Chiropractic manipulation of neck may cause stroke

chiropractic-ad-cardI usually don’t dwell too much on chiropractic, because so many other bloggers mock them so well. Chiropractors are generally antivaccination, they practice junk medicine in areas in which they are not trained, and they are essentially quacks utilizing some mystical alternative medicine, taking money from people who think they’re getting real medical treatment.

Basically, chiropractic is the belief in the “vertebral subluxation processes” that purportedly can be used to treat and cure a vast range of diseases which have no scientifically verified connection to vertebral anatomy. It’s based on the same general type of pseudoscientific mysticism that one finds with acupuncture.

Of course, modern chiropractic has tried to divorce itself from the vertebral subluxation, and attempted to evolve into the slightly more mainstream chiropractic treatment technique that involves manual therapy, including manipulation of the spine, other joints, and soft tissues. Chiropractic treatment also includes exercises and health and lifestyle counseling. Barely anything more than a good masseuse would provide to an individual.

Despite this evolution of chiropractic to the point that some health insurance companies actually pay for the procedures, chiropractic is a typical pseudoscience–make outlandish claims, minimize or ignore the risks, and make money off of those who think, or want to believe, that it works.

It’s appalling that some people, many who think that vaccines are dangerous (they’re not), believe that a chiropractor, who has very little real medical training, should manipulate the neck of a baby to treat some imaginary, or even real, condition. It boggles the mind.

So, what does real science say about chiropractic? Not much according to statistically powerful systematic reviews (which stands at the top of the hierarchy of evidence, so if the reader is going to cherry-pick some lame primary study with 20 patients, don’t bother). Here is an analysis of a bunch of chronic and acute conditions that can be treated by many chiropractors:

One of the areas that has always had the most number of supporters, along with boatloads of anecdotal evidence of success, is the chiropractic treatment of lower back pain. Everyone knows someone who claims that the chiropractor has fixed their ailing back. However, a recent systematic review published in Spine, which examined 20 high quality randomized clinical trials of spinal manipulative therapy (SMT) and lower back pain found that:

SMT is no more effective for acute low back pain than inert interventions, sham SMT or as adjunct therapy. SMT also seems to be no better than other recommended therapies. Our evaluation is limited by the few numbers of studies; therefore, future research is likely to have an important impact on these estimates. Future RCTs should examine specific subgroups and include an economic evaluation.

What can we conclude from all of these systematic reviews? Chiropractic has barely any clinical usefulness, and even where there maybe some positive results, it’s very weak and probably isn’t clinically significant. But maybe if you feel better, and there’s little risk, why should anyone complain?

Unless there is a serious health risk from chiropractic.


The American Heart Association (AHA), one of the leading organizations that advocate for better cardiovascular health, published a systematic review and a statement in the AHA’s journal Stroke, that stated that treatments involving cervical manipulative therapy (CMT) of the neck, a chiropractic treatment that involves of the vertebrae, may be associated with stroke.

CMT treatments appear to cause cervical artery dissection (CD), which is a small tear in the walls of arteries that pass through the neck to the brain. CAD is the cause of up to 25% of ischemic strokes in individuals who are younger than 45 years old. According to lead author, José Biller, M.D., professor and chair of neurology at the Loyola University Chicago Stritch School of Medicine,

Most dissections involve some trauma, stretch or mechanical stress. Sudden movements that can hyperextend or rotate the neck — such as whiplash, certain sports movements, or even violent coughing or vomiting — can result in CD, even if they are deemed inconsequential by the patient.

Chiropractic techniques for CMT vary amongst practitioners, and admittedly, some may be extraordinarily careful in what they do. Unfortunately, some manipulations used as therapy by chiropractors forcefully thrust to extend and rotate the neck. By doing so, this type of neck manipulation could cause a vertebral artery dissection, because there are four arteries, one on each side (carotid arteries) and two on the back side of the neck (vertebral arteries).

The authors of the Stroke article described their systematic review of 4 case-control studies (see this article for an analysis of different types of clinical studies)–the results showed a relatively large risk for arterial dissection after CMT by a chiropractor. However, because of the nature of these studies, it was difficult to determine if the risks were statistically significant. The authors concluded that:

CD is an important cause of ischemic stroke in young and middle-aged patients. CD is most prevalent in the upper cervical spine and can involve the ICA or VA. Disability levels vary among CD patients with many having good outcomes, but serious neurologic injury can occur. Clinical reports suggest that mechanical forces play a role in a considerable number of CDs, and population controlled studies have found an association of unclear etiology between CMT and VAD stroke in young patients. Although the incidence of CD in CMT patients is probably low, and causality difficult to prove, practitioners should both strongly consider the possibility of CD and inform patients of the statistical association between CD and CMT, prior to performing manipulation of the cervical spine.

If you’re just stubborn, and insist on seeing a chiropractor, despite the scientific fact that it doesn’t work, and despite the risk of stroke might be high, you should be aware of the signs and symptoms of arterial dissection, because your chiropractor probably is too unethical to actually describe the risk to you (as opposed to real doctors who always describe both the benefit and the risk).

According to the American Heart Association, you should seek emergency medical evaluation and treatment if you develop any neurological symptoms after neck manipulation or trauma. These include:

  • Pain in the back of your neck or in your head;
  • Dizziness/vertigo;
  • Double vision;
  • Unsteadiness when walking;
  • Slurred speech;
  • Nausea and vomiting;
  • Jerky eye movements.

The best scientific evidence, as established by systematic reviews published by top researchers in high impact factor journals, states that there is little or no evidence that chiropractic does anything to treat any medical condition. Some practitioners and patients can provide weak anecdotes or beliefs about the effectiveness of chiropractic, but that’s not scientific data.

Maybe people see chiropractors because they think they feel better (though placebo effects do that). But one should weigh that non-effect with the small but clear risk that spinal manipulation can lead to a stroke. And if you have a serious stroke, no chiropractor is going to help you, it will take real physicians with real medications to prevent serious harm, and even then it’s not a sure thing.

TL;DR version

  1. There is no scientific evidence, as established by high quality systematic reviews, that chiropractic has any significant clinical effect.
  2. It might cause a stroke.
  3. It doesn’t make sense to take a very dangerous risk for no benefit.
  4. But if you are convinced by anecdote and the placebo effect that chiropractic works, be aware of the symptoms of arterial dissection and stroke.
  5. However, don’t see a chiropractor. It’s a waste of money.

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