Texas Chiropractic College, Pasadena, Texas, United States of America.

Purpose   1) To systematically collect and synthesize available reports of CAD that have been associated with cSMT in the literature and
2) assess the quality of these reports.

Methods   A systematic review of the literature was conducted using several databases. All clinical study designs involving CADs associated with cSMT were eligible for inclusion. Included studies were screened by two independent reviewers for the presence/absence of 11 factors considered to be important in understanding the relation between CAD and cSMT.

Results   Overall, 43 articles reported 901 cases of CAD and 707 incidents of stroke reported to be associated with cSMT. The most common type of stroke reported was ischemic stroke (92%). Time-to-onset of symptoms was reported most frequently (95%). No single case included all 11 factors.

Conclusions   This study has demonstrated that the literature infrequently reports useful data toward understanding the association between cSMT, CADs and stroke. Improving the quality, completeness, and consistency of reporting adverse events may improve our understanding of this important relation.

Copyright: © 2013 Wynd et al.   This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding:   Greg Kawchuk receives salary support from the Canada Research Chairs program. Sunita Vohra receives salary support from Alberta Innovates-Health Solutions. Training support for Shari Wynd was provided by the Alberta Canadian Institutes of Health Research (CIHR) Training Program in Bone and Joint Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests:   The authors have declared that no competing interests exist.

In the area of harms reporting, one topic that has received significant attention is cervical spinal manipulation therapy (cSMT), an intervention most often administered by chiropractors [1, 2] to treat musculoskeletal complaints of the head and neck [3] including headaches [4]. If harms are associated with cSMT, they most commonly involve additional head and neck pain [2]. While these adverse events tend to be self-limiting [2], more serious adverse events have been reported such as neurovascular sequelae and stroke. More specifically, injuries such as cervical artery dissection (CAD), whether vertebral, internal carotid, or vertebrobasilar, have been reported to be associated with cSMT [5-7]. Although this subset of adverse events appears to occur infrequently [1, 8, 9], understanding the relation between CADs, stroke and cSMT is important given the medical [7], societal [1], economic [9], and legal [8] implications of any event leading to cerebrovascular compromise.

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Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

A new device, described as an ECG for the eye, appears to accurately distinguish stroke from other causes of dizziness in the emergency department.

Note that the bedside device feeds webcam video from goggles mounted with an accelerometer to computer software that looks for abnormal corrective eye movements when the head turns.

A device described as an ECG for the eye accurately distinguishes stroke from other causes of dizziness in the emergency department (ED), a small proof-of-concept study showed.

When tested on 12 patients in the ED for acute vestibular symptoms, the device picked out all six vertebrobasilar strokes that were subsequently diagnosed with MRI, David Newman-Toker, MD, PhD, of the Johns Hopkins Hospital, and colleagues reported online in Stroke.

The bedside device feeds webcam video from goggles mounted with an accelerometer to computer software that looks for abnormal corrective eye movements when the head turns.

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University of Calgary, 2500 University Drive N.W., Calgary, Alberta, Canada T2N 1N4. Tel: 403-220-8525; Fax: 403-284-3553; email: walter@kin.ucalgary.ca

In recent weeks, we have learnt that chiropractors may have to carefully review the application of high-speed, low-amplitude spinal manipulative treatments to the neck. The concern is the possible risk associated with neck manipulation. Specifically, vertebral artery dissection, or ther mechanical injury, are an acknowledged, albeit a very low, risk.

The vast amount of research on vertebrobasilar injury in the past has been focused on blood flow through the vertebral artery during diagnostic, and before and after manipulative treatment. There was (is) concern that vertebral artery occlusion may occur during neck manipulation, and that a lack of blood supply to the brain may lead to a series of complications. This line of argument has always struck us as weak, because a high-speed, low-amplitude thrust to the cervical spine lasts typically less than 150 ms, and the brain has sufficient oxygen to survive such a small amount of (possible) loss of blood flow from one of its many supply arteries.

Another way of attempting to gain insight into the possible risk of neck manipulation and vertebrobasilar accidents is a statistical (epidemiological) approach. The basic question that people would like to answer is: are people who receive neck manipulative treatments at a greater risk of vertebrobasilar accidents than people who do not receive such treatments? On the surface, this approach seems feasible, and so it would be, if the occurrence of such accidents was high (let’s say one time in a hundred or a thousand). However, it appears that we deal with incidence rates (if there is an actual incidence) of one in several millions (i.e. very low). Therefore, any statistical pproach has a miniscule power, and a couple of “fluke accidents” (i.e., accidents that occur, let’s say in a chiropractic clinic, but in reality have nothing to do with the chiropractic treatment) may produce a “statistical error” that may persist for years in a community as small as Canada.   Also, using an epidemiological approach, the question of “cause and effect” cannot be resolved.

When starting to tackle the problem of the mechanics of neck manipulative treatments three years ago with my student B. Symons (DC), we were surprised that, to the best of our knowledge, there were no data on what actually happens mechanically to the vertebral artery during cervical spinal manipulation. I was further surprised, when asked to review a case on a vertebrobasilar accident, that one of the arguments went as follows: Pathology revealed no dissection of the vertebral artery, therefore, the vertebrobasilar accident cannot be associated with chiropractic treatment.

