J Manipulative Physiol Ther 1985 (Sep); 8 (3): 163–174
NOTE: This article is reprinted exclusively at Chiro.Org with permission of National College of Chiropractic, and from the editor of JMPT and Chiropractic Technique, Dana Lawrence, D.C. Thanks, Dana!
A review of the literature reveals strong evidence for both the mechanical model of disease production (structural) and the neurobiological model (functional). Outdated models which attempt to describe a scientific basis for chiropractic theory are inadequate and indeed harmful to the progress and acceptance of chiropractic. Pragmatic or empirical arguments that "Chiropractic works and that's what counts" have served a useful purpose, but now must be augmented by extant research findings. The "paradigm shift" is on. Research investigators around the world are focusing on the multiple components of the chiropractic subluxation complex (CSC), a definitive, provable clinical entity. No longer can "informed" critics support the accusation that "chiropractic practice is based upon irrational, untenable premises." Only a few more pieces of the puzzle need to be fitted into place to produce the "big picture," i.e., the vertebral column is one of the most neglected vital organs in the human body--the sine qua non of the neurobiomechanical system--which influences every structure and function. Historically, its role in maintaining health has been almost totally ignored and for nearly a century chiropractors have battled against the consequences of this neglect. The scientific community is about to see that chiropractic is leading the way in discovering the "new world" in health care. Past, present and future research is discussed.
From the Full-Text Article:
Arguments rage inside and outside the chiropractic profession, the consequences of which seem to evoke a defensiveness not respected by any true professional. It has even been suggested by erudite chiropractors that the term subluxation should be deleted from chiropractic terminology because it is misleading and confusing. The hue and cry for evidence supporting a scientific basis for chiropractic theory has prompted this literature review. The essential components for the chiropractic
What's the big idea? "Chiropractic Postulates" are as fundamental to the chiropractic theory as "Koch's Postulates" are to the germ theory; simply stated: "The chiropractic subluxation complex (CSC) causes pathophysiology, which in turn causes pathology. Correction of the CSC restores normal physiological processes and the reversible pathology reverses." [1, 2]
Chiropractic has been practiced in Canada and the United States for almost all of this century, but so far it has hardly been studied at all. When 97,000 New Zealand citizens asked their government to compensate them for chiropractic care in its National Health Care Program, on the same basis as medical care, the New Zealand parliament decided that a study of chiropractic should be conducted befure making any decision. The medical profession has regarded chiropractic as unscientific and based upon fallacies. The report concluded that modern chiropractic is far from being an unscientific cult. If a particular type of therapy produces predictable clinical results on a variety of ailments, and does it consistently after other orthodox therapies failed, the scientific posture is to make every effort to find out why a particular therapy is etTective. Conversely, it would be very unscientific to disregard the clinical results, to Ignore the obvious facts and attempt to "sweep them under the rug" as though they didn't happen. On this basis it has been orthodox medicine, and particularly political medicine, which has maintained an "unscientific" posture on the subject of chiropractic.
It can be accurately said that chiropractic is a proven, safe and effective therapy which is still in search of scientific proof as to WHY it is effective. To obstruct proper research into why it is effective is unscientific, improper by any standard of comparison, and is not in the public interest. "Until chiropractic students are confronted with the necessity of utilizing the various kinds of knowledge they have acquired at college, little integration of knowledge will take place. The education most chiropractic students have received in the sciences has convinced them that scientific research will ultimately provide convincing explanations of why chiropractic works. 
Chiropractic leaders, despite their sincere intent to promote chiropractic science, have not recognized that advances in chiropractic science, as in any science, will only develop when the individual scientist is free to challenge authority and to conduct experimental studies according to his/her own vision of Palmer's insight. Keating and Meeker state that "Chiropractors are their own worse enemy" when fighting over their differing philosphies and theories. "Less well recognized, but perhaps more important, are dangers to chiropractic which derive from a number of pervasive and self-damaging assumptions. Exemplary are notions that 'chiropractic'works' and that 'chiropractic gets results.' Those assumptions may be true, but their acceptance on faith is a serious impediment to chiropractic development as a clinical art and science. The vacuity of the claim that 'chiropractic works' is a hazard to the profession. 
The first in-depth objective study of the chiropractic profession conducted in Canada revealed that far from being "cultish," chiropractors are usually working to extend their professional relationships with other health care occupations. Doctors Kelner, Hall, and Coulter have concluded that "what became clear during the research, and was far from apparent when it began, is that chiropractic has evolved a distinctive model of health care, has developed a distinctive model of health education, has found a broad measure of social acceptance, and appears to have a distinctive contribution to make to the overall system of health care." Vear observed, "There can be no doubt that chiropractic was born by chance and survived through tenacity. The explanations for clinical successes which followed this birth were sought in the neurology of the day." Until the past decade, neurology and its biological phenomena have dominated chiropractic thinking, almost to the exclusion of other more fundamental biomechanical principles. The European school of thought, somewhat because of the strong influence by scholarly Swiss chiropractors, has long supported the biomechanical concept for chiropractic. Most European investigators have departed from the traditional North American viewpoint, where neurological insult was the major premise used to defend chiropractic. "It seems reasonable to suppose that the traditional chiropractic "subluxation", the 'fixation-dysarthrosis' of the European school and the 'osteopathic lesion' are all part of the same process. The traditional and simple subluxation is indeed a complex neurobiomechanical entity which has yet to be fully understood. Under what circumstances the mechanical component becomes of greater significance than the neurological component has not been definitely determined; nor, for that matter, has the opposite. 
"It is my biased opinion that modern chiropractic was given birth to at the NINCDS conference held in Bethesda, Maryland in February 1975. On that occasion many of the world's foremost authorities in biomechanics, x-ray, physiology, statistics, chiropractic sciences, etc., met to identify the status of manipulative therapy in health care. After two days of intense presentation, the consensus of the participants was that the state-of-the-art of the scientific community could not provide scientific support for manipulative therapy: however, neither could the same scientific community disprove the value of manipulative therapy. Since that memorable occasion, there have been two additional NINCDS conferences dealing with the same subject with more and more scientific evidence supporting the viewpoint that there is a significant relationship between manipulative therapy and neurophysiological response. 
"The preceding report gave constructive criticisms and suggestions to both chiropractic and medicine and offered recommendations as to what role chiropractic must play within the National Health delivery systems. On one controversial area it was stated that patients treated chiropractically have ailments that can be recognized as musculoskeletal (type M) and organic (type 0). It is concluded that chiropractic can be effective with musculoskeletal conditions and a limited number of organic and/or visceral symptoms, and that the latter classification should be in concurrent medical care if practicable." 
During the past decade there has been an ever increasing reference to literature regarding the neurobiomcchanical mechanism in subluxation as a primary causative factor. McKenzie, Cyriax, Bourdillon, Maigne, and Menell are a few authorities within the organization of medicine who consistently practice manipulative therapy. In review of the current and past literature concerning manipulation and normalization of abnormal mechanics, and a variety of spinal pathologies, Brantingham has made a comprehensive search of the literature base in this field. 
Nilsson of Denmark, a D.C. and M.D. has stated, "I still hear my colleagues in chiropractic use 50 year old explanatory models when describing what they are trying to do by manipulation. The use of clearly outdated models is usually not a problem when we're dealing with laymen. But, when communicating with professionals from other biological sciences, it is no
good mumbling vaguely about 'restoring' some unspecified nerve supply, or possibly "improving blood supply" to an area". In an attempt to help his colleagues on this point, Dr. Nilsson set forth a model which was with the "type 0" (organic effects) produced by biomechanical dysfunctions. (Incidently, "osteopathic lesion" is now referred to as "somatic dysfunction").
It is my intention to review the literature regarding what might be termed_ncurobiomechanical dysfunction as a component of the chiropractic subluxation complex (CSC). Nilsson discusses two clinical entities, otitis media and bronchial asthma in describing his model. He says that "argument for treating bronchial asthma should be that a cervical fixation might cause facilitation, either by mechanically irritating the vagal ganglia in the upper cervical region, or as pointed out by Wyke, by decreasing mechanoreceptor input to the brain stem, resulting in decreased inhibition of reflex activity. By removing the facilitated vagal reflex activity we would increase the level of antigen stimulation necessary to set up a bronchoconstrictor reflex. This means that we, without influencing the allergic response itself, would be able to move the clinically manifest asthma down into the group of subclinical asthma, where no symptoms are present, unless there is a really massive allergen exposure." 
Thirty three years ago the Annals of Allergy Journal reported that scoliosis causes asthma by interfering with the sympathetic nervous system: the vagus being unopposed causes bronchiolar constriction. 
In order to illustrate the multicausal nature of disease the asthmatic model was selected. Bouhuys attributes two main factors to the pathogenesis of asthma: (1) increased sensitivity to the bronchoconstrictive effects of histamine. (2) posture. The effects of inhaled histamine were more pronounced when the patient was supine than in the upright 50 degrees head up position. 
Wilson discusses treatment of asthma in two parts. The patient's responsibility in relation to rest, upper thoracic fixation, diet, breathing exercises, elimination and avoidance of airborne irritants. The physician's responsibility entails the alignment of the upper thoracic vertebra and freeing of the 4th and 5th ribs on both sides. A technique is discussed to free the diaphragm, alignment of the occiput, cranial flexion and inhibition between the 4th and 5th thoracic transverse processes. 
The pathogenesis of asthma runs the gamut from the role of sex hormones to vasoreactivity. 
