May 12, 2003 -- If you've got a pain in the neck, think twice
about getting your neck cracked. Spinal manipulative therapy, as chiropractors
call it, increases your risk of stroke.
The overall risk is probably very small. But the link between
stroke and neck cracking is real, says neurologist Wade S. Smith, MD, PhD,
director of the neurovascular service at the University of California, San
"Some neurologists think chiropractors are causing a lot of
strokes, but we think it is a very low risk," Smith tells WebMD. "I don't think
it is so low that a patient doesn't need to be informed about it. The
consequences of a stroke can be enormous. People should be aware that spinal
manipulation increases risk of stroke. Anybody who does a procedure of any kind
that carries a risk should tell their patients about that risk."
One of the leading causes
of stroke before age 45 is something called cervical arterial dissection.
That's when one of the two arteries that wind through the back of the neck to
the brain starts to tear. The lining of the artery bleeds and forms a blood
clot. This clot can easily enter the brain and cause a fatal stroke.
Earlier studies in Canada compared stroke registries with
medical records. Strokes in younger adults were strongly associated with seeing
a chiropractor. Was there a real cause-and-effect connection? Smith looked for
His team looked at all patients under the age of 60 who from
1995-2000 visited two large medical centers for cervical dissections resulting
in strokes or the passing stroke-like episodes called transient ischemic
attacks. They found 151 such patients; 51 were available for study. The
patients were compared with 100 age-matched patients whose strokes were not due
to arterial dissection. All were asked a battery of questions -- including
whether they had head or neck pain in the 30 days before their stroke, and
whether they got a spinal manipulation during that time.
Of the 51 patients, seven (14%) remembered getting their necks
cracked before their stroke. Only 3% of the control patients remembered seeing
a chiropractor in the month before their stroke. After controlling for all
other factors, getting a spinal adjustment upped the risk of stroke
"If a person has any of the symptoms
of stroke, he or she should bypass the chiropractor and go directly to the
hospital," Smith says.
These red flags are:
One side of the body becomes weak, numb, or paralyzed.
Trouble speaking or difficulty understanding speech.
Loss of balance or coordination; dizziness.
Sudden severe headache.
"Neck cracking," or cervical spinal manipulation, is the chiropractic technique that most concerns neurologists.
To make this adjustment, the practitioner often gives the neck a high velocity
twist. Chiropractors are trained to know the anatomy of the neck. Other kinds
of practitioners, Smith says, may not be so well aware of the risks. He notes
that many chiropractors already are adopting a less forceful technique for