Joint Degree Programme in IIT Madras, CMC Vellore & Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
Department of Spine Surgery, Christian Medical College, Vellore, India.
Med Eng Phys. 2023 Aug;118:104016. doi: 10.1016/j.medengphy.2023.104016. Epub 2023 Jun 28.
Instrumentation alters the biomechanics of the spine, and therefore prediction of all output quantities that have critical influence post-surgically is significant for engineering models to aid in clinical predictions. Geometrical morphological finite element models can bring down the development time and cost of custom intact and instrumented models and thus aids in the better inference of biomechanics of surgical instrumentation on patient-specific diseased spine segments. A comprehensive hexahedral morphological lumbosacral finite element model is developed in this work to predict the range of motions, disc pressures, and facet contact forces of the intact and instrumented spine. Facet contact forces are needed to predict the impact of fusion surgeries on adjacent facet contacts in bending, axial rotation, and extension motions. Extensive validation in major physiological loading regimes of the pure moment, pure compression, and combined loading is undertaken. In vitro, experimental corridor results from six different studies reported in the literature are compared and the generated model had statistically significant comparable values with these studies. Flexion, extension and bending moment rotation curves of all segments of the developed model were favourable and within two separately established experimental corridor windows as well as recent simulation results. Axial torque moment rotation curves were comparable to in vitro results for four out of five lumbar functional units. The facet contact force results also agreed with in vitro experimental results. The current model is also computationally efficient with respect to contemporary models since it uses significantly smaller number of elements without losing the accuracy in terms of response prediction. This model can further be used for predicting the impact of different instrumentation techniques on the lumbar vertebral column.
器械会改变脊柱的生物力学，因此预测所有对术后有重要影响的输出量对于帮助临床预测的工程模型来说非常重要。几何形态有限元模型可以降低定制完整和器械模型的开发时间和成本，从而有助于更好地推断手术器械对特定于患者的病变脊柱段的生物力学影响。本工作开发了一个全面的六面体形态腰骶部有限元模型，以预测完整和器械脊柱的运动范围、椎间盘压力和小关节接触力。需要小关节接触力来预测融合手术对弯曲、轴向旋转和伸展运动中相邻小关节接触的影响。在纯力矩、纯压缩和组合加载的主要生理负荷状态下进行了广泛的验证。在体外，比较了文献中六项不同研究的实验通道结果，生成的模型与这些研究具有统计学上显著的可比值。所开发模型的所有节段的屈伸和弯矩旋转曲线都很好，并且在两个单独建立的实验通道窗口以及最近的模拟结果内。轴向扭矩旋转曲线与五个腰椎功能单元中的四个的体外结果相当。小关节接触力结果也与体外实验结果一致。与当代模型相比，当前模型在计算效率方面也具有优势，因为它使用的元素数量明显减少，而在响应预测方面不会失去准确性。该模型还可以进一步用于预测不同器械技术对腰椎的影响。