Parasympathetic predominance theory was measured by salivation, heart rates and pulmonary flow rates.  Abnormalities in the area of T3, T4 and T5 caused reduced sympathetic transmission in combination with a partial beta adrenergic block, abnormal epinephrine secretion, allergens and emotional upset.  Multiple thoracic rotations from T1 to T5, with extreme spasticity of paravertebral musculature throughout the spine, were noted.  The effect of pathophysiologic reflexes from other body parts on lung disorders, such as asthma, bronchitis, etc had to be considered.  A comparison of the effect of chiropractic treatment on respiratory function in patients with respiratory symptoms, and patients without was performed.  Respiratory distress of spinal origin, dorsal spine radiculitis.  "Bronchial asthma should not be considered a disease without prospects of cure or improvement." A thorough search for "interference zones" by the specialist is indicated. The employment of skin vaccines may be necessary.  Excessive airway irritability in asthma is due to multiple causes, i.e. minor genetic defects, excessive bronchospasm related to cholinergic sensitivity including reflex vagal effects. the effects of catecholamines on DNA synthesis. Adrenergic and cholinergic homeostasis modulating the antigenic histamine release, defects in the balance between AMP and GMP levels. 
In reference to the subluxation complex Korr states, "Through the network of interneurons, practically any afferent, segmentally related or not, may exert some influence. To all these sources of impulses must be added the suprasegmental sources -- all of the higher centers, from medulla to cerebral cortex -- which contribute to the descending spinal tracts. It is, indeed, most important to keep in mind that the efferent neurons do represent final common paths shared by a host of impulse sources, in addition to those associated with joint and supporting tissues. In this light, it is apparent that the articular derangement, the osteopathic lesion, or the chiropractic subluxation cannot be conceived as THE CAUSE of disease: rather it is one of many factors simultaneously operating (in fact, it is doubtful whether there is ever a single cause of any effect, whether there is ever an isolated etiological factor in any clinical entity. Each factor operates in the context of many factors and produces certain effects only in a certain combination of factors). The lesion/subluxation is a most important factor-- it is a sensitizing factor, a predisposing factor, a localizing factor, a channelling factor. The lesion/subluxation sensitizes a segment of the cord, lowers the barrier, facilitates, without necessarily producing symptoms, although evidence of its presence may be demonstrated by the osteopathic physician." 
Evidence for the multicausal nature of health and disease is so ubiquitous it is difficult to debate. Disease may be thought of in the light of the analogy of a loaded gun which will not fire unless the trigger is pulled. However, if the gun is not loaded, pulling the trigger will not cause firing. It takes a combination of factors. It seems that almost every disease is a case of a loaded gun and a trigger mechanism.
The word anecdote is derived from the Greek "anekdotus" and the French "an-ekdidonai" meaning NOT GIVEN OUT -- literally UNPUBLISHED items, narratives of secret or private details of history. "Usually an event of curious interest told without malice and with an intent to amuse or please, often biographical and characteristic of some notable person, especially of his/her likeable foibles."
When pole vaulter Billy Olson, former holder of the indoor world record, hurt badly enough to want to drop out of the '82 Vitalis/U.S. Olympic Invitational Meet, director Ray Lumpp personally enscorted him to the chiropractor for help. Olson's back and legs were in such bad shape, the chiropractor's twisting and cranking so rough, Olson thought he'd never move again. Yet, on his next jump he cleared the bar and went back to the chiropractor for more. Then on his next attempt he set his first national record, with a height of 18' 6 1/2"". This story qualifies as an anecdote.
It is one of many thousands of anecdotes told during the past 90 years and is largely responsible for passing. on "secret or private details of history." It is an event told to please. It is biographical and characteristic of some notable person that is an especially likeable foible. No doubt these anecdotes will continue to be told by enthusiastic supporters of chiropractic. While this indicates that "chiropractic works," such pragmatics are not enough to promote the growth of chiropractic science. No matter how persuasive, the proof of efficacy does not come from anecdotes, no matter how well or how truly reported. This is not to say that anecdotes are wrong or of no value. The father of Eclectic psychiatry, Adolph Meyer, innovated the use of chronology in diagnosis, which chronicled events in the patient's life history to conelate with the possible emotional traumas. Today the use of a simple diary is common practice in scientific reporting. Darwin carefully made notes and observed natural phenomena recording similarities and differences. Gregor Mendel did the same in observing genetics. Science is defined as "a branch of study which is concerned with observation and classification of factors, especially with the establishment (and strictly the quantification) of verifiable general laws chiefly by induction and hypothesis." Art on the other hand, is knowledge made efficient by skill. In chiropractic we have certainly used art (as well as philosphy) to great benefit; however, the scientific community has not accepted chiropractic theory and hypothesis. Science has historically moved away from anecdotes, homilies and metaphors toward factual documentation of measured data, published according to standard protocol.
