Nordic Seating Symposium October 4. – 6. 2006
in Copenhagen
Preventive care through postural management and dynamic stability
Erik Bergh
PHYSIOTECH AS
Norway
Preventive care through postural management and dynamic stability.
Objective.
Too many wheelchair users still suffer from secondary illnesses. Activity outside the wheelchair is encouraged, but for practical reasons, users sit in their wheelchairs for many hours every day. We would like to focus on the concept that variations in sitting position, even minor ones, might be of vital importance in preventing a number of secondary illnesses.
I will also try to show that minor movements, which I call micro variations, are of major importance in carrying out daily activities and maintaining good sitting comfort in the wheelchair. In order to prevent instability, when users perform these micro variations and changes in position, they need to utilise external stabilising forces. This is what I refer to as Dynamic Stability.
Introduction.
Poison alert
If we were to be threatened with a weapon such as a gun or an axe, we would be immediately aware of a serious risk to our health and wellbeing. We would be very likely to take defensive action; and quickly.
If we compare the axe and the gun to pressure sores we can see and understand the preoccupation of therapists and professionals with pressure management and preventive action – the threat is obvious and dangerous and requires immediate defensive action.
However, if someone introduces us to junk food we are much less likely to perceive it as a threat to our health and wellbeing and may accept it as a normal part of life requiring no defensive action. However, over the long term, junk food can be just as deadly as the axe or gun but much more dangerous because the threat goes unnoticed.
Junk food is what I refer to as the slow poison of good health.
With poor positioning and lack of movement for wheelchair users, the threat is less obvious but it can, in the long term, cause a serious and perhaps irreversible decline in health and wellbeing and even premature death.
Poor seating and lack of movement should be considered a slow poison.
In his way it will remind and encourage us to acknowledge the threat and to take defensive action.
Secondary illnesses
When we disagree in our seating discussions I have found that we quite often have different references and therefore different starting point for our discussions. I would like to inform you of my definitions and references.
The interesting and challenging cases in wheelchairs are the chronic users. They have limited, or no, walking ability and they have impaired trunk stability.
Chronic wheelchair users live longer today than a few decades ago. The challenges in terms of secondary illness increase with increasing age.
We know quite a lot about the kind of secondary illnesses suffered by wheelchair users (1):
Pressure ulcers Respiratory failure
Bladder problems/kidney failure Bowel problems
Contractures Osteoporosis Spasticity
Cardiovascular failure
We also know a great deal about the aetiology of these secondary illnesses. The chronic use of a wheelchair must share the blame for many of these conditions. A static and chronic sitting position is not good for any human being, especially those with disabilities and with reduced trunk stability.
In spite of the intense focus on secondary illnesses it is still a major problem in our countries. We must conclude from the evidence that we still have a long way to go.
An example from Norway shows that the National Health Services estimated their expenses on treating pressure ulcers to 1 billion NOK in 2002. (€ 125.000.000)
This is the cost of the treatment of approx. 30 000 pressure ulcers in a population of 4.5 million inhabitants. The pain and suffering conditions of the affected persons is an even more tragic story.
If chronic use of wheelchair and one-sided sitting position are among the biggest problems, what are the most effective remedies?
Positional movement
There is of course no simple remedy; we have to take several different measures. From what I have read and from my own experience I would like to focus on the most effective one: Positional movement
Transfer to alternative seating and support surfaces or devices.
In order to achieve variation in position we recommend that the client gets out of the wheelchair as often as possible. This sounds simple enough, but for most clients it is not feasible. Most wheelchair users demand that they be mobile at the same instant the need for mobility occurs. It is perceived as impractical and in some ways undignified not to be mobile at will.
Transfer may also be difficult and, quite typically, the clients in most need of variation are the clients with the greatest transfer problems.
Wheelchairs with macro variation facilities
Some people in the rehab industry have responded to these needs and designed wheelchairs which allow some variation in position. The products give the clients the opportunity to change position while sitting in the chair. There are numerous designs;
wheelchairs with tilt in space and angle adjustable backs. And lately we have seen very practical chairs which incorporate a stand-up function.
In Norwegian rehab hospitals all the SCI patients are offered a wheelchair with a stand- up function. Unfortunately more than half of them decline this offer.
The explanation may not always be simple, but in my experience the stand-up function, or other variation facilities in the manual wheelchair, are accompanied by an increase in weight with a consequent reduction in the performance of the wheelchair. At present this applies to all models on the market. With power chairs it is easier, but not all functions can be combined without making the chair longer or more difficult for transfer.
