The Council on Chiropractic Practice,
Clinical Practice Guidelines, Chapter 9: Patient Safety
Considerable visibility and public scrutiny surrounds possible risks associated with Spinal Adjustment and Manipulation. Non-serious side effects are relatively common
and may consist of localized discomfort, headache, or fatigue that resolves within 24–48 hours. The concern raised by scientific and popular media reports in the United States and Canada are that chiropractic “manipulation” of the cervical spine is associated with stroke.
However, not only is the incidence stroke difficult to determine with chiropractic adjustment, some argue that there is no rationale for linking chiropractic adjustment with
vascular dissection at all. Case reports of adverse events following spinal “manipulation” are common as are published commentaries on the relative risks of chiropractic. However, solid scientific evidence of a causal relationship between such adverse events and the “manipulation” is lacking. Furthermore, spinal adjustment and spinal manipulation are not synonymous terms. In the case of strokes purportedly associated with manipulation, the panel noted sgnificant shortcomings in the literature. A summary of the relevant literature follows:
Lee  attempted to obtain an estimate of how often practicing neurologists in
California encountered unexpected strokes, myelopathies, or radiculopathies following
chiropractic manipulation. Neurologists were asked the number of patients evaluated over
the preceding two years who suffered a neurological complication within 24 hours of
receiving chiropractic manipulation. Fifty-five strokes were reported. The author stated,
Patients, physicians, and chiropractors should be aware of the risk of neurologic
complications associated with chiropractic manipulation. No support was offered to
substantiate the premise that a causal relationship existed between the stroke and the
event(s) of the preceding 24 hours.
In a letter to the editor of the Journal of Manipulative and Physiological
Therapeutics, Myler 
wrote, I was curious how the risk of fatal stroke after cervical
manipulation, placed at 0.00025% 
compared with the risk of (fatal) stroke in the
general population of the United States. According to data obtained from the National
Center for Health Statistics, the mortality rate from stroke in the general population was
calculated to be 0.00057%. If these data are correct, the risk of a fatal stroke following
cervical manipulation is less than half the risk of fatal stroke in the general
Jaskoviak  reported that not a single case of vertebral artery stroke occurred in
approximately five million cervical manipulations at the National College of Chiropractic
Clinic from 1965 to 1980.
Osteopathic authors Vick, et al.  reported that from 1923 to 1993, there were only
185 reports of injury associated with several million treatments.
Pistolese  has constructed a risk assessment for pediatric chiropractic patients.
His findings covering approximately the last 30 years indicate a risk of a neurological
and/or vertebrobasilar accident during a chiropractic visit about one in every 250,000,000
An article in the Back Letter  noted that In scientific terms, all these figures
are rough guesses at best... There is currently no accurate data on the total number of
cervical manipulations performed every year or the total number of complications. Both
figures would be necessary to arrive at an accurate estimate. In addition, none of the
studies in the medical literature adequately control for other risk factors and
Leboeuf-Yde et al.  suggested that there may be an over-reporting of spinal
manipulative therapy related injuries. The authors reported cases involving two fatal
strokes, a heart attack, a bleeding basilar aneurysm, paresis of an arm and a leg, and
cauda equina syndrome which occurred in individuals who were considering chiropractic
care, yet because of chance, did not receive it. Had these events been temporally related
to a chiropractic office visit, they may have been inappropriately attributed to
In many cases of strokes attributed to chiropractic care, the operator was not a
chiropractor at all. Terrett  observed that manipulations administered by Kung Fu
practitioner, GPs, osteopaths, physiotherapists, a wife, a blind masseur, and an Indian
barber were incorrectly attributed to chiropractors. As Terrett wrote, The words
chiropractic and chiropractor have been incorrectly used in numerous publications dealing
with SMT injury by medical authors, respected medical journals and medical organizations.
In many cases, this is not accidental; the authors had access to original reports that
identified the practitioner involved as a non-chiropractor. The true incidence of such
reporting cannot be determined. Such reporting adversely affects the reader's opinion of
chiropractic and chiropractors.
