Oliveira Dulce A, