To develop an anatomically based customizable finite-element (FE) model of the pelvic floor support system to simulate pelvic organ prolapse (POP): POP-SIM1.0. This new simulation platform allows for the construction of an array of models that objectively represent the key anatomical and functional variation in women with and without prolapse to test pathomechanism hypotheses of the prolapse formation. POP-SIM1.0 consists of anatomically based FE models and a suite of Python-based tools developed to rapidly construct FE models by customizing the base model with desired structural parameters. Each model consists of anatomical structures from three support subsystems which can be customized based on magnetic resonance image measurements in women with and without prolapse. The customizable structural parameters include presence of levator ani (LA) avulsion, hiatus size, anterior vaginal wall dimension, attachment fascia length and apical location in addition to the tissue material properties and intra-abdominal pressure loading. After customization, the FE model was loaded with increasing intra-abdominal pressure (0-100 cmH2O) and solved using ABAQUS explicit solver. We were able to rapidly construct anatomically based FE models with specific structural geometry which reflects the morphology changes often observed in women with prolapse. At maximum loading, simulated structural deformations have similar anatomical characteristics to those observed during clinical exams and stress magnetic resonance images. Simulation results showed the presence of LA muscle avulsion negatively impacts the pelvic floor support. The normal model with intact muscle had the smallest exposed vaginal length of 11 mm, while the bilateral avulsion produced the largest exposed vaginal length at 24 mm. The unilateral avulsion model had an exposed vaginal length of 18 mm and also demonstrated a tipped perineal body similar to that seen in clinical observation. Increasing the hiatus size, vaginal wall length and fascia length also resulted in worse pelvic floor support, increasing the exposed vaginal length from 18 mm in the base model to 33 mm, 54 mm and 23.5 mm, respectively. The developed POP-SIM1.0 can simulate the anatomical structure changes often observed in women with prolapse. Preliminary results showed that the presence of LA avulsion, enlarged hiatus, longer vaginal wall and fascia length can result in larger prolapse at simulated maximum Valsalva.

中文翻译：

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开发基于解剖学的可定制盆底支撑系统三维有限元模型：POP-SIM1.0。

开发基于解剖学的可定制盆底支撑系统有限元 (FE) 模型来模拟盆腔器官脱垂 (POP)：POP-SIM1.0。这个新的模拟平台允许构建一系列模型，客观地代表有或没有脱垂的女性的关键解剖和功能变化，以测试脱垂形成的病理机制假设。POP-SIM1.0 由基于解剖学的有限元模型和一套基于 Python 的工具组成，这些工具旨在通过使用所需的结构参数定制基础模型来快速构建有限元模型。每个模型由三个支撑子系统的解剖结构组成，这些子系统可以根据有或没有脱垂的女性的磁共振图像测量结果进行定制。可定制的结构参数包括提肛肌 (LA) 撕脱的存在、裂孔大小、阴道前壁尺寸、附着筋膜长度和顶端位置，以及组织材料特性和腹内压力负荷。定制后，有限元模型加载腹内压增加 (0-100 cmH2O)，并使用 ABAQUS 显式求解器进行求解。我们能够快速构建具有特定结构几何形状的基于解剖学的有限元模型，该模型反映了在脱垂女性中经常观察到的形态变化。在最大载荷下，模拟的结构变形与临床检查和应力磁共振图像中观察到的结构变形具有相似的解剖学特征。模拟结果表明，LA 肌肉撕脱的存在会对盆底支撑产生负面影响。肌肉完整的正常模型的最小暴露阴道长度为11毫米，而双侧撕脱产生的最大暴露阴道长度为24毫米。单侧撕脱模型的暴露阴道长度为 18 mm，并显示出与临床观察相似的倾斜会阴体。增加裂孔尺寸、阴道壁长度和筋膜长度也会导致盆底支撑更差，暴露的阴道长度从基础模型中的 18 毫米分别增加到 33 毫米、54 毫米和 23.5 毫米。开发的POP-SIM1.0可以模拟脱垂女性中经常观察到的解剖结构变化。初步结果表明，LA撕脱、裂孔扩大、阴道壁和筋膜长度较长可导致模拟最大Valsalva时较大的脱垂。