Etiology and pathogenesis

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The significance of morphological changes 9

2.2 Theoretical aspects of manipulation therapy 10
2.3 The significance of functional disturbances 12
2.4 Motion segment and joint dysfunctions 13

2.4.1 The barrier 13
2.4.2 Joint play and restriction 14
2.4.3 Reflex changes in joint restriction 15
2.4.4 Is restriction an articular phenomenon?16
2.4.5 The possible mechanism of restriction and manipulation 16
2.4.6 The effect of manipulation 17
2.4.7 The pathogenesis of restriction 17
2.5 The spinal column as a functional unit 19

2.5.1 The spinal column and balance 20
2.5.2 Key regions of the spinal column in dysfunctions 20
2.5.3 The importance of nervous control 21
2.6 Dysfunctions of the spinal column in childhood 24
2.7 Restrictions and their sequelae 26
2.8 The significance of disturbed motor patterns (stereotypes) 27
2.9 Sequelae of disturbed movement patterns 29

2.9.1 Walking and standing 29
2.9.2 Straightening up from a forward-flexed position 29
2.9.3 Raising the arms 30
2.9.4 Weight carrying 30
2.9.5 The effect of respiration on the locomotor system 30
2.10 The significance of constitutional hypermobility 33
2.11 Reflex processes in vertebrogenic dysfunctions 34
2.12 Radicular pain 36
2.13 The term ‘vertebrogenic’37
2.14 Conclusions 38

2.1. The significance of morphological changes

Chapter 1 indicated the great range of application of manipulative therapy and most methods of reflex therapy, which can be used for many different cases of pain in the locomotor system; these often involve pain whose cause and therefore treatment remain controversial. For a long time they were generally considered to be of inflammatory origin, for the simple reason that this provided the easiest explanation for the pain. Indeed we still speak of rheumatic diseases, for example ‘soft tissue rheumatism,’ and many terms ending in ‘-itis’ bear witness to this attitude (spondylitis, arthritis, radiculitis, neuritis, fibrositis, myositis, and panniculitis, for example). Since, however, inflammation is a well-defined pathological condition which can be demonstrated or disproved, the inflammation theory became untenable and had to be abandoned for lack of evidence.
Pathological anatomy and the use of radiology to examine pathology in living patients (X-rays) played their part by demonstrating degenerative changes. In place of terms ending in ‘-itis’ we speak of spondylosis, arthroses, and ‘diskopathy.’ This approach offers the possibility of explaining the changes in tissues that are sometimes bradytrophic. Vascularization of the intervertebral disk becomes reduced at quite a young age and the nucleus pulposus dries out: the water content decreases from 90% in the first decade of life to 70% in the third decade. According to Schmorl, 60% of women and 80% of men at age 50 show evidence of degenerative changes of the spinal column, while by the age of 70 the figure is 95% for both sexes.
The very abundance of degenerative changes makes it difficult to define their pathogenetic significance. Whereas the number of degenerative changes increases with age, back pain occurs most often between the fourth and sixth decade, to become less common in old age. Subjects with considerable degenerative changes may be completely without clinical symptoms; alternatively they may suffer an attack of acute pain which subsides after a time (while the degenerative changes remain the same) to leave them once more symptom free. There can even be severe pain in young patients with no degenerative changes at all.
The main difficulty is the fact that the term ‘degenerative’ is so poorly defined. It is used on the one hand for destructive lesions typically only found in the hip and knee, and on the other hand for changes of little clinical significance, and which are better described as normal ‘wear and tear.’ Often the change is a compensatory process or adaptation – as in scolioses, in hypermobility, or even instability (for example in spondylolisthesis) which can thus be stabilized. It is often difficult to distinguish between changes resulting from trauma and degenerative ones. When we find degenerative changes, we should begin by asking about their clinical relevance. It is a mistake to draw clinical conclusions without good reason from the mere existence of non-destructive degenerative changes seen on X-ray; they do not in themselves justify speaking of ‘degenerative disease.’
There is certainly some correlation between degenerative changes and herniated disk; with a few exceptions, herniation occurs mainly in disks already showing some degenerative change. The discovery that disk herniation can be a cause of pain was an important step historically, but the success of surgical treatment was often so striking that disk lesions came to be held responsible for most of the many instances of pain related to the spinal column. The principles that applied to radicular syndromes, mainly in the lumbosacral region, were uncritically applied to a whole range of complaints in all parts of the spinal column. ‘Diskopathy’ became the fashionable word for what we now refer to as vertebrogenic (or spondylogenic) disease.
Everyday practice contradicts this view and serves to correct it. Although disk surgery is a routine procedure for radicular syndromes of the lower limbs, it is rarely performed for low-back pain or radicular syndromes of the upper limbs, and not at all for simple neck pain or vertebrogenic headache. Nor is disk herniation the only possible cause of pain in radicular syndromes of the lower limbs: in operation statistics no disk herniation is found in about 10% of the cases; many radicular syndromes resolve without operation, and this is true even of cases in which medical imaging had found a herniated disk. Disk herniation can sometimes persist after the symptoms have disappeared, although resorption is also possible. Not only that; computed tomography (CT) or magnetic resonance imaging (MRI) examination frequently reveals a herniated disk in healthy individuals in whom it is of little relevance. It is only significant when it correlates with clinical findings.
To conclude, in the overwhelming majority of cases of back pain and associated clinical symptoms the morphological changes discussed above do not provide an explanation. For this reason this type of pain is referred to as ‘nonspecific’ (Jayson 1970) or ‘idiopathic’ (without any morphological diagnosis).

