The Chailey Approach to Postural Management:
The Theory and Practice of a Twenty-four Hour Approach
Terry Pountney, MA MCSP, Eur Ing;
R L Nelham, B.Eng, C.Eng, MIMechE, FIPEM, FISPO, SRCS;
Alice Goldwyn, MSc, B.Eng
INTRODUCTION
This approach has been developed over the past 15 years and is based on the Chailey Levels of Ability. It is a move away from customised seating, which primarily focused on comfort and function, and systematically addresses the issues of improving motor ability and development of deformity. It covers the 24 hour day and is a combination of positioning, hands on treatment and active exercise which is backed up by a programme of education for parents and carers . Equipment providing postural support in lying, sitting and standing as part of a twenty four hour programme has three main aims: to promote normal movement; improve practical ability and reduce deformity. The role of all these functions is interlinked and all are interdependent.
The Chailey Levels of Ability describe the developmental biomechanics of posture and form the basis of the Chailey adjustable postural support systems (CAPS). This equipment is designed to position the child at a higher level of ability by altering the loadbearing surfaces and position of the trunk, pelvis, shoulder girdle and limbs. The aim of the equipment is to achieve a Chailey Level of Ability of 4 or above in each of the positions. The components of this level include maintenance of symmetry, a neutral or anteriorly tilted pelvis, a protracted shoulder girdle, a chin tuck and active movement within the base of support .
The Chailey lying support is intended to be used as part of the 24 hour postural management programme for daytime use and sleeping. It can be set up for use in prone and supine . The lying support is adjusted and fitted to each child and requires no further adjustment each time it is used. The child must be positioned carefully to ensure the pelvis is correctly aligned. As the child grows the support can be adjusted for growth.
The CAPS II seating system is designed to emulate an upright sitting posture. It is an adjustable seat that provides a stable sitting base, trunk support and shoulder girdle protraction and provides the foundation for active movement of the head, arms and hands. The basic seat design consists of a cushion on a horizontal base, ramped forward from the gluteal crease to support the femora in a horizontal position. A sacral pad maintains the pelvis in an upright position and this stepped forward from a curved backrest to account for the difference in thoracic and pelvic dimensions. The sacral pad extends to the lumbosacral junction. The kneeblock maintains the pelvic position by applying a force through the femora to the hip joint. The force of the sacral pad and kneeblock are applied equally and in opposite directions and serve to maintain the pelvis in an upright position. These forces are at a minimum when the pelvis is in a neutral plane. Lateral pelvic supports help to maintain the pelvis in a symmetrical position. The seat length is crucial to achieving correct pelvic alignment .
The kneeblock and sacral pad can be used to prevent windswept deformities developing or to control existing windsweeping. The kneeblock corrects the asymmetry by bringing the adducted hip into a neutral position by an abduction force on to the medial aspect of the thigh but with no contact to the front of the knee; the abducted hip is brought into neutral position by an adducting force on the lateral aspect of the thigh; derotation of the pelvis is achieved by the force pushing back through the femur of the previously abducted hip by the kneeblock which is in contact with the knee anteriorly. The sacral pad and lateral pelvic pads counteract the forces applied by the kneeblock.
CHAILEY STANDING SUPPORT
The Chailey standing support aims to position a child so that loadbearing takes place through flat feet, vertical femora, anteriorly tilted pelvis, an upright trunk posture and provides sufficient control to be able to move away from the support. The shoulder girdle is protracted allowing free arms and hands for activity.
The elements of the standing support, which enable this posture to be achieved are a horizontal standing base, with adjustable foot supports providing the correct standing base and a contoured support for the trunk and thighs, which is angled slightly forwards from the vertical at the hips so that the trunk is supported forward over the base. This contoured surface needs to be fairly soft so that it allows some active hip and knee extension. Lateral pelvic and thoracic supports act to stabilise the pelvis and maintain symmetry whilst an abduction wedge maintains the hips in a slightly abducted position. A narrow anterior thoracic support will allow protraction of the shoulder girdle and free movement of the arms. A pelvic strap stabilises the pelvis whilst a loose chest strap allows some movement of the upper body. The tray is positioned at elbow height which is appropriate for play .
THEORETICAL BASIS OF POSTURAL MANAGEMENT
Theories of neuroplasticity and musculoskeletal underpin the provision of postural management based on normal postures. In early development the Neuronal Group Selection Theory suggests that the structure and function of the central nervous system is dependent on behaviour and function. Selection of the movement repertoire is based on movement experience and postural management can be used to alter this experience favourably .
Neuroplasticity occurs throughout life in response to changes from internal and external sensory input. Functionally based activities have been shown to be most effective in achieving change. Neuroplastic changes occur in response to movement stimulated by sensory input. Postural management offers consistent sensory input and improved function both of which contribute to neuroplasticity .
Motor learning theory indicates that numerous repetitions are required to change motor patterns. 1000,000 repetitions are needed for a consistent competent movement pattern to be laid down . It is important therefore to shift the balance towards desired movements and away from abnormal patterns. Hands on therapy alone is not sufficient and needs reinforcing through postural management over much longer periods of time .
The dynamic systems theory describes the interaction of multiple body systems with task and environment and recognises that adaptation to changing physical, environmental and task constraints changes in any part of system can change motor performance. Freezing degrees of freedom is a recognised process in skill acquisition and the co-ordination of numerous joints and muscles. Freezing out enables early control of movement by fixing joints that are not essential to the movement except for stability. Degrees of freedom are then gradually released as skills are learnt to allow fluid movement. Postural management can act to freeze out degrees of freedom and increased control of movement. Higher levels of function are possible within the equipment as the number of motor tasks requiring attention at any one time is reduced and concentration can be focused on specific motor or cognitive tasks.
MUSCLE & BONE ADAPTATION
Muscle and bone are extremely adaptable tissues which change in response to growth, use and disuse, function, nutrition and biomechanical forces. Muscle length changes occur in response to growth, with muscle lengthening following bone growth. Asymmetrical postures causes lengthening and shortening of opposing muscle groups and abnormal movement patterns lead to an imbalance of muscle activity .
Growth plates are vulnerable to effects of asymmetrical/abnormal forces. Intermittent compression stimulates growth but increased compression on one side causes a decrease in growth or a change of direction of growth. Forces applied by equipment need to reflect normal stressing that provides compression and allows some movement.
To achieve normal musculoskeletal development children need to experience forces at the chronological age not the developmental age. That is symmetrical lying at 3 months, seating at 8 months and standing at 12 months.
RESEARCH ON POSTURAL MANAGEMENT AND HIP DISLOCATION
35 - 40% of all children with cerebral palsy will experience hip dislocation but in children unable to walk independently at 5 years this rises to 60%. Hip dislocation occurs as a result of faulty loading of muscle and bone. A study of postural management and hip dislocation in a retrospective study of 60 children and young adults with bilateral cerebral palsy who had been receiving postural management for minimum of 2 years was undertaken. The outcome measures used were the Chailey Levels of Ability and hip migration percentage
The study found a significant difference between children using the Chailey 24 hour postural management programme prior to hip subluxation than those entering programmes after subluxation or other types of postural management (c 2 p< 0.05).
Currently a prospective study is underway to determine more accurately the level of postural use required to maintain hip integrity .
REFERENCES