Micro variations
Micro variation is the change of the position of the upper body without moving the pelvis on the seat.
We have some evidence and some empiric data to claim that micro variation is important to prevent secondary illnesses. (6,7,8)
The choice of wheelchair
The user will prioritise functions that will help with mobility and practical daily tasks.
To make these tasks as simple as possible to execute they usually choose a light weight, compact wheelchair with good driving and manoeuvring performance.
In order to optimize the driving performance in the manual wheelchair we must fit the chair to the client in one specific sitting position. This is because changes in position will affect the balance point and hence the driving characteristics of the wheelchair.
For many wheelchair users therefore we are not only talking about the chronic use of the wheelchair. We are also talking about a chronic sitting position.
The chronic sitting position.
The chronic sitting position has been the subject of intense debate over many years.
What is the optimum seat angle and how do we shape the seat? How high should the back be made and what is the most suitable back angle?
In my experience each client is so different from others that it is difficult to talk about rules and principles. But there is undoubtedly a need for some guidelines and
references. In my experience the most important ones are comfort and vertical balance.
Still there are some misunderstandings regarding these two concepts, and I would like to share a couple of examples with you:
“ – it is important that the seat is not too comfortable. It can lead to a passive attitude in the client…”
And
“ – I position the client as vertical as possible. In that way the client gets to develop trunk stability…”
A few years ago I was driving down to the coast on a nice summer morning. I enjoyed my new car with its nice comfortable seats. I reflected that is important to have
comfortable seats when you sit in the same position more than 2 hours. In the same instant I was struck by the comparison with chronic wheelchair users.
Comfort
The two concepts of comfort and vertical balance will sometimes be contradictory .I have decided that I should always start with comfort.
How do we define comfort? I have read several definitions and one of the most logical ones for me is also quite simple:
“Perception of comfort can perhaps best be defined by the lack of discomfort, i.e.
unpleasant sensations of pain and pressure in the muscles, joints, and other parts of the body (Dirken 1994)”(3).
In what way is comfort influenced over time? ” – when we observe an individual’s sitting behaviour we find that an element of variation is constantly present: the position of the upper part of the body in relation to the backrest can be changed by placing the greater part of the load alternately on the left an then the right buttock; the trunk can also be moved forwards, changing the load distribution on the seating surface; a new sitting posture can be adopted by taking up a new position in relation to the backrest.”
(3)
Those of us not using a wheelchair, change position in our seats more or less
unconsciously. We are not only changing position to change the load on the buttocks, we also change position in order to relax the different muscles in the upper body and upper extremities.
Perception of comfort is partly related to the suitability of a sitting posture for a particular activity. This means that it will always be a need for changes of position, sometimes only minor ones, to get the optimum comfort for different activities.
We have therefore two forces that stimulate the user to change position, both in pursuit of comfort: the need to change load for improved comfort and the need to change position to suit different activities.
Both will lead to micro variations in position.
The vertical balance
There is however a challenge to the micro variation.
We position the client as vertical as possible in order to be comfortable when she is doing different tasks during the day.
In order to change activities there will be a need to be stable in several different positions.(10) For many clients the stability is obtained from outside forces like the support from the wheelchair back upholstery.
The external support
In my experience we see 4 different scenarios with our clients who willingly want to make minor changes of position in their wheelchairs:
1. When a person wants to change position in the wheelchair seat but lacks the necessary stabilizing forces from their muscles, and from the wheelchair, they will fall out of the chair. Fortunately we do not see this very often. However I have seen and heard elderly people in nursing homes shout for help. We may think they are demented, but I have seen examples where they are slowly falling out of their wheelchairs. They feel the discomfort and helplessness and they are unable to do anything about it.
2. The client lacks trunk stability and we have adapted the seat in such a way that he will be supported at all times. This is a common situation among multi handicapped children. We give them a good location and support for the upper body with a high back, thoracic supports and a four-point harness. This gives the child a stable position but at the same time it denies the child the opportunity to move. We have deprived them of the opportunity for micro variations in posture.
3. The third scenario is most commonly seen among SCI Tetraplegics. The Tetraplegic’s choice is a simple, low back for the wheelchair. Their choice has two motives. The first one is vanity. The second one is that, for practical
reasons, SCI Tetraplegics frequently choose freedom to move at the expense of stability. A more supportive back will inhibit their opportunity to move and change position. But now they have lost their stability. To compensate, they slide forward in their seats, turn and use the upper extremities to establish the necessary stability in a vertical sitting position.
