The chiropractic profession welcomes valuable research into the understanding of these injuries. Doctors of chiropractic have contributed valuable research to the physiological, epidemiological and clinical understanding of these injuries. However, this retrospective study in Neurology failed to uncover any new information that would significantly enhance the current body of research on this topic. The authors of the study concluded there was a relationship between a neck treatment and one rare type of stroke--a Vertebral Artery Dissection (VAD). This is an unusual variety of stroke that has also been associated with many other commonplace activities such as talking on the telephone, swimming, stargazing, overhead work, hair shampooing, and even sleeping.
Although the study found cases where vertebral artery stroke appeared to be correlated with a chiropractic visit, the stroke may not have been caused by the actual treatment. Scientific evidence implicating a neck treatment as a true cause of this type of stroke is still preliminary and controversial.
Vertebral artery dissections are commonly preceded by symptoms of headache or neck pain days -- or even weeks -- before the actual stroke occurs. The "true stroke" might occur later only after the formation of a blood clot at the site of arterial injury, which then breaks free and lodges in one of the blood vessels in the base of the brain. The patient might have been seeing the chiropractor for treatment of symptoms that were actually caused by an arterial dissection already in progress -- a stroke would have eventually occurred on its own without chiropractic treatment.
A recent biomechanical study measured the forces transmitted to the vertebral artery during cervical spine manipulation. This study found that the forces transmitted to the artery during this procedure are less than 1/9th the force necessary to stretch or otherwise damage a normal vertebral artery. The forces measured during a neck manipulation were actually less than the forces measured during normal movements of the neck.
Based upon this study and other recent evidence, many experts now believe that it is physically impossible for a competently performed neck adjustment to cause a vertebral artery dissection unless the artery already has a significant pre-existing weakness.
In fact, the best estimates of the odds of suffering a serious complication from a chiropractic neck treatment are about one incident out of every two million treatments -- the same odds that you will die in a commercial airline crash. The great majority of practicing doctors of chiropractic will never seen such an incident in their lives, despite that fact that most they perform hundreds or thousands of neck adjustments per year.
Even the most conservative conventional treatment for neck and back pain - - prescription non-steroidal anti-inflammatory drugs (NSAIDs) -- are hundreds of times more likely to cause a serious reaction than the drug-free chiropractic approach to these conditions. Less conservative treatments such as neck surgery are also used for some conditions similar to those chiropractors treat with spinal adjustments. There is a 3 to 4 percent rate of complication for cervical spine surgery, and 4,000-10,000 deaths per million. These risk rates are thousands of times greater than the most extreme estimates of risks from spinal adjustments.
Moreover, "doing nothing," or not treating patients with neck and back pain, carries risks as well. These may include increased rates of disability, abuse of prescription narcotics or illegal drugs for pain relief, disruption of work and social activities, and the risk that an uncomplicated short-term pain condition will become chronic and permanent.
Numerous studies have established that spinal manipulation and other forms of manual therapies are safe and highly effective forms of treatment for common types of neck pain and stiffness and for common headaches. One recent study documenting the effectiveness and safety of neck manipulation was performed by the Duke University Evidence-Based Practice Center and released in 2001. It found cervical manipulation appropriate for both tension-type headache and "cervicogenic" headache -- a sub-category of tension headache that is associated with specific neck symptoms.
In addition, it noted that "cervical spinal manipulation has a very low risk of serious complications" which may be "one of its appeals over drug treatment."
Unfortunately, no simple screening test exists that can reliably determine if a patient's neck symptoms are being caused by a vertebral artery dissection or a much more common cause such as muscular tightness or joint stiffness. The ACA is encouraging research into this area, rather than retrospective studies that fail to provide any useful information and condemn a form of treatment that has been proven to be safe and effective for patients with common forms of neck pain and headache. The ACA has taken an active role in educating doctors of chiropractic to recognize possible risk factors and encourages all doctors of chiropractic to immediately refer any high-risk patients to other specialists for further evaluation.
Although all available evidence demonstrates that there is an extremely small risk of major complications from chiropractic neck treatments, this is still an area of concern for the chiropractic profession. The ACA and the chiropractic profession will continue to work closely with other medical professionals on this matter, for the best interests of our patients.
Journal
Neurology