How spinal manipulation could cause a stroke

March 3, 2017 • 8:45 am

After my denunciation by chiropractors and their advocates over the last few days—opprobrium that I welcome—Reader Pliny the in Between, whose website is The Far Corner Cafe, put together a series of drawings showing how spinal manipulation, such as that practiced by chiropractors, could produce a stroke. This, for instance, is what a real doctor, Orac, thinks may have caused the death of model Katie May (read his earlier post on this as well). May, 34, went to a chiropractor for a “neck adjustment” after a fall in 2016 that caused her neck pain; she had a stroke almost immediately after the adjustment, and died three days later.

Click on the screenshots to enlarge each of the five diagrams.






Here is what Orac concludes about Katie May’s death:

If you cringe when you hear the pop during the violent twist given to the neck, you’re not alone. So do I. It is that “high velocity, low amplitude” (HVLA) twist that can injure the intima of the artery, setting up the condition for a stroke. What surprises me is that the risk isn’t much higher than what studies show. The human body is more resilient than one would imagine, and, absent pre-existing atherosclerotic disease, the risk remains low. On the other hand, given that there is no benefit from HVLA chiropractic neck manipulation, the risk-benefit ratio is basically infinity, because the potential benefit is zero. Also, the risk might be small, but, as Katie May shows us, the the consequences of that risk can be catastrophic.

Another aspect I discussed was whether Katie May’s stroke could have been due to the trauma she suffered at her photo shoot a day or two before her first chiropractic manipulation. Now that we know, assuming that TMZ is accurately relaying the results of the coroner’s report, that May had a tear in her left vertebral artery, it’s almost certain that the chiropractor accidentally killed her through neck manipulation. That is what the coroner concluded, that this injury to her vertebral artery occurred during chiropractic neck manipulation.

In the end, there is no longer any reasonable doubt. Katie May’s death was unnecessary and due to her subjecting herself to the quackery that is chiropractic.


50 thoughts on “How spinal manipulation could cause a stroke

    1. I am at work now – seeing patients for back and neck pain. I just (literally 2 minutes ago; I walked out of the room and came directly to write this comment) saw a guy who said he gets back pain a few times a year while doing his daily exercise routine (pushups, etc.). It usually goes away within 24 hours. He had an episode last week which didn’t go away within the first 24 hours. After three days of lingering, mild pain he went to a chiropractor. The chiropractor, he said, “worked me over pretty good.” He left the chiropractor with increased pain and it continued to increase throughout the day until dinner. When he rose from his seat after dinner, his left leg felt numb and his knee buckled when he put weight on it. A CT scan shows an extruded disc fragment. It is very clear that the chiropractor took a mild disc injury and made it much worse. I hear this same story on a regular basis.

    1. @Peter N One person killing another is homicide.

      More correctly it should be classed as manslaughter or murder or criminally negligent homicide – the latter being the just ruling [that didn’t materialise] when that NYC cop Daniel Pantaleo killed Eric Garner

  1. And some would still say, well if it makes you feel good. About eight years ago I discovered I had ascending aortic aneurysm and that required a big time operation. I don’t know if the quacks have anything for that but the only thing known to work requires a thoracic surgeon and you hope, a pretty good one. Anyway, I will be sticking with the real doctors.

  2. Sad. You always hear how people went to a chiropractor for a back ache and it was cured almost right away so they keep going back for more cure every month or so. This may be a harmless waste of money, or not. But if the chiropractor encourages more different kinds of treatments like neck twists, the risk goes up while the benefit goes down.
    Another thing is, the profession is not well controlled. A practitioner can come up with bizarre treatments on her own just to enhance her fleecing ability.

  3. There’s no benefit of snapping the neck? Well, I do it all the time myself, because I’m stiff. And it helps, but of course only temporarily. What is the recommended way of getting rid of a stiff neck? Continuous exercise (movement) of the joints are probably best I guess.

    1. Usually I put two tennis balls in a sock and then put that behind my neck….this won’t work like a miracle, but it does seem to help.

    2. You “snapping the neck” on your own is very different from when someone does it for you.

      See 2:23 in this video to see the crazy in action:

      With reference to that video this is what Orac writes, QUOTE: It’s not difficult to see how a rapid rotation of the head could potentially stretch the basilar arteries. Generally, chiropractors describe this as “high velocity, low amplitude” (HVLA), which it is, but, given the constraints of vertebral artery anatomy, high amplitude is not required to cause injury. With HVLA, it is quite possible to tear the intima (the lining of the artery consisting of vascular endothelial cells). Intimal tears become “sticky” for platelets, leading them to lodge there and start to form a clot.

