Pedicle screw-rod insertion is a common surgical procedure used for treating degenerative spinal diseases. Optimized design of such implants is necessary to avoid undue strains at the bone–implant interface. In this work, ideal optimized implant design is defined as one for which the strain difference between intact bone and bone after implantation at six interfacial positions is zero. To achieve this, genetic programming (GP) based symbolic regression (SR) metamodels are built from limited data obtained from expensive but highly accurate finite element (FE) models. The FE models are generated from CT scan data. A cumulative objective function is expressed in terms of GP-based SR metamodels which is then combined with a genetic algorithm (GA) to predict patient-specific optimum implant designs.

中文翻译：

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基于符号回归元模型的患者特定脊柱植入物（椎弓根螺钉固定）的优化设计

椎弓根螺钉插入是一种常见的外科手术，用于治疗退行性脊柱疾病。此类植入物的优化设计对于避免骨-植入物界面处的过度应变是必要的。在这项工作中，理想的优化种植体设计被定义为在六个界面位置植入后完整骨和骨之间的应变差为零。为实现这一目标，基于遗传编程 (GP) 的符号回归 (SR) 元模型是根据从昂贵但高度准确的有限元 (FE) 模型中获得的有限数据构建的。FE 模型是根据 CT 扫描数据生成的。累积目标函数以基于 GP 的 SR 元模型表示，然后与遗传算法 (GA) 结合以预测患者特定的最佳种植体设计。