Daniel David Palmer, creator of the nebulous subluxation and father of chiropractic.

Daniel David Palmer, creator of the nebulous subluxation and father of chiropractic.

The chiropractic industry must be feeling the pressure. Billboards, signs on the sides of buses, chiropractic victims’ organizations, and lawsuits are telling the world that chiropractic neck adjustments can cause strokes. The risk is very small, but it is very real. We have addressed the subject before on this blog here, here, and here.

Chiropractors are in denial and are trying to shift the blame elsewhere. A correspondent sent me copies of a pamphlet and a “distribution kit” that the FCER (Foundation for Chiropractic Education and Research) is selling to chiropractors so they can inform the public about cervical artery dissection (CAD). It is advertised as a campaign to help the public recognize warning signs of stroke; but in my opinion, it amounts to a cynical, self-serving ploy to divert attention away from neck manipulation and to spread biased information about the recent study in Spine by Cassidy et al.

Dr. Crislip has already eviscerated the Cassidy study so I will only describe it briefly here. It compared patients who had had a vertebral artery stroke to controls and looked at health billing records to see if they had visited a doctor or a chiropractor in the previous year. Patients with strokes were more likely than controls to have seen a provider but they were not more likely to have seen a chiropractor than to have seen a doctor before their hospitalization. They concluded “The increased risks of VBA [vertebrobasilar artery] stroke associated with chiropractic and PCP [primary care provider] visits is likely due to patients with headache and neck pain from VBA dissection seeking care before their stroke.” This is nothing but speculation and is not supported in any way by the data in the study.

The Cassidy study did not even try to determine whether patients who saw chiropractors had their necks manipulated. It was not designed to answer the real question: whether rapid thrust neck adjustments can cause strokes in patients who would not otherwise have strokes. The answer to that question is clearly “yes.” We have plenty of “smoking gun” case reports of patients who had no symptoms of stroke until their neck was rapidly manipulated by a chiropractor and who were subsequently found to have tears in the vertebral artery, often bilaterally. There is a plausible mechanism related to the anatomy and the way the artery is tethered between two bony restrictions and stretched by rotation/extension. When a healthy asymptomatic young person collapses on the chiropractor’s table immediately after a neck adjustment and is found to have torn arteries, there can be little doubt about what happened.

It is likely that chiropractic strokes are under-reported: Sandra Nette’s class action suit is being joined by victims who had not previously reported their experiences, and one of my neighbors recently had a mild stroke after a chiropractic neck adjustment and will never see a chiropractor again but he did not sue and his case was not reported in any medical journal. I don’t think he even went back to tell the chiropractor what had happened.

The FCER kit includes a patient template letter, an attorney template, an MD template, and a media release template designed to be personalized with the individual chiropractor’s name and printed on his letterhead and sent out with a copy of the pamphlet. They say the chiropractic profession [sic] is trying to reduce the incidence of stroke from treatment by educating practitioners and patients about the warning signs of CAD and that both medical and chiropractic treatment (spread the blame!) of neck and head pain “can make the problem worse” when those symptoms are present.

They are logically inconsistent: they say they are trying to reduce the incidence of stroke “from treatment,” but at the same time they are saying a vertebral artery dissection (essentially a stroke in progress) was already present before treatment and symptoms of head and neck pain from stroke were the reason patients sought treatment. They seem to be admitting that neck adjustments can cause strokes but at the same time they are implying that the beginnings of the stroke preceded the treatment, so the treatment isn’t really responsible.

The press release says

The research in the journal Spine, which showed that patients seeking inappropriate treatment for CAD – regardless of whether treatment was delivered by a medical or chiropractic doctor – were are [sic] at risk for stroke.”

This is a complete misrepresentation of the study, which did not differentiate between strokes due to CAD and strokes caused by other mechanisms, did not present any evidence that patients who sought care already had CAD, and did not even record what symptoms led patients to seek care or what treatments were given. And of course it couldn’t show that patients were “seeking inappropriate treatment.”

In an ideal world, Spine would issue a statement that their study was being mis-represented and mis-used. As the New England Journal of Medicine has done in the past.

The pamphlet has a handy table contrasting the symptoms of CAD, migraine, tension headache and neck pain. CAD is characterized not by head or neck pain, but by dizziness, double vision, difficulty swallowing, speaking or walking, intense nausea or vomiting, numbness and confusion. We have no way of knowing whether the patients in the Cassidy study had these symptoms or had CAD when they sought treatment.