The vast majority of cases of pain are not associated with demonstrable morphological changes in the locomotor system. In effect, therefore, these are patients with ‘no diagnosis.’

2.2. Theoretical aspects of manipulation therapy

The explanation originally given for the effect of manipulative therapy was that it involved ‘repositioning’; the understanding was that what was being treated was an incomplete dislocation, for which ‘subluxation’ became the accepted term. This was what Hippocrates believed, and probably also Still and most practitioners providing manipulative treatment down the ages. Indeed, the sight of a patient with acute lumbago or wry neck, unable to straighten up, who receives successful manipulation treatment and becomes able to stand erect, makes it little wonder that they did see this as the likely explanation. The reason that physicians have had to abandon the subluxation theory lies in the radiographic findings, since X-rays show no change for the individual segments before and after manipulation. The only change is in the abnormal posture, whose cause is muscular.
It has been shown by M Berger (personal communication) by means of cineradiography that when the head moves to an extreme position and back, it does not return to the same neutral position as before. We were able to confirm this by means of transoral radiography (see Figure 2.1).
An analogous effect was demonstrated by Jirout (1979a) for synkineses of the cervical spine in the sagittal plane on side-bending; when images were taken in the neutral position before and after maximum side-bending, the position of the spinous processes was generally found to be changed.
The conclusion that can be drawn from these observations is that in a structure consisting of such a number of mobile elements there can be no absolute, fixed neutral position. The same applies to any changes there may be following manipulation. It will be shown below that manipulation operates only on disturbed function, that is mobility in the affected motion segment. If, however, there is no absolute neutral position, it follows that manipulation enables the motion segments of the spinal column to adopt the position that is most favorable in the particular circumstances.

If the mobility of the motion segments of the spinal column is normal, the spinal column itself knows far better than the person giving treatment which position it should adopt for each particular posture or load.

According to the literature, some authors, such as Cyriax, Maigne, and Stoddard, believe that manipulation exerts some kind of effect on the disks. However, it is difficult to see how manipulation could achieve repositioning of a herniated disk when its exact position can never be known. Another point to consider is that manipulation is also effective in treating other locations, where there are no disks, such as the limb joints, the atlanto-occipital and atlantoaxial joints and the pelvis. Clinical experience supports this: manipulation is most effective in situations where there is no disk herniation, and often fails precisely in cases where there is.

The precise examination techniques used by osteopaths have also provided a clearer idea of the effect of manipulation therapies; these are indicated when we find movement restriction in a joint or a vertebral motion segment, and if manipulation is successful, normal mobility is restored. In other words, manipulation does not achieve a change of structure, as Still thought, but normalization of mobility; that is of function.
This is also true in cases of acute lumbago or acute wry neck: the position of the neck or the back in such cases is not in fact abnormal in itself; it is only the fact that the patient is unable to straighten from a position, such as flexion, or rotation plus inclination, that is pathological. Manipulation (mobilization) simply frees mobility and thus enables the patient to return to the neutral position. Acute lumbago and wry neck are in fact an exception in this regard; in the vast majority of cases the position observed is normal and the finding is simply one of movement restriction in the joint (or vertebral motion segment).

Manipulative techniques are used to diagnose and treat only functional movement restrictions in a joint or vertebral motion segment. The purpose of manipulation techniques is simply to normalize disturbed function.

