any particular patient. Again, it is hard to imagine such a nebulous entity being the foundation of comprehensive healthcare approach, much less one claimed to be scientific in its foundations.
To their credit, a growing minority of chiropractors recognize that the VS is a myth and seek to identify legitimate, scientific explanations for the limited but well-demonstrated benefits of chiropractic therapy in treating lower back pain. Such evidence-based chiropractors have been trying to reform their profession since the 1960s, with pretty limited success. Some of the most conclusive evidence against the existence of the VS comes from chiropractors themselves applying truly scientific methods to the evaluation of this pseudoscientific concept.
A review of the literature which appeared in a chiropractic journal in 2009 evaluated the research evidence concerning the VS to see if it met standard criteria for a cause-effect relationship between the VS and disease.
Miritz TA. Morgan L. Wyatt LH. Greene L. An epidemiological examination of the subluxation construct using Hill’s criteria of causation. Chiropr Osteopat 2009;2:17-13.
The criteria for causation in epidemiology are strength (strength of association), consistency, specificity, temporality (temporal sequence), dose response, experimental evidence, biological plausibility, coherence, and analogy. Applied to the subluxation all of these criteria remain for the most part unfulfilled.
There is a significant lack of evidence to fulfill the basic criteria of causation. This lack of crucial supportive epidemiologic evidence prohibits the accurate promulgation of the chiropractic subluxation.
The fact that in over 100 years since the beginnings of chiropractic no one has been able to demonstrate the existence of the foundational concept for the method, the vertebral subluxation, doesn’t prevent the author of the veterinary clinics article from describing it in detail, with diagrams and lots of scientific terminology. She then goes on to make a wide variety of therapeutic claims, identifying chiropractic as a successful intervention for disease in exotic species.
As evidence for these claims, she cites quite a few textbooks and other writings of her fellow chiropractors, but virtually no relevant clinical trials. The author acknowledges this lack of research support but, in a technique common among practitioners of unproven approaches, she places the blame for this everywhere except on the chiropractic community:
Chiropractic research is in it’s infancy compared to traditional medicine largely due to lack of funding and proprietary interest in chiropractic as well as historical staunch opposition from the American Medical Association and other medical groups.
For a treatment approach that has been in existence for a century, with 50,000 licensed chiropractors in the U.S. alone, and with annual revenue for chiropractic treatment estimated at $10 billion in the U.S., it is hard to justify failing to subject the practice to rigorous scientific scrutiny due to lack of funds.
And while there once was organized opposition to chiropractic on the part of the American Medical Association, this vanished after an antitrust lawsuit finally settled in 1987. The judge found that while the AMA had a legitimate concern about the unscientific nature of chiropractic and the inadequate evidence for safety and efficacy, it did not have the right to organize a boycott against the practice. Organizations representing conventional healthcare providers have done nothing to stop chiropractors from pursuing rigorous scientific evidence to support the theory of the VS or the safety and efficacy of chiropractic treatment.
Yet despite all of that, the only convincing evidence that has emerged to support chiropractic treatment is in the care of humans with lower back pain, in which chiropractic is about as effective as conventional care. This does not justify the application of chiropractic for any other medical condition or the use of chiropractic in non-human animals without appropriate research to justify this. And it certainly does nothing to support the pseudoscientific nebulosity that is the vertebral subluxation. As long as chiropractors cling to this notion and make claims for their practices beyond what is justified by real evidence, the practice will continue to be a pseudoscientific one.