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The Scientific Brief Against Chiropractic:
Lack of Scientific Support for Chiropractic Theory


Perturbation of the Distribution of Nervous Impulses

Chiropractors claim that subluxations, or partial displacements, of the vertebrae cause a perturbation of the distribution of nervous impulses to tissues and cells. Neurophysiologists have developed methods of recording the passage of impulses in nerves. Exceptionally sensitive apparatus is available to anyone wishing to use it. No scientific study has been published on the subject by a chiropractor. No chiropractor has ever defined, either quantitatively or qualitatively, what chiropractic means by perturbation of nervous impulses. It is their number, their amplitude, their frequency, the speed of their propagation, or their wave patterns which are affected? All of these qualities can be identified, recorded, and studied. It is no longer permissible to accept empirical statements. Proof should have preceded practical application. With the first point untenable, the rest crumbles. In pure scientific logic, the argument should not need to go farther than this.

Perturbation of Health and Determination of Illness

Chiropractors affirm that alterations in the distribution of nervous impulses to tissues and cells disturb the state of health and provoke the illnesses which they treat. By what experimental proof have they demonstrated a causative relationship between disturbances of nervous flow and the development of illnesses which they claim to cure? Here, again, absolutely none. The defectiveness of this link in this chain, added to the defectiveness of the first, increases, if that be possible, the fallacy of the whole.

It is indeed astonishing that there has been such a lack of effort, or of concern for scientific truth, especially if one considers the effort which has gone into selling the theory to the general public—when the world to be convinced was the scientific world. Let the theory gain acceptance in the world of scholars, and all the troubles of the chiropractor will vanish.

The Localization of Obstructions

Once again, chiropractors affirm that their technique enables them to detect and localize "obstructions which, in the mechanics of the human body, alter the distribution and physiologic action of nervous impulses." They explain that in most cases these anatomic modifications are barely beyond the limits of the physiologic state. It seems reasonable that generations of men over the past 68 years would have accumulated data and developed increasingly accurate and sensitive methods of measuring and recording.

It should also be pointed out that anyone, chiropractor or layman, can buy an x-ray machine, since no law restricts the sale or use of such apparatus. Chiropractors have therefore been at liberty to use x-ray pictures and fluoroscopy in their studies. It should also be pointed out that many challenging diseases occur in the region of the vertebral column, and anyone who regularly examines this region must undoubtedly become reasonably skilled in recognizing deviations from normal which might be shown in malpositions of vertebrae, localized pains, spasms, muscular atrophies, bone spurs, inflammatory nodules, limitations of movement, etc. Every such person should be able, by means of these observations, to pinpoint the site in the vertebral column of the pathological process.

Therefore, it seems necessary to cast grave doubt on the diagnostic reliability of chiropractic examinations, if one considers that in many more serious and more extensive diseases of the vertebral column it is necessary to inject into the spinal canal a substance opaque to x-rays (a technique which chiropractors do not use) so that a highly trained specialist may achieve an accurate diagnosis of the location of the pathologic process. Chiropractors, with lesser means, claim a greater precision of diagnosis. But here again, no scientific proof supports the claim.

The Use of X-rays by Chiropractors: "Spinography"

One might think that chiropractors taking x-ray pictures could derive as much information from them as anyone else, and thus achieve a radiologic diagnosis as precise and accurate as that of a medical radiologist. The chiropractor generally purchases x-ray apparatus and uses it in a way which is termed Spinography or radiography of the spine. However, chiropractors are prone to exceed the limits of their competence and to obtain x-ray images of many various organs—in the interpretation of which they are handicapped by their lack of the lengthy and specialized training which is indispensable for the proper evaluation and interpretation of structures as seen on film.

A casual survey reveals that only about ten percent of the chiropractors of the Province of Quebec do not have x-ray apparatus. The 90% who do may be divided into two groups: Approximately two thirds, or 60% of the total, use equipment adequate for authentic "Spinography." The remainder, about 30% of all chiropractors, use films of small dimension in apparatus of low intensity.

To the chiropractor, classical "Spinography" consists of a single picture, 36 inches high and 14 inches wide, of the entire vertebral column. This film is obtained with a very wide stream of radiation, which blankets almost the whole trunk of the body as it penetrates from the front to the film at the back. It is unusual for the chiropractor to take a side view, since the technical difficulties are great and the resulting film even less satisfactory than the antero-posterior view.

Lines, traced in radio-opaque ink on one of the fluorescent screens inside the cassette which contains the film, superimpose on the spinographic picture a white graph, usually in two-inch squares. In theory, the purpose of these squares is to help visualize disturbances in the longitudinal alignment of the vertebral column. This technical detail does not really provide a better demonstration of possible changes in vertebral structure, external or internal; on the contrary, it may interfere with visibility.