Kelner points to the differences between chiropractic and medical education and states that medicine has depended upon science and that this has permeated medical education. Further, that it serves to "blunt the capacity of medical students to consider the human factor in health care. There is a tendency to cultivate an objective detachment toward their patients. Even teaching rounds often become a matter of sitting around a table studying a patient's charts rather than visiting at the bedsides of the sick." He also states, "Chiropractic students are actively engaged to develop personalities with their patients. Their instructors regarded this as an essential aspect of successful chiropractic therapy."  Some people seem to believe that love of people and love of science are incompatible.
The inductive, rational processes of scientific thinking require a publication of acceptable research protocols. If one refuses to follow the rules of the game, then WHATEVER YOU SAY OR DO HAS NOT BEEN SAID OR DONE and will not be documented in the scientific literature. In science, therefore, if your work is not acceptable for publication, WHATEVER WORK YOU DO, HAS NOT HAPPENED.
Consider the following scientific literature base supporting the premises and theories of the chiropractic subluxation complex (CSE). The five components of the CSC are: kinesiopathology, neuropathophysiology, myopathology, histopathology and biochemical. The recent literature review by Brantingham  references chiropractic, osteopathic and medical textbooks and research of the kinesiopathological cQmponent. The overwhelming volume of evidence supporting segmental vertebral hypomobility (SVH) or "fixation" systematically documents the malfunction of the vertebral motion units. It leads the way toward more definitive research regarding the nature of the functional block to free movement, as well as how manipulation and normalization of abnormal mechanics, hypomobility and compensatory hypermobility may decrease degenerative joint disease and improve the long term prognosis for spinal health. What is not so well documented are the other components of the CSC. The remainder of this paper will deal primarily with the neuropathophysiological component, with some references to the myopathology, histopathology and biochemical components. The latter three factors, however, must be addressed in future publications. Literally hundreds of research papers dealing with the neurological component are readily available for study and integration into the CSC hypothesis.
Speransky found that experimental damage to the spinal cord or nerve roots results in pathological changes of pulmonary tissue and found successful treatment of pneumonia by intracutaneous injections of novocaine at C1 to T5 posterior root dermatomes through the neurotrophic effect. The treatment must be directed not only at the diseased lung, but also at
the associated nervous disturbance.  Suh found that "aberrant neurological activity resulting from mechanical disorders of the spine is due to compression of i spinal nerves at the intervertebral foramina. 
Maintenance of axons in peripheral nerves depends on lhe continual delivery of fresh cytoplasm elaborated in the cell bodies. The cytoplasm, apparently propelled in a peristaltic manner by the axon, is continually moved out of the cell body and along the entire length of the axon and all of its branches, supplyiog them with components that are used in axonal maintenance, an activity that is not supplied by other sources, such as blood or other extracellular fluids. The total volume of neuroplasm may be replaced several times each day. [83, 89, 90, 94] Nerve root compression can elicit radicular symptoms. Axons may receive amino acids, proteins and RNA precursors from sources other than their cell bodies through the axonal sheath.
Haldeman observed "compression of a nerve interferes with the impulse transmission, causing muscle paralysis, vasodilation and trophic ulcers. Nerve interference at a single vertebral level does not impair visceral organ function due to the multiple spinal level ncne origins.  Parkins studied the blocking effects of pressure on the visceral motor and the somatic motor functions of the facial nerve.  The neurophysiology of vertebrogenic pain has been investigated by other authors. [27, 39] Compression and facilitation effects on conduction velocity was measured in nerve entrapment, such as the lateral femoral cutaneous nerve and disturbances at the IVF and these two types of neuropathies differentiated. [45, 43, 95, 24, 23, 8]
Korr has studied axonal delivery of neuroplasmic components and produced definitive research findings. Labeled isotopes were applied to the hypoglossal nuclei in rabbits, which traveled down the hypoglossal nerves and after several days began entering only the muscles cells of the tongue. Prevention of axonal delivery of one side caused unilateral labeling of the tongue. He concluded that axonal conveyance of neuroplasmic components to peripheral cells may provide a basis for trophic influences of neurons on other cells.  Korr also found lesion segments within the spinal cord behave as if they were in a state of facilitation, resulting in aberrant motor and sensory neural responses, as well as detectable palpatory signs.  He observed neurochemical and neurotrophic consequences of nerve deformation. The affected segments are maintained in a hyperirritable state. This condition can be ameliorated by manipulation.  He reports four distinct periods of protein delivery in axonal transport and certain amphibia and mammals can regenerate entire limbs. It is believed that nerves tell the muscle which actions to perform. [89, 90] Chronic hyperactivity of sympathetic nerves is detrimental to the tissues and organs which they innervate and may be related to musculoskeletal dysfunction in the spinal area. The sympathetics influence skeletal muscle, peripheral sensory mechanisms, central nervous system, collateral circulation, bone growth, adipose tissue, reticuloendothial system and endocrine system. [79-83]