Discussing this particular statement within the chiropractic community, it became apparent that mechanical injury to the vertebral artery was an accepted, but very, very very rare occurrence; but nevertheless, accepted. And all this without a shred of scientific evidence about the mechanics of the vertebral artery during cervical manipulation.

So, when does the vertebral artery, or for that matter, any tissue, become injured?

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By Todd Neale, Senior Staff Writer

A large Danish registry study found that the risks of thrombotic stroke or myocardial infarction (MI) roughly doubled in women taking oral contraceptives with low-to-moderate doses of ethinyl estradiol.

Note that the overall number of thrombotic strokes or MIs was small.

The relative risks of thrombotic stroke and myocardial infarction (MI) are higher among users of hormonal contraception, although absolute risks remain low, a Danish study showed.

Use of oral contraceptives combining low-to-moderate doses of ethinyl estradiol and various progestins was associated with up to 2.3 times the risks of thrombotic stroke or MI compared with non-use, according to Øjvind Lidegaard, DrMedSci, of Copenhagen University Hospital, and colleagues.

The type of progestin in the pill had little effect on the risks, the researchers reported in the June 14 issue of the New England Journal of Medicine.

To put the risk in perspective, they estimated that among 10,000 women taking a pill combining desogestrel with ethinyl estradiol at a dose of 20 μg for 1 year, two will have arterial thrombosis and seven will have venous thrombosis.

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In general, I find the reporting at MedScape to be top notch, but I have significant problems with their 4-20-11 essay titled: “The Potential Complications of Chiropractic Therapy”.

Answer this question:

If I sneeze, and there is a car accident across the street,
have we discovered the *cause* of car accidents?

The scientific method would propose that we sneeze a hundred times, and count the car accidents.

That’s how you begin to determine if there is an actual relationship between one event (like drinking milk) and it’s potential consequences (like developing cancer).

The Bone and Joint Decade Task Force was appointed by the World Health Organization (WHO) to look at the causes of, and treatments for neck pain, and after years of review, they published their results in the prestigious Spine Journal. One of the most relevant articles (to this conversation) was titled:

“Risk of Vertebrobasilar Stroke and Chiropractic Care: Results of a Population-based Case-control and Case-crossover Study”
Spine 2008 (Feb 15); 33 (4 Suppl): S176–183

CONCLUSION: VBA stroke is a very rare event in the population. The increased risks of VBA stroke associated with chiropractic and PCP visits is likely due to patients with headache and neck pain from VBA dissection seeking care before their stroke. We found no evidence of excess risk of VBA stroke associated chiropractic care compared to primary care.

There was an association between chiropractic services and subsequent vertebrobasilar artery stroke in persons under 45 years of age, but a similar association was also observed among patients receiving general practitioner services. This is likely explained by patients with vertebrobasilar artery dissection-related neck pain or headache seeking care before having their stroke.

This Blog (and our website in general) has published regularly on this topic:

WARNING: Conducting an Orchestra Can Cause Vertebral Artery Dissection and Stroke
http://www.chiro.org/wordpress/?p=5005

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During the past decade, the issues of cerebrovascular accidents [CVAs] and spinal manipulation have become linked in a debate of ever-increasing intensity. A copious number of studies have investigated spinal manipulation as a putative causative factor of CVAs; however, a common theme among these is the failure to adequately explore the possibility that the majority of CVAs may be spontaneous, cumulative, or caused by factors other than spinal manipulation itself. The problem is only exacerbated by the sometimes hysterical reactions apparent in the mass media over the past three years in reaction to the flawed investigations. [1]

Previous studies have shown that vertebral artery dissections (VADs) have been “caused” by things as innocuous as:

Salon shampoos
Archery
Coughing
Dental procedure
Watching aircraft
Telephone call
Yawning
Bleeding nose
Overhead work

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There are certain types of accusations that are impossible to respond to, without sounding like a guilty party, trying to weasel out of a tight spot.   The accusation that chiropractic somehow “causes stroke” is one such unsupported and impossible-to-defend claim.

The simple truth is that there is absolutely no scientific evidence to demonstrate that chiropractic adjusting in the cervical region has ever “caused” a stroke.   Here’s a perfect example of how flawed that logic really is:   If I sneeze, and there is a traffic accident down the street, it may be convenient to claim that the sneeze “caused” the accident (especially if you stand to benefit financially from that claim), but where is the evidence?

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Recent reports of individuals suffering strokes proximal to receiving chiropractic care are sensationalized by the media all out of proportion to their actual frequency. Although medicine openly admits that tens of thousands die needlessly from medical care, even from things as innocous as venipuncture, that doesn’t excuse chiropractors from the duty to protect their patients.

The Stroke and Chiropractic Page was crafted to keep our profession abreast of information that may help predict (and perhaps prevent) strokes in our patients.