Large films of this type, taken in the antero-posterior view only, have very limited diagnostic value. Ever since the earliest days of medical radiology, physicians have known the necessity of two views at right angles to one another antero-posterior and lateral—because the antero-posterior view alone superimposes all structures, organs, and tissues in a two-dimensional picture. A view at right angles separates these superimposed elements and provides the third dimension. Thus the two views, front and side, are considered obligatory and are used systematically in medical radiology; even then, they are only an indispensable minimum and a first step to adequate x-ray evaluation. The side view in "Spinography," however, is quite rare. Even rarer in chiropractic are oblique views at a 45° angle, right and left—yet this is standard or even routine practice in medical radiology.

Over and above these techniques, where any uncertainty remains as to the existence, nature, or extent of a lesion, a whole series of special procedures is available to the medical radiologist for greater diagnostic precision—stereography, tomography, myelography, angiography, x-ray cinematography, etc, according to the case. These procedures, because of their complexity, often require the collaboration of various experts—orthopedists, neurologists, neurosurgeons, et al)—not only for their technical execution but also for the interpretation of the x-ray shadows and their correlation with the clinical findings.

These procedures were created and perfected to provide the closest possible approach to exact truth, and to allow the greatest possible precision in establishing the existence, the minute localization, and the veritable nature of any lesion.

It can be seen that these methods leave "Spinography" far behind, since, in addition to their rigorous technical requirements, they demand a truly profound knowledge of what is normal and what is not. In comparison with radiologic methods used by physicians in studying the vertebral column, "Spinography" in the chiropractic sense seems a very primitive technique, as likely to confuse as to inform, and able at best to provide gross information of limited reliability.

Even if pictures are taken at an adequate distance (six to eight feet) from x-ray tube to film, the curvatures (normal or abnormal) of the vertebral column cause some degree of superimposition of the shadows of adjacent vertebrae, the one on the other. The oblique direction of the x-rays in relation to these curvatures causes only certain vertebrae to be clearly distinguished from their neighbors above and below; and, indeed, focusing on a small area with careful aim is essential for the proper study of the outline and internal structure of each bone and of its relations to contiguous anatomical elements.

The difference in transparency between the air-filled thorax and the organ-filled abdomen, as well as differences in shape, thickness, and position between thoracic and lumbar vertebrae, cause a single film to show the thoracic vertebrae too darkly and the lumbar vertebrae too palely for proper diagnosis of their fine details of structure.

Radiologists accustomed to using large-scale films have devised compensatory screens to equalize the densities of thoracic and lumbar vertebrae in their pictures. Only rarely do chiropractors use these compensatory screens.

It is, therefore, because of the poor diagnostic quality of these oversize films that physicians reject their use for accurate evaluation of normal and abnormal conditions of the spine. Small sectional views are of much more diagnostic value than a single broad picture, since they provide a more accurate perspective of architectural relationships; they allow the photographic density to be adjusted for each region; and they require less scatter of x-rays, thereby giving a better quality of film and reducing the risk of genetic effects.

It may be estimated that about 30% of chiropractors use small films, but their reason for doing so is not the same as that of medical radiologists; rather, it is because their machines have insufficient power to take films at greater distance. They are therefore obliged to use longer exposure times, which impair the sharpness of detail.

It is common to hear chiropractors affirm that:

(a) They see "subluxations" in their x-rays which radiologists, neurologists, orthopedists, rheumatologists, physiatrists and others are unable to, or do not know how to see;

(b) The "subluxations" to which they refer are not the same as those defined in classical medical terms. (But words are words nonetheless, and to avoid the confusion of Babel it seems necessary to adhere to dictionary definitions and accepted usage.)

Chiropractic was officially born in 1895, the year in which Roentgen discovered x-rays. Although chiropractors originally claimed that their hands alone sufficed for the detection of the most minor defects of the spine, and for the relief of the supposed effects of the hypothetical pinching of spinal nerves, more and more of them have come to include the prestige of the x-ray machine in their arsenal of persuasion.

In all the years that they have been talking about them, chiropractors have never been able to furnish proof of these mysterious subluxations which they alone are able to see. They may convince their clients, but never—with or without "Spinography"—have they provided proof of their pretensions to men of science.

