Roger Wilhelm, D.C.

“Manipulation” and “Chiropractic” are not Synonyms

Background

Joint Manipulation

Joint manipulation is the applying of a force to a joint that helps that joint move better. It is classically associated with an audible sound. All people, trained and untrained, are capable of manipulating joints and eliciting an audible sound.

Manipulation is a lay term. It is often used synonymously with the word chiropractic. Yet, importantly, chiropractors technically do not manipulate joints. Chiropractors adjust joints.

Joint Adjustment

Manipulation implies the movement of a joint to the point of creating an audible sound, but the line-of-drive and the control of the amplitude (distance) is not precise. In contrast, the term for manipulation that has a specific line-of-drive direction and control of the amplitude is adjustment. Chiropractors deliver spinal adjustments, not manipulation. The mastery of spinal adjusting takes years of study, training, and practice. After completing college with a biological curriculum, the educational requirements to be a chiropractor take an additional 4 academic years at an accredited chiropractic college. The point is that chiropractors are extensively trained in the science and art of specific line-of-drive manipulation, or what would properly be called the chiropractic adjustment.

There are 18 chiropractic colleges in the United States and many more throughout the world (1). Some of the chiropractic colleges are universities that grant academic degrees in addition to the Doctor of Chiropractic degree (DC). Others only grant Doctor of Chiropractic degrees.

Beginning in the 1970s, chiropractic education became accredited through the United States Department of Education via the Council for Chiropractic Education (1): All 18 of the chiropractic colleges in the United States are accredited by the Council for Chiropractic Education.

In the United States, the licensure of chiropractors is controlled by the individual states, and all 50 U.S. states officially license chiropractors, allowing them to practice with their Doctor of Chiropractic degree (DC). Chiropractors are considered to be primary portal health care providers, which means (in part) that the public may choose chiropractic care without requiring a referral from another health care provider.

As a result of their education and examination procedures, chiropractors are legally allowed to provide a number of services to their patients. These include physical therapy, exercise, tissue work, dietary advice, use of supplements, the taking of and the interpretation of x-rays, etc. The central core of chiropractic clinical practice is the use of mechanical care, and the primary form of mechanical care is specific line-of-drive manipulation (the chiropractic adjustment).

A typical chiropractic visit involves an assessment of posture and joint motion (possibly with the use of x-rays), helping the chiropractor assess the manner in which his/her patient exists and functions mechanically in a gravity environment. Abnormal findings are usually treated mechanically and primarily with the use of the chiropractic adjustment.

Chiropractors are extensively trained to be mechanical providers of care. Ninety-three percent of patients who chose to initially see a chiropractor do so for spinal pain complaints (2). Satisfaction among patients with these complaints is exceptionally high (2).

•••

Joint movement is divided into three categories (3, 4, 5, 6, 7):

• Active Motion
• Passive Motion
• Periarticular Paraphysiological Space Motion

Active Motion

Active motion is the type of motion joints experience when people move any part of their body. It requires active contraction of our muscles. Active motion is the typical motion joints experience when people engage in the activities of normal life (showering, dressing, preparing meals, driving, working, shopping, etc.) and exercise.

Active motion, including specific exercise active motion, only benefits the narrowest range of tissues (the active range), and as such the therapeutic benefit of active motion (exercise) is limited. When a specific joint is moved through the maximum active range of motion, a natural physiological barrier is met, beyond which no additional motion is possible without passive assistance. The important concept is that joints have the ability to move beyond the active range, and this can be done without causing any stress or injury to the joint.

Passive Motion

 Passive motion is the passive moving of a joint further than the motion achieved with active motion. Passive motion always affects a greater range of tissue than does active motion. This allows passive motion techniques to better address (treat, manage) tissue fibrosis and joint stiffness.

Accepted and beneficial passive motion applications include stretching, Pilates, yoga, etc. A variety of health care providers, including chiropractors, are trained and able to isolate specific joints that are lacking optimal motion and to “push” the joint beyond the active range of motion and into the passive range of motion. Again, this is accomplished without any tissue injury.

At the end of the passive range of motion, another “barrier” is encountered. This is called the elastic barrier. Movement beyond the elastic barrier is not only beneficial, it is often critically required. It is also difficult to appropriately achieve without training. Noted orthopedic surgeon WH Kirkaldy-Willis states (6):

Periarticular Paraphysiological Space Motion

“At the end of the passive range of motion, an elastic barrier of resistance is encountered.”

“If the separation of the articular surfaces is forced beyond this elastic barrier, the joint surfaces suddenly move apart with a cracking noise.”

