When D.D. Palmer, a magnetic healer, claimed that he had cured deafness by thrusting on a displaced 4th thoracic vertebra, there was good reason to question the claim since the nerves responsible for hearing are contained in the skull. Some chiropractic historians have suggested that the cure was fabricated in a move to follow the approach of osteopathy, a new method of healing. Today, many chiropractors continue to claim that vertebral subluxations can affect organ function by interfering with nerve flow in spinal nerves, a view that is scientifically indefensible since spinal nerves supply musculoskeletal structures apart from the autonomic nervous system that supplies the body’s organs.
There Is No Evidence to Indicate that Vertebral Subluxations Affect Organ Function
In 1895, D.D. Palmer, the founder of chiropractic, announced that 95 per cent of diseases are caused by displaced vertebrae that place pressure on spinal nerves,1 giving birth to the subluxation theory that serves as the foundation of chiropractic. Today, chiropractic is defined as a method of adjusting a “vertebral subluxation complex,” an asymptomatic and undetectable “joint dysfunction” (involving nerves, muscles, connective tissues, blood vessels, and other factors) alleged to affect organ system function and general health. There is no credible evidence to support such a speculation as a foundation for a health-care profession.
Spinal nerves are commonly compressed by bony spurs and by herniated discs. Even the most severe compression of a spinal nerve, which may cripple the supplied musculoskeletal structures, does not cause organic disease. Vertebral misalignments, which are common in structural deviations from normal, rarely affect spinal nerves. A real orthopedic subluxation which causes musculoskeletal symptoms has never been associated with organic disease and is not the same as an elusive chiropractic vertebral subluxation complex.
Spinal nerves supply the sensory and motor (voluntary) functions of musculoskeletal structures. Involuntary function of the body’s organs is regulated by a chain of autonomic nerve ganglia and plexuses located outside the spinal column and by autonomic cranial and sacral nerves that pass through solid bony openings, unaffected by vertebral subluxations. The all-important vagus nerves are autonomic cranial nerves that originate in the brain stem, traversing openings on each side of the base of the skull to pass down through the neck, thorax, and abdomen to supply the body’s organs. Preganglionic autonomic fibers, which emerge from the spinal cord and pass through spinal segments from the first thoracic vertebra to the second lumbar vertebra, terminate in para-vertebral trunk and splanchnic ganglia.
The vagus nerves along with autonomic ganglia and nerve plexuses provide overlapping sympathetic and parasympathetic nerve supply from many directions and sources (in concert with chemical, hormonal, and circulatory factors) to assure continued function of the body’s organs, independent of spinal nerves.2 This is why severance of the spinal cord in the neck area (at or above C4 to C5), shutting off brain impulses to spinal nerves, can cause paralysis of muscles from the neck down while the body’s organs continue to function. (Severance of the spinal cord above C5 can cause fatal respiratory paralysis.) Transplanted organs, reconnected with blood supply, function without reconnection of severed nerves.
Since the spinal cord ends at the level of the 2nd lumbar vertebra, spinal nerves pass down from the spinal cord (like the hair on a horse’s tail) to exit openings between the lumbar vertebrae and the solid bony openings (foramina) in the sacrum, supplying bladder and bowel sphincter muscles. These nerves, like vagus nerves, are not subject to compression by a vertebral misalignment. Sacral nerves, however, can be compressed by protrusion of a lower lumbar disc into the spinal canal, affecting voluntary control of bladder and anal sphincter muscles (cauda equina syndrome), a medical emergency that requires the immediate attention of a neurosurgeon. Spinal manipulation should not be done as a treatment for a herniated disc anywhere in the spine, especially in the lumbar spine where massive disc protrusions can occur.
Subluxation Theory Continues to Define Chiropractic
Spinal manipulation, massage, and other forms of manual therapy may have some neurological and physiological effects that might be beneficial in temporarily relieving back pain symptoms. But there is no evidence to indicate that such effects have a significant effect on organ function or general health.
A recent study by academic chiropractors concluded that “No supportive evidence is found for the chiropractic subluxation being associated with any disease process or of creating suboptimal health conditions requiring intervention.”3 Another independent study by academic chiropractors revealed that “Despite the controversies and paucity of evidence the term subluxation is still found often within the chiropractic curricula of most North American chiropractic programs.”4
Despite the implausibility of chiropractic subluxation theory, state laws and chiropractic publications in the United States continue to define chiropractic as a method of correcting vertebral subluxations to restore and maintain health.5 A 2015 publication of the National Board of Chiropractic Examiners (NBCE), Practice Analysis of Chiropractic 2015, states that “The specific focus of chiropractic practice is known as the chiropractic subluxation or joint dysfunction. A subluxation is a health concern that manifests in the skeletal joints, and, through complex anatomical and physiologic relationships, affects the nervous system and may lead to reduced function, disability, or illness.”6 This definition of chiropractic is in keeping with a paradigm formulated by the Association of Chiropractic Colleges (ACC) in 1996, signed by 16 North American chiropractic college presidents:“Chiropractic is concerned with the preservation and restoration of health, and focuses particular attention on the subluxation…a complex of functional and/or structural and/or pathological articular changes that compromise neural integrity and may influence organ system function and general health.”6
Spinal Manipulation as a Treatment Option
It’s important to understand that while a chiropractic adjustment based on subluxation theory has been rejected by the scientific community, generic spinal manipulation used in the treatment of mechanical-type back pain has a plausible basis that makes it acceptable in mainstream healthcare.
