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Spinal Curvature Corrections Research Physiology and Clinical Considerations

CONCEPT OF HISTODYNAMIC STRESS If the reader can grasp the significance of Breig's following statement he/she will appreciate and comprehend "the europhysiology - pathophysiology cycle of postural change." "In flexion of the cervical spine, two or more cervical vertebrae are abnormally angulated as a result of, for instance, osteochondritis or disc degeneration, the dura will be overstretched along the posterior longitudinal iigament. Such an effect may also arise from a protrusion into the canal from its anterior aspect, which raises the dura. Conversely, relaxation of the pons-cord tract is due to slackening of its suspensory apparatus along the whole canal. This means the greater the straightening of the pons-cord tract fibers, the more marked the relaxation and shorter the range of displacement, until there is ultimately just a local effect. This means that the risk of histodynamic stress is eliminated. To summarize, when the distance between two adjoining vertebrae is shortened the dura, nerve roots, dentate ligaments and spinal cord in the associated sections are relaxed; this is accompanied by a slight reduction in the tension of more remote structures." There is now a common denominator to neurological distress and that is the tension that can be built 'up in the pons - cord tract by the process that reduced its elasticity, such as scar formation, fibrotic adhesions and postural distortions produced by subluxations.,The spinal cord doesn't have to be grossly compromised by tumors or disc herniation or fractures to have serious effects. The common denominator of nerve root and spinal cord tension can be seen in the fact that identical symptoms can be; produced by different etiological factors. "That pathologic axial stretching of the hind brain, cord and nerves in both the posterior fossa and the spinal canal can produce neurologic symptoms simultaneously in widely separated" parts of the body is obviously of major significance in diagnostics. It is possible that some neurologic phenomena hitherto regarded as independent may now be found to have a common origin. An explanation is also provided for the fact that similar symptoms are often ultimately elicited by heterogenous processes such as basilar impression, superficial arachnitis or sclerotic changes within the nerve tissues, exostosis, spondylosis, and tumors." Of some clinical importance is the finding that the cord ,and its nerves slacken in dorsal extension. The greatest effect of the shortening and consequent slackening of the cord is found in dorsal extension of the cervical spine. In this position the part of the cord and its nerVes can then be moved quite freely. It is known from experience that in many cases of, for instance, laid under the neck so that the head is flexed backwards.In this position the intervertebral foramina are narrow. Hitherto it has been thought that the roots are then compressed by spondylitic protrusions. It was found, however, on fresh cadavers that the slackened nerve roots can pass over large bony protrusions without being stretched. The repeated compression and extension of the nerve tissue can assume a pathologic significance as soon as its' plasticity and elasticity are reduced by such "processes as inflammation, atrophy, scarring and enoplasm, and this fact must be "taken into account in the field of neuropathology: for it may throw new light on the causation of certain types of organic nervous diseases. Internal deformation of the tissue cannot be ruled out as a factor in any disease of the nervous system even in inflammatory and degenerative conditions of the hind brain, cord, and associated nerves, and in some cases it will be of primary pathogenic significance. That mechanical phenomena can be the cause of some nervous diseases is indisputable. SOFT TISSUE DEFORMATION Rheology - The study of soft tissue deformation. In the effort to remodel cervical curve, (or the entire spine) there has been small effort, beyond a passing reference to ligamentous creep, to understand the actual mechanism that controls tissue deformation. C!B.P. is the leading edge in posture correction in the chiropractic field and we must know how the postural change of soft tissue structures occurs. "Until recently, biomechanics has dealt mainly with interactions between anatomical parts; contact forces in joints and relative displacements of components. Since the need for information about how single components deform under given loads is increasing, it would obviously be desirable to extend the oncepts of biomechanics to include the continuum mechanical analysis. -- Classical continuum mechanics consists of three types: analysis of strain, analysis of stress, and material analysis. These three kinds of analysis give rise to three sets of equations: equations of compatibility, equations of equilibrium (or motion) and constitutive (material) equations:. The first two sets of equations are independent of the material involved, and could be adopted unaltered; only the material analysis is specific in biomechanics. Material analysis in general is commonly called rheology." We have studied the interrelationship of parts, namely bones and joints, but have neglected or at least not given the same importance to how soft tissue conforms to subluxation degeneration, postural distortion and most significantly, their correction and maintenance. STRESS - STRAIN RELATIONSHIPS STRESS: "The external forces are in balance, so