Last summer, news reports about a young woman who had a stroke after a visit to a chiropractor brought renewed attention to a rare but potentially devastating condition. Known as a cervical artery dissection, it's a tear in the lining of one of the main arteries that carry blood to the brain (see illustration). The quick, jolting neck movements or "adjustments" (also known as cervical manipulative therapy) done by some chiropractors and other care providers may trigger or exacerbate a tear.
"In my practice, I've taken care of a number of people who had a stroke on the chiropractor's table or soon after the visit," says Dr. Natalia Rost, a Harvard Medical School professor and chief of Stroke Services at Harvard-affiliated Massachusetts General Hospital. However, a host of other activities and situations that cause sudden, jerky neck movements can also cause tears in the delicate arteries in the front and back of the neck, she says.
The activities she worries about the most? Bungee jumping, riding a roller coaster, and white-water rafting are at the top of her list. Dissections have also been reported after strenuous weight lifting, high-impact and high-intensity workouts, and head-flinging dance moves. Whiplash sustained in a car accident can cause a cervical artery dissection. Two other documented triggers: hyperextending your neck while practicing yoga, and tipping your head back to have your hair washed at a salon sink. (To help prevent this problem, ask your hairdresser for a neck extension, a small cushion that props up your neck to prevent neck strain.)
Putting the risk in perspective
Of course, millions of people do these activities every day without experiencing any consequences. Cervical artery dissections are rare, occurring in only about three in 100,000 people per year. "In reality, these dissections may be more common than we realize. The good news is that, as with many injuries, the body repairs and heals the damage naturally," says Dr. Rost.
Younger people are more likely to engage in activities that might precipitate a tear, which is the main reason cervical artery dissections are more common in this age group. In fact, they are one of the most common causes of stroke in people under age 50. As people age, other types of strokes (such as those caused by brain arteries clogged with fatty plaque and blood clots that come from the heart) become more common. But dissections can strike older people as well: one study found that one in 14 people diagnosed with a cervical artery dissection was 60 or older.
What is a cervical artery dissection?
The two arteries that run up the front of the neck (the carotid arteries) and two others on the back of the neck (the vertebral arteries) are collectively known as the cervical arteries.
A tear in the lining of one of these arteries — called a cervical artery dissection — causes blood to leak between the layers of the artery wall. The body's natural response to stop the bleeding by forming a clot may backfire, as a large clot may block blood flow through the artery or break off and lodge in a brain artery. Either scenario can cause a stroke.
Photo courtesy of Dr. Natalia Rost, Massachusetts General Hospital
Know the warning signs
A cervical artery dissection causes unusual, persistent, and severe pain in the neck and head that typically occurs either during or immediately after the activity that triggered the neck strain. With a carotid artery tear, the pain often spreads along the side of the neck up toward the forehead, eye, cheek, or teeth. A vertebral artery tear may cause a sharp pain at the base of the skull and back of the head. If you experience such pain — especially if you also have stroke symptoms such as dizziness, double vision, jerky eye movements, unsteadiness while walking, or slurred speech — call 911 immediately. However, be aware that stroke symptoms can develop hours, days, or even a week after the dissection symptoms begin.
Neck pain from a vertebral artery dissection may be one reason people seek care from a chiropractor. "Chiropractors will correctly contend that they didn't cause the dissection in the first place. But neck manipulation can make the situation worse, either by worsening the tear or dislodging a clot, which can precipitate a stroke," says Dr. Rost. Her advice: don't let anyone use any amount of force to push, press, or move your neck.