Chiropractic and Stroke Incidence
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 innocuous 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.
This Introduction reviews those physical findings that may indicate whether a new or existing patient is in the prodromal state of stroke onset, so that we can refer them for co-management. I hope you will read this information closely.
Chiropractic and Stroke
Stroke is one of the leading causes of death. The CDC reports that 700,000 people experience a stroke each year, and that 160,000 of them are fatal. The risk of death from stroke also increases with age.
Statistics, reviewed between the years 1979 to 1991, found that the yearly incidence rates of death by stroke for those in the 25–44 years age bracket was only 3,418 deaths, whereas at the age of 65 or above, incidence rates increased to 140,938 deaths yearly. 
Stroke is characterized by the sudden loss of circulation to an area of the brain, resulting in a corresponding loss of neurologic function. Also called a “Cerebrovascular Accident” (CVA), stroke is a nonspecific term, which describes a cross–section of pathophysiologic causes, which include thrombosis, embolism, and hemorrhage. 
Chiropractors are particularly interested in strokes caused by “Vertebral Artery Dissection” (VAD). Dissections of the Carotid Artery (CAD) or the Vertebral Artery (VAD) are relatively rare. The combined incidence of both VAD and CAD is estimated to be 2.6 per 100,000. However, cervical dissections are the underlying etiology in as many as 20% of the ischemic strokes presenting in younger patients aged 30–45 years. Among all extracranial cervical artery dissections, CAD is 3–5 times more common than VAD. The female–to–male incidence ratio is 3:1 
|Thanks to the Neuroscience Homepage
for the use of this picture!
A more accurate sketch
The path of the Vertebral Artery is well described elsewhere.  The portion referred to as Segment III follows a “tortuous” route from the transverse foramen of C2, running posterolaterally to loop around the posterior arch of C1”. This is the most common site for VAD associated with cervical manipulation. The rest of this page is devoted to examining the causes of Vertebral Artery Dissection. VAD has occurred following actions as trivial as coughing, rotating the head to back a car out of a driveway, and other “normal” activities like archery and visits to the hairdresser. (See the collected abstracts below).
Most reported cases of VAD have similar characteristics: The underlying and pre-existing disease of the intima of the artery, and an “initiating event” which involves rotation and/or extension of the cervical spine. Chiropractic manipulation (which is typically the diversified technique) has been labeled the “proximal event” in reported cases of stroke-after-manipulation because of it’s reliance on a rotational component. Even thought more than 90% of the profession uses that technique, the reported incidence of VAD is still only about 1 out of 3 million manipulations. 
A well-balanced report in the Canadian Medical Association Journal , states that “neck manipulation as a therapeutic strategy for head and neck pain is common and may be effective” and concludes that until methods of identification of “high risk” populations improves, chiropractors should inform all patients of possible serious complications before neck manipulation (informed-consent).
The Stroke Page is devoted to demonstrating the astounding safety of the chiropractic adjustment. When compared to many medical procedures used for the same complaint, the chiropractic adjustment is hundreds to thousands of times safer! Refer to the “Comparison of Death Rates Attributed to Various Causes” Chart below.
Dr. Scott Haldeman et al. wrote a follow–up article to the Canadian Stroke Consortium piece cited above. They reviewed 10 years worth of malpractice claims files in Canada for it’s 4500 chiropractors.
They found that:
“The likelihood that a chiropractor will be made aware of an arterial dissection following cervical manipulation is approximately:
1:8.06 million office visits,
1:5.85 million cervical manipulations,
1:1430 chiropractic practice years and
1:48 chiropractic practice careers.
This is considerably less than the estimates of 1:500,000–1 million cervical manipulations, which has been promulgated by a questionable survey of some neurologists”. .
An recent in-depth retrospective review  of patient files from reported cases of VAD attempted to evaluate the characteristics of the treatment rendered, and the presenting complaints of those patients. They found:
25 % cases presented with sudden onset of new and unusual headache and neck pain often associated with other neurological symptoms that may represent a dissection in progress; A second, earlier study  also notes vertigo or unilateral facial paresthesia is an important warning sign that may precede onset of stroke by several days.
There was no apparent dose-response relationship to these complications;
They occurred following any form of standard cervical manipulation technique, including rotation, extension, lateral flexion and non-force and neutral position manipulations, and
Based upon this review, stroke, particularly vertebrobasilar dissection, should be considered a random and unpredictable complication of any neck movement, including cervical manipulation.
