Seating systems for children with cerebral palsy : study of acceptability and effectiveness
Background. Adaptive seating systems are used with children with cerebral palsy to promote function and independence and to prevent the development of deformity. A seating system that uses a sacral pad and kneeblock to control the pelvis was investigated. Methods A mixed methodology design was employed. Acceptability was addressed through the development and administration of matching questionnaires to the parents and therapists of the children participating in the project. Effectiveness was investigated by measuring pressure at the sacral pad, force exerted through a kneeblock, seated postural alignment and seated function; during a case controlled trial, where children were seen 6 times over a period of 6 months. Children removed their kneeblocks for a period of one month between visits 3 and 4. The force, pressure and postural alignment data were statistically analysed. Theoretical biomechanical analyses were also performed. Results Questionnaire results showed important differences between parents and therapists views of the seating systems. Therapists concentrated on postural management, whilst parents were concerned with day-to-day management of the child. There were few statistically significant differences over the 6-visit trial for force, pressure or postural alignment. There were no statistically significant correlations between force measured at the kneeblocks and pressure exerted through a sacral pad, nor between force and postural alignment. Statistically significant effects on hip abduction and hip rotation were found on removal of kneeblocks. Finally, individual biornechanical analysis illustrated positive effects for hip abduction for some children, but a tendency to increase deformity in half of the children. Conclusions Adaptive seating systems that use a kneeblock and sacral pad may achieve hip rotation and abduction for children with cerebral palsy. However, no other improvements in posture were seen, and biomechanical analysis showed an increase in tendency of the children to develop secondary deformity.