      1. A bit late followup (it was me who wrote as ”staraffinity” before, I forgot to enter my full name).

        I’m not questioning the risk of letting someone else snap my neck, I’m questioning the claim that there are no benefit whatsoever. There is a temporary relief I think, but that’s it.

        Thanks everyone for your tips! I also think massage is really good and of course staying mobilised i.e. exercise.

        The thing is I’ve been getting naprapathic treatment (seems very similar to chiropractic) and I’ve had my neck snapped there a few times. Definitely won’t do it again after reading this about possible stroke, especially since it only helps short term.

  4. This is true. There’s a syndrome we see called locked-in syndrome, where severed spinal arteries from chiropractic cervical spine manipulation cause spinal cord infarction, that can lead to paralysis from the neck down (as well as death). However, to be fair, the rate is estimated to be anywhere from 1:10,000 to 1:2,000,000. Strokes probably happen at a higher rate, but the rate is still low. But I completely agree: given no benefit to rotational cervical manipulation for neck pain has ever been shown in studies that I’m aware of, no good reason to take even a small chance.

    1. This is a polite inquiry & not snark – I had difficulty interpreting your post Alex.

      I don’t understand the stats for a start – what is “estimated to be anywhere from 1:10,000 to 1:2,000,000”?
      Are you saying as many as 1 in 10,000 chiropractic visits result in LIS?
      Or 1 in 10,000 chiropractic patients? Or 1 in 10,000 cervical spine manipulations?
      Or something else?

      Whatever you mean I don’t see how to put estimated upper & lower bounds on the figures – unless chiropractors report the numbers/types of treatments they administer. Perhaps they do.

      I also wonder how many strokes occur that are caused by chiropractors, but the connection is not detected or the stroke is so minor that not even the victim is aware they’ve had one.

      1. Cai X et al. 2014. Case misclassification in studies of spinal manipulation and arterial dissection

        Cai et al. quoted some estimates of risk for cervical arterial dissection “1 in 958 manipulations to as low as 1 in 5.85 million manipulations”.

        Cai et al. concluded: Prior studies grossly misclassified cases of cervical dissection and mistakenly dismissed a causal association with manipulation. Our study indicates that the odds ratio for spinal manipulation exposure in cervical artery dissection is higher than previously reported.

        Cai et al. challenged the findings of Cassidy et al. 2008 who had suggested the association which had been reported in several trials between visits to chiropractors and and CED was due to patients already having the condition before attending.

              1. No. My bad I didn’t make it clear. I realised as soon as I saw it go up.

        1. @Leigh Jackson Thank you very much! And here’s the link to the paper for others who might like a look:

          There seems to be a lot of room for improvement in the monitoring of chiropractors so that we can better detect any good/bad outcomes & shrink those huge error bars somewhat! I would like chiropractics banned, but failing that I would like every patient visit to go on that patients general medical record [date, time & treatment given].

          Question for anyone: Are there locales or circumstances where chiropractors have access to ones medical records in the same way as real doctors or are they manipulating in the dark? I would suppose for example that Chiro’s based in hospitals might, whereas ones in the Mall may not. And would they understand the significance of what they’ve read anyway?

          1. I’m thinking of USA/Canada when I asked the question – but info about the state of play anywhere else would be interesting also.

      1. Michael,
        No offense taken. I found the stats from a quick medical literature search. There aren’t, as you might imagine, a lot of studies about this. As you rightly imply, studying the true incidence of stroke and vertebral artery dissection that occur as a direct result of cervical spine manipulation is difficult. To clarify what I meant (and in re-reading my post, I see I wasn’t clear at all), the incidence of vertebral artery dissection is estimated to be anywhere between 1:10,000 and 1:2,000,000. The reason for the vast range is the variance found in different studies. You ask a good question at the end of your post. We don’t know the answer.

        And, yes, I’m the Chicago Alex Lickerman of ImagineMD.

        1. And whoops, I didn’t clarify enough. That stat I quoted was connected to the risk not for a visit to a chiropractor but to an episode of cervical spine manipulation.

        2. Is this an incidence for true dissection only or does it include symptomatic intimal tear with thrombogenisis?

        3. @Alex – thank you for the clarification. I have this ‘feeling’ that the true extent of chiropractic horrors is vastly underestimated.

          I shudder at the thought of wealthy little old dears with a touch of arthritis being ‘manipulated’ [both senses] by clowns with a chiropractic certificate, a white coat & a winning smile.

  5. Apart from the mortality issue, chiropractic use is still a poor substitute for a healthy lifestyle. At least it’s not as bad as anti-vaccination.