The most recent in-depth review, published in the Feb 15, 2008 Spine Journal  was completed by members of the Spine Decade Task Force. It reviewed 10 years worth of hospital records, involving 100 million person-years. Those records revealed no increase in vertebral artery dissection risk with chiropractic, compared with medical management, and further stated that “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.”
It is now becoming apparent that chiropractors may have prematurely accepted the notion that cervical adjusting/ manipulation could be a “causative” event for VAD. That was a reasonable and professional response to case-studies and reports in the peer-reviewed medical literature, which was often based on a pattern of medical mis-reporting later documented by Terrett. 
The recently published “Current Concepts: Spinal Manipulation and Cervical Arterial Incidents 2005” (NCMIC)  concludes in it’s Executive Summary: “Unfortunately, opinion rather than fact has tended to dominate discussions regarding CVAs and chiropractic, even though there has been no definitive evidence that chiropractic adjustments (actually) cause strokes. The good news is that this monograph notes that a causative relationship between chiropractic manipulation and stroke is unlikely. There is an associative relationship between the two because people may go to chiropractors for relief of stroke-related symptoms”.
It also recommends that chiropractors pay close attention when patients present with sudden onset of headache/neck/face pain that’s different than the patient has had previously.
If so, evaluate for a history of:
Drugs/medication (smoking, oral contraceptives);
Physical trauma (which may have damaged arterial structures);
Connective tissue diseases (autosomal dominant polycystic kidney disease, Ehlers-Danlos type IV, Marfan Syndrome, Fibromuscular Dystrophy);
Genitourinary system (frequent urinary tract infection, hematuria);
Nervous system (dysarthria, dysphagia, visual changes, dizziness, confusion, giddiness and vertigo);
Cardiovascular system (stroke, TIAs, mitral prolapse, aortic dilation, hypertension).
Differentiating “normal” head and neck pain from a CVA:
- Transient Ischemic Attacks (TIAs)— often have similar symptoms to a CVA. If the patient suffers from carotid TIAs, get a quick medical referral. The patient may suffer a complete stroke after only a few episodes.
- Dizziness, unsteadiness, vertigo, giddiness— Question the patient about:
- Aggravating factors, such as neck position or head movement
- If any of the other 5 Ds and 3 Ns exist (see below)
- Whether new symptoms have occurred or existing symptoms aggravated by previous cSMT
- Migraine headaches— When a patient presents with a migraine, stroke is uncommon and is usually in the posterior cerebral artery.
- Cervicogenic headaches— primary features:
- Mechanical precipitation or aggravation of head pain
- facet joint tenderness
- neck muscle tenderness
- palpatory pressures reproducing head symptoms
If so, then evaluate for the “signs” of a stroke. Can they: smile, raise both arms, stand steady on both feet with their eyes closed. speak a simple sentence with several vowels that run together, such as “Simple Simon Says”, or stick out their tongue?
These are also known as the 5 D’s and the 3 N’s:
||→||Double vision or other vision problems|
||→||Sudden numbness/weakness of face/arm/leg|
||→||Vomiting or queasiness|
||→||Loss of sensation on one side|
||→||Involuntary rapid eye movements|
If you suspect that your patient may have had (or is having) a stroke, do NOT adjust their neck, and get them to a hospital for an evaluation MRI/MRA.
It’s also advisable to not offer the patient anything to eat or drink, and that you do NOT allow patients who improve spontaneously to drive home.
Remember that transient ischemic attacks (TIA) are warning signs for stroke. The symptoms are similar to CVAs although they can resolve spontaneously. Protect your patient by advising an immediate medical referral.
Thanks to the Association of Chiropractic Colleges and Gerard Clum, D.C., President of Life Chiropractic College West, for supplying us with 73 educational slides for your review. This educational PowerPoint slide show is titled:
eMedicine Journal 2001 (Aug 17); 2 (8)
eMedicine Journal 2002 (May 30); 3 (5)
CMAJ 2000; 163 (1): 38–40
The Chiropractic Experience
CMAJ 2001; 165 (7): 905–906
J Neurol 2002 (Aug); 249 (8): 1098–1104
Can J Neurol Sci 2000 (Nov); 27 (4): 292-296
J Manipulative Physiol Ther 1995 (May); 18 (4): 203-210
From NCMIC ~ The Executive Summary (8 pages)
Spine 2008 (Feb 15); 33 (4 Suppl): S176–183