About the spine (Briefly)

It is well known that the human spine consists of hard vertebrae separated by elastic discs..

Each disc is a protein ring whose jelly-like elastic nucleus consists of glucosaminglikans capable of absorbing and expelling water, depending on external influences. By the time we are 20-22 years old the spine has completed its development and is about to enter an early ageing phase, showing signs of wear and tear.Degeneration in the intervertebral discs is a consequence of constant pressure.

   The elastic jelly-like nucleus of the disc begins to dry up and the disc becomes flatter, resulting in loss of resilience. The disc’s membrane (fibrous ring) linking two adjacent vertebrae and enclosing the jelly-like nucleus starts to protrude beyond the edges of the vertebrae. In time the process of degeneration in the fibrous ring leads to the development of cracks and ruptures. In exceptionally inauspicious conditions body movements lead to a breaking out of the jelly-like nucleus through the fibrous rings, resulting in the formation of hernia of the disc. Even in the absence of the destruction of the fibrous ring, with the natural ageing process comes increased pressure on the lower of two vertebrae. This leads to the growth of osseous and cartilaginous tissue around the edges of the vertebra. This process between vertebra and intervertebral disc changes the natural form of the structural elements of the spine and leads to osteochondrosis.
The decrease in the distance between the vertebrae and the deformation of the bodies of the vertebrae and vertebral discs leads to squeezing of the nerve roots in the spine and irritation of the numerous nerve ends in the tissue around the spine.
The irritated nerves send impulses to the central nerve system and the sufferer feels pain in the spine. Signals from the nerve ends go also via the spinal cord to the muscles bending and unbending the vertebral segment and controlling the tone of the corresponding blood vessels. Under the influence of the constant painful irritation the muscles become tense and shrink and muscle blockade can occur: the spinal segment loses its mobility. It is as if the organism switches off the painful part. At first full spinal mobility is maintained at the expense of neighbouring segments, but with increasing pressure they also gradually switch off. This can disrupt regulation by the nerves of the function of muscles, joints, tendons and practically all internal organs. As a consequence of this disruption symptoms characteristic of a variety of disorders will appear, depending on which part of the spine is involved..
 
  
 
  

Much research has shown that the physiological changes described here are inherent in all human beings as a biological species. As a result of these changes from 40 to 80 per cent of the world’s population suffer from various diseases of the spine. Pronounced symptoms of osteochondrosis reveal themselves between the ages of 35 and 55, when people are most active.

As shown above, the development of spinal illnesses starts from structural changes of the intervertebral discs. These changes are connected not only with age. Many factors impinge on these structural changes: hereditary factors and genetically ordained movement stereotypes, obesity and sedentary lifestyle, illnesses of the internal organs, hormonal and vascular disorders, weakness of the immune system, incorrect pressure on the spine, uncomfortable postures and, of course, traumas.

One of the principal methods of prevention and treatment of spinal illnesses is the restoration and maintenance of the essential elastic characteristics of the intervertebral discs, restoration of their sizes, provision of their alimentation, blood supply for dispersal of the infiltrates and excessive salts, and the creation of conditions for the healing of cracks.

This is achieved by the correct measure of spinal stretching. This method is conditional upon an anatomically correct form and degree of spinal curvature for each individual during stretching. Intensification of this treatment can be achieved by moderate vibration and warming.

All the foregoing can be achieved by using the ‘KVS’ bed.

Many theories exist concerning the origin, mechanism and development of the spine’s degenerative-dystrophic illnesses, in particular osteochondrosis. Analysis of these theories leads to two main conclusions: (1) the key element in the pathogenesis is the degeneration of the intervertebral disc, resulting in a change of its biochemical qualities; (2) the main cause of the degeneration of the disc is improper pressure on the spine and its influence on spinal functions.

The causes of this improper pressure can be divided into three categories: (a) reduced possibilities of the spine and the body as a whole (for example, genetic and acquired disorders of the metabolism in the intervertebral disc; insufficient ‘muscle endowment’ – defects in the co-ordination of movements and so on) when there is normal pressure on the spine and muscles; (b) excessive statodynamic loading on the spine while the functional possibilities of the organism are normal; (c) reduced functional possibilities of the spine with increased statodynamic loading.