“This additional separation can only be achieved after cracking the joint and has been labeled the paraphysiological range of motion. This constitutes manipulation.”

Joint manipulation (adjusting) “requires precise positioning of the joint at the end of the passive range of motion and the proper degree of force to overcome joint [resistance].”

“With experience, the manipulator can be very specific in selecting the spinal level to be manipulated.”

There are a number of benefits from moving joints past the elastic barrier and into the periarticular paraphysiological space range of motion. The best-documented benefit is the reduction of pain. The goal is to move past the elastic barrier and into the periarticular paraphysiological space without exceeding the limit of anatomic integrity. This skill requires training and practice. This is precisely why chiropractors have four years of training in an accredited institution, after college, and are licensed by the state after successfully passing all licensing examinations.

Misuse of the Word Chiropractic

Defamation is any false information that harms the reputation of a person, business, or organization. With this definition, the purposeful misuse of the word “chiropractic” would potentially defame all chiropractors and the entire chiropractic profession.

The misuse of the word “chiropractic” in medical publications is not new; it is a decades-long problem. It is documented that when both the professional and lay press ascribe a manipulative injury to the vertebral artery that they apply the words “chiropractic” and “manipulation” as being synonymous; they are not. Many people “manipulate” and yet they are not trained and licensed chiropractors.

An early whistleblower on this abuse of the chiropractic profession is researcher Alan Terrett from Australia. Dr. Terrett has shown that often, in the literature, when an untrained person manipulates a patient and causes an injury, the literature inappropriately labels the manipulator as being a chiropractor (8). The list of discovered manipulators included:

A Blind Masseur
An Indian Barber
A Wife
A Kung-Fu Practitioner
Self-Manipulation
A Medical Doctor
An Osteopath
A Naturopath
A Physical Therapist

Dr. Terrett states:

“This study reveals that the words chiropractic and chiropractor commonly appear in the literature to describe spinal manipulative therapy, or practitioner of spinal manipulative therapy, in association with iatrogenic complications, regardless of the presence or absence of professional training of the practitioner involved.”

“The words chiropractic and chiropractor have been incorrectly used in numerous publications dealing with spinal manipulative therapy injury by medical authors, respected medical journals and medical organizations.”

“In many cases, this is not accidental; the authors had access to original reports that identified the practitioner involved as a non-chiropractor. The true incidence of such reporting cannot be determined.”

“Such reporting adversely affects the reader’s opinion of chiropractic and chiropractors.”

“It has been clearly demonstrated that the literature of medical organizations, medical authors and respected, peer-reviewed, indexed journals have, on numerous occasions, misrepresented the facts regarding the identity of a practitioner of manual therapy associated with patient injury.”

“Such biased reporting must influence the perception of chiropractic held by the reader, especially when cases of death, tetraplegia and neurological deficit are incorrectly reported as having been caused by chiropractic.”

“Because of the unwarranted negative opinion generated in medical readers and the lay public alike, erroneous reporting is likely to result in hesitancy to refer to and underutilization of a mode of health care delivery.”

•••

Another noted pioneer of the misuse and abuse of the word “chiropractor” in medical literature is Adrian Wenban. Dr. Wenban is presently the principal of the Barcelona College of Chiropractic. He holds a B.Sc. (Anatomy), a B.App.Sc. (Chiropractic), a M.Med.Sc. (Clinical Epidemiology) and a P.Gr.Cert. (Medical Education). He has worked in 5 different countries. In 2006, Dr. Wenban published a study titled (9):

Inappropriate Use of the Title ‘Chiropractor’
and Term ‘Chiropractic Manipulation’ 
in the Peer-reviewed Biomedical Literature

This publication by Dr. Wenban was based on a review of the literature using PubMed, identifying allegations of injury caused by chiropractic cervical spine manipulation. Dr. Wenban contacted the lead authors of these publications to confirm or rule out chiropractic participation. He notes:

“… authors suggest the care provider was a chiropractor and that each patient received chiropractic manipulation of the cervical spine prior to developing symptoms suggestive of traumatic injury.”

“… the principal researcher revealed that the care provider was not a chiropractor.”

“In the case series, which involved twenty relevant cases, the principal researcher conceded that the term chiropractor had been inappropriately used and that his case series did not relate to chiropractors who had undergone appropriate formal training.”

“The results of this year-long prospective review suggest that the words ‘chiropractor’ and ‘chiropractic manipulation’ are often used inappropriately by European biomedical researchers when reporting apparent associations between cervical spine manipulation and symptoms suggestive of traumatic injury.”

