A new study finds there is no evidence of excess risk of stroke following chiropractic spinal manipulation, according to a February 2008 report in the journal Spine. In the study, researchers noted that patients are no more likely to suffer a stroke following chiropractic treatment than they would after visiting their family doctor's office.
The study goes on to say that any observed association between a vertebrobasilar artery (VBA) stroke and chiropractic manipulation is likely due to patients with an undiagnosed vertebral artery dissection seeking care for neck pain and headache before their stroke.
"This may prove to be one of the most important and significant studies in the profession's history," said ACA President Glenn Manceaux, DC. "The results of this study confirm that chiropractic manipulation is a safe and appropriate course of treatment."
The issue of stroke being associated with a chiropractic neck adjustment focuses around the very rare occurrence of a tear to the vertebral artery as it passes through the sides of the upper cervical vertebrae and into the base of the skull. An injury to the arterial wall may lead to formation of a blood clot, which can break free and travel upward until it lodges in one of the smaller blood vessels in the base of the brain, blocking circulation.
There are many reports in the literature of cervical artery dissections (CADs) occurring after everyday activities that most people would consider non-traumatic, such as turning the head when driving, having your hair washed at a beauty salon, or sleeping on your stomach.
A research paper published in 2001 in the Canadian Medical Association Journal found there is only a one-in-5.85-million risk that a chiropractic neck adjustment will be associated with a subsequent CAD and stroke.
In this new study, the Canadian team looked at nine years of data in Ontario, and found that only 818 patients with a VBA stroke were reported among a population of some 11.5 million people. Unlike a previous study in 2001 that investigated the relationship between chiropractic visits and vertebral artery stroke, researchers in this study also studied visits to family doctors that preceded this kind of stroke.
According to the study's authors, "Because the association between chiropractic visits and VBA stroke is not greater than the association between PCP visits and VBA stroke, there is no excess risk of VBA stroke from chiropractic care."
Stroke Warning Signs
While there are no standard screening procedures to identify patients with neck pain who are also at risk of a VBA stroke, health care providers should be aware of the following stroke warning:
> Sudden difficulty speaking (slurred speech) understanding what people are saying > Sudden onset of confusion or altered mental status, such as loss of consciousness, or recognizing people who should be familiar > Sudden numbness or tingling on one side the face or body, or both > Sudden onset of dizziness or unsteadiness, loss of balance or coordination, or both > Sudden difficulty walking or standing upright > Sudden severe headache > Sudden severe unexplained upper-neck pain > Sudden trouble with vision or sight