A 2011 Cochrane Systematic Review of spinal manipulative therapy for chronic low-back pain reported that “High-quality evidence suggests that there is no clinically relevant difference between SMT [spinal manipulative therapy] and other interventions for reducing pain and improving function in patients with chronic back pain.”7 A 2012 Cochrane review of spinal manipulative therapy for acute low-back pain concluded that “SMT…appears to be no more effective than other recommended therapies.”8 A 2012 National Center for Complementary and Alternative Medicine review of back-pain studies reported that “Overall, studies have shown that spinal manipulation is one of several options─including exercise, massage, and physical therapy─that can provide mild-to-moderate relief from low-back pain. Spinal manipulation also appears to work as well as conventional treatments such as applying heat, using a firm mattress, and taking pain-relieving medications.”9
Although some studies have indicated that spinal manipulation may not be more effective than a variety of other treatment methods for relieving back pain, many manual therapists know from experience that spinal manipulation can, on rare occasions, provide dramatic and permanent relief when manipulation restores mobility by breaking down adhesions or by unlocking binding vertebral facets. In my own practice as a chiropractor, I had many patients who simply loved a back-cracking back rub. Despite the controversy surrounding the use and effects of spinal manipulation, generic spinal manipulation deserves a place as an option in the armamentarium of physical medicine.
Aside from physical effects, spinal manipulation based on subluxation theory has powerful placebo and nocebo effects that perpetuate such treatment beyond reasonable use. Manipulation can produce popping sounds caused by separation of joint surfaces (cavitation) in normal joints. Such popping is not considered to be significant, but it can have a powerful placebo effect among those who believe that the popping sound signals correction of a dangerous subluxation. Unfortunately, some chiropractors allow their patients to believe that a popping sound means that vertebral subluxations are always present, producing a nocebo effect that lures fearful chiropractic patients and their families into a program of regular spinal adjustments in order to maintain health by keeping their vertebrae aligned.
According to WebMD, 22 million Americans visit chiropractors annually. Of these, about 7.7 million are seeking relief from back pain.10 While spinal manipulation and physical therapy modalities may be helpful in the treatment of musculoskeletal problems, it is important to be on guard to avoid spinal manipulation or any treatment method based on subluxation theory.
Subluxation Theory Perpetuated as a Belief System
There are no indications that the nonfalsifiable subluxation theory, the foundation of chiropractic, will ever be discarded by all chiropractors. With no plausible or scientific rationale to support it, subluxation theory based on the tenets of a founding father will continue to be perpetuated as a belief system by subluxation-based factions in chiropractic, as in the case of homeopathy and traditional osteopathy. Chiropractic subluxations that are not detectable by conventional methods will continue to be “located” by such dubious chiropractic procedures as thermography, applied kinesiology, and leg-length check.
A Global Summit Conclusion
In September of 2019, 50 researchers from 28 countries met in a Global Summit to announce that there is no evidence that there is an effect of SMT (Spinal Manipulative Therapy) for the management of non-musculoskeletal disorders. “This finding challenges the validity of the theory that treating spinal disorders with SMT has a physiological effect on organs and their function.11
Until chiropractors quit hanging up wall charts to indoctrinate patients in subluxation theory, it will continue to be necessary to voice opposition to vertebral subluxation theory on the behalf of consumers and evidence-based chiropractors in order to facilitate informed choice.
References
1. Palmer, Daniel David. 1910. The Chiropractor’s Adjuster: A Textbook of the Science, Art, and Philosophy of Chiropractic for Students and Practitioners. Portland, Oregon. Portland Printing House.
2. Homola, Samuel. 2006. Chiropractic: History and Overview of Theories and Methods. Clinical Orthopaedics and Related Research. 444:236-242.
3. Mirtz, Timothy A., Lon Morgan, Lawrence H. Wyatt, et al. 2009. An epidemiological examination of the subluxation construct using Hill’s criteria of causation. Chiropractic and Manual Therapies. 17:13.
4. Mirtz, Timothy A., Stephen M. Perle. 2011. The prevalence of the term subluxation in North American English-Language Doctor of Chiropractic programs. Chiropractic and Manual Therapies. 19:14.
5. Bellamy, J.J. 2010. Legislative alchemy: The U.S. state chiropractic practice acts. Focus on Complementary and Alternative Therapies. 15(3):214-222.
6. Christensen, M G, Martin W. Kollasach, John K. Hyland, et al. 2015. Practice Analysis of Chiropractic 2015.Greeley, Colorado; National Board of Chiropractic Examiners.
7. Rubinstein, Sidney M., Marienke van Middelkoop, Willem J.J. Assendelft, et al. 2011. Spinal manipulative therapy for chronic low-back pain. Cochrane Database Systematic Review. February 16. (2):CD0081123.
8. Rubinstein, Sidney M. Caroline B. Terwee, Willem J.J. Assendelft, et al. 2012. Spinal manipulative therapy for acute low-back pain. The Cochrane Library. September 12. (2):CD008880.
9. National Center for Complementary and Alternative Medicine. 2012. Spinal manipulation for low-back pain: What the science says. NCCAM Clinical Digest. May.http://nccam.nih.gov/health/providers/digest/backpain-science?nav=cd.
10. Skarnulis, Leona. 2022. Chiropractic Care for Back Pain. WebMD. https://www.webmd.com/back-pain/guide/chiropractic-pain-relief/
11. Cote P, Hartvigsen J, Axen I, et al. The Global Summit on the efficacy and effectiveness of spinal manipulative therapy for the prevention and treatment of non-musculoskeletal disorders. A systematic review of the literature. Chiropractic and Manual Therapies. February 17, 2021.