Facilitation is referred to as that state in which nervous impulses can be elicited with minimal amounts of stimulation. This leads to exaggerated responses or, as facilitation of the motor pathways leads to sustained muscular tensions, postural asymmetries and limited and painful motions. There is elaboration on the autonomic component in relation to sympatheticotonia and visceral response. The osteopathic lesion and chiropractic subluxation represents a facilitated segment of the spinal cord maintained by endogenous impulses entering the corresponding dorsal root. Therefore, all structures receiving efferents from the segment are potentially exposed to excessive excitation or inhibition. Proprioceptors in muscles are the most important source of afferent impulses which result in changes in the cord associated with the lesion/subluxation. Clinical evidence of the lesion/subluxation includes hyperalgesia, autonomic asymmetry, restricted joint movement and abnormal texture or tone in soft tissues. Pathophysiological evidence includes muscle contraction in abnormal tissue, abnormal action potentials measured by electrode needle insertion, low reflex thresholds, microscopic tissue abnormalities, and facilitation in the motoneuron pools. The relationship between the lesion/subluxation and visceral and higher center functions is demonstrated. [86, 88, 91]
Many examples have been given of sympathetic nervous system inf1uences on enzyme activity, mitosis, synthesis of nucleoproteins, regulation of RNA and DNA, growth and development, endocrine organs, reticuloendothial system, development of colateral circulation, activity on bone Cells, in fact, on every function and tissue in the body. Both afferent and efferent pathways have been studied in relation to viscerosomatic and somatovisceral reflexes. Many authors have investigated various neuropathways of reflex symptoms that travel from internal organs to appropriate cutaneous areas via the spinal cord. Malliani found that single sympathetic fibers consistently responded to rises in arterial pressure, either by decreasing or increasing its arterial firing rate. They were also fibers which decreased the firing rate. Both responses, increases or decreases in firing rate, were reflex in nature, for they were abolished by interrupling afferent fibers running through the stellate ganglion. Schwartz found that certain reflex impulses are mediated solely through the stellate ganglion , requiring no central connections of the ganglion. It is evident from the findings that there are some sensory fibers which belong intrinsically to the autonomic nervous system. 
Sato studied somatosympathetic reflexes and their central reflex pathways. He states, "This knowledge of cutaneo-visceral reflexes will be clinically useful in offering the visceral functions of humans."  Kurtz found that localized
stimulation of the skin produced circulatory changes in the GI tract. Localized skin warming and application of vacuum cups produced vasodilation in the cutaneous area and GI tract whereas, cooling produced vasoconstriction."  Lewit studied 79 adolescents with peptic ulcers. The main emphasis was on changes in the function of the spinal column, in particular movement restriction, and on reflex changes in the skin and muscles. The results are statistically highly significant and are strong evidence that there does exist a characteristic spinal pattern in peptic uleer.  Sato studied anesthetized animals with central neuraxis intact, found segmental cutaneous stimulation produces reflex changes in heart rate by changing tonic activity of the sympathetic cardiac nerve. Stimulation of abdominal skin produced a reflex sympathetic change in gastroduodenal tonus. Stimulation of perineal skin caused either a reflex increase in vesical tonus through a reflex increase in pelvic discharge activity or a reflex inhibition of the micturation contraction of the bladder through a reflex inhibition of pelvic nerve activity. [61, 62, 68-70, 77]
Somatovisceral and viscerosomatic reflexes are classified in three categories: spinal, interspinal and supraspinal. The galvanic skin reflex has a simple sympathetic reflex under nervous control alone, and was used for studying central inhibition of autonomic reflexes. Electric stimulation of the bulbar ventromedial reticular formation, a cerebellar anterior lobe, the caudate nucleus and the frontal cerebral cortex each inhibits the galvanic skin reflex. These suprasegmental (brain) structures were studied for stimulus threshold and the degree of inhibitory effect. 
It must be kept in mind that any segmentally related structure which sends afferents to the spinal cord may be an important participant in the establishment or maintenance of the subluxation complex. In fact through the network of inner neurons, practically any afferent, segmentally related or not, may exert some influence. To all these sources of impulses must be added the suprasegmental sources, all the higher centers, from medulla to cerebral cortex -- which contribute to the descending spinal tracts. Many of these arc continuous and highly variable sources of impulses. They exert their influence -- excitatory or inhibitory -- upon efferent neurons at every level of the spinal cord.  The response of sympathetic neurons to various afferent nerves have been observed by many investigators. Coote found certain muscle afferents have a chemoreceptor function and are responsible for mediation of pressor reflex during muscle exercises. Increased coronary flow which increased coronary arterial pressure evoked a reflex increase in sympathetic discharge in the white ramus of the third thoracic spinal nerve and the inferior cardiac nerve. Some receptors were excited by increased coronary arterial pressure alone, others by coronarv sinus occlusion, and still others by myocardial ischemia. Some receptors were excited by all three stimuli. [52, 53, 55, 56]
Sato concluded that somatic afferent volleys have a twofold action on the sympathetic nervous system, a more generalized action via the supraspinal sympathetic reflex centers and a more circumscribed action on the preganglionic neurons at the segmental level.  Kirchner caused electrical stimulation of the medullary depressor area and caused inhibition of the spinal and supraspinal reflex discharges. It was concluded that spinal reflex pathways received some inhibitory descending influences from the medulla oblongata.  Kirchner also suggests that the inhibitory coupling between supraspinal levels and sympathetic preganglionic units is mediated, at least in part, by propriospinal neuronal systems which survive after chronic spinal section. The results also suggest that continuous descending tracts exist, and that both continuous propriospinal descending tracts may be converging on to' some common neural element.
