Pain in the neck

angry doc is still in pain, but they won't give him any respite...

Nevertheless, you can be sure that despite this letter, he will not be seeing a chiropractor for his pain:


Stroke risk after visiting chiropractor? Not true

WE refer to last Thursday's article by The New York Times published by Mind Your Body, "Fact or fiction: Little risk of stroke from neck adjustments". It was indeed fiction.

The author used a "survey of only 55 cases" from neurologists. Fortunately, recent scientific studies, in 2007, like The Neck Pain Task Force, came up with more definite facts on the matter.

The study - which analysed a total of 818 Vertebral Artery (VBA) strokes over the nine-year inception period in Ontario - concluded that VBA stroke is a very rare event and that the risk of VBA stroke associated with a visit to a chiropractor's office appears to be no different from the risk of VBA stroke following a visit to a medical clinic.

"Our research has led us to believe that the association between VBA stroke and chiropractic care is likely due to patients with headache and/or neck pain from a VBA dissection seeking care in the prodrome of a stroke," explained the study's lead author, Dr David Cassidy, professor of epidemiology at the University of Toronto and senior scientist at the University Health Network at Toronto Western Hospital. In other words, the patients were already having the problem prior to visiting a physician.

"We found no evidence of excess risk of VBA stroke associated with chiropractic care beyond that associated with primary physician care," said Dr Cassidy. He added that these rare strokes have also been reported after ordinary neck movements such as looking up at the sky, turning the head while backing up a car and extending the neck into a hair salon's wash basin.

Other researches have also shown that when certain studies were scrutinised, the practitioners performing the manipulation were actually not chiropractors.

Chiropractors are trained professionals with an evidence-based tertiary education; and belong to the only profession that specialises in spinal manipulation.

We are trained to do a thorough history and physical assessment to screen patients who might be at risk for the rare incidence of VBA stroke.

As an association, we ensure that all our members meet the international standards of education and are in good standing in their countries of origin and adhere to our code of ethics and practice guidelines.

To this end, we encourage the public to seek only those chiropractors who are members of The Chiropractic Association (Singapore). Our website: http://www.chiropractic.org.sg

Dr Robert Wasserman, D.C.
President
The Chiropractic Association (Singapore)

Dr Terrence Yap, D.C.
Vice-president of The Chiropractic Association (Singapore)
Asian Council Representative, World Federation of Chiropractic


So is a visit to the chiropractor's office really as safe as a visit to a medical clinic?

angry doc does not have access to the full paper mentioned in the letter, but fortunately it has been discussed on Science-Based Medicine, where Mark Crislip noted that if you look at the data by age, you will find that:


"... if you are less than 45 and visit a chiropractor, there is a strong association between that visit and a stroke in the next 24 hours."


(A similar finding was also noted in an eariler paper.)

He further noted that:


"Young people should not have any stroke. In the young, vertebral artery dissection is a common cause of a rare event. It is also the worry from chiropractic neck manipulation. If you could find an effect of chiropractic, it would be in the young. And they do. The people who have an increase in stroke are those under age 45. And it is a big association: odds ratios from 3 to 12.

The association is most noticeable in the first 24 hours after seeing a chiropractor. Usually if you rip an artery it is symptomatic right away. Again, we do not know if these people had dissection or not. We only know they had stroke of some sort, within a day after seeing a chiropractor. One would predict that if there were an association between chiropractic and stroke you would most easily find it in the young and the effect would be most noticeable in the first day or so after the chiropractic visit.

And this article confirms this association.

Note the word association. Association is not causation. You would need a prospective study comparing stoke rates from chiropractic patients vs non chiropractic patients to find causality."


He concluded thus:


"My conclusion, from reading the paper in its entirety, rather than the abstract, is that a population that should not have a stroke, the young, has a marked increase association with stroke 24 hours after visiting a chiropractor and that given the rarity of a vertebral artery dissection as a cause of stroke in the elderly, the elderly is not a group that one could easily find an increase in stroke after chiropractor visit.

To quote the paper:

“We have not ruled out neck manipulation as a potential cause of some VBA strokes. On the other hand, it is unlikely to be a major cause of these rare events. Our results suggest that the association between chiropractic care and VBA stroke found in previous studies is likely explained by presenting symptoms attributable to vertebral artery dissection.”

Note the word major. I agree it is not a major cause of stroke, at least in the elderly. In the young, the highest odds ratio, 12, for a stroke is in the first 24 hours after visiting a chiropractor is twice what has been found in prior studies. As mentioned above, a case control study cannot determine causality, just association.

Given the number of chiropractor visits and the rarity of vertebral artery tear, chiropractic is probably a rare cause of a rare event.

However, given that chiropractic neck manipulation is worthless magical thinking, ANY stroke is one too many."

(emphasis mine)


Other aspects of the paper are also reviewed in the article, so it is well worth a read.

What angry doc is curious about is whether those patients who were admitted for VBA strokes after a visit to the chiropractor had any neck manipulation done at all, because if chiropractors are trained to be able to detect strokes, and their interperetation of the study is that patients who visited a chiropractor and were subsequently found to have a VBA stroke may in fact have been presenting with the prodrome of the stroke, then surely they should *not* have undergone neck manipulation.

Or is neck manipulation a cure for VBA stroke?