Three-dimensional Effects of Bracing in Adolescent Idiopathic Scoliosis

Scoliosis is a 3D deformity of the spine with curvatures occurring in three planes.

The efficacy of bracing in correcting the frontal deformity is now well-accepted after the Bracing in Adolescent Idiopathic Scoliosis Trial (BRAIST). Restoration of the sagittal alignment is one of the fundamental goals in scoliosis treatment. The investigators have previously demonstrated on fulcrum bending radiographs that there is coupling between the frontal deformity, thoracic kyphosis and apical vertebral derotation. The investigators' findings suggest that there may be natural coupling of the frontal and sagittal deformities towards "self-normalisation" during correction of the curves. The effect of bracing on the sagittal alignment and 3D deformity in scoliosis is currently not well-understood. If there is a tendency for the natural curve behaviour to return towards a more normal sagittal alignment, then bracing may exert a similar effect on the 3D profile. Understanding how the 3D deformity is affected by bracing allows further insight into curve progression and brace effectiveness.

Few studies in the literature have addressed the sagittal profile and 3D correction by bracing. Of those, the findings were based on vertebral reconstructions obtained from CT-scan, finite element analysis modelling, or studying the changes in the rib cage rotation. However, the investigators propose to measure the 3D profile using the modern EOS ® system, which allows biplanar radiography and 3D calculations and a more accurate measurement of vertebral wedging.