In vivo geometrical evaluation of Cheneau–Toulouse–Munster brace effect on scoliotic spine using MRI method

Objectives. The aim was to quantify the immediate effect of the Cheneau–Toulouse–Munster brace (worn at night) on scoliotic curvatures in vivo. Design. A three-dimensional geometrical model of the spine was developed using magnetic resonance images. Background. Many corrective ortheses were proposed for the orthopaedic treatment of idiopathic scoliosis. Simple radiographs were not sufficient to analyse the three-dimensional spinal deformations. So, three-dimensional geometrical models were developed using stereoradiography and axial tomography. MRI has been only used clinically for investigation of intervertebral disc disorders. Method. MRI examination had been performed on 14 girls having an idiopathic scoliosis and wearing a first Cheneau–Toulouse–Munster brace. The protocol investigated was performed with and without brace. Using an in-house image processing software and the pre-post processing software Patran, two geometrical models of the spine (spine without brace and spine with brace correction) were obtained, respectively, for each patient, the models including the vertebral bodies. Results. Our method reproducibility was found to be 0.5 mm on the displacements and 2.5° on the rotations. The Cheneau–Toulouse–Munster brace decreased the coronal shift forward, the coronal tilt, the axial rotation, and increased the sagittal shift forward and the sagittal vertebral tilt. Discussion. The results showed that the Cheneau–Toulouse–Munster brace had a three-dimensional and personalised action on vertebrae. This technique using MRI provides no irradiation and allows the soft tissue visualisation, but actually is not dedicated for clinical use and is limited to the lying position.