If CAD was already present, but the patient only had head or neck pain without these neurologic symptoms, there would be no reason to suspect CAD and neither the patient nor the chiropractor would see any contraindication to neck manipulation. Manipulation could be expected to produce further tearing, bleeding, and completed stroke, and might well kill the patient. In the absence of neurologic symptoms, there is no reliable way to predict which patients are at risk of stroke.

If the usual neurologic symptoms of CAD were present, any health care provider should have been able to recognize the warning signs of an emergency and send the patient directly to a hospital rather than trying any outpatient treatments. Neck manipulation is clearly contraindicated in these cases. It is good to educate patients, but I don’t see any need for this campaign to “educate practitioners.” If there are chiropractors or MDs out there who can’t already recognize the warning signs of stroke, they should lose their licenses.

But what about the patients who present for care with no symptoms of CAD and without even complaining of head or neck pain? Stroke victims are clearly NOT just patients who went to a chiropractor with head or neck pain. Some were being treated for things like low back pain or shoulder pain. Some patients like Sandra Nette had no pain at all: she had a catastrophic stroke after neck manipulation done simply for health maintenance purposes. Laurie Jean Mathiason, a 20 year old woman, received 186 manipulations of her neck over a 6 month period when her original complaint was lower back pain. The 186th one killed her. 186 treatments in 6 months? I can’t help but ask: how many treatments does it take before you realize that they aren’t working?

The pamphlet resorts to the fallacious “death by medicine” tu quoque argument, saying that the risk associated with non-steroidal anti-inflammatory drugs (NSAIDs) is much greater than the risk of injury from neck adjustments. At least there is evidence that NSAIDs relieve pain; there is no evidence that neck adjustments relieve low back pain, shoulder pain or pain elsewhere in the body that is commonly treated with neck adjustments. There is no evidence that neck adjustments maintain health. There is evidence that neck adjustments relieve certain types of neck and head pain, but there is no evidence that the presumably more dangerous rapid thrusts are any more effective than gentle mobilization methods.

Their own arguments undermine their position. The pamphlet says the risk of stroke with neck adjustments is estimated at anywhere from one in 4 million to one in 400,000, and it also says “ANY risk of injury is too big” – so isn’t that a reason to avoid neck adjustment entirely? And it says providers should choose “the treatment that is likely to provide the greatest benefit compared to risk.” Since chiropractic has not given us any evidence that rapid thrust neck adjustments offer any significant benefit, doesn’t that rule them out as a viable option?

They list all the other factors that have been associated with CAD, such as hanging out the laundry, sitting in a barber’s chair, turning the neck while driving, Tai Chi, watching aircraft… anything that extends and rotates the neck. The unspoken implication is that the stroke would have happened anyway even if the patient hadn’t seen a chiropractor, and that chiropractic manipulation is no more traumatic than watching airplanes. That’s clearly wrong, because more force is exerted when a chiropractor rapidly twists a relaxed neck than when someone extends his own neck to look at the sky. When someone turns his neck himself, his muscles actively stabilize the neck and protect it from injury.

If chiropractors really wanted to understand the risks and minimize them, here’s what they could do. They could establish a database of every patient who received neck manipulations, listing their presenting symptoms, specifying exactly which type of neck manipulations were done, and following each patient up with phone calls to determine whether symptoms of stroke had developed after treatment. That would (1) establish the true incidence of stroke following neck adjustments, (2) determine whether strokes were more common with certain specific types of adjustments, and (3) determine whether patients were seeking “inappropriate” care for pre-existing symptoms of CAD. This could be done at little expense and would answer clinically significant questions.

This FCER public information campaign is a disgrace. It misinterprets the Cassidy study and it fails to address the real issues. It’s marketing, not public service. And it’s not science. If chiropractors really want to reduce the risk of stroke, this is not the way to go about it. I can only echo Eeyore from Winnie the Pooh, “Pathetic,” he said. “That’s what it is. Pathetic.”

Addendum: Coincidentally, just as I was writing this I received this e-mail anecdote from a reader: “I had been physically assaulted several days earlier and just wanted to be looked over. I wasn’t in any pain, no physical problems whatsoever, just a cut on my head… The chiropractor twisted my neck really hard, and for a whole year now I’ve been having neck pains on a daily basis.” Not a stroke, but an example of a patient who had NO symptoms before neck adjustment and who had them afterward. Whether or not you believe the treatment caused his chronic neck pain, it is clear that there was NO indication for neck manipulation in this patient. Even if the risk is less than one in 4 million, what benefit would have justified the risk for this patient?



Posted by Harriet Hall