Albert Mitsos MD

Vertebral Artery Dissection: Chiropractic Manipulation

A vertebral artery dissection due to chiropractic or other lesser forms trauma is most common in the 45 and under age group.  Beyond this age, vertebral artery dissection is uncommon from minor trauma.  Causation in Vertebral artery dissection is further complicated due to the fact that beyond significant trauma such as motor vehicle accidents and the athletic injuries, a direct cause and effect relationship is not well established.


Chiropractic manipulation is viewed as producing Vertebral artery dissection in between 1 in 400,000 and 1 in 5 million chiropractic adjustments.  The most commonly cited statistic is one in one million.  Giving all benefits of a doubt to a theory of Chiropractic causation, one may choose to use the 1 in 400,000 statistic.  Using this number implies that Chiropractic associated vertebral artery dissections are not as common as thought.

Therefore, in order to establish or refute a causal relationship one must rely to a very significant extent on the history and medical records, which predate the chiropractic manipulation.  The first occurrence in this process is an intimal tear.  The symptoms which occur when the inner lining defect occurs are indistinguishable from musculoskeletal disease.

Thus, the theory that the individual coincidentally was in a chiropractor’s office when symptoms began does not apply as it is not unusual for an individual, who suffers what they perceive to be a musculoskeletal condition to seek the medical attention of a chiropractor.

Example 1: 16 year old male

This case involves a 16-year-old male, who was an avid snowboard enthusiast and would develop occasional musculoskeletal traumas.  In this case, the individual had developed neck pain following a snowboarding incident and sought the care of a chiropractic physician.

Following cervical spine manipulation at the first visit to the chiropractor, the patient developed nausea, vomiting, and dizziness.  The patient was taken to a nearby emergency room where a magnetic resonance angiogram (MRA) was performed.  This demonstrated a vertebral artery dissection on the right.  An MRI evaluation of the brain demonstrated a cerebellar infarct on the right.

This individual was treated using standard anticoagulation for this condition and resolved most of his neurologic complaints within a three-month period.  Plaintiff’s theory in this case was that the chiropractic care was negligent and it was the cervical spine manipulation which produced the vertebral artery dissection and subsequent stroke.  The defense theory was that this individual had developed neurologic deficits prior to the first visit to the chiropractor.

This theory was based on the fact that the patient completed an intake questionnaire upon arriving at the chiropractor’s office.  The patient wrote that the cause of his neck pain was an event that occurred greater than one year prior to the chiropractic visit.  Further, the patient suffered difficulty completing his name, signature, and date of birth on the questionnaire.  It is clearly demonstrated that this individual had developed symptoms of a stroke prior to the first visit with a chiropractor.  This case was settled.

Example 2: Male 30s

This claim involves a male, in his late 30s, who alleged to have suffered a right vertebral artery dissection and cerebellar stroke secondary to chiropractic manipulation.  This patient was seen prior to the first chiropractic visit for neck pain and migraine headaches.  The migraine headaches were a longstanding issue for this patient.  However, stated in the history portion of medical records prior to the chiropractic treatment was in fact that the nature of the migraine headaches had definitely changed in recent days to weeks.

The patient suffered three weeks of what was thought to be musculoskeletal pain to his neck area.  The patient also participated in exercise at a local health club.  The neck pain developed while involved in exercise at the health club.  During the chiropractic manipulation, the patient developed nausea, vomiting, and blurred vision.  At the nearby emergency room, an MRA demonstrated a vertebral artery dissection and an MRI evaluation of the brain demonstrated a concurrent cerebellar infarct (stroke).

Plaintiff’s theory was that the individual did not have neurologic symptoms prior to the chiropractic treatment and did following the chiropractic treatment and therefore causal relationship existed.  Defense theory was that a proximate relationship in and of itself is not adequate to establish causation.  Other factors must be entertained.  It was stated that this gentleman did not suffer symptoms of a vertebral artery dissection or neurologic signs prior to the chiropractic treatment.

However, as stated in the article, the first symptoms of the vertebral artery dissection are indistinguishable from a musculoskeletal conditions of the neck.  This individual clearly demonstrated musculoskeletal symptoms which, as it turns out were actually symptoms of a vertebral artery dissection and not a muscle strain.  Further, the migraine headaches were stated to have changed in nature prior to the chiropractic treatment.  This change is very common in  vertebral artery dissection.  Those with existing migraine headaches will often state that the nature of these headaches had changed.