“In those cases, reported here, the spurious use of terminology seems to have passed through the peer-review process without correction.”

“These findings provide further preliminary evidence, beyond that already provided by Terrett, that the inappropriate use of the title ‘chiropractor’ and term ‘chiropractic manipulation’ may be a significant source of over-reporting of the link between the care provided by chiropractors and injury.”

•••

On February 1, 2024, an epub appeared in the American Journal of Forensic Medicine and Pathology, titled (10):

Self-Chiropractic Cervical Spinal Manipulation
Resulting in Fatal Vertebral Artery Dissection

It appears that the authors, editors, and publisher of this article have defamed the chiropractic profession. In this sad case, chiropractic had nothing to do with it and hence should not have been mentioned in the article, let alone in the title of the article. When an untrained lay person self-manipulates her own neck causing her own death, and the published journal article titles the event “self-chiropractic cervical manipulation,” it is blatantly false and defames chiropractors and the entire chiropractic profession. Furthermore, it biases the healthcare community, healthcare practitioners, patients, and the legal system against the chiropractic profession. This should cast shame on the authors, editors, and publisher of this article.

This case involves a 43-year old woman who had a significant history of long-standing hypertension and headaches. She also had a past history of laying down with her neck on the top step of a staircase and self-manipulation of her neck which would afford her headache relief. It should be stressed that she was not a chiropractor and no chiropractors were present.

On this last day of performing this self-manipulation, she experienced a worsening of headache, then vomiting, then she went unresponsive. She was transported to the emergency department where she was pronounced deceased.

At autopsy, a dissection of the right vertebral artery was identified. Additionally, a histologic examination revealed underlying chronic vascular hypertensive degenerative changes. The autopsy report concluded:

“The cause of death was determined to be vertebral artery dissection because of the injury sustained during self-chiropractic maneuver.”

The authors also add:

“The vertebral artery is potentially more prone to damage from the mechanical effects of hypertension, and an increased susceptibility of the vertebral artery to other triggering conditions (eg, minor trauma) can result from chronic hypertension.”

“In [this] case, the history of hypertensive-range blood pressure readings (suspected to represent systemic essential hypertension) may have contributed to the propensity for vascular dissection.”

Despite the blatant misuse of the word “chiropractic” in this article, there are potential lessons, including:

• Lay manipulation of the cervical spine would typically target the atlas-axis articulation. This would potentially affect the V3 portion of the vertebral artery in extension and rotation, which is the anatomical site that theoretically would be most vulnerable to a traumatic dissection. It should be noted that trained chiropractors are aware of this theory and are trained not to do the extension-rotation-thrust maneuver of the atlas-axis articulation.
• The histopathological findings in this study suggest that chronic hypertension can lead to hypertensive vascular changes in the central nervous system vasculature, increasing the risk of cerebral vascular events. Due diligence might include taking the patient’s blood pressure and modifying adjustive techniques as deemed appropriate on patients with a history of uncontrolled chronic hypertension.

Incidence

The incidence of vertebral dissection in the society, unrelated to chiropractic care, is 1-1.5/100,000 persons yearly (11).

In 2001, a study was published in the Canadian Medical Association Journal and titled (12):

Arterial Dissections Following Cervical Manipulation:
The Chiropractic Experience

The lead author, Scott Haldeman, is a historic and contemporary giant in the chiropractic profession. His list of accomplishments includes a chiropractic degree (DC), a medical degree (MD), a PhD, and a DSc. Dr. Haldeman is a clinical professor of neurology at the University of California, Irvine.

The authors of this study reviewed all malpractice data from the Canadian Chiropractic Protective Association to evaluate all claims of stroke following chiropractic care over a 10-year period of time. This data was compared with the number of cervical manipulations performed each year by chiropractors covered by the Canadian Chiropractic Protective Association.

The authors note that there were more than 4,500 licensed chiropractors in Canada during the study period. These chiropractors performed approximately 134.5 million cervical manipulations during the 10-year assessment period, or approximately 13.45 million cervical manipulations per year. They observed 23 cases of stroke or vertebral artery dissection following cervical manipulation reported during this 10-year period, or 2.3 cases per year. An analysis of these numbers revealed:

• 1 event per 8.06 million chiropractic office visits
• 1 event per 5.85 million chiropractic cervical manipulations
• 1 event per 1,430 chiropractic practice years
• 1 event per 48 chiropractic practice careers

The authors concluded:

“[These numbers are] significantly less than the estimates of 1 per 500,000–1 million cervical manipulations calculated from surveys of neurologists.”

