Neck Adjustment: Benefits and Safety

The mandate of the Chiropractors’ Association of Australia (CAA) and its members is to make the care of patients their first concern, to practice safely and effectively, and to maintain a high level of professional competence and conduct that is essential for good care.

Part of the core values of the Chiropractors’ Association of Australia (CAA) is to value the importance of intellectual honesty, scientific and academic excellence and the maintenance of integrity in serving the individual, the community and the chiropractic profession.


The objective of the chiropractic adjustment is to restore, maintain and improve health and well-being. It does this by using the mechanical nature of the adjustment to make an input into the nervous system to assist the body to return to optimal function. Chiropractors determine where best to deliver an adjustment by looking for very small changes in a joint’s biomechanical function, along with other clinical evidence such as changes in the function of the nervous system and the body’s muscles, connective tissues such as tendons and ligaments, and various vascular structures. Often a dysfunctional joint will produce discomfort and pain in the joint and associated tissue; however, even in the absence of pain, your chiropractor may still be able to identify clinical findings that indicate chiropractic adjustment should be considered.

The safety and effectiveness of chiropractic spinal adjustment have undergone considerable scrutiny from individuals and organizations within the health care and scientific communities, as well as from chiropractors themselves. Few health-care interventions have been assessed as extensively. All objective assessment is welcomed by the profession.

The result of this extensive study is a significant body of evidence surrounding the efficacy of chiropractic care. Over the last 25 years, at least five formal government studies from around the world have found spinal adjustment therapy to be safe, effective and cost-effective.

Complementing the government inquiries are numerous scientific and clinical studies (including randomized controlled trials) assessing the appropriateness, effectiveness, and cost-effectiveness of chiropractic spinal adjustment.


Neck adjustment (chiropractic spinal adjustment, or manipulation, of the cervical vertebrae from C1 to C7) is a precise procedure, generally applied by hand. It has been shown to improve joint mobility in the neck, restoring range of motion and reducing muscle hypertonicity, and thereby, relieving pressure and tension. In relation to the risk of stroke associated with neck adjustment, the CAA believes it is valuable to provide our members and the public with timely, accurate information that will enable them to continue to weigh the relative risks and benefits of the treatment options which typically include one or more of: (1) doing nothing to relieve a pain condition or joint dysfunction which may be or may become chronic; (2) use of medication to relieve symptoms; (3) neck adjustment; and (4) surgical intervention.

Unfortunately, much of the information now available to the public is based on faulty or biased research 5 .   Many studies on the incidence of stroke are flawed or lack credibility. The problems with these studies include:

(1)   the results are inconsistent with the exhaustive, systemic literature reviews;

(2)   chiropractic treatment is singled out as having an “unacceptable” or “inappropriate” risk while precipitating events and predisposing factors unrelated to cervical adjustment (such as sports and lifestyle activities, previous neck injury, disease, and congenital anomaly) are undervalued or ignored;

(3)   neck adjustment is assumed to be a cause or even the cause of stroke without any effort to identify whether that assumption is valid or what the causal connection might be; the research currently available is not capable of making a causal connection between neck adjustment and stroke;

(4)   the published natural causes of stroke are not recognized and accounted for; and

(5)   no or insufficient attention is given to the nature of the adjustment involved in the treatments at issue.

There are, however, more recent studies that provide more careful and complete consideration of the safety of neck adjustment. According to these studies, the risk of stroke is actually quite small.

In the 2001 version of Current Concepts in Vertebrobasilar Complications following Spinal Manipulation, Dr. Allan G. Terrett assumed risk of stroke of one in 2,000,000 patient treatments based on a comprehensive review of the existing literature concerning the incidence of stroke following neck adjustment. Research recently published in the Canadian Medical Association Journal reports the risk at one in 5,000,000 patient treatments. In 1996, the journal Spine, published “Manipulation and Mobilization of the Cervical Spine: a systematic review of the literature” in which the risk of stroke was stated to be between one and two per 1,000,000 treatments. These estimates are far below the risks commonly associated with many other medical and pharmaceutical interventions.

