Biomechanical evaluation of Cheneau-Toulouse-Munster brace in the treatment of scoliosis using optimisation approach and finite element method.

The aim of the study was to investigate the mechanisms of the Cheneau-Toulouse-Munster (CTM) brace in the correction of scoliotic curves, at night in the supine position. Magnetic resonance imaging (MRI) and Computer tomography (CT) acquisitions were performed in vivo on eight girls having an idiopathic scoliosis and being treated for the first time using a personalized CTM brace. Personalized 3D finite element models of the spine were developed for each patient, and an optimisation approach was used to quantify the forces generated by each brace on each scoliotic spine. A sensitivity study was undertaken to test the assumptions about intervertebral behaviour and load transmission from the brace to the spine. The computed CTM brace forces were 9-216N in the coronal plane and 2-72N in the sagittal plane. Personalized spinal stiffness properties should be included in spine models because, in this study, partial correction resulted from the application of higher estimated forces than for total correction. Partially reduced spines should be stiffer than totally reduced spines. The sensitivity study showed that the computed brace forces were proportional to the intervertebral Young's modulus and should be analysed as estimated data. Better knowledge of brace forces should be helpful in brace design to achieve the best correction of first scoliotic deformities.