It is important to emphasize:

• The incidence of vertebral dissection in society, unrelated to chiropractic care, is 1-1.5/100,000 persons yearly.
• The incidence of vertebral artery dissection associated with chiropractic cervical adjustments is 1 per 5.85 million chiropractic cervical adjustments.
• A chiropractor would have to be in clinical practice for 1,430 years to be statistically associated to a single vascular event.

Biomechanical Studies
Walter Herzog and the University of Calgary

Walter Herzog, PhD, is a Professor of Kinesiology and Director of the Human Performance Lab at the University of Calgary. He has more than 1,000 published scientific studies. His lab at the University of Calgary has done more primary research pertaining to vertebral artery injury as related to the chiropractic adjustment than any other facility globally. In 2012, his group published (13):

Vertebral Artery Strains During High-speed, Low Amplitude
Cervical Spinal Manipulation

This study presented the first ever data on the mechanics between C1/C2 during cervical manipulation performed by chiropractic clinicians. These authors concluded:

“VA strains obtained during SMT are significantly smaller than those obtained during diagnostic and range of motion testing, and are much smaller than failure strains.”

“We conclude from this work that cervical SMT performed by trained clinicians does not appear to place undue strain on VA, and thus does not seem to be a factor in vertebro-basilar injuries.”

“The maximal strain values for the ROM testing at each segmental level were always greater than the corresponding strain values for the SMTs, suggesting that neck SMTs impose less stretch than turning your head, or extending your neck while looking up at the sky.”

“Therefore, based on the mechanical tests performed here, one should be able to conclude that stretching of VA during neck SMTs does not cause any damage of the VAs.”

“The VA is never really strained during spinal manipulative treatments but that the VA is merely taking up slack as the neck and head are moved during SMT, but that there is no stress and thus no possibility for microstructural damage.”

“The results from this study demonstrate that average and maximal VA strains during high-speed low-amplitude cervical spinal manipulation are substantially less than the strains that can be achieved during ROM testing for all vertebral artery segments.”

“We conclude that cervical spinal manipulations, as tested here, are safe from a mechanical point of view for normal, healthy VA.”

In 2023, Dr. Herzog and colleagues from the University of Zurich, and the University of Calgary published a follow-up study titled (14):

Vertebral Arteries Do Not Experience Tensile Force During Manual Cervical Spine Manipulation Applied to Human Cadavers

These authors note:

“Certain cervical spine manipulations are associated with neck extension and rotation, leading to suggestions that these interventions stretch the vertebral artery (VA), thereby causing tissue damage.” 

“Population-based studies suggest that there is no causal link between cervical spine manipulation and VA damage/stroke, rather there is a temporal (time) link.”

“In previous studies, the effects of cervical spine manipulation (using cervical spine extension and rotation and delivered at the end-range of segmental movement) delivered by chiropractors on the VA of cadaveric donors have been reported.”  

“[These studies have] concluded that arterial length changes experienced during cervical spine manipulation were almost an order of magnitude lower than the length changes required to mechanically disrupt the artery and thus, a single typical manipulative thrust was unlikely to mechanically disrupt the artery.”

The findings of these authors include:

“No segment of the VA was ever stretched during cervical spine manipulation, but merely elongated (some of the natural slack of the VA was taken up).”

“[Of the 518 cervical spine manipulations applied in this study, the length change during the manipulative thrust] never came close to the failure length changes.”

These authors concluded:

“During cervical spine manipulations (using cervical spine extension and rotation), arterial length changes remained below that slack length, suggesting that VA elongated but were not stretched during the manipulation.”

“The VA was slack in its resting, in-situ length and required an average of 33.5% elongation prior to first force occurrence, suggesting that the VA is not stretched during cervical spinal manipulation, but merely some of the slack naturally present is taken up during the procedure.”

“The results of this study, in conjunction with previously published results that VA length changes during spinal manipulation are about half of those experienced during normally achievable head and neck movements, suggest that the VA cannot be mechanically damaged by elongation that occurs during cervical spinal manipulation (using cervical spine extension and rotation).”

“Our analysis revealed that the VA is never stretched during any of the cervical spine manipulations, thus any force felt by a clinician must originate from structures other than the VA.”

“At peak lengths during cervical spine manipulation (using cervical spine extension and rotation), longitudinal VA length changes remained below that slack length, suggesting that VA elongated but were not stretched during the intervention.”