4. The last scenario is the client sitting with a dynamic upper body support. The dynamic upper body support will help them to get the necessary stability when they move and change position with their upper body. The character of this support will not only support them in different positions, it will also support the client when he wants to get back to the starting point. This means the support must be progressive.
We have already seen examples of equipment that will give dynamic support. The harnesses made of neoprene are one example. We have also examples of dynamic thoracic supports. In my opinion there is unfortunately still a long way to go for the rehab industry to take this challenge seriously. It is a fact that almost all the dynamic products available are optional accessories. None of the manufacturers have dynamic products as standard on their wheelchairs.
Prevention.
We have some evidence and some empiric data to claim that micro variations are important in preventing secondary illnesses:
1. First of all we see that micro variations will change the load on the buttocks. It is the movement of the upper body that makes this change of load. The very best evidence we have is the comparison between active users who self propel and those users who do not. Minor movements through propulsion and daily routines are known to have an effect on interface pressures, the transients arising
providing a level of random but effective remission of pressure peaks thus providing an important element of a pressure management environment. (11)
2. Secondly we know that respiratory illnesses are one of the most common causes of death among for example SCI. Small changes of position in the upper body will lead to improved ventilation.
3. The importance of exercise and movement to cardio-vascular health, blood circulation and cell viability is well understood but activity and movement is also important for the tissue deformation which encourages lymphatic flow - a significant factor in maintaining our immune system.
4. Movement is the natural antidote to the tendency, with decreased activity, for the connective fibres of ligaments and tendons to begin to adhere to each other losing resilience and making them vulnerable to sudden overload.
5. Studies of SCI shows that more than 80% of the users sitting in wheelchair for several years suffer from back pain.(5) It is however difficult to identify the exact cause of this pain. There are reports stating that some of the pain must be related to the degeneration of the intevertebral discs. Avascular cells such as the intervertebral discs depend upon diffusion for nourishment, repair and the removal of waste products. Movement of the spine can aid the hydration and diffusion process and reduce the risk of degeneration caused by prolonged static loading. (12)
Conclusion
The opportunity for momentary relief through small movements at will is an important component of mental as well as physical well-being and goes largely unnoticed in those not affected by disabling conditions.
Practical tests in wheelchair assessments demonstrate, in many cases, that following the provision of an effective, dynamic upper body support, with the opportunity for minor movement, the client reports less pain, less discomfort and less skin redness
Many Therapists are aware of these issues but lack the forum in which to voice their concerns, share their views and thereby attract the attention and activity of those who can stimulate, support and undertake the appropriate research.
We are convinced that preventive care through postural management and dynamic stability is of more importance than science has yet concluded. We encourage the scientific community to seek conclusive evidence. If such evidence is forthcoming we believe that manufacturing industry will be compelled to provide us with more suitable products in the future.
References
1. Thomas P Stewart; The Physiological Aspects of Immobilization and the Beneficial Effect of passive Standing. 1989 Retec
2. Bengt Engstrøm: Ergonomi, Sittande & Rullstolar, 1996
3. H.A.M. Staarink: Sitting posture, comfort and pressure, 1995 Delft University Press
4. Clare Wright; Postural Management and Early Intervention in Seating: What’s the Evidence?, 2006 International Seating Symposium
5. Samuelsson K, Larsson H, Thyberg M, Tropp H. 1996. Back pain and spinal deformity - common among wheelchair users with spinal cord injuries. 1996 Scand J Occ Ther 3:28-32.
6. Tam EW; Pelvic movement and interface pressure distribution during manual wheelchair propulsion. 2003
7. Harris GE; Thoracic suspension: quantitative effects upon seating pressure and posture. 1987
8. Bar CA; Evaluation of cushions using dynamic pressure measurement. 1991 9. Mooney V; Rehabilitation and exercise for a healthy back. 2001
10. Kamper D; Preliminary investigation of the lateral postural stability of spinal cord-injured individuals subjected to dynamic perturbations. 1999
11. Aissaoui R; Effect of seat cushion on dynamic stability in sitting during a reaching task in wheelchair users with paraplegia. 2001
12. Urban JPG; Nutrition of the intervertebral Disc. Focus Issue on Disk Degeneration. 2004