Thus, there were symptoms of a musculoskeletal strain and a change in the nature of migraine headaches both consistent with the onset of vertebral artery dissection, which often leads to neurologic sequelae.  It was asked by the plaintiff whether this was to be considered a coincidence that the individual was in a chiropractor’s office when neurologic symptoms developed.  There was a defense verdict in this case.

The Medical Process

There are three layers to any major artery, the inner or intima, the middle or muscle layer, and the outer or advantitia.  To begin the process, the intima must be cracked.  This will create a defect in the inner lining of the vessel causing platelets (first clotting agents) to deposit themselves at the torn intima.  These platelets can break off and produce embolism, which can then lead to stroke further up the circulation.  A thrombus can occur within the dissected material and extend beyond the confines of the intimal tear producing a thrombotic embolus, which is more likely to produce a stroke.  The bubble effect of the inner lining of the vertebral artery can become adequately large to produce a complete obstruction of the vertebral artery thus producing a larger stroke.

It is for this reason that the evolutionary process of the dissection can take various times.  Therefore, a temporary relationship as the sole element of causation does not apply in vertebral artery dissections.  As stated above, a direct cause and effect beyond significant trauma such as a motor vehicle accident or sporting events is not established.  

Associated medical conditions must also be considered.  Certain medical conditions are associated with vertebral artery dissections.  This is an association and not necessarily a cause and effect relationship.  Thus, even if the pre-existing medical conditions are present this does not refute a causal connection to the condition.  Vertebral artery dissections occur in association with minor trauma and certain medical conditions.  One must compare these conditions to the clinical scenario suffered by the individual.

Early Symptoms

If symptoms occur three weeks to a month prior to chiropractic manipulation, causation due to a minor event becomes more likely.  Once a dissection begins, it will take on the life on its own and progress over time with or without intervention.  One of the common scenarios when chiropractic manipulation is associated with a vertebral artery dissection is that chiropractors adjust these individuals on more than one occasion and it is on the last manipulation that a neurologic event occurs.

Medical History

When determining causation in this scenario one should review the records with attention to whether the individual is receiving any benefit from the chiropractic treatments assumed to be for a musculoskeletal condition.  If this is a spontaneous or a minor trauma induced dissection, chiropractic manipulation will not significantly improve the symptoms consistent with musculoskeletal disease.  The common history seen in the medical records will be the patient suffered mild increase in symptoms after chiropractic care and then returned to their baseline symptoms without improvement.  This implies that the chiropractic treatment is not successful due to the fact that musculoskeletal conditions are not producing the symptoms and rather this is a vertebral artery dissection, which is going to progress with or without chiropractic intervention.   One must also be sure of the method used by a chiropractor.  If the chiropractor is using posterior to anterior motion of the neck, this is a competent cause of arterial tear.  Further significant rotational movement is also a competent cause of this condition.  However, most chiropractors presently no longer use these maneuvers and move the head when adjusting in a side to side a movement, which is not adverse to the vertebral artery.


When evaluating causation of chiropractic manipulation to vertebral artery dissection, one must look at the onset of symptoms, which brought the individual to the care of a chiropractor.   Review past history for medical conditions stated above such as collagen vascular disease, hypertension, and migraine headaches.  It is very important to review the clinical scenario from the onset of symptoms through the development of neurologic symptoms.  Remember, it is not coincidence that a patient is in a chiropractor‘s office when this occurs.  It is the symptoms that have caused a patient to present themselves for treatment.

In fact, a large study was done comparing people with musculoskeletal neck pain who sought medical attention from family non-chiropractic physicians and chiropractic physicians.  The assumption was that the chiropractic physicians manipulate and non-chiropractic physicians do not.  The study demonstrated that there is no difference in vertebral artery dissections between the two groups.

One should review the clinical progress as it pertains to symptoms while the patient is in chiropractic care.  If symptoms are not resolving over the course of two, three or four treatments then one must entertain the theory that the chiropractic treatments are being rendered for a condition that is not musculoskeletal and will not improve.

Once all of this data is compiled, a cogent response to causation between chiropractic manipulation and vertebral artery dissection can be made.  It should be stated that the evaluation as listed above cuts both ways.  If in fact, the symptoms of musculoskeletal condition are not present prior to the chiropractic visitation and no other risk factors are present, one would be suspicious for a causal relationship.  As stated, however, this must rely on the medical facts and clinical scenario leading up to and during the treatment process. 

About the Author

Albert Mitsos MD is a causation expert witness who specializes in medical malpractice cases. He is board certified in Forensic Traumatology. Dr. Mitsos is located in Schaumburg, Illinois and can be reached at (847) 634-2206 or