Management of scoliosis with special seating for the non-ambulant spastic cerebral palsy population--a biomechanical study.

OBJECTIVE: To investigate the effects of special seating on lateral spinal curvature in the non-ambulant spastic cerebral palsy population with scoliosis. DESIGN: Prospective study with matched pairs (same subject pre- and post-intervention). BACKGROUND: It is thought that special seating can improve the sitting posture of individuals with spastic cerebral palsy. However, there is little known about how the seating can affect a scoliosis. METHOD: The shape of the spine was measured with subjects sitting in an assessment chair with a clear backrest. The measurement recorded was the "spinous process angle", an approximation to the Cobb angle. The forces exerted on the subject by the chair were measured by electrical resistance strain gauged transducers attached to the lateral support pads and seat base. Measurements were taken with three alternative arrangements of lateral support pads: upper body unsupported in configuration 1; two lateral pads at the same height in configuration 2; body supported by a 3-point force system in configuration 3. RESULTS: Configuration 3 gave a mean correction of +35% in the spinous process angle compared to configuration 1 (P=0.000) and the forces applied through the two lateral thoracic pads were, on average, of similar magnitude (mean values of 51 and 47 N). In comparison, for configuration 2 the mean correction was only +18.7% (P=0.004) and on average the pad on the concave side of the scoliosis applied a much larger force to the chest wall than the pad on the convex side (mean values of 36 and 17 N respectively). CONCLUSIONS: Significant static correction of the scoliotic spine can be achieved with an arrangement of lateral pads on a seating system that applies a 3-point force system to the sides of the body. RELEVANCE: The results suggest that the position of the lateral pads on a special seating system is important and, by the careful configuration of these supports, significant correction of a scoliosis can be obtained for a person with spastic cerebral palsy. Also the methodology and equipment from this study are potentially useful for the assessment and fitting of special seating for individuals with scoliosis.

Early development of systems analysis in natural resources management from man and nature to the miami conservancy district.

Contemporary approaches to natural resources and environmental decision-making typically draw on a "systems" perspective to assess and improve management strategies. This paper describes the early genesis of the systems analysis approach. It concentrates on a period between the mid-19th to early 20th centuries. During the early part of this period, George Marsh's Man and Nature and related works laid out an approach to problem-solving that recognized the relationship among physically disperse elements in the environment, the need to balance benefits against costs, the potential for using quantitative modeling to understand management options, and the importance of integrating human and natural components into solutions. In the early 20th century, the Miami Conservancy District project brought this approach to fruition with its use of complex simulation and optimization modeling, detailed cost-benefit analysis, and its linking of economics, engineering, science, and law into a far-reaching solution to a complex water resources problem. The objective of this paper is to describe the early development and application of this conceptual approach to problem-solving. An examination of the origins of natural resources systems analysis can broaden one's perspective of the contemporary field to understand its roots as a philosophy for environmental problem-solving.