  6. Wonderful illustrations. I am reminded of my late high school biology teacher and his work. (He told us something like after his undergraduate degree in biology he considered both teaching and medical illustration as careers; his comparative anatomy diagrams were great.)

  7. “Cai et al. challenged the findings of Cassidy et al. 2008 who had suggested the association which had been reported in several trials between visits to chiropractors and and CED was due to patients already having the condition before attending.”

    If the patient already has the condition before seeing the chiropractor, one would think the chiropractor should verify whether or not the condition is present before starting manipulation, and then not manipulate if a dangerous condition is found.

    1. Statement by the American Heart Association:

      Although the incidence of CMT-associated CD in patients who have previously received CMT is not well established, and probably low, practitioners should strongly consider the possibility of CD as a presenting symptom, and patients should be informed of the statistical association between CD and CMT prior to undergoing manipulation of the cervical spine.

      1. Correction.

        Where I wrote CED I should have said CAD, meaning cervical arterial dissection.

        In the statement from AHA,
        CMT means cervical manipulative therapy and CD means cervical dissection.

  8. I love chiropractic I think it’s so much better than medicine people don’t realize how many people die a year from medication holistic is the way to go

    1. I bet medicine saves a heck of a lot more people than it kills. Chiropractic doesn’t save anyone.

  9. Sometimes I think people go to chiropractors and other alternative health care practitioners because they just want to be listened to. My doctor has the worst bedside manner and had utterly refused to help me with some things and allow me to see a specialist. If I have a complaint, say about fatigue, he’ll run the blood work, show that it’s normal and that’s that. His conclusion is I’m making it up. I had a friend whose doctor really dig into her issues and found she had thyroid problems but he ran and ran the tests and different times. My conclusion: ugly white girls just aren’t worthy of medical attention. Pretty girls who just cough a little get more. This is where people just go to any quack to feel someone gives a shit.

  10. There was just a second large study published in a peer-reviewed journal by Cassidy demonstrating no increase in this type of stroke in patients who see chiropractors over those who see medical doctors. It is true, however, that the “real doctors” you refer to are the third leading cause of death in our country, with iatrogenic injury causing over 250,000 deaths per year. That’s a fact, look it up. Your post here is aptly titled “how spinal manipulation could cause a stroke”, kind of like “how pigs could fly”. I’d suggest using some scientific data……

    1. Ummm. . . if you’re the Craig Roberts who runs the Sierra Spine and Fitness Clinic, then you’re also responsible for the misstatements below. Is there scientific evidence for all of this? I doubt it!

      You’re losing money writing on this site instead of bilking patients (I notice your site has a “store”!).

      tudy after study has shown the effectiveness of chiropractic on a myriad of musculoskeletal disorders (those affecting the muscles, joints, and ligaments of the body). These disorders include those of the jaw (TMJ), shoulders, elbows, wrists, hands, hips, knees and feet in addition to those of the spine. The gentle, effective, drugless art of chiropractic gets people better faster.

      But what about health beyond the musculoskeletal system? I have observed in my own practice what chiropractors have observed for the past one hundred and ten years—patients receiving chiropractic care often benefit in amazing ways. It is not unusual for a patient being treated for low back pain to find that his ulcers disappear, or that her vision improves, or that he gets sick less, experiences increased vitality, or enjoys improved digestion. Why do people respond this way?

      Your nervous system controls literally every function of your body. The nervous system coordinates the movements of your muscles and joints, monitors and adjusts the tension in your blood vessels, regulates your blood pressure and the amount of blood flow to your muscles and organs, regulates the function of all of your organs, and directs the function of your hormonal and immune systems. A good immunologist will tell you that there is no boundary between your immune system, your endocrine system (your hormonal system—hormones carry messages throughout your body and direct the function of various systems) and your nervous system. The nervous system is the master control governing all the functions of your body!

      The spine is not only a complicated system of joints that allows us to bend, twist, absorb shock and move freely, it is the “housing” of a large part of our nervous system. Every “wire” that leaves your brain to communicate with your joints, muscles, organs, arteries and veins, skin, etc., travels through your spine. This information highway is the focus of chiropractic.