2.3. The significance of functional disturbances

As the above makes clear, it is above all clinical experience in the use of manipulation for diagnosis and treatment that constantly reaffirms, in countless patients, the principle that treatment, if technically successful, brings normalization of restricted mobility in the joint or motion segment. Normalization goes hand in hand with the restoration of function (bending or rotation to the left or right; in the case of the limbs, symmetrical findings in the left and right limb). Normalization of function also brings relief of pain.
A similar principle applies not only to the passive mobility of joints, but also to active muscle function. Janda in particular demonstrated the significance of muscular stereotypes and showed that faulty movement patterns (disturbances of these stereotypes) produce abnormal stress on passive structures, especially joints.
Closely associated with movement patterns is the matter of body statics. In fact, static overload and its consequences have become an extremely important issue in our modern technologically developed society with its general lack of mobility. Here too we find that correction of faulty posture frequently relieves pain. The contribution made by Brügger is particularly helpful in this connection, since he has made a special study of the hunched sitting posture and its treatment.
Manual functional diagnosis thus served as a model for many other dysfunctions of the locomotor system. The muscle trigger point (TrP) most clearly demonstrates the close connection with pain. In saying so we should stress that morphological lesions are also associated with disturbances of function. This is most clearly the case for herniated disks and may explain spontaneous recovery and recovery after conservative treatment (including manipulation). A similar situation applies to rehabilitation in traumatology, where our primary aim is to improve function despite the presence of irreversible structural changes, where the aim of rehabilitation is to achieve functional compensation.
As will be shown in more detail later, function and its disturbances are rarely confined to one site or structure. Diagnosis must therefore take in the locomotor system as a whole, and consequently the terms ‘vertebrogenic’ or ‘spondylogenic’ will no longer suffice. Even in back pain, muscle function and its nervous control play an important role, as do the functions of the pelvis and lower limbs. Since ‘vertebrogenic’ diseases or lesions include such well-defined pathological conditions as ankylosing spondylitis and osteoporosis, the decisive criterion for the use of manipulation and other measures aimed at restoring function is whether the patient’s complaint is due (mainly or exclusively) to dysfunction, or to structural (pathomorphological) changes.
The solution is not simple, and the problem lies in the fact that the method of examination has not yet been precisely defined. It is the great weakness of important methods of treatment – such as manipulative therapy, remedial exercise, and other methods concerned with improving the functioning of the motor system – that they are often more concerned with the method than with its object or its potential for diagnosis.
In many fields of medicine the significance of findings relating primarily to function is now well recognized. In the locomotor system, however, where function is paramount, this aspect finds least acceptance. Yet the functioning of the locomotor system is extremely complex, and diagnosis of disturbed function is correspondingly difficult. Nor is there a specific medical specialty responsible for this area; functional disturbances seem to be the realm of everyone and of no one. There is an additional disadvantage in that, for the most part, the only means of investigating dysfunctions of the locomotor system is by inspection and palpation. Today these are often regarded as ‘subjective’ and dismissed, while instrumental and laboratory methods are regarded as objective.

2.4. Motion segment and joint dysfunctions

Dysfunctions of joints and vertebral motion segments (see Figure 2.2) fall into two categories: hypermobility and restricted mobility; manipulative therapy is concerned only with restricted mobility. Clinical criteria are the decisive factor in identifying such restriction, and are judged from the qualitative point of view as well as quantitatively. A reduced range of motion is easy to recognize and measure in a joint, but much more difficult in motion segments of the spinal column. Qualitative changes are therefore of considerable diagnostic value when dealing with the spinal column.
This is the case when the finding is one of increased resistance, and especially a lack of ‘springing’ at the end of the range of motion, with abrupt resistance encountered in the end position of the joint or motion segment. In a normal joint the extreme position is never reached abruptly, and a slight increase of pressure can always increase the range of motion. In a joint with functionally restricted mobility, this springing or giving way has been lost and we abruptly encounter a hard barrier. This, termed joint ‘restriction’ (sometimes ‘blocking’ or ‘blockage’), is perhaps the most significant sign in diagnosis.

2.4.1. The barrier

The concept of the ‘barrier’ is a familiar one in the osteopathic literature. Three kinds of barrier can be identified:

1. The anatomical barrier, created by the bony structures.
2. The physiological barrier, which is clinically significant and is found at that point in the examination where the first, minute degree of resistance is felt; the barrier yields slightly with a sense of ‘springing.’
3. The pathological barrier, which restricts motion and is felt as a hard, abrupt stop, lacking the sense of spring. In addition there is often a change in the neutral position; for example in rotation of the head or trunk, so that this becomes asymmetrical (see Figure 2.3).

The barrier as a phenomenon was originally defined with reference to joints, but is also useful in relation to the elasticity and mobility of soft tissues, including muscles. The barrier is therefore relevant for all mobile structures; it has a protective function.