the object is stationary, but reaction forces within the material are developed to maintain equilibrium by limited deformation. These internal forces resisting deformation are called stress. The external forces are in balance, that is, upward push of the floor equals the body weight, but an internal reactive force system also exists in balance. As the bone defers, there are forces of molecular cohesion holding it together and resisting the applied load. These forces, developed within an object, resist loading and deformation and are known as stress." STRAIN: The external forces generated by gravity or any other outside force applied to a body will change the shape of that body either temporarily or permanently. The . effects may range from gross to infinitely small. Change of shape is called deformation and represent a change in dimensions. Strain is a technical term used to express deformation. Strain is a measure of how much a body is deformed by a stress. It is the Iongation (if the strain is tension strain) divided by the original length (change in length/original length). "A strain occurs whenever a load, no matter how small, is applied to a material object, no matter how strong. The strain may be obvious, or special apparatus may be needed to detect it, as, would be the case of detecting the strain caused by a mouse walking over a steel beam. But the strain always occurs." STRESS VS. STRAIN When stresses and strains in structures are studied in detail, relationships appear between them which are important in understanding the behavior of structural materials. In a structure carrying a load, the stress divided by the elastic strain caused by the load is called Young's Modulus. It is a measure of the stiffness of the material, Le., its resistance to being strained by the load. The larger the modulus, the stiffer the material. "Stiffness refers to the relationships between stress and strain in a material. The degree of stress is associated with a given strain indicates resistance to deformation. It is the ratio of stress to strain. When we consider subluxation complexes that distort postural balance and create nerve irritation, we should include in that consideration the analysis of stress and strain. For the correction of postural dysfunction and subluxation, soft tissue stress and strain must be included in the treatment plan. Stress and strain relationships can be an explanation of some of the stiff cases that frustrate. the practitioner. Postural distortions are strains that put asymmetrical loads onto bones and soft tissue structures. The resistance in the body to those unbalanced strains creates stresses that are larger at the area of greatest strain. This imbalance will set up greater unit stresses in those areas of increased strain that will deform the soft tissue components at a. higher more rapid rate and inhibit the restorative capabilities of ligaments, tendons, and fascia in that high strain area. Removing postural distortions and subluxations is a conjunctive effort of osseous replacement and rebalancing of soft tissues stress. In Chiropractic, treatment has historically been to move' osseous segments. Soft tissue resistance to that movement has been ignored or neglected past the realm of clinical "feel". In the spectrum of Chiropractic that ranges from physical therapy to nutrition and includes hard and soft adjusting procedures, I do not know of one system of analysis, exception C.B.P., that incorporates osseous realignment and soft tissue rehabilitation with aJ common goal in mind; namely, subluxation and postural correction.J.I< POSTURAL DISTORTION IS A$YMMETRICAI STRAiN: It is obvious that gravitational loads effect the spine. These loads effect the spine in either one of two capacities. One is beneficial and the other is detrimental. Beneficial loads are generated when the spine is in a normal, optimal position. The ,oad is then symmetrical and generates balanced stresses into the soft tissue surrounding the spine. These balanced forces enhance the spine's ability to maintain its normal position,. In s,ubluxation configurations and postural distortions, the loads are detrimental as they apply asymmetrical strains which initiate imbalanced stresses into the soft tissue components. In either case, the soft tissue has to overcome resistance to d form. Prior to deformation, the status quo is the preferred position. An Inherent characteristic of tissue is that it resists deformation. Once that deformation is initiated, it will adapt (or maladapt) and continue in its new orientation. When a spine subluxates, the internal or external concussion of forces, compel the soft tissue elements to change their. orientation from balanced stresses countering balanced strains to one of imbalanced stresses countering symmetrical strains. To restore a subluxated spine, adjustive forces need to overcome the inherent characteristics of soft tissue to remain in the unhealthy status quo. Once this soft tissue resistance is overcome, the spine can accommodate to the original position of normal structural balance and efficiency. SUBLUXATION AND RHEOLOGY Previous chiropractic methodology sought to adjust the osseous segments and 'gnored the soft tissue components of the subluxation configuration. Segmental adjustments to enhance ran e of motion or reduce symptomatic complex is a partial application of the full art 0f Chiropractic rehabilitation. Adjusting procedures that rely on segmental corrections are limited in their effectiveness because the soft tissues are left in an symmetrical binding position. The