In the most general sense, the pathogenesis of the degenerative-dystrophic illnesses – first of all osteochondrosis of the spine – can be described as follows. Because of loading in excess of the functional possibilities of the spinal column, and in particular of the intervertebral disc, there begins in the pulpy nucleus of the most overloaded vertebral-motor segment(s) accelerated wear of the mucopolysacharides which are providing the necessary hydration of the nucleus and its biochemical characteristics. The cell elements of the nucleus become exhausted after a period of compensatory activity and there can be no remedying of the deficiency of mucopolysacharides.

As a result the tension of the nucleus reduces, the inner disc pressure lessens and so do the amortization possibilities of the intervertebral disc. Some morphological and biomechanical characteristics of the discs, with the different levels of degeneration, are shown in Table 1.

The reduction of the amortization possibilities leads to a situation where under normal pressure the disc is compressed more than usual, loses its inherent thickness (the sign of overloading of the vertebral-motor segment) and, because the nucleus cannot create proper internal disc pressure, the fibrous ring does not receive normal stimulation for tension. The intervertebral disc, whose degree of degeneration is fluctuating between 0 and 1, becomes ‘flabby’ instead of tense; the rigidity of the connection between neighbouring vertebrae reduces and their mobility relative to each other slightly increases. In a number of cases the increased amplitude of the dislocations of the vertebrae relative to each other in the horizontal plane (which becomes possible because of increased mobility) results in irritation of the ends of the Recurrent Nerve in the fibrous ring of the intervertebral disc and reflex tension of the appropriate paravertebral muscles. This reflex is directed at reducing abnormal mobility of the changed vertebral-motor segment which in principle can have a negative influence on the adjacent part of the spinal cord and spinal nerve. Prolonged tension of the paravertebral muscles holding in place neighbouring vertebrae in the affected segment causes overloading and tiredness of muscles, disruption of their metabolism and the appearance of unpleasant feelings ranging from slight discomfort to constant moderate aching.

   Table 1, showing the characteristics of the lumbar intervertebral discs with various degrees of degeneration.

Table of modifications

Degree of the degeneration The morphologic characteristics Average internal disk pressure kg/cm2 Internal disk pressure in % 0 Jelly-like substance of the pulpy nucleus. Semi-liquid nucleus separates easily from the fibrous ring. Fibrous ring is compact, elastic, glittering. 2.7 100 1 The nucleus is more fibrous with increased density. The boundary between pulpy nucleus and the fibrous ring is clearly seen. 2.0 74.1 2 Contours of the nucleus are not clear. The elasticity of the fibrous ring is lessened. There are few cracks in the ring. 1.3 47.4 3 Under a microscope a cross-section of the disc resembles a fibrous mass with many cavities and cracks in pulpy nucleus and fibrous ring. Practically it is difficult to distinguish between the structure of nucleous and ring. In nucleus zone there are knots of cartilage tissue. Peripheral osteophytes are evident in the tissue surrounding the disc. 0.6 2.22

At this initial stage of the disease sharp stabs of pain can sometimes be experienced. During rotational movements, especially when turning is combined with bending or lifting heavy objects, abrupt dislocation occurs between one vertebra and another because of increased mobility in the affected vertebral-motor segment. Quite often such dislocation causes so-called block in the intervertebral joint and a peculiar click can be heard at the time of the blocking. By ‘block’ is meant fixation of the vertebrae of the vertebral-motor segment in the extreme physiological position of lateral or frontal bending. This coincides with rotation to that side where the disc protrudes because of the ‘spreading’ effect. This occurs during movement of the pulpy nucleus to the rear part of the intervertebral disc in the course of bending or bending with rotation. This mutual positioning of the blocked elements of the segment results in its overloading together with protrusion of the disc’s fibrous ring. If the protrusion occurs at the point of outlet of the spinal nerve symptoms of its irritation will appear.

As a rule there is pain – rather intensive pain. By reflex action there is convulsive contraction of the paravertebral muscles not only at the level of the affected vertebral-motor segment but also at that of neighbouring segments. Because the protrusion is asymmetrical and the nerve is irritated on one side, the muscular tension is also asymmetrical. If the intensity of the pain is high other parts of the body’s musculature become subject to spasms and besides pain there is a noticeable loss of mobility.

In a physiological sense this reflex reaction provides maximum reduction of the risk of further dislocation of vertebrae relative to each other in a horizontal plane and avoidance of increased protrusion of the disc and lessening of irritation of the nerve. In the first hours of its onset the muscular spasm plays not only a positive but also a negative role, preserving the anti-physiological position of the elements of vertebral-motor segment. This anti-physiological position is accompanied by obvious clinical symptoms, first of all pain.