Chiropractic Safety

Two recent (2022 and 2023) large studies have specifically looked at the incidence of adverse events caused by trained medical doctors and chiropractors performing spinal adjustments (specific line-of-drive manipulations). These studies involved 345,789 individual patients and 3,642,389 spinal adjustments (15, 16). The incidence of vascular injuries/events was zero. This study supports the incidence numbers cited by Haldeman above (12).

•••

Chiropractic care is in a unique position. These last two robust studies document the extreme safety of chiropractic care. When a patient fails to respond to chiropractic care, medical referral is standardly done by chiropractors with the intention of benefiting the patient with the best of both approaches to healthcare. With education, medical professionals will hopefully appreciate that many biases against the chiropractic profession exist as a consequence of the literature’s misuse of the word “chiropractic.”

REFERENCES

1. cce-usa.org; accessed March 23, 2024.
2. Adams J, Peng W, Cramer H, Sundberg T, Moore C; The Prevalence, Patterns, and Predictors of Chiropractic Use Among US Adults: Results From the 2012 National Health Interview Survey; December 1, 2017; Spine; Vol. 42; No. 23; pp. 1810–1816.
3. Sandoz R; Some Physical Mechanisms and Effects of Spinal Adjustment; Annals of the Swiss Chiropractic Association; 1976; Vol. 6; pp. 91-141.
4. Haldeman S; Modern Developments in the Principles and Practice of Chiropractic; Appleton-Century-Crofts; New York; 1980.
5. Kirkaldy-Willis WH; Managing Low Back Pain; Churchill Livingston; (1983 & 1988).
6. Kirkaldy-Willis, WH, Cassidy JD; Spinal Manipulation in the Treatment of Low-Back Pain; Canadian Family Physician; March 1985; Vol. 31; pp. 535-40.
7. Fischgrund JS; Neck Pain, Monograph 27; American Academy of Orthopaedic Surgeons; 2004.
8. Terrett AG; Misuse of the literature by medical authors in discussing spinal manipulative therapy injury; Journal of Manipulative and Physiological Therapeutics; May 1995; Vol. 18; No. 4; pp. 203-210.
9. Wenban AB; Inappropriate use of the title ‘chiropractor’ and term ‘chiropractic manipulation’ in the peer-reviewed biomedical literature; Chiropractic and Osteopathy; August 22, 2006; Vol. 14; No. 16.
10. Fink C, Bryce CH, Knight LD; Self-Chiropractic Cervical Spinal Manipulation Resulting in Fatal Vertebral Artery Dissection: A Case Report and Review of the Literature; American Journal of Forensic Medicine and Pathology; February 1, 2024; Epub
11. Kwan-Woong Park, Jong-Sun Park, Sun-Chul Hwang, Soo-Bin Im, Won-Han Shin, Bum-Tae Kim; Vertebral Artery Dissection: Natural History, Clinical Features and Therapeutic Considerations; Journal of the Korean Neurosurgical Society; September 2008; Vol. 44; No. 3; pp. 109–115.
12. Haldeman S, Carey P, Townsend M, Papadopoulos C; Arterial Dissections Following Cervical Manipulation: The Chiropractic Experience; Canadian Medical Association Journal; October 2, 2001; Vol. 165; No. 7; pp. 905-906.
13. Herzog W, Leonard TR, Symons B, Tang C, Wuest S; Vertebral artery strains during high-speed, low amplitude cervical spinal manipulation; Journal of Electromyography and Kinesiology; October 2012; Vol. 22; No. 5; pp. 740-746.
14. Gorrell LM, Sawatsky A, Edwards WB, Herzog W; Vertebral Arteries do Not Experience Tensile Force During Manual Cervical Spine Manipulation Applied to Human Cadavers; Journal of Manual & Manipulative Therapy; August 2023; Vol. 31; No. 4; pp. 261-269.
15. Kim S, Kim G, Kim H, Park J, Lee J, and nine more; Safety of Chuna Manipulation Therapy in 289,953 Patients with Musculoskeletal Disorders: A Retrospective Study; Healthcare; February 2, 2022; Vol. 10; No. 2; Article 294.
16. Chu E, Trager RJ, Lee L, Niazi IK; A Retrospective Analysis of the Incidence of Severe Adverse Events Among Recipients of Chiropractic Spinal Manipulative Therapy; Scientific Reports; January 23, 2023; Vol. 13; No. 1; Article 1254.

“Authored by Dan Murphy, D.C.. Published by ChiroTrust® – This publication is not meant to offer treatment advice or protocols. Cited material is not necessarily the opinion of the author or publisher.”