Another error made in these reports was failure to differentiate cervical manipulation
from specific chiropractic adjustment. Klougart et al.  published risk estimates which
revealed differences which were dependent upon the type of technique used by the
The panel found no competent evidence that specific chiropractic adjustments cause
strokes. Although vertebrobasilar screening procedures are taught in chiropractic
colleges, no reliable screening tests were identified which enable a chiropractor to
identify patients who are at risk for stroke.
After examining twelve patients with dizziness reproduced by extension rotation and
twenty healthy controls with Doppler ultrasound of the vertebral arteries, Cote, et
al.  concluded, We were unable to demonstrate that the extension-rotation test is a
valid clinical screening procedure to detect decreased blood flow in the vertebral artery.
The value of this test for screening patients at risk of stroke after cervical
manipulation is questionable. Terrett  noted, There is no evidence which suggests that
positive tests have any correlation to future VBS (vertebrobasilar stroke) and SMT (spinal
manipulative therapy). Despite this lack of evidence, some have suggested that failure to
employ such tests could place a chiropractor in a less defensible position should
litigation ensue following a CVA. 
Informed consent revisited.
J Aust Chiro Assoc 1990; 20(4):134-138.
Informed consent - the new reality.
J Can Chiro Assoc 1988; 32(2):91-94.
Efforts to prevent malpractice suits.
Princeton Insurance Company, Princeton, NJ, May 4, 1989.
The nature of the informed consent doctrine and the chiropractor.
J Can Chiro Assoc 1984; 28(2):272-274.
General considerations of consent.
J Chiro 1985; 22(12):52-53.
Jackson R, Schafer R.
Basic chiropractic paraprofessional manual, Chapter XII.
ACA, Des Moines, 1A. XII:3-4, 1978.
Ethical issues surrounding informed consent. Part II. Components of a morally valid consent and conditions that impair its validity.
Urol Nurs 1989; 9(4):4-9.
Neurologic complications following chiropractic manipulation: a survey of California neurologists.
Neurology 1995; 45:1213.
Myler L. Letter to the editor.
J Manipulative Physiol Ther 1996;19:357.
Dabbs V, Lauretti WJ.
A risk assessment of cervical manipulation vs. NSAIDS for the treatment of neck pain.
J Manipulative Physiol Ther 1995; 18:530.
Complications arising from manipulation of the cervical spine.
J Manipulative Physiol Ther 1980; 3:213.
Vick D, McKay C, Zengerle C.
The safety of manipulative treatment: review of the literature from 1925 to 1993.
JAOA 1996; 96:113.
Risk assessment of neurological and/or vertebrobasilar complications in the pediatric chiropractic patients.
Journal of Vertebral Subluxation Research 1998; 2 (2): In Press.
What about the serious complications of cervical manipulation?
The Back Letter 1996; 11:115.
Leboeuf-Yde C, Rasmussen LR, Klougart N.
The risk of over-reporting spinal manipulative therapy-induced injuries; a description of some cases that failed to burden the statistics.
J Manipulative Physiol Ther 1996; 19:536.
Misuse of the literature by medical authors in discussing spinal manipulative therapy injury.
J Manipulative Physiol Ther 1995; 18:203.
Klougart N, Leboeuf-Yde C, Rasmussen LR.
Safety in chiropractic practice, Part I; The occurrence of cerebrovascular accidents after manipulation to the neck in Denmark from 1978-1988.
J Manipulative Physiol Ther 1996; 19:371.
Cote P, Kreitz B, Cassidy J, Thiel H.
The validity of the extension-rotation test as a clinical screening procedure before neck manipulation: a secondary analysis.
J Manipulative Physiol Ther 1996; 19:159.
Vertebrobasilar stroke following manipulation.
NCMIC, Des Moines, 1996, page 32.
The Chiropractic Neurological examination.
Aspen Publishers. Gaithersburg, MD 1992.
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