The definition of the physiological barrier given above is not universally accepted. It is defined in an osteopathic publication (Kuchera 1997) as the limit of active motion. We consider this definition to be of no practical use on the grounds that passive examination of the barrier is used to investigate movement restrictions, both for motion segments and for joint play. The objection applies all the more to soft tissue diagnosis.
In chiropractic, this barrier is defined as the limit of maximum passive motion, the important point being that passive motion has a greater range than active motion. If manipulation were to be performed on a barrier defined in such terms, it would elicit an intense stretch reflex. This would rule out any gentle techniques, let alone relaxation on the part of the patient. Perhaps there is an explanation here for the harshness of technique used by some chiropractors.
The definition we have given above for the physiological barrier must therefore stand. It is useful both in diagnosis and as a principle that underlies our treatment, which produces release. We recognize fully that this does involve subjective evaluation. The first, minute resistance is found by means of palpation, which of course depends on the experience of the practitioner.

2.4.2. Joint play and restriction

There are two types of joint movement, both of which are affected by restriction:

1. Functional movement: movement that can also be performed actively.
2. Joint play (according to Mennell 1964): movement of the joint which can only be brought about passively. This comprises a translatory (sliding) movement of one joint surface against the other, sometimes also rotation, and also distraction of the joint facets.

To give an example, actively we can flex, extend, or side-bend a finger, whereas passively it can be shifted against the metacarpal in any direction, rotated, or distracted by axial pull. These movements can not only be sensed by palpation, but can be demonstrated radiographically (see Figure 2.4 and Figure 2.5).

The diagram according to Kaltenborn (1989) (see Figure 2.7) shows the direction in which joint play is freest.

2.4.3. Reflex changes in joint restriction

Restriction in a joint and particularly in a vertebral motion segment produces reflex changes, mainly in the segment concerned, affecting the cutaneous and subcutaneous tissue and muscles. Korr (1975) speaks of ‘facilitation’ in the segment.
The movement restriction itself is associated with muscular tension (TrP or spasm); this can similarly be said of the straight-leg raising test and of the antalgic posture in lumbago or acute wry neck. Korr, a physiologist who worked on the problem of manipulative therapy, said of the role of the muscles: ‘While usually thinking of muscles as the motors of the body, producing motion by their contraction, it is important to remember that the same contractile forces are also used to oppose motion’ (Korr 1975).
From this we can conclude that, in their role as a brake, muscles act as a considerable and highly variable impediment to mobility in a dysfunctional joint. Korr continues: ‘The high-gain hypothesis is consistent with, and offers an explanation for, the steeply rising resistance to motion (‘bind’) in one direction and the equally precipitous collapse of resistance (increasing ‘ease’) in the opposite direction … They [the muscles] would also be provoked into stronger and stronger contraction by the exaggerated spindle discharges as motions that tend to lengthen the affected muscles occur’ (Korr 1975).
This would also explain the hard ‘feel’ in the end position. All the clinical findings encountered in restriction might therefore be explained as the result of muscle activity and not as a disturbance of the joint itself. That is why osteopaths prefer to speak of ‘somatic dysfunction’ (Greenman), a term that includes the dysfunction of the joint, the muscles, and the soft tissues.
The role of shortened muscles in movement restriction is emphasized by Janda. Muscle relaxation techniques are used with much success in order to mobilize joints. It is therefore appropriate at this point to consider the actual role of the joint in restriction.

2.4.4. Is restriction an articular phenomenon?

Clearly the view that passive movement is exclusively the expression of articular function is not one that can be maintained. In fact, as Korr has shown, most clinical findings in joint restriction can be explained by muscle activity controlled by the gamma system. If this is the case, what role is played by the joint itself?
If we are dealing with a reflex response, what is the origin of the stimulus that evokes it? It must surely be more than mere coincidence that techniques which have been found in a purely empirical manner to be effective in manipulation correspond to joint anatomy. The importance of joint play is also consistent with this, as is the fact that the popping sound, or ‘click,’ that is heard on successful manipulation comes from the joint. The hypotonus regularly observed following such manipulation is however a muscular phenomenon.
There are some joints that are not under the direct control of a particular muscle; obvious examples are the sacroiliac, the acromioclavicular and the tibiofibular joints. Yet muscular fixation of these joints (other than the acromioclavicular joint) is regularly found. In the case of the sacroiliac joint, for example, this is caused by the pelvic floor, the ischiocrural muscles, or the piriformis; in the tibiofibular joint by the biceps femoris.
In order to investigate further the role of the joint, we undertook the following experiments: in patients who were about to undergo operation under anesthetic with artificial respiration, the cervical spine was examined shortly before operation. Restrictions were found in ten patients, and the exact location and direction determined. The patients were re-examined under anesthesia, which used mainly thiopental, nitrous oxide and 100g succinylcholine iodide, the patients being in a state of complete muscle relaxation. This involved brief interruption of the intubation. In all cases the movement restriction remained unchanged during narcosis.