Considerable data demonstrating both specificity and convergence which regulate a cardiovascular and other visceral sympathetic spinal reflexes show recordings from numerous levels of sympathetic preganglionic fibers. [14, 37, 48, 49] Reflex volleys in sympathetic nerves can be elicited by electrical stimulation of somatic afferents. The reflex response was shown to be dependent on an intact pathway through the medulla oblongata. This study provides evidence that the active inhibitory mechanism is associated with supraspinalstructures.  Working with psychological stressors, Barrell found that the threat of a very painful electric shock was related to some visceral and somatic responses. The experimental subjects either attempted to confront or to avoid this stressor. Those who confronted the threat had a higher trapezius contraction response on the electromyograph (EMG). Those who avoided the threat had higher heart rates. The results indicated that these specific stress orientations expressed themselves in the body through specific physiological response profiles. In other words, some subjects were muscle reactors and others were heart reactors. These experiments show the supraspinal intluence on lower spinal centers.  Many research protocols demonstrate the visceral pain patterns caused by a flooding of the internuncial pool in the spinal cord with afferent and visceral impulses stimulating the anterior horn cells, causing muscle spasm of associated levels. Miller demonstrated that the same symptom complex occurs after coronary occlusion as it does in shoulder-hand syndrome.  Davis studied 43 patients complaining of attacks of substernal or precordial pain of nerve root origin, the symptomatology simulating coronary artery disease. 
Prevalent among doctors of chiropractic is the mechanical model of disease production. Structural abnormality, the relation of structure to function, is discussed in terms of the neurological component. The precise mechanism however, has remained obscure and often naively reductionistic. Indeed, while most chiropractors have gone beyond the notion that subluxation cuts off the nerve supply, similar to stepping on a water hose, present day explanations are not enhanced by research information that is readily available. These outdated models seldom include biochemical or histological components. It should be remembered that mechanical disorders of the spine invariably show concommitant changes in biochemistry and histology. The trophic influences of the nervous system and their biochemical and histological components have been studied by numerous investigators. The role of neural impulses in the regulation of rates of synthesis and concentration of enzyme and isoenzyme proteins in the skeletal muscles have revealed muscular dystrophies of neurogenic origin and primary myopathies due to neurotrophic effects. 
It is particularly interesting that chiropractors seldom explain to patients the real reason for multiple visits in the manipulation/adjustment of chronic vertcbral fixatons. Donatelli presented a basic review of the biochemical and histological effects of immobilization on periarticular connective tissue. Biochemical changes within the matrix of periarticular structures result from lack of movement. Movement is essential for the prevention of contracture and adhesion formation within the joint. Movement is also necessary for proper orientation of collagen fibers as they develop. The matrix changes reported with immobilization are relatively uniform in ligament, capsule, tendon and fascia. These changes involve extracellular water loss and glycoaminoglycans (GAG) depletion along with collagen cross linking changes. The most significant change is a reduction in GAG content within the matrix. Akeson's studies report a 40 percent decrease in hyaluronic acid and 30 percent decrease in chondroitin with little or no change in total collagen content. In addition, within the joint space and its recesses, there is excessive connective tissue deposition in the form of fatty fibers infiltrate, which later matures to form scar tissue, adhering to intra-articular surfaces, further restricting motion. 
It seems rational that the chiropractor, in presenting a report of findings to a patient with grade III vertebral fixations, either ligamentous or articular, would include an explanation of these biochemical and histological changes. The reason that 50 or 60 visits are necessary over a period of many months is due fo the adventitious fibrils, fibrosis, scar tissue, etc., would seem more rational than trying to explain the necessity of replacing a "bone out of place" perhaps 60 times or more.
Korr concludes that, "the osteopathic lesion (or chiropractic subluxation) represents a facilitated segment of the spinal cord, maintained in that state by impulses of endogenous origin, entering the corresponding dorsal root. All structures, receiving efferent nerve fibers from that segment are, therefore, potentially exposed to excessive excitation or excessive inhibition." A subluxation is associated with a segment of the spinal cord which is hyper-excitable to all impulses which reach it, and that the hyper-excitability may extend to any neurons, having their cell bodies in that segment. Given an articular disturbance, which through the mechanisms discussed, determines the location of the low threshold segments, then the severity of the subluxation, the associated pathology and the response to treatment will be to a great extent, determined by how much additional neuron pressure from other sources is chronically present. Such pressure may present upon all the segments, but because of the lowered synaptic barriers, the effects will be exaggerated at the subluxated segment. Thus the subluxation not only focuses, it magnifies. This superimposed excitation may come from any of the sources previously enumerated and others which converge upon the anterior horn cells and the other efferent neurons: the cortex, the basal ganglia, cerebellum, the vestibular nuclei, bulbar center, the eyes or any steady, tonic source of impulses.