rheologic models of tissue deformation show that the'! characteristics of the separate soft tissue structures. When a chiropractic practitioner deals only with the mechanical characteristics of the osseous structures in the adjusting technique, and ignores the rheological characteristics of the soft tissue components of the subluxation, those rheological characteristics will cause the soft tis ue compor:'lents to re-attain the pathological pre-adjustment configuration. In other words, a corrected normal spine will take the strains of daily living along with the micro and not-so-micro traumas and deform them back into its normal posture. A subluxed spine will take the deforming adjustive force and slowly reform it to the characteristic shape of its subluxation. Attempts at adjusting a subluxation without changing the 'posture dooms the effort to failure because the tissue is adapted to its malposition. Any effort to move the spine short of structural' correction will fail. JOINT FIXATION - A PRODUG, OF SOFT TISSUE STIFFNESS Decreased range of motion does not necessarily indicate joint fixation in the classic subluxation definition. There is evidence that most joint stiffness and loss of mqtion is not a frictional lock of articular planes or degenerative osteoarthritic . immobility, rather a condition of soft tissue fibrosis. "Joint stiffness is thought to be related primarily to soft tissues stiffness rather than actual grafting of bone nd cartilag,e surfaces. In all but the most severe joint degeneration, stiffness is due to stretching resistance of soft tissue structures and friction between soft tissue surfaces. The energy required to overcome stretchtng resistance is 100 times that to overcome joint surface friction." FIBROTIC REACTION IN LIGAMENT INJURY "Fibrous scars are common phenomena that may follow upon all kinds of wounds, contusions, etc. The degree of fibrosis depends on the severity of simultaneous irritation during healing, viz. infection and foreign bodies. Fibrosis is more apt to occur where there is traction on a wound. In brief, any condition that delays ,healing promotes the development of fibrosis." "Fibrosis that goes deeper, may involve various other structures and compromise their function. When the tissue sustains an injury, there will as in other sites be serofibrinous effusion followed by deposition of fibrin between the various tissue layers, around the joints, tendons, tendon sheaths, ligaments and within and between muscles. In this fibrin connective tissue will form and again shrink so that all these structure will be plastered together with firm adhesions. Edema and tissue fluids are not removed by the muscular pump, and cicatrization rapidly entails limitation of movement." LIGAMENT HEALING TIME PERIODS "Pathological changes after a mild sprain at the end of one week revealed edema, fibroblastic proliferation, and infiltration with lymphoid cells in the inj red ligaments and capsule near'the bony attachments. There were similar changes in the synovial tissue with an increase in the joint fluid and evidence of hemorrhage into the subcutaneous tissues. Two and three weeks after sprain there were still signs of acute inflammation of the synovial tissue and a great increase in fibroblasts in the soft tissues surrounding the ligament and capsule. At four weeks there were no remaining gross external signs, but ligaments and synovia still revealed microscopic signs of old hemorrhage, few fibroblasts, more collagen fibers, and less infiltration with leukocytes and lymphoid cells. At six weeks, healing was complete with a late stage of fibrosis, and with shrinkage and contracture of the structures of connective.' "The severe sprains revealed a fibrillar degeneration of the surface layers of cartilage, especially at the margins of the joint surfaces on the affected side; there was also definite evidenee of a tearing injury at the point of insertion of ligament to bone. The process of repair persisted for eight to ten weeks." "A tendon injury, like that of bone, heals in two stages. First a tangled mass of collagen fibers, called a scar or tendon callus, is produced by fibroblasts, which are made by progenitor cells 'that were stimulated by the injury. This stage may take about 5 weeks. After the initial scar is made it is' then remodeled and gradually replaced by new tendon, Le., collagen fibers which are lined up paralleled to the pull or tension on the tendon (or ligament, capsule or fascia). This stage may take three years." It has been well documented that sprain and strain injuries resolve in six to ten weeks depending on which authority is read. However, this resolution is only the primary stages of the healing process. The subsequent stage of healing is one of structural reorgani ation, where the body part aligns itself to the external strains. In this new orientation, the soft tissue components mold a new fibrous network along stress axes. This later stage of healing is of utmost essential rehabilitation of the structure to its full capacity of normal position and optimum function. If the patient (or the doctor) is unaware of this last phase and terminates care prior to completion of soft tissue remodeling, asymmetric strains orient the stress axes in non-correct angles for muscular application and efficiencly. The joint motion is thus distorted. The patient now enters the pathophysiological cycle in a downward spiral compounding the initial injury with a positive feedback loop of soft tissue and subluxation degeneration.

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