Furthermore, every physician knows that it suffices to have a patient bend slightly forward, or back, or to either side, to see evidences of movement—or, in other words, of displacements of articular surfaces one upon the other—in x-ray pictures. Such displacements are obviously phenomena of normal movement in the skeletal system, but when "stopped" in an x-ray photograph give an impression of permanence. In other words, the taker of the film may create, voluntarily or involuntarily, false "subluxations." A small error in the positioning of the patient's feet, for example, or in the alignment of his body at the instant of taking the picture, would be sufficient to give a false impression to an improperly trained person.

Long and repeated experience has taught orthopedists, radiologists, and indeed all physicians, that deviations of the spine, with displacements of articular surfaces of small or even large degree, and distortion of the intervertebral spaces where the discs are found, may result from a difference in the lengths of the two limbs, or from a tilt of the pelvis.

Abnormal curvatures of the spine, and malformations or malpositions of these elements of the skeleton, are often encountered on x-rays; they may be congenital, or due to disturbances of growth, or may even be sequelae of previous ailments (tuberculosis, poliomyelitis, cancer, injury, etc) . Even in these cases, it must be remembered that spinal disturbances often accompany lower static disturbances—in the pelvis, the legs, or the feet; these latter may be the fundamental problem, and may therefore require correction before the vertebral column can be evaluated and treated.

In summary, "Spinography" is much more apt to deceive chiropractors and their clients than to prove the presence or absence of nerve pinching or the nature of the supposed compression.

However, the precision of radiologic information does not seem to be the chief aim of the chiropractor. Let us take, for example, what a teacher of chiropractic instructs his students on the value of "Spinography." In a book entitled Modern X-Ray Practice and Chiropractic Spinography, P. A. Remier, a member of the staff of the Palmer College of Chiropractic in Davenport, Iowa, devotes a short chapter to 50 "Reasons why the chiropractor should spinograph every case." From this list, one can select at least 13 reasons which seem to have little to do with science:

  1. It promotes confidence.
  2. The analysis could not be complete or correct without the spinograph.
  3. It creates interest among patients.
  4. It procures business.
  5. It attracts a better class of patients.
  6. It adds prestige in your community.
  7. It builds a reliable reputation.
  8. It is an investment and not an expense.
  9. It provides good interest on your investment.
  10. Its income makes it possible to arrange a better service.
  11. It enables one to care for more patients daily.
  12. It helps to eliminate the so-called starvation period that many practitioners go through.
  13. It discloses the other fellow's mistakes.

It must be concluded that the manner in which chiropractors make use of x-rays demonstrates that they lack the necessary background in physics, biology, pathology, and clinical medicine to be able to use them effectively and safely on human beings. They may easily learn to operate an x-ray machine and to develop a film, but their deficiencies in basic knowledge, in equipment, and in technical training prevent them from turning out, consistently and safely, the documents necessary for the x-ray diagnosis of diseases or defects of the vertebral column, the craniospinal axis, or other organs or tissues.

The chiropractor's lack of medical background in radiology exposes him to letting serious illnesses pass unnoticed, or to giving unwarranted pathological significance to normal shadows. In other words, there is the Scylla of failing to see the disease which exists, and there is the Charybdis of thinking disease is present when actually it is not.

There is also a temptation to exhibit the x-ray picture in order to impress the patient, and to beguile him into accepting chiropractic manipulation.

Over and above all this is the undeniable fact that "Spinography," i.e., the single x-ray of the whole spine on which chiropractors rely, has never demonstrated the pinching of a nerve, since nerves are not visible on x-ray films and can only be demonstrated by the injection of liquid or gaseous contrast media.

A further fact: After the age of 40, perfectly normal vertebral columns become rapidly rarer and rarer. It is unusual after that age to see spines without x-ray evidence of aging, including thinning of the discs and thinning and slipping of articular surfaces—but this in no way proves that nerves are pinched. The longer a man lives, the more impressive the radiologic changes in his vertebral column become.

Readjustment of the Vertebrae

Chiropractors claim to relieve obstructions by readjusting the vertebrae through manipulation. Once the vertebral column has been realigned, they instruct the patient in methods of preventing a recurrence. There is no denying that the vertebral column can be influenced by mechanical means; some means, however, have been shown to be quite dangerous. The issue revolves around the fact that no chiropractor has ever produced an original study of scientific value on the subject. There is surely no lack of scolioses, kyphoses, and lordoses—frank deviations of the vertebral column—in the population. It is astonishing to find that in precisely these conditions which might be dramatically helped if the manipulative technique were valid, chiropractors neither evince a special interest nor claim a special success.

One is forced to conclude that chiropractic has no scientific foundation. Invented empirically, it has developed in the same unbroken empiricism, taking no account of even the most minimal requirements of scientific proof. The same is true of its methods of application; it remains an unproven hypothesis which should not be risked in the treatment of ill persons.

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