Important as is the structural factor, treatment of it alone is not to treat the patient as a whole. The fact that psychic stress, emotional imbalance, etc are reflected in motor activity and a generally lowered reflex threshold can be seen in the familiar illustration of an exaggerated knee jerk of a tense individual. Such supraspinal influences impinge directly or through inner neurons on the anterior horn cells and increase their excitabiility and activity. In a segment already sensitized by subiuxation, the effects will be especially severe. Just as important is the fact that descending impulses may exacerbate the subluxation and produce increased effect on segmentally related organs and may cause or intensify pain and make the subluxation less responsive to manipulative therapy. To treat the structural source of bombardment is only to half treat and to neglect a most important part of the subluxation. Korr observes that such clinical disturbances appear to be aberrant versions of local and regional feed-back mechanisms. These abnormal reflexes become chronic and self-sustaining and often impair healing and recovery. Also, abnormal somatosympathetic reflexes produce dysfunctional segmental coupling, resulting in segmental relationships as seen in referred pain. Effective manipulative therapy improves afferent input so that sympathetic hyperaclivity is alleviated. [96, 97]
May considers the usefulness of spinal manipulation in the treatment of joint subluxation. Cervical spondylosisis treated by manipulation resulted in the alleviation of a wide range of symptoms.  Maigne observed irritation of the sympathetic fibers in the cervical spine has many clinical ramifications: "Headache, vestibular troubles, auditory troubles, visual disturbances, pharyngolaryngeal disturbances, vasomotor, secretional, and psychic disturbances may result. An examination of the cervical spine is essential. Manipulation of the neck chieves excellent results in many of these conditions. 
Brunarski discusses functional considerations of spinal manipulative therapy.  Neurotherapy is a term used by Gross to describe every type of treatment which acts through the autonomic nervous system and influences pathological functional disturbances.  Four types of refex changes in vertebrogenic disorders can be differentiated: (1) Vertebrogenic and reflex changes imitating internal disease. (2) Reflex changes and vertebrogenic lesionws develop during the acute stage of internal disease, presumably as a consequence of pain stimulation from the diseased organs and therefore secondary to muscular spasm, causing abnormal mobility in the corresponding segment and leading to blocking. (3) Reflex changes during the chronic stage of the disease. It is at this stage that manipulation and reflex therapy are most effective. If, however, reflex changes recur in spite of therapy, this points to recurrence of the underlying visceral disease. (4) Internal disease caused by vertebrogenic lesions. 
Harakal states, "Treatment of the somatic dysfunction (subluxation) can be accomplished by many manipulative procedures directed to the affected tissues. Such somatic treatment results in normalization of the related neural, vascular and lymphatic components that favor return to more normal function and well-being.  Space does not permit further references to the research literature on the therapeutic approach to the CSC.
Halderman has presented 4 areas of research which must be considered to satisfy the basic criteria on which the proposed neurobiological mechanism of manipulative therapy rest.  Korr urges of his profession, that a "concerted effort must be made by the osteopathic profession to define its objectives for research, procure the necessary funding, and acquire society's support.  Johnston discussing segmental behavior during motion, "A palpatory study of somatic relations is concerned with removing the idea of a subluxation (osteopathic lesion) from the confinement of the joint and placing
it into the area of a larger organizational relationship.  Haldeman discusses the importance of neurophyslological research into the principles of spinal manipulation. He points out that most spinal adjustments are performed to relieve pain. Some studies suggest that nerve root pressure does not cause pain. "Visceral changes occur when there is pressure on both the sensory and motor nerves." Somatovisceral reflex physiology and its importance is discussed.  Haldeman investigated the history of neurology and that of the 'evolution of chiropractic theory to see whether or not the theory, as presented by doctors of chiropractic, was compatible with experimental evidence in neurology, and try to determine the basis of conflict between chiropractic and neurological science. 
