Oliveira Dulce A, Parente Marco P L, Calvo Begoña, Mascarenhas Teresa, Natal Jorge Renato M
INEGI, LAETA, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
INEGI, LAETA, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
J Biomech. 2016 Feb 29;49(4):594-601. doi: 10.1016/j.jbiomech.2016.01.014. Epub 2016 Feb 5.
Several studies have shown that pelvic floor injuries during a vaginal delivery can be considered a significant factor in the development of pelvic floor dysfunction. Such disorders include a group of conditions affecting women like urinary incontinence, pelvic organ prolapse and fecal incontinence. Numerical simulations are valuable tools that are contributing to the clarification of the mechanisms behind pelvic floor disorders. The aim of this work is to propose a mechanical model implemented in the finite element method context to estimate the damage in the pelvic floor muscles by mechanical effects during a vaginal delivery of a fetus in vertex presentation and occipitoanterior position. The constitutive model adopted has already been successfully used in the simulation of childbirth and the structural damage model added has previously been applied to characterize the damage process in biological soft tissues undergoing finite deformations. The constitutive parameters were fit to experimental data available in the literature and the final proposed material model is suitable to estimate the mechanical damage in the pelvic floor muscle during a vaginal delivery. The computational model predicts that even an apparently uneventful vaginal delivery inflicts injuries to the pelvic floor muscles, particularly during the extension of the fetus head, having been obtained more than 10% of damaged fibers. As a clinical evidence, the present work allows to conclude that the puborectalis component of the levator ani muscle is the most prone to damage.
多项研究表明，阴道分娩期间的盆底损伤可被视为盆底功能障碍发展的一个重要因素。此类疾病包括一系列影响女性的病症，如尿失禁、盆腔器官脱垂和大便失禁。数值模拟是有助于阐明盆底疾病背后机制的宝贵工具。这项工作的目的是提出一个在有限元方法框架内实现的力学模型，以估计在头先露枕前位胎儿阴道分娩过程中机械作用对盆底肌肉造成的损伤。所采用的本构模型已成功用于分娩模拟，新增的结构损伤模型先前已应用于表征经历有限变形的生物软组织中的损伤过程。本构参数与文献中的实验数据拟合，最终提出的材料模型适用于估计阴道分娩期间盆底肌肉的机械损伤。计算模型预测，即使是看似顺利的阴道分娩也会对盆底肌肉造成损伤，尤其是在胎儿头部伸展期间，受损纤维超过10%。作为临床证据，本研究可以得出结论，肛提肌的耻骨直肠肌部分最容易受损。