2.4.5. The possible mechanism of restriction and manipulation

The importance of the experiment just referred to lies first in demonstrating that the joint does also play a part in restriction; and second in showing that there is (also) a mechanical resistance. It was Emminger (1967) who first suggested that this might be attributed to a trapping of the meniscoids as previously described by Töndury and others. Kos & Wolf (1972) showed in addition that these meniscoids do also exist in the limb joints.
The physiological role of the meniscoids is to fill the changing joint space as it alters during movement, since they are a highly mobile structure. Most joints have very incongruous facets; without the meniscoids to perform this role, gapping of the joint would occur during movement. The meniscoid is intimately connected with the joint capsule. Clearly such well-nigh chaotic-seeming motion must be prone to disturbance. However, Cihák (1981) points out that the deep layers of the multifidus muscles are linked with the joint capsule and so control this mechanism.

This diagram clearly illustrates the mechanism of manipulative techniques. High-velocity, low-amplitude (HVLA) techniques cause gapping of the joint capsule, as a result of which the meniscoid has only a short constricted area to overcome (Figure 2.9). In repetitive mobilization, the meniscoid is freed during the back-and-forth movement of the joint facets, and all that is apparently needed as we wait for release to occur is the relaxation of the muscles, which widens the joint space.

2.4.6. The effect of manipulation

The effect of successful manipulation is two-fold:

1. It restores mobility, including joint play.
2. It produces an intense reflex reaction in all structures where changes had been present before manipulation. This occurs most strongly in the musculature, where a previous state of increased tension (TrPs; occasionally spasm) is replaced following manipulation by hypotonia. The skin, too, becomes easier to fold and stretch, and soft tissues easier to shift against each other. Tension is thus reduced in all tissues, especially in the corresponding segment. Depending on the significance of the vertebral motion segment or the joint concerned, the effect of the manipulation also extends to distant segments; this will be discussed later. The effects referred to here can not only be observed clinically, but can also be objectively demonstrated by physiological methods (see Figure 2.10, Figure 2.11, Figure 2.12 and Figure 2.13).

2.4.7. The pathogenesis of restriction

Overload and abnormal load

Modern civilization brings with it very one-sided, unvaried posture and movement, causing muscular imbalance. Lack of movement together with static or postural overload are a characteristic feature of modern life. Disturbed movement patterns and static overload are probably the most frequent causes of reversible restrictions and of their occurrence and recurrence.


Trauma is a further potential cause. It is important to point out that the borderline between patient groups suffering from overload and those suffering the effects of trauma can in fact be very fluid, because it is not always easy to say what should and should not be interpreted as trauma. It is usually defined as a force acting on the body and capable of damaging structure or function. However, even under normal conditions the forces acting on the spinal column are considerable. If these forces are suddenly increased because of sudden, unexpected movement, especially if this involves contraction of the powerful muscles of the back, it becomes extremely difficult to distinguish between overload and trauma. The somewhat vague term ‘microtrauma’ is then used.

Reflex processes

A further complex of causes involves reflex processes within the segment. As has been stated already, the spinal column is routinely involved in disease processes in the body. Vertebral restrictions can therefore occur following – and also as a result of – disease elsewhere in the body. The primary condition creates a stimulus in the segment, which in turn produces a spasm (TrP) in the corresponding region of the erector spinae muscle, in particular in the deep layer. The effect is muscular fixation of the vertebral motion segment: a restriction. This is the same mechanism that, according to Hansen & Schliack (1962), leads to scoliosis in visceral disease.
Today it is possible to distinguish a number of characteristic patterns related to visceral disease (see Chapter 7) which points to certain pathogenetic rules. Another characteristic feature of this type of restriction is its recurrence if the internal disease relapses or exacerbates. Admittedly, however, we know more about visceral influence upon the spinal column than about the influence of the spinal column on visceral organs.

2.5. The spinal column as a functional unit

The most important functions performed by the spinal column are:

• giving support and protection to neural structures
• being the axis of motion for the body
• helping to maintain the balance of the body.

As we can see from the first two functions listed, these roles are contradictory; Gutmann (1965)

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