Suh found aberrant neural activity resulted from mechanical disorders of the spine, due to compression at the IVF. Two changes in the nerve were anoxia and mechanical deformation sufficient to achieve complete conduction blockage.  Some of the problems in research methodology of proving efficacy of manipulation, according to Phillips, are the placebo, Hawthorne, and Pygmalion effects.  Anderson shows experiments for hormone regulation, protein nutrition through neurons and impulses directing cell functions. Recommendations are outlined for implementing future researcb expanding the scientific basis of chiropractic.  Subluxation may result in inflammatory processes, edema and compression at the IVF. After a few weeks the compression of the nerve trunk leads to degeneration of the nerve fibers. Higley compares this research with those investigators outside the chiropractic ·profession.  Keane outlined the research that is being done in chiropractic by prominent researchers.  Droz found from statistical evaluation that 60 percent of recurrent sciatica occurred without apparent external cause.  In a study of 456 selected patients, Doran found "no strong reasson for recommending manipulation over physiotherapy or corset. "  The neurobiologic mechanism in manipulative therapy was reported on by Jenness in 1978.  The five areas most important according to the Delphi study for future research and the role of FCER was reported by Phillips.  Haldeman discusses the consequences resulting from a lack of research in establishing the efficacy of spinal manipulation.  Haldeman, in another study, reports 6 possible explanations for noting chiropractic therapeutic success in a particular illness. He states that research of spinal manipuiation is absolutely essential if chiropractic is to survice, and that such controlled research is both possible and desirable. The need for a computer simulation model of the spine to study analytically the nature of subluxation was pointed out by Suh. The deficiency of numerical or analytical factual_ relationships can be greatly aided by a computer technology.  Brennan proposes a research design for controlled clinical trials for evaluating chiropractic manipulation.  In 1952, a paper by Adelman and Weiant enthusiastically reported that subluxations causing irritation of posterior root fibres created skin hyperemia shown on infra-red photography, which disappeared after manipulation.  In 1970, Haldeman reported a similar finding on 50 subjects using a "synchrotherme" instrument.  Hildebrandt reviews chiropractic research by using postural roentgenology as a commendable achievement and benefit to the health care professions and public at large.  The use of a personality appraisal test, the Minnesota multiphasic Personality Inventory was discussed by Josefowitz in predicting success of treatment along with differentiation of functional versus organic causes of pain.  The NINCDS conference was reported in 1975 by Tilley. 
Chiropractic is evolving from its empirical pragmatic and anecdoted base of "use validity" to its present scientific literature base. Worldwide research papers from multidisciplines are contributing to the scientific support of chiropractic theory. The "chiropractic subluxation complex" may now be defined and described as a definitive clinical entity having broad and deep implications concerning pathogenisis. Its corrolary, the absence of subluxation complex, also serves as a model
for health and homeostasis by virtue of a normal neurobiomechanical system the sine qua non of which is the vertebral column; undoubtedly the most neglected vital organ in the human body.
Proof of efficacy of the chiropractic therapeutic approach requires validation of the assumption that adjustive procedures affect the kinesio component of a subluxation directly and other components indirectly and that the neurological component is affected in a normative or homeostatic direction. This in turn promotes a healing response at segmental, intersegmental and suprasegmental levels of the neuraxis, cerebrospinal and autonomic nervous systems. Key constituents as discussed in this paper involved integration of the nervous system, the endocrine system, and the internal milieu.  Asthma was the disease model selected to illustrate all the components and their pathophysiological role in the chiropractic subluxation complex. This model clearly shows the multicausal nature of disease process. Almost without exception all disease can be seen as multicausal and holistic (rather an "un-holistic" and fragmented expression).
As physicians, doctors of chiropractic are required to sort out primary from compensatory abnormalities. The detection of deviant or abnormal findings is not necessarily clinically significant. "Pathological curiosity" can be a diagnostic trap which confounds the issue with irrelevant data. This kind of preoccupation not only leads the doctor astray, it can produce iatrogenic disease, both physical and emotional. "First. do no harm," is the physician's oath. What the doctor SAYS may be as crucial in the healing process as what he/she DOES. This applies to the sins "of omission and of comission."
Diagnostic and therapeutic decisions based on valid data will prove to be the most efficacious. Therapy employed in daily practice is not a question of right or wrong, but whether it is appropriate. The right treatment for the right patient at the right time, by the right doctor is probably appropriate and efficacious. The doctor needs to use all of his/her brain -- left brain and right brain -- to process the relevant data. The computer axiom GIGO, "garbage in, garbage out" applies. Therefore. accuracy of the doctors' data base is prerequisite to accurate decision making -- the stuff of which belief systems are made. Unfortunately, too many beliefs are made up from "garbage in, garbage out." Beliefs can change by admItting new data and going beyond personal bias. The world is no longer believed to be flat. The "flat world" paradigm has been repbced and mankind now treats the world diiTerently. Mankind will treat disease differently when there is a shift to the new health paradigm. Obviously, there will notbe a change until the belief system permits it.
Chiropractic subluxation complex is so comprehensive and holistic (the sum is greater than all its parts) that conceptually, philosophically, and scientifically it is a big enough structure to house the new paradigm.
What's the big idea? -- the chiropractic subluxation complex. Its five major components were discussed and bibliographed with particular emphasis on the neurological and biomechanical components.
NOTE: These references are scanned as graphic (JPG) files, and are large files. The ORC importing (as a text file) generated so many errors, that I had no choice but to scan them as graphics.
References 1 to 47
References 47 to 94
References 94 to 122
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