Strokes occur all too often in the general population. The Australian National Stroke Foundation website reports as follows: “Stroke is Australia’s second single greatest killer after coronary heart disease and a leading cause of disability. In 2010, Australians will suffer around 60,000 new and recurrent strokes – that’s one stroke every 10 minutes”. Nevertheless, the websites of the National Stroke Foundation of Australia and its counterparts in the U.K, and the U.S. – the Stroke Association (U.K.) and the American Stroke Association – do not reference neck adjustment as a factor contributing to the risk of stroke.


How might neck movement be associated with stroke?

Over the years, researchers and health professionals have drawn an association between the onset of stroke symptoms and certain activities of daily living involving the movement of the neck (see “Activities of Daily Living and the Risk of Stroke” below). In this context, an “association” means that the two events seem to occur at or near the same time, or in conjunction with one another, but there is no certainty that one event caused the other, or in fact, that the two events are in any way related. A dilemma for those seeking to determine the nature of the relationship between neck movement and stroke is that the incidents which led to the association being drawn – strokes occurring in conjunction with or following an activity of daily living involving neck movement –   are relatively rare, and therefore, difficult to study and understand.

Nevertheless, current theories suggest that in exceptional cases and likely when the individual has some unidentified predisposition, movement of the neck may start or contribute to a series of events leading to stroke.

According to this thinking, neck movement might disrupt the lining of one of the two vertebral arteries which, as indicated by their name, run up through the vertebrae of the neck and bring blood to the back of the brain. As the disruption to the lining of a vertebral artery heals, a thrombus, or blood clot, can form. In some cases, blood can also collect in a pocket between the layers of the artery wall which expands and, either by itself or together with a thrombus, limits or blocks the flow of blood to the brain. When some or all of these events occur, a person may experience symptoms of stroke. Usually, though, these symptoms do not persist, and no permanent injury results.

A bigger concern is when small pieces of a thrombus break off and travel to the narrower arteries in the back of the brain, where they become lodged and cut off blood supply. This process can cause areas of brain damage known as infarcts and lead to the neurological symptoms and more lasting injury associated with “stroke”. One theory is that in some cases, instead of causing damage to the vertebral artery, neck movement may simply dislodge or break off pieces of a thrombus that was already present, either as a result of a prior injury or because of disease.

Who is susceptible to stroke in association with neck movement?

The science in this area is also evolving. The traditional risk factors of stroke (such as: poorly- controlled high blood pressure, obesity, smoking, family history of cardiovascular disease) do not necessarily risk factors for stroke in association with neck movement. They do not appear to be helpful indicators of who is at risk for the series of events described above. Emerging science points to connective tissue diseases (including Ehlers – Danlos syndrome, Marfan’s syndrome, fibromuscular dysplasia, osteogenesis imperfecta, and multiple exostosis syndromes) as a significant factor in the potential for arterial damage leading to stroke.

What type of neck movement may lead to stroke in susceptible individuals?

Many seemingly benign, everyday activities that involve movement of the neck have been associated with strokes in susceptible individuals, including turning of the head while reversing a vehicle; cradling a telephone handset between one’s ear and shoulder; overhead work; undergoing dental procedures; swinging a golf club; hanging up laundry; and, having one’s hair washed at a beauty salon.

Can other factors or activities contribute to the potential for stroke?

Yes. Risks of stroke are inherent in certain medical procedures, pharmaceutical interventions, and lifestyle activities. For instance, certain levels of tobacco and alcohol consumption are known to contribute to the potential for stroke. In addition, there is a one in 24,000 risks of stroke arising from the use of the birth control pill.

How is neck adjustment related to stroke arising from neck movement?

Some researchers have suggested an association between the neck movement involved in neck adjustment and the occurrence of stroke moments, minutes, hours, and in some cases, days later. Given the presumed association between neck movement and stroke (see the response to the question “How might neck movement be associated with stroke?” above, where it is noted that “in this context, an ‘association’ means that the two events seem to occur at or near the same time, or in conjunction with one another, but there is no certainty that one event caused the other, or in fact,   that the two events are in any way related”), it is, perhaps, understandable why people might    assume a cause-and-effect relationship, particularly when there is a relatively short interval between treatment and the onset of the neurological symptoms associated with stroke. However, there is presently no medical or scientific evidence effectively linking neck adjustment to stroke in a causal way.

The only research which has attempted to measure the physical effects of neck adjustment on the vertebral arteries contradicts the existence of any causal relationship. A 2002 study found that neck adjustment did not result in strain sufficient to damage the arteries, and in fact, may create less strain than neck movement during common activities of daily living. Further, a 2008 study found that neck adjustment did not exacerbate pre-existing vertebral artery damage in canine subjects.

