Infinite models in scoliosis: a review of the literature and analysis of personal experience.

The purpose of this study was to introduce infinite models in scoliosis and to analyze personal experience. Based on a three-dimensional patient-specific finite element model of the spine, rib cage, pelvis and abdomen, a parametric individual model of a thoracolumbosacral orthosis was built. Three standard strap tensions (20, 40, 60 N) were loaded on the back of the brace to simulate the strap tension. The I-Scan distribution pressure measurement system was used to measure the pressure of the different regions and the equivalent forces in these regions were calculated. The spinal curve changes and the forces acted on the brace generated by the strap tension were evaluated and compared with the measurement results. The reduction of the coronal curvature was approximately 60% for a strap tension of 60 N. The sacral slope and the lordosis were partially reduced in this case. The brace modified the axial rotation at the deformed vertebrae. The forces generated in finite element analysis were in good agreement with the measurement. The findings supported the feasibility of such an approach to analyze individual bracing biomechanics, which may be useful in the design of more effective individual braces.