      Consider that your stomach lining completely replaces itself every five days—your entire body replaces 98% of itself in one year! Most people imagine that disease is a static occurrence–in reality, disease is a pattern—a process that perpetuates itself. For example, consider what happens if you have a stomach ulcer for a week. After 5 days the ulcer is affecting a totally different stomach lining than it originated in a week before! If the nervous system is able to shift the pattern, as a new stomach lining is produced it can overcome the ulcer. The medical approach is to eradicate the bacteria (H. pylori) in the stomach that is associated with the ulcer. Interestingly, this bacteria is present in over 50% of people over 50 years old in this country, yet most of these people do not experience ulcers—clearly the bacteria does not cause the ulcer, it only takes advantage of a predisposition toward disease. The philosophy of chiropractic is to treat the source of this predisposition to disease. Again, to use the example of the ulcer, this source can be lifestyle related (nutrition, sleeping patterns, stress), or it can be related to the function of the spine.

      To finish out the example of the ulcer, and to add proof to the pudding, a research study found that patients with duodenal ulcers (duodenal ulcers are those that affect the duodenum, which is the part of the small intestine that occurs just downstream from the stomach) receiving chiropractic care had pain relief and healing in an average of 3.8 days! A similar group receiving standard medical care took an average of ten days longer to heal and faced the hazards associated with medication. –Journal of Manipulative and Physiologic Therapeutics 1994 17(5):310-313.
      The healing power of chiropractic comes from its ability to affect the nervous system.

      That journal you reference is an organ for chiropactors; as it says, “The JMPT is the premier biomedical publication in the chiropractic profession and publishes peer reviewed, research articles and the Journal’s editorial board includes leading researchers from around the world.” Other journals not devoted to quackery have consistently shown that chiropractic doesn’t work as claimed and is, at best, no better than placebos. I suggest you read this article, a peer reviewed article in a journal not run by quacks. It concludes, contrary to your grandiose claims:

      Chiropractic was defined by D.D. Palmer as “a science of healing without drugs.” About 60,000 chiropractors currently practice in North America, and, worldwide, billions are spent each year for their services. This article attempts to critically evaluate chiropractic. The specific topics include the history of chiropractic; the internal conflicts within the profession; the concepts of chiropractic, particularly those of subluxation and spinal manipulation; chiropractic practice and research; and the efficacy, safety, and cost of chiropractic. A narrative review of selected articles from the published chiropractic literature was performed. For the assessment of efficacy, safety, and cost, the evaluation relied on previously published systematic reviews. Chiropractic is rooted in mystical concepts. This led to an internal conflict within the chiropractic profession, which continues today. Currently, there are two types of chiropractors: those religiously adhering to the gospel of its founding fathers and those open to change. The core concepts of chiropractic, subluxation and spinal manipulation, are not based on sound science. Back and neck pain are the domains of chiropractic but many chiropractors treat conditions other than musculoskeletal problems. With the possible exception of back pain, chiropractic spinal manipulation has not been shown to be effective for any medical condition. Manipulation is associated with frequent mild adverse effects and with serious complications of unknown incidence. Its cost-effectiveness has not been demonstrated beyond reasonable doubt. The concepts of chiropractic are not based on solid science and its therapeutic value has not been demonstrated beyond reasonable doubt.

    2. Iatrogenic injury is a serious problem, no question. Which is why, for the roughly 25 years I was a practicing trauma surgeon, every institution with which I was affiliated, conducted a weekly morbidity and mortality conference where any adverse outcome was discussed and assessed through peer review. Preventable or potentially preventable complications were passed on the Care Quality committee for review and action.

  11. Conceptually, it might make sense that HVLA adjustments could tear the dissection further.. But to put things into perspective, if chiropractors could apply enough force to further injure a patient.. Every single time someone got into a car accident, which has way more force, people would be dying and having strokes and aneurysms. The truth is, people aren’t having strokes and aneurysm after accidents, so why do people think someone could apply that much force by hands?

    1. @Mark Allen You have written nonsense

      Look at image 2 above – specifically the externally applied hyper-rotation of the neck. Clearly the physics of the situation requires you to use terms such as acceleration & torque not just “force” alone. Chiropractors talk about the low force, but neglect to examine the very quick twisting of the neck vertebrae through [what looks to me to be] 60 degrees!

      In nearly all car accidents today, with the use of airbags, the accelerations/deaccelerations are less than HVLA because the time interval is substantially longer. Also most car accident injuries to the neck are of the forward/backward type & NOT rotational as per HVLA – apples ‘n’ oranges.

    2. Couple of things: Other than little kids who have very plastic spines, severe A/P forces such as are seen in an MVC, will usually result in c-spine fracture before you might reach the threshold for shear injury to the vertebrobasilar vessels. With modern head rests and airbags those types of injury are a lot less common. Not really comparable to the rotational injury type. And remember it’s less about the force in this case and more about exceeding the normal limits of rotation stretching the vessels which causes this type of injury.

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