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Dynamic Chiropractic – February 12, 2001, Vol. 19, Issue 04

If Your Only Tool is a Hammer

By Paul Sprieser, BS,DC,DIBAK
In the New England Journal of Medicine, October 8, 1998, Vol. 339-No. 15, there appeared three articles about chiropractic. The one that caught my interest was "A Comparison of Active and Simulated Chiropractic Manipulation as Adjunctive Treatment for Childhood Asthma."

This was a randomized, controlled trial of chiropractic spinal manipulation for children with mild or moderate asthma.

This group of 91 children who had continuing symptoms of asthma, despite usual medical therapy, was randomly assigned to receive either active or simulated chiropractic manipulation for four months. None had previously received chiropractic care.

The primary consideration was the outcome measurement of the change in the base line of peak expiratory flow, measured in the morning and evening in both treatment groups. The consideration of what appears to be objective outcomes, that of peak flow rates, spirometric results, and airway responsiveness, do not take into consideration many other chiropractic techniques that might make a greater difference than is shown in this study.

The outcome of this study showed a small increase of 7 to 12 liters per minute in peak expiratory flow in both groups. Symptoms of asthma and use of beta-agonists decreased and the quality of life increased in both groups, with no significant differences between the groups. There were no significant changes in spirometric measurements or airway responsiveness.1

I believe conclusions that were drawn in this study are erroneous. In children with mild or moderate asthma, the addition of chiropractic spinal manipulation to usual medical care provided no benefit.


I read this study a number of times and found quite a number of ambiguities that made it very difficult to understand. First, the number of children in the study is stated to be 91, but the results showed 38 in the active-treatment group and 42 in the simulated-treatment group; a total of 80. The study tells us that 10 subjects dropped out (four in the simulated-treatment group and six in the active-treatment group, which would make 81 - not 80 as claimed in the study. To compound the numerical mystery, the authors refer in the "sample size" section to the "enrollment of 72 subjects (36 in each group)," when referring to "estimates of variability in peak expiratory flow (within-group SD, 15 percent)." It's been said that statistics don't lie - statisticians do!

In this study we don't know how many subjects were male and female, but we do know the ages of these children were broken down into age groups: 7-12 and 13-16. Also lacking is any indication of the height and weight of these children, which could be a significant factor in the findings.

A "small increase of 7 to 12 liters per minute in peak expiratory flow" was noted. What is the normal rate expected in this sample based upon age, sex and height? None of these variables are explained. Why not? What would be the normal respiratory rate of this sampling of cycles per minute, since there is, according to these findings, "a small increase of seven to 12 liters per minute"? What percentage do these numbers really represent?

One letter to the editor concerning the study addressed what is meant by active vs. simulated adjustment. The letter noted: "The simulated chiropractic treatment (or adjustment) consisted of low-velocity, low-amplitude impulses that did not produce joint cavitation, whereas active treatment consisted of high-velocity, low-amplitude thrusts that produced joint cavitation.2"

What does joint cavitation or the audible release really mean? As a chiropractor that has practiced 31 years and used AK techniques for nearly the same length of time, I have used respiratory assisted adjustments that produce neither cavitation nor sound, and make structural changes in the vertebra being adjusted. The cavitation or audible release is what Dr. George Goodheart calls "popping and praying," and I say this with no disrespect to my fellow chiropractors.

The physiological reason for cavitation is the synovial fluid, which consists of glycoprotein and is 15 percent carbon dioxide. When you move a joint past its normal range of motion, you cause a low-pressure zone that causes the bubbles to implode. There is a natural negative pressure in the synovial cavity of -8 to -10 mm hg that is increased as the joint goes beyond its normal range of motion.3 The low pressure draws the carbon dioxide and water vapor out of the solution, creating a bubble. This process is called "cavitation." This bubble collapses almost instantly, and the fluid crashing in from all sides makes the noise.4 Does this audible sound mean a vertebral correction has been made? It might, depending on what criteria you also apply to this, such as muscle testing, therapy localization and challenge.

What is noted in the editorial letter is that what was claimed to be a simulated adjustment probably wasn't simulated, but an actual structural correction without the audible sound, which most chiropractors are accustomed to hearing. Therefore, the idea that one group was not adjusted is erroneous. Since both groups improved, the original researchers believed that this was a placebo effect. This is not justified, since the physiologic effects of manipulation were applied to both groups. The improvements in both groups show the efficacy of chiropractic treatment and the dual utilization of both medication and chiropractic treatment for the asthmatic child.

However, staying with our medical model and the need for double blind studies, the next flaw in this study is that these children were also receiving bronchial dilators along with chiropractic treatment. If this study were structured properly, we would have part of this sampling receiving only chiropractic care.


This study concluded: "In children with mild or moderate asthma, the addition of chiropractic spinal manipulation to usual medical care provided no benefit." This sounds vaguely familiar, for those of us in the chiropractic profession that know the attitude of medicine toward us. I wonder how such a prestigious journal, the New England Journal of Medicine, would accept such a poor and flawed study and publish it. It is hard to believe their criteria for medical studies would be this shoddy.

Good common sense should be used to treat and administer to asthmatic patients. Asthma, like hypertension, is not a disease, but a complex symptom with many causes: The cause may be structural, such as a subluxation; it may be chemical, such as with low blood sugar, hypoadrenia, and allergies; or it may have psychological origins, as with overprotective parents -requiring a "parentectomy."5

Let's not make our philosophy so simplistic as to have only one cause and only one cure!

Author's note: I titled this paper after a quote from Time magazine. Motivational and behavioral theorist Abraham Maslow commented: "If the only tool you have is a hammer, you will see every problem as a nail." I paraphrase his quote when I teach AK classes. "If the only tool you have is an adjustment, you see every problem as a subluxation."


  1. Balon, Jeffrey. A comparison of active and simulated chiropractic manipulation as adjunctive treatment for childhood asthma. New England Journal of Medicine October 8, 1998, Vol. 339, No. 15.
  2. Jongeward Brian V,DC. Chiropractic manipulation for childhood asthma, letter to the editor. New England Journal of Medicine February 4, 1999, Vol. 340, No. 5.
  3. Guyton, Arthur C,MD. Textbook of Medical Physiology, third edition. W. B. Saunders Co, Philadelphia, 1966.
  4. Unsworth, Dowson, Wright. Joint Sounds Due to Cavitation, 1971.
  5. Brody, Philip K. The Merck Manual, 15th edition, Merck Sharp & Dome, 1987.

Paul Sprieser,BS,DC,DIBAK.
Parsippany, New Jersey

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