Effects of posture and spinal bracing on respiratory function in neuromuscular disease.

Effects of posture and spinal bracing on lung function were studied in 40 children with neuromuscular disease, 20 of whom had scoliosis and were non-ambulant. Change from sitting to supine position had little effect on lung function in ambulant children, but caused a significant 12% reduction in forced vital capacity in a group of 16 non-ambulant children with scoliosis, suggesting diaphragmatic weakness in some. Spinal bracing, using a rigid supporting jacket, resulted in a significant reduction in mean vital capacity of 22%. The degree of impairment in forced vital capacity was proportional to the severity of the scoliosis (as measured by the Cobb's angle), to the amount of correction achieved by the brace, and to the degree of diaphragmatic weakness. Spinal bracing in a child with established severe scoliosis causes appreciable respiratory impairment, and this may explain why it is less likely to be tolerated than early prophylactic bracing.