Weekend Article: Oh no they didn't!

[Special Note]

This weekend article is a bit different.

As opposed to writing about an event or cutting-edge discovery or change in policies, the article will be about scientific findings and how and why we make certain decisions based on criteria. Most importantly, it will hopefully serve as a reminder that (a) correlation between two events does not equate causation between said events, and (b) just because something was published by a scientific community does not mean it is beyond reproach. These things should be taken into consideration for the following article.

Things might get ugly.

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On August 7, 2014, the American Heart Association (AHA) and the American Stroke Association (ASA) published a scientific statement about cervical arterial dissections (CDs) and reviews their statistical association with cervical manipulation therapy (CMT). Being that CDs are a statistically high cause for stroke in young and middle-aged adults, the statement sought to review the current state of how CDs are diagnosed and place a particular microscope on how CMT correlates with CDs.

Just to eliminate any confusion, cervical manipulation therapy is a broad term referring to "cervical spine manipulation by any healthcare professional and includes cervical adjustments by chiropractors" (Biller 3). To better define the "healthcare professionals" referred to in the article, AHA elaborates by saying "the majority of spinal manipulations performed in North America are done by chiropractors; however, they are also done by members of the allopathic, osteopathic, and physical therapy/physio-therapy professions" (Biller 3). And because so many people in the United States (and few other territories) use chiropractors and other alternative medical professionals to treat cervical and spinal ailments, they saw fit to review the ways in which these treatments were performed in order to better understand CMT and any possible connection it might have with the rather high incidences of CDs in young adults -- which, by the way, account for 8-25% of strokes in patients under 45 years of age (Biller 1).

So far so good, right? We have so far: a scary high incidence rate of CD in young adults and a sparse connection with CMT -- which, for the most part, is performed by chiropractors and other alternative medical professionals.


Well, it turns out, CDs are a minority when it comes to ischemic strokes (2% in fact), and because of the small incidence rate, only a handful of studies were available that show any sort of connection with CMT at all (Biller 3). Only case-control studies were available to give any sort of usable data, and of those, only 4 exist that provide information on the connection at all -- give them a read. The data from pages 3-4 on Biller's statement provides all the pertinent results and conclusions.

So, not much help there. It actually looks more like the danger of stroke in all of those patients came from the fact that they visited a chiropractor to help them with neck pain rather than any other sort of physician. The AHA says that the patients, while not necessarily having CDs after CMT, should be given a proper warning about the risk of CD in conjunction with CMT when visiting a chiropractor or other healthcare provider (Biller 5).

Basically, the findings of the AHA were for the most part inconclusive and vague at best. Don't take my word for it: the following paragraph was in the conclusion to their statement.

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 (Biller 14).

In stepped the American Physical Therapy Association (APTA), who wrote a challenge to the article stating that it vastly de-emphasizes the role of the PT in clinical decision making and that judgments made by PTs may reduce the risk associated with CDs in CMT.

Timothy Flynn, PT, PhD, OCS and immediate past president of the American Academy of Orthopaedic Manual Physical Therapists, said that the risk has been studied for over two decades and measures have been put in place to mitigate the risk associated with CMT (APTA 4). He continues to warn readers, however, that the AHA article must be placed in context. "Anti-inflammatory drugs, injections, and surgery for the treatment of neck pain or headaches have much larger risks than manipulation," said Flynn (APTA 6).

Indeed, the AHA has studied the effects of chemical treatments on patients with chronic pains:

...A 2007 AHA scientific statement¹⁰ indicated that for patients with a prior history of or at high risk for heart disease, certain pain relievers known as COX-2 inhibitors could increase risk for heart attack, stroke, and high blood pressure. Also, a 2013 study in Spine¹¹ found that patients who had cervical spine surgery were at significant risk of cardiac and breathing problems as well as gastrointestinal, neurological, blood cell, and urinary tract complications. In addition, there was a greater risk of death after cervical spine surgery among patients older than 65 who had a history of heart problems (APTA 7).

APTA concluded their response by saying that the incidence of CDs after spinal manipulation are rare, and for research purposes there has been no link between the incidence of CD and CMT. "In a 2002 review¹² of 64 cases of cerebrovascular ischemia, or lack of blood flow to the brain, associated with cervical spine manipulation, researchers concluded that strokes after manipulation appear to be unpredictable and should be considered a rare complication of this treatment approach" (APTA 8).

Flynn concluded by saying that APTA provides physical therapists with the tools to properly understand the biomechanics of cervical spine manipulation, including the risks associated with the treatment. "Physical therapists understand the small risk of stroke associated with cervical manipulation, and they base decisions regarding the select use of this procedure on a detailed and ongoing evaluation and a treatment plan that is consistent with patient preferences" (APTA 9).


American Physical Therapy Association (APTA). (2014). APTA responds to American Heart Association cervical manipulation paper [Press release]. Retrieved from http://www.apta.org/Media/Releases/Consumer/2014/8/7/

Biller, Jose, et al. (2014). Cervical arterial dissection and association with cervical manipulation therapy: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke: Journal of the American Heart Association, 1-20. Retrieved from http://stroke.ahajournals.org/content/early/2014/08/07/STR.0000000000000016.full.pdf+html