Encinares degradados

The control of body posture includes the align- ment of body segments to each other and to the supporting surface. It requires a reference point around which movement can occur. The choice of position, both for support and for the per- formance of movement, must be considered in respect of changes in tone, the influence of gravity, potential structural deformities and preservation of tissue viability (Dufosse & Massion 1992, Pope 1992).

Movements are regularly performed on pa- tients who are unconscious, paralysed, or who have hypertonus, in order to maintain muscle and joint range. An understanding of normal movement as described in Chapter 3 is essential to ensure that movements are performed cor- rectly. Emphasis should be placed on functional

movements, ensuring an appropriate response throughout the whole body, rather than on purely movements of an isolated part.

Passive joint motion refers to any movement of an articulation that is produced by some external force (Frank et al 1984). By implication, the term 'passive' indicates that what is done is outside the patient's control and, as such, passive move- ment must be considered a powerful tool. Pa- tients who are unconscious or who have flaccid paralysis have no resistance to any force applied, whereas those dominated by stereotyped hyper- tonic posturing tend to resist movements out of these patterns.

In a recent study, Nelles et al (1999) demon- strated that passive elbow movements in hemi- plegic stroke patients before clinical recovery elicit some of the brain activation patterns described during active movement after sub- stantial motor recovery (Chollet et al 1991, Weiller et al 1993). It is suggested that the recruit- ment of ipsilateral sensory and motor pathways early after stroke may be critical for return of voluntary control.

In the clinical setting, the term 'passive' is often inappropriate in that, irrespective of their level of consciousness, patients should be involved in the activity. Verbal instruction should be given as each movement is carried out, to inform patients of the desired response and what is expected of them, and attention given to the degree of proximal mobility and alignment to effect optimal limb movement. It is only in this way that the maintenance of muscle and joint range becomes a dynamic activity rather than a mindless, routine procedure performed on the patient.

It is impossible for the physiotherapist to repli- cate, for a paralysed patient, the full gamut of functional activity undertaken in everyday life. Normal movement is dependent upon the activ- ation of appropriate agonists and antagonists, with adjustment of synergists and postural fixa- tors (Marsden 1984). Appropriate positioning is of great importance in enabling effective move- ment with this concurrent response throughout the body. For example, elevation of the arm in normal subjects is influenced by the degree

of thoracic excursion which complements this action. If the spine becomes stiff and immobile and is unable to accommodate to the arm move- ment, this movement will be performed ineffect- ively and may traumatise the shoulder joint and surrounding structures.

Limitation of range of movement is a common complication in patients with musculoskeletal and neurological conditions (Williams 1990, Pope 1992). Many authors stress the importance of passive movements to prevent this occurrence (Frank et al 1984, Pope 1992, Soryal et al 1992, Daud et al 1993, Davies 1994). However, Davies (1994), while advocating the use of passive move- ments, emphasises the need for caution, and Silver (1969) and Daud et al (1993) identified a relationship between passive movement and heterotopic bone formation in patients with spinal injury. Patients who are unable to signify pain and discomfort are at particular risk if the limb is taken to the extreme of range by a ther- apist intent on 'maintaining range of movement'.

The use of passive movement remains contro- versial. Vigorous, forceful movements carried out in the presence of severe hypertonus may cause microtears in muscle which may lead to calcifica- tion of the muscle (Ada et al 1990). Movement of a joint where there is inadequate muscular control may also lead to overstretching of tissues around the joint (Frank et al 1984). This is in part due to the lack of reciprocal activity which under normal circumstances provides proximal control and stability. Soryal et al (1992) described three patients with Guillain-Barre syndrome who had 'profound disability and social handicap over 1-3 years after acute neurological presentation pri- marily as a result of reduced joint mobility rather than neurogenic weakness'. This was considered to be the result of either inadequate passive movement or excessive passive movement, in the presence of hypotonia, traumatising the joints and surrounding structures.

When muscle is immobilised in a shortened position there is both a reduction in the muscle fibre length due to a loss of serial sarcomeres and a remodelling of the intramuscular connective tissue, leading to increased muscle stiffness (Goldspink & Williams 1990). Mobilisation of the

muscle is therefore essential to minimise these structural changes. Periods of stretch as short as half an hour each day have been found to be effective in preventing loss of sarcomeres and reducing muscle atrophy in neurologically intact mice (Williams 1990). However, Tardieu et al (1988), in a study of the soleus muscle of children with cerebral palsy, demonstrated that it was necessary for the muscle to remain in a length- ened position for 6 hours to prevent contracture.

Passive movements of the limbs may be per- formed on patients once or twice a day. This is particularly so for patients in an intensive care setting where passive movements are often carried out as a routine procedure. The time taken in carrying out these movements varies, but due to other constraints, rarely exceeds 1 hour a day in total. If, for the rest of the time, the patient is dominated by stereotyped patterns which maintain the muscles in a shortened posi- tion, this intervention, on its own, is unlikely to be effective in the maintenance of muscle and joint range. Other strategies must be developed to produce a more lasting effect in the control of body posture and movement.

Early mobilisation of the patient should be encouraged as and when the medical condition allows. Movements of the limbs while the patient is confined to bed are difficult in terms of facili- tating activity within the trunk. Where bed rest is unavoidable, it is important to maintain ade- quate movement of the trunk to maintain mobil- ity and to stimulate postural adjustments when moving the limbs.

Of equal importance is the mobility of the nervous system itself and how it adapts to body movement (Maitland 1986, Butler 1991, Hall et al 1993, Shacklock 1995). Mobilisation of the ner- vous system is used extensively in the assess- ment and treatment of pain syndromes but it is only quite recently that its importance has been recognised in the treatment of patients with neurological disability (Davies 1994, Panturin & Stokes 1998). Patients who are unable to move or who are dominated by hypertonic stereotyped postures are in as great a danger of developing shortening of neural structures as they are of loss of range of the musculoskeletal system.

Davies (1994) advocates the use of specific tension tests for the maintenance or restoration of adaptive lengthening of the nervous system. Therapists are advised to study the techniques carefully and to practice them on normal subjects prior to using them in the treatment of patients with neurological dysfunction.

POSITIONING

Different postures and positions, and their influ- ence on tone and movement, are discussed in Chapter 3. These should be considered in deter- mining the most appropriate position for treat- ment of patients with differing types of abnormal tone. However, the optimal position is not always possible due to the patient's medical condition or the presence of contractures, and modification is necessary.

Throughout this section 'acceptance of the base of support' refers to the ability of the patient to adjust appropriately to the contours of the supporting surface.

Positioning in a variety of postures is recom- mended particularly for patients dominated by

severe hypertonus. Many patients with increased tone demonstrate a degree of asymmetry which, without treatment, may lead to contracture within the stereotyped patterns. An example of this pattern of contracture is illustrated in Figure 6.3.

The pattern includes:

• rotation of the pelvis relative to the thorax • lateral flexion of the trunk

• 'windswept' lower limbs • unilateral hip adduction • abduction of the opposite hip

• bilateral knee flexion (Pope et al 1991). This pattern of contracture not only precludes sitting and standing but also adversely affects the patient's ability to accept the base of support in supine and side-lying.