Biomechanical action of a corrective brace on thoracic idiopathic scoliosis: Cheneau 2000 orthosis.

PURPOSE: To provide a detailed description of the mechanisms responsible for the corrective effect of the rigid brace Cheneau 2000.
METHODS: Morphology of thoracic scoliosis is presented, including surface trunk asymmetries and radiological deformation. Biomechanical rules, applied to achieve curve correction in the three planes, are the subject of a comprehensive review.
RESULTS: Tissue transfer in the three dimensions, elongation effect, rib cage 'derotation' and bending are the passive mechanisms of correction. Restoring of physiological thoracic kyphosis is promoted by a special combination of pads and free spaces in the brace. Hypercorrection is achievable in some clinical situations, especially for the trunk imbalance. Attention is attached to the active mechanisms of corrective bracing, comprising the modeling of vertebral growth, asymmetrically guided respiratory movements, repositioning of the spatial arrangement of trunk muscles and the anti-gravitational effect.
CONCLUSIONS: Contemporary corrective orthosis for idiopathic scoliosis should take advantage of specific passive and active mechanisms. Preservation of the function of the vertebral column as a flexible framework for the human body, as well as the preservation of the respiratory function of the thorax stay ambitious goals to approach, and a significant progress over recent years has been observed.