Today I would like to write about a topic that many, many people, patients or not, have wondered: Do chiropractic neck adjustments cause stroke? To support my explanation, I will be providing some peer-reviewed research and some common sense food-for-thought. Hopefully by the end of this blog post, any questions you might have had will have been answered.
In theory, a disturbance of blood flow to the brain can cause a stroke, or loss of brain function. One of the ways this lack of blood flow can occur is by tearing of the vertebral artery; we have two vertebral arteries, one on each side of the cervical (neck) spine. It has been argued that the position in which a chiropractor will place a patient’s neck, followed by the thrust necessary for a successful spinal adjustment, places the patient at risk of a “vertebrobasilar accident”, or a stroke.
While in theory this seems reasonable, in reality, a cause and effect relationship is not likely.
Here are some important factors to consider:
Position of head and neck:
In order to target the exact joint that will be manipulated by the chiropractor, the head and neck are placed in a very specific position before applying a thrust. This position is always completely within the patient’s given range of motion; thus, the patient will not feel any sense of discomfort. If this were not true and the patient were in fact uncomfortable due to having his head and neck being placed in a position outside of his normal anatomical range of motion, his muscles would be contracting and resisting the chiropractor so much so that performing a spinal adjustment against this resistance would, quite simply, just not be possible.
Force of thrust:
Although chiropractic adjustments can admittedly look somewhat aggressive (YouTube makes me cringe!), they are quite gentle. The quick thrust of only 2-4 lbs happens in the blink of an eye. Multiple studies have shown that the strains on the vertebral arteries obtained during cervical spinal manipulation are significantly smaller than those obtained during routine diagnostic and range of motion testing. More importantly, these strains are much smaller than failure strains, which are strains that cause vertebral artery tearing. Thus, cervical spine manipulation does not seem to place any undue stress on the vertebral arteries, and therefore, does not seem to be a factor in vertebral artery injuries. Please read http://www.ncbi.nlm.nih.gov/pubmed/20534313 for more information on this.
No causal relationship between manipulation and stroke:
In 2008, Cassidy et al. http://www.ncbi.nlm.nih.gov/pubmed/18204390 investigated associations between chiropractic patient visits and vertebrobasilar artery (VBA) strokes, and family doctor patient visits and VBA strokes. It was discovered that there was an equal number of positive relationships between patients who had visited their chiropractors and patients who had visited their GPs, followed by a VBA stroke. To clarify, roughly the same number of people had a stroke following a visit to their chiropractor or their family doctor, regardless of the treatment received at either health care practitioner’s office. Thus, since only chiropractors perform spinal manipulation and medical doctors do not, it can be concluded that the spinal manipulation was not what caused these VBA strokes.
Two common symptoms of stroke are neck pain and headaches. It is likely that patients presented to their medical doctor or their chiropractor with these symptoms, and both chiropractors and family doctors failed to recognize that these primary complaints were due to patients already having a stroke in progress, therefore requiring emergency hospital care. This is exactly why any neck pain patient who presents to any good primary health care practitioner, whether a general practitioner or a chiropractor, will receive an extremely thorough history and physical examination before proceeding with treatment, to ensure that any head and neck complaints are managed appropriately and that the patient is a good candidate for the proposed treatment plan.
And some common sense facts to consider…
Our spines and vertebral arteries are quite durable. If our bodies were too fragile to withstand the position and force of thrust from cervical spinal manipulation, VBA strokes would be happening at an extremely high frequency in contact sports, in motor vehicle accidents, from craning our heads back to get our hair washed at the hairdresser’s, and in chiropractic schools all around the world, where students learn how to perform neck manipulation on each other, day after day, year after year. Imagine the headlines!
Simply put, VBA strokes are a rare event, and even though they are associated with neck adjustments, this is merely an association relationship, not a causal relationship. If there were a causal relationship between cervical spine manipulation and stroke, I’m certain chiropractors’ insurance premiums would be much, much higher than they are today!
So there you have it- some scientific, and some common sense arguments to support that cervical spine manipulation is a relatively safe and effective treatment option for those with neck pain, stiffness, and headaches. As always, please feel free to contact me should you have any questions or comments.
Until next time,
Dr. Julia Viscomi