DEVELOPMENT OF TREATMENT WITH RESPECT TO IDIOPATHIC SCOLIOSIS

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Objectives of the present research were as follows.1. To confirm a buckling hypothesis for idiopathic scoliosis that is buckling phenomena induced by growth of vertebral bodies2. Based on the buckling hypothesis, to identify optimum reinforcement parts to prevent the buckling phenomena3. To make it possible to analyze etiology for individuals of patients and to indicate the optimum treatments for them Results were as follows.1. A spinal finite element model with thoracic cage was constructed using 68,582 elements and 84,603 nodes. Material properties of disks and joints were identified by comparing with the experimental results by literatures. From the results of the first to the seventh or eighth buckling modes for 49 cases changing growth parts, it was shown that the fourth and the sixth buckling modes are mechanical etiology for clinical shapes of single and double curves respectively. On the other hand, to observe these buckling phenomena by experiment, mechanical spine models were … More constructed using data of the numerical model. With these models, the change in the second natural vibration eigenvalue was measured by experimental modal analysis. The obtained result showing a decrease in the second natural vibration eigenvalue with the growth of vertebral bodies is confirms of the buckling hypothesis.2. Shape gradient density, sensitivity in another word, with respect to maximization problem of the critical growth of vertebral bodies to the fourth and sixth buckling modes was analyzed by the finite element method. Based on the numerical results, possibility to identify optimum reinforcement parts to prevent the buckling phenomena of various modes was demonstrated.3. To deform the spinal finite element model to fit individuals of patients, a numerical method was developed using formulation of morphing problem of finite element models to three dimensional voxel model constructed from CT or MRI images. Applying the method to fitting two dimensional finite element models to CT images and the spinal finite element model to standing X-ray image of idiopathic scoliosis, applicability to individuals of patients was demonstrated. However, etiology analysis for individuals of patients was left in the future work. Less