The pain provokes the spasm of the musculature which is also painful. It is possible to break this vicious circle with the help of purposeful remedial measures or by restful.routine or confinement to bed.

Other clinical symptoms are conditional upon the locality of the process – ie which nerve is irritated (see Figure 1). For instance, involvement in the process of the middle chest vertebral-motor segments with irritation of the corresponding nerves can imitate heart pain of the same type as stenocardiac pain.

A restful routine, better bed routine, results in most cases in the gradual disappearance or, at least, a considerable decrease of all the clinical symptoms of the attack. The purposeful medical treatment, naturally, accelerates the process of sanogenez. Therein, it is thought, lies the removal of the overloading from the affected vertebral-motor segment. (As is known, the level of internal disc pressure in a prone position is about 1.5 times less than in an erect position and 2 – 2.5 times less than in a sedentary position). Because the fibrous ring retains its elasticity, the protrusion of the disc disappears.

That is why the initial period of development of osteochondrosis is also called the period of mobile protrusions. The irritation of the nerve decreases, muscle tension diminishes, the disposition of the elements of vertebral-motor segment more or less normalizes, the pains and restriction of movement disappear or decrease. So in the initial stage of the development of spinal osteochondrosis there are:

• overloading of the vertebral-motor segment(s), absolute or relative;
• periodical appearance of mobile protrusions;
• asymmetric spasm of paravertebral muscles;
• some restriction of bodily movement, especially in the region of the affected vertebral-motor segment;
• discomfort in the region of the affected segment.

There can also be other peculiarities conditioned by the irritation of the spinal nerve at the level of the affected vertebral-motor segment. In the initial phase of the development of osteochondrosis the bouts of illness occur infrequently, the periods of remission when the clinical symptoms are absent are prolonged. The process can be long delayed at this stage with the help of prompt intervention and careful treatment. The spinal column is an indivisible functional system. Chronic overloading even of one vertebral-motor segment leads from the very beginning to the reconstruction of the work of the spine as a whole. So blockade of the affected segment noticeably restricts its functional possibilities. Other segments are obliged to take over part of its function, with the result that they are in turn overloaded and in time exposed to the degenerative process.

Here we have in mind not so much neighbouring segments as functionally connected formations. An example of such connection is vertebral-motor segment Occ – C2. It is connected with the cervical-thorax passage (C7 – T1), chest part (T3 – T4), sacrum-iliac passage (L4 – S1) and the lumbar region (L2 – L4). All the vertebral-motor segments have similar connections. These facts further underline the importance of timely treatment of the disease. Prompt treatment of the affected segment in the initial stage of the illness is the best protection of the connected healthy segments/

Thus, already in the initial stage of the illness the supportive, defensive and motor functions of the spine suffer. The metabolic function of the spinal column was not specifically studied in relation to the degenerative-dystrophic illnesses and it is not possible to say anything definite about its condition.

The process of degeneration in the affected segments increases with continuing relative overloading of the spine. The degree of the disc’s degeneration ranges from 1 to 2 and in some cases to 3 degrees. The overloaded bodies of the vertebrae react in a certain way to lessen the increased pressure on the closed laminae: there is a growth (an expansion) of the peripheral zones of these laminae (a so-called edge growth), increasing the supportive area and reducing the pressure on the laminae. These growths have certain clinical significance in the cervical part because they worsen the condition of the blood circulation in the vertebral arteries. In the other parts of the spinal column these osseous changes do not play a considerable role.

The degeneration of the disc increases. The nucleus loses to a considerable extent its hydrostatic qualities. Consequently the intervertebral disc loses its ability to react adequately to the axis loading. The fibrous ring is exposed to chronic vertical overloading which it is unable to counter. This overloading accelerates the ring’s degeneration. Its inner fibres begin to crack little by little until, reaching the exterior layers, they facilitate penetration of the substance of the nucleus to the disc’s peripheral parts. With the small increase in the exterior loading the nucleus substance is directed towards the cracks, causing the stable protrusion of the thin edge of the fibrous ring.

These changes at first have the same effect as mobile protrusion. These protrusions remain almost constant, unlike the protrusions of the initial stage of the illness. Because the protrusion of the ring is independent of the aggravation of the process, this stage of the disease is called the period of fixed protrusion. The blocks in the affected vertebral-motor segments promote growth of the protrusion and accordingly intensification of the illness. The mechanism of this development resembles the one described above.

