New Study Finds Common Chiropractic Technique Associated With Stroke

The American Heart Association has published a statement warning that there may be an association between stroke and chiropractic therapy involving neck manipulation, although they are unable to confirm whether neck manipulation actually causes stroke or not. This continues a debate that has been ongoing in recent years, in which various experts have argued over the merits and shortcomings of neck manipulation within therapy.

Manipulation of the cervical spine or neck region is a common therapy utilized by chiropractors for many patients complaining of neck, upper back, and shoulder/arm pain, as well as headaches. Proponents of the technique say it relieves pain and improves range of motion, but concerns have long been raised over the potential for injury to result from the energetic thrusts and rotations sometimes used in neck manipulation.

In 2012, a review article published online in the journal BMJ seriously called into question the effectiveness of neck manipulation. In this review, the benefits of the treatment were discussed, along with the possibility of neck manipulation being linked to serious injury and stroke. After evaluating the evidence from previous studies, lead researcher Dr. Neil O’Connell and colleagues concluded that the technique is “unnecessary and inadvisable.”

Specifically, numerous studies have found that neck manipulation is associated with a risk of cervical artery dissection, a form of arterial tear that accounts for 8 percent to 25 percent of stroke cases in patients younger than 45, the authors said in background information.

In the new statement, which was published in the journal Stroke, the American Heart Association (AHA) recommends that patients should be informed of this potential risk prior to receiving neck manipulation therapy.

Cervical artery dissection

A cervical artery dissection (CD) is a small tear in the layers of walls in the arteries in the neck. If the tear becomes dislodged into the bloodstream, it can form a clot and cause an ischemic stroke by blocking one of the blood vessels in the brain.

Such a tear “occurs with a sudden movement that can hyperextend or rotate the neck, such as one you may see with whiplash or sporting events, or even violent coughing or vomiting,” said statement author Dr. Jose Biller, chair of neurology at Loyola University Chicago Stritch School of Medicine. These types of movements can cause serious injury “even if they are deemed inconsequential by the patient,” Dr. Biller added.

Even though they vary among health professionals, Dr. Biller says that the techniques for cervical manipulation often “include a rotation of the neck and sometimes a forceful thrust” that can enact the same sudden movements associated with cervical artery dissection.

The relationship between CD and neck manipulation therapies came to light after several case control studies were carried out. So far, four large studies have found a statistically significant link. However, these investigations were not designed to test causal relationships and as a result, it is unclear whether neck manipulation causes  Nevertheless, the AHA said the evidence is strong enough to warrant the recommendation to warn patients of the risks.

“Although a cause-and-effect relationship between these therapies and CD has not been established and the risk is probably low, CD can result in serious neurological injury,” said Dr. Biller. “We strongly believe that patients should be informed of this association before undergoing neck manipulation.”

Uncertainty remains

One reason the relationship between CD and neck manipulation is tricky to evaluate is that one of the symptoms of CD is neck pain, which can precede a stroke by several days. This neck pain may lead people to seek treatment such as neck manipulation in order to relieve their symptoms.

Some chiropractors advocate “screening tests” with the hope of detecting individuals prone to stroke due to neck manipulation. These tests, which include holding the head and neck in positions of rotation to see whether the patient gets dizzy, are not reliable, partly because manipulation can rotate the neck further than can be done with the tests.

Listening over the neck arteries with a stethoscope to detect a murmur, for example, has not been proven reliable, though patients that have one should be referred to a physician. Vascular function tests in which the patient’s head is briefly held in the positions used during cervical manipulation are also not reliable as a screen for high-risk patients because a thrust that further stretches the vertebral artery could still damage the vessel wall.” In a chapter in the leading chiropractic textbook, Terrett and a colleague have stated:

Even after performing the relevant case history, physical examination, and vertebrobasilar function tests, accidents may still occur. There is no conclusive, foolproof screening procedure to eliminate patients at risk. Most victims are young, without [bony] or vascular pathology, and do not present with vertebrobasilar symptoms. The screening procedures described cannot detect those patients in whom [manipulation] may cause an injury. They give a false sense of security to the practitioner.

For now, the safest route is to avoid the procedure all together. If you choose to pursue neck manipulation therapy, be sure to see a physician beforehand to undergo a full physical exam. This could also help identify underlying problems — such as a herniated disc— and allow your doctor to first try other types of treatment to relieve the pain.

The AHA recommends seeking medical evaluation urgently if neurological symptoms develop following either neck manipulation or trauma. Such symptoms include the following:

• Dizziness or vertigo
• Double vision
• Erratic eye movements
• Nausea and vomiting
• Pains in the neck or head
• Slurring of speech
• Unsteadiness.

“Tell the physician if you have recently had a neck trauma or neck manipulation,” Biller said. “Some symptoms, such as dizziness or vertigo, are very common and can be due to minor conditions rather than stroke, but giving the information about recent neck manipulation can raise a red flag that you may have a CD rather than a less serious problem, particularly in the presence of neck pain.”