The adolescent idiopathic scoliosis (AIS) is a 3D deformity of the spine whose origin is unknown and clinical evolution unpredictable. In this work, a mixed theoretical and numerical approach based on energetic considerations is proposed to study the global spine deformations. The introduced mechanical model aims at overcoming the limitations of computational cost and high variability in physical parameters. The model is constituted of rigid vertebral bodies associated with 3D effective stiffness tensors. The spine equilibrium is found using minimization methods of the mechanical total energy which circumvents forces and loading calculation. The values of the model parameters exhibited in the stiffness tensor are retrieved using a combination of clinical images post-processing and inverse algorithms implementation. Energy distribution patterns can then be evaluated at the global spine scale to investigate given time patient-specific features. To verify the reliability of the numerical methods, a simplified model of spine was implemented. The methodology was then applied to a clinical case of AIS (13-year-old girl, Lenke 1A). Comparisons of the numerical spine geometry with clinical data equilibria showed numerical calculations were performed with great accuracy. The patient follow-up allowed us to highlight the energetic role of the apical and junctional zones of the deformed spine, the repercussion of sagittal bending in sacro-illiac junctions and the significant role of torsion with scoliosis aggravation. Tangible comparisons of output measures with clinical pathology knowledge provided a reliable basis for further use of those numerical developments in AIS classification, scoliosis evolution prediction and potentially surgical planning.

青少年特发性脊柱侧弯 (AIS) 是脊柱的 3D 畸形，其起源未知且临床演变不可预测。在这项工作中，提出了一种基于能量考虑的混合理论和数值方法来研究整体脊柱变形。引入的力学模型旨在克服计算成本和物理参数高度可变性的限制。该模型由与 3D 有效刚度张量相关的刚性椎体构成。脊柱平衡是使用机械总能的最小化方法找到的，它绕过了力和负载计算。使用临床图像后处理和逆算法实现的组合来检索刚度张量中显示的模型参数的值。然后可以在整体脊柱尺度上评估能量分布模式，以研究给定时间的患者特定特征。为了验证数值方法的可靠性，实现了脊柱的简化模型。然后将该方法应用于 AIS 的临床病例（13 岁女孩，Lenke 1A）。数值脊柱几何形状与临床数据平衡的比较表明数值计算非常准确。患者随访使我们能够强调变形脊柱的顶端和交界区的能量作用、骶髂关节处矢状弯曲的影响以及扭转与脊柱侧弯加重的重要作用。