The penetration of the nucleus’s substance into the cracks in the laminae of the fibrous ring has other consequences. Because the outside layers of the ring contain the sensitive ends of the spinal nerve, the mechanical irritation of them by the penetrated mass of the pulpy nucleus causes pains, muscular spasms, etc. Very soon, if fractions of the nucleuss’s substance remain in the crack in the ring, reactive sceptic inflammation develops – the immune mechanisms are switching on. During the exudation phase of the inflammation the sensitive ends of the spinal nerve are irritated by products of the tissue’s disintegration which causes pain and reflector muscle spasm.

The proliferation phase of the inflammation is characterized by the autolysis of perished tissue and the products of decay. The exudate is dissolving, the pain is gradually diminishing. The proliferation is changing into the regeneration of the connective tissue and the formation of the connective tissue scar.

Thus in the second phase of the illness its clinical manifestations are more expressed and the supportive, motor and protective functions of the spinal column are suffering even more than before.

Later on, with the development of the process, the crack can break through the membrane of the intervertebral disc. The substance of the nucleus is prevented by the back longitudinal ligament from falling into the spinal canal, resulting in hernia of the intervertebral disc. The hernia is very prominent, it can be higher than the disc itself. This process can go further and even lead to the breaking of the back longitudinal ligament.

The substance of the pulpy nucleus can cause lesion of the spinal cord by irritation or pressure by the hernia protrusion or by substance which has fallen into the spinal canal. The vessels feeding the spinal cord can also be subjected to pressure, leading to ischemic lesion. If the hernia or its sequestrums get into the region of the intervertebral aperture then one or other spinal nerve comes under pressure. In most cases the development of the hernia is caused by overloading of the spinal column and a sharp increase of inner disc pressure. It happens either because of the lifting of heavy objects, awkward movement involving elements of bending and rotation, falling or even coughing or straining.

The formation of the hernia is characterized by very obvious clinical symptoms defined by the level of the affected vertebral-motor segment, the volume and locality of the fallen hernia contents and the possibility of their shifting along the spinal canal. Very serious neurological lesions can result, connected with the direct pressure on a section of the spinal cord or disruption of the blood supply because of squeezing of blood vessels. In less serious cases the lesion can be limited to the region of one spinal nerve with disruption of the region of its innovation. It is important to add that most cases of disability caused by osteochondrosis of the spine belong to this stage.

What mostly happens, following treatment and a long stay in bed (taking pressure off the spine), is that the hernia contents become subject to fibrosis, their volume becomes noticeably smaller, their shifting in the spinal canal disappears. Quite often the squeezing of the nerve or vessel formations decreases or disappears. Relative clinical well-being is restored.

So in this third stage of the disease the clinical picture is very distinct and the functions of the spinal cord are depressed to the maximum extent. The degeneration of the intervertebral disc reaches the third stage.

Later on comes complete fibrosis of the intervertebral disc; blockage in the intervertebral joints changes from functional to functional-organic. Oseous growth is expanding. The biomechanical effect of these processes is a lessening of pathological mobility in the vertebral-motor segment and accordingly the clinical manifestations of the illness are also less apparent. Then comes the fourth stage of the illness (the period of fibrosis of the intervertebral disc): deformation spondilosis. In the final stage of the process – osteofibrosis of the intervertebral disc – osteofibrosis increases, the osteophytes of neighbouring vertebrae grow together and the result is complete organic block of the ankylosis spondiloarthrosis type. Consequently mobility in the vertebral-motor segment is totally absent. This stage of the illness is characterized by moderate clinical symptoms. The function of the spine suffers, but less than at the previous stage.

The motor and support functions are most depressed, the protective function less so.

In this outline of the pathogenesis of the degenerative-dystrophic lesion of the spinal column, particularly osteochondrosis, most attention has been given to the biochemical aspects which, in our opinion, play the key role

To sum up, the leading biomechanical parts at all stages of the development of the pathological process are:

• relative overloading of the vertebral-motor
• segment(s);
• reflex muscular spasm of the paravertebral musculature, as a rule asymmetric, limiting mobility in the affected segment and at the same time conserving the position of the vertebrae relative to each other;
• the block in the affected vertebral-motor segment.

It is precisely to these parts of pathogenesis that the function of the autogravitational bed ‘KVS’ is directed.