IEEE Trans Biomed Eng. 2024 Oct;71(10):3055-3068. doi: 10.1109/TBME.2024.3408076. Epub 2024 Sep 19.
Electrical stimulation is known to enhance bone healing. Novel electrostimulating devices are currently being developed for the treatment of critical-size bone defects in the mandible. Previous numerical models of these devices did not account for possible uncertainties in the input data. We present the numerical model of an electrically stimulated minipig mandible, including optimization and uncertainty quantification (UQ) methods that allow us to determine the most influential parameters.
Uncertainties in the optimized finite element model are quantified using the polynomial chaos method that is implemented in the open-source Python toolbox Uncertainpy. The volumes of understimulated, beneficially stimulated, and overstimulated tissue are considered quantities of interest because they may significantly impact the expected healing success. Further, the current is a substantial quantity, limiting the lifetime of a battery-driven stimulation unit. With sensitivity analyses, the most critical parameters in the numerical model can be identified. Thus, we can learn which parameters are particularly relevant, for example, when conceptualizing the stimulation unit or planning the manufacturing process.
The results of this study show that the parameters of the electrode-tissue interface (ETI), as well as the conductivity within the defect volume, have the most significant impact on the model results.
The UQ results suggest that careful characterization of the ETI and the dielectric tissue properties is crucial to reduce these uncertainties.
The numerical model regarding uncertainties yields important implications for reliable implant design and clinical translation.
电刺激已被证实可促进骨愈合。目前正在开发新型电刺激装置，用于治疗下颌骨的临界尺寸骨缺损。这些装置的先前数值模型没有考虑到输入数据中的可能不确定性。我们提出了电刺激小型猪下颌骨的数值模型，包括优化和不确定性量化 (UQ) 方法，使我们能够确定最具影响力的参数。
使用多项式混沌方法对优化有限元模型中的不确定性进行量化，该方法在开源 Python 工具包 Uncertainpy 中实现。未受刺激、有益刺激和过度刺激组织的体积被视为感兴趣的数量，因为它们可能会显著影响预期的愈合成功率。此外，电流是一个重要的数量，限制了电池驱动刺激单元的使用寿命。通过灵敏度分析，可以确定数值模型中最关键的参数。因此，我们可以了解哪些参数特别重要，例如，在构思刺激单元或规划制造过程时。
本研究的结果表明，电极-组织界面 (ETI) 的参数以及缺陷体积内的电导率对模型结果的影响最大。
UQ 结果表明，仔细表征 ETI 和介电组织特性对于降低这些不确定性至关重要。
关于不确定性的数值模型为可靠的植入物设计和临床转化提供了重要的启示。
