Edzard Ernst
MD, PhD, MAE, FMedSci, FRSB, FRCP, FRCPEd.

The chiropractic attempt to have the cake and eat it has failed

Published Tuesday 28 October 2014

One of the problems regularly encountered when evaluating the effectiveness of chiropractic spinal manipulation is that there are numerous chiropractic spinal manipulative techniques and clinical trials rarely provide an exact means of differentiating between them. Faced with a negative studies, chiropractors might therefore argue that the result was negative because the wrong techniques were used; therefore they might insist that it does not reflect chiropractic in a wider sense. Others claim that even a substantial body of negative evidence does not apply to chiropractic as a whole because there is a multitude of techniques that have not yet been properly tested. It seems as though the chiropractic profession wants the cake and eat it.

Amongst the most commonly used is the ‘DIVERSIFIED TECHNIQUE’ (DT) which has been described as follows: Like many chiropractic and osteopathic manipulative techniques, Diversified is characterized by a high velocity low amplitude thrust. Diversified is considered the most generic chiropractic manipulative technique and is differentiated from other techniques in that its objective is to restore proper movement and alignment of spine and joint dysfunction.

Also widely used is a technique called ‘FLEXION DISTRACTION’ (FD) which involves the use of a specialized table that gently distracts or stretches the spine and which allows the chiropractor to isolate the area of disc involvement while slightly flexing the spine in a pumping rhythm.

The ‘ACTIVATOR TECHNIQUE’ (AT) seems a little less popular; it involves having the patient lie in a prone position and comparing the functional leg lengths. Often one leg will seem to be shorter than the other. The chiropractor then carries out a series of muscle tests such as having the patient move their arms in a certain position in order to activate the muscles attached to specific vertebrae. If the leg lengths are not the same, that is taken as a sign that the problem is located at that vertebra. The chiropractor treats problems found in this way moving progressively along the spine in the direction from the feet towards the head. The activator is a small handheld spring-loaded instrument which delivers a small impulse to the spine. It was found to give off no more than 0.3 J of kinetic energy in a 3-millisecond pulse. The aim is to produce enough force to move the vertebrae but not enough to cause injury.

There is limited research comparing the effectiveness of these and the many other techniques used by chiropractors, and the few studies that are available are usually less than rigorous and their findings are thus unreliable. A first step in researching this rather messy area would be to determine which techniques are most frequently employed.

The aim of this new investigation was to do just that, namely to provide insight into which treatment approaches are used most frequently by Australian chiropractors to treat spinal musculoskeletal conditions.

A questionnaire was sent online to the members of the two main Australian chiropractic associations in 2013. The participants were asked to provide information on treatment choices for specific spinal musculoskeletal conditions.

A total of 280 responses were received. DT was the first choice of treatment for most of the included conditions. DT was used significantly less in 4 conditions: cervical disc syndrome with radiculopathy and cervical central stenosis were more likely to be treated with AT. FD was used almost as much as DT in the treatment of lumbar disc syndrome with radiculopathy and lumbar central stenosis. More experienced Australian chiropractors use more AT and soft tissue therapy and less DT compared to their less experienced chiropractors. The majority of the responding chiropractors also used ancillary procedures such as soft tissue techniques and exercise prescription in the treatment of spinal musculoskeletal conditions.

The authors concluded that this survey provides information on commonly used treatment choices to the chiropractic profession. Treatment choices changed based on the region of disorder and whether neurological symptoms were present rather than with specific diagnoses. Diversified technique was the most commonly used spinal manipulative therapy, however, ancillary procedures such as soft tissue techniques and exercise prescription were also commonly utilised. This information may help direct future studies into the efficacy of chiropractic treatment for spinal musculoskeletal disorders.

I am a little less optimistic that this information will help to direct future research. Critical readers might have noticed that the above definitions of two commonly used techniques are rather vague, particularly that of DT.

Why is that so? The answer seems to be that even chiropractors are at a loss coming up with a good definition of their most-used therapeutic techniques. I looked hard for a more precise definition but the best I could find was this: Diversified is characterized by the manual delivery of a high velocity low amplitude thrust to restricted joints of the spine and the extremities. This is known as an adjustment and is performed by hand. Virtually all joints of the body can be adjusted to help restore proper range of motion and function. Initially a functional and manual assessment of each joint’s range and quality of motion will establish the location and degree of joint dysfunction. The patient will then be positioned depending on the region being adjusted when a specific, quick impulse will be delivered through the line of the joint in question. The direction, speed, depth and angles that are used are the product of years of experience, practice and a thorough understanding of spinal mechanics. Often a characteristic ‘crack’ or ‘pop’ may be heard during the process. This is perfectly normal and is nothing to worry about. It is also not a guide as to the value or effectiveness of the adjustment.

This means that the DT is not a single method but a hotchpotch of techniques; this assumption is also confirmed by the following quote: The diversified technique is a technique used by chiropractors that is composed of all other techniques. It is the most commonly used technique and primarily focuses on spinal adjustments to restore function to vertebral and spinal problems.

What does that mean for research into chiropractic spinal manipulation? It means, I think, that even if we manage to define that a study was to test the effectiveness of one named chiropractic technique, such as DT, the chiropractors doing the treatments would most likely do what they believe is required for each individual patient.

There is, of course, nothing wrong with that approach; it is used in many other area of health care as well. In such cases, we need to view the treatment as something like a ‘black box’; we test the effectiveness of the black box without attempting to define its exact contents, and we trust that the clinicians in the trial are well-trained to use the optimal mix of techniques as needed for each individual patient.

I would assume that, in most studies available to date, this is precisely what already has been implemented. It is simply not reasonable to assume that a trial the trialists regularly instructed the chiropractors not to use the optimal treatments.

What does that mean for the interpretation of the existing trial evidence? It means, I think, that we should interpret it on face value. The clinical evidence for chiropractic treatment of most conditions fails to be convincingly positive. Chiropractors often counter that such negative findings fail to take into account that chiropractors use numerous different techniques. This argument is not valid because we must assume that in each trial the optimal techniques were administered.

In other words, the chiropractic attempt to have the cake and eat it has failed.

Posted in alternative medicine, bogus claims, chiropractic, clinical trial, commercial interests, conflict of interest, critical thinking, evidence, pseudo-science, spinal manipulation, study design | Tagged , , ,

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