On top of that, another 2008 study found almost the same rate of association between physician visits and stroke as was observed with chiropractor visits. The similarity in the association suggests patients may be visiting their family doctors and chiropractors with head and neck pain caused by an artery that is already dissecting or damaged. Patients with a damaged artery typically experience severe and sudden neck pain that is unlike anything they have experienced before.

Health-care practitioners, including chiropractors, must be alert to patients who attend their clinics complaining of such symptoms. Careful questioning about the symptoms is essential. If there is uncertainty about the origin of the symptoms, delaying treatment is the right course of action. The chiropractor may also consider referral for medical evaluation.

What about damage to the carotid arteries?

Like the vertebral arteries, the carotid arteries pass blood through the neck to the brain. Some researchers have postulated a similar association between neck adjustment and dissection of the internal carotid artery, which, of the two carotid arteries, is anatomically closest to the upper vertebrae of the neck. However, an American study released in 2003 identified only 13 instances of carotid artery dissection occurring relatively close (in some cases, days) after a neck adjustment in the 34 years between 1966 and 2002. Comparing this number to the estimated number of chiropractic adjustments that occurred during that time, the researchers calculated the relative risk of carotid artery dissection following adjustment at 1 in 601,145,000. Accordingly, they concluded there was no cause and effect relationship between neck adjustment and carotid artery dissection.

Who is qualified to perform spinal adjustments?

Under the Health Practitioner Regulation National Law Act 2009, s 123, the Australian government has designated health-care procedures involving spinal manipulation be restricted to only chiropractors and health professionals that have adequate postgraduate qualifications/training. However, the public must understand that these professionals are not equally qualified to deliver this treatment.

Chiropractors consistently maintain a high standard of education, training, and experience with regard to performing the spinal adjustment.

The chiropractic profession is the only health service provider group with spinal adjustment as its core education and practice. To minimize, prevent and possibly eliminate risks to the public, chiropractic education embarks on a very tedious, rigorous and extensive educational process, particularly in the application of adjustment as a treatment form. Chiropractic training in Australia involves five-year, University courses. These courses are of similar length and depth as medical courses but focus on promoting healthier lifestyles via better body function, rather than on drugs and surgery. After entering practice, Australian Chiropractors are also required to undertaken continuing professional development to keep their skills current and stay up-to-date with the latest scientific research.

Without the same level of training, education and practice, other health professions with some competence in general manipulative therapy, cannot be expected to provide spinal adjustment with the same level of competence and safety as chiropractors, nor can they be expected to achieve the same results.

Before receiving a spinal adjustment from a health-care professional other than a chiropractor, the CAA recommends that patients ask the practitioner concerned to explain in detail his or her particular training and competency to perform the intended procedure.


Dr. Andrew Arnold states, ‘it is crucial that patient decision making is based on informed consent.’

The chiropractic profession has been vigilant in providing timely, accurate information to help patients evaluate their health care choices and weigh the relative risks and benefits of treatment options.

Recent research and scientific studies and government analyses continue to support the safety, efficacy, and cost-effectiveness of chiropractic spinal adjustment. Despite the high profile given to the subject of treatment-related strokes, patient statistics reveal that increasing numbers of health consumers rely upon chiropractic as a safe, effective and non-invasive means of resolving head, neck and back pain, with over 215,000 Australians visiting a chiropractor each week.

Nevertheless, the CAA urges all health care consumers to thoroughly investigate the benefits and risks associated with every health procedure and pharmaceutical intervention and reiterates its commitment to patient safety and well-being through established initiatives to raise public awareness, including:

(1)   engaging in open, honest dialogue with the public and the media;

(2)   providing accurate, thorough information on a timely basis;

(3)   ensuring that the risks and range of treatment options are fully disclosed to all patients; and

(4)   supporting the development of ongoing research into the benefits and risks of adjustment in the treatment of neck and back pain.

About the Author:

Dr. Andrew Arnold is a Chiropractor at Cranbourne Family Chiropractic and Wellness Ctr.

Call Cranbourne Family Chiropractic and Wellness Centre on 59984554 for more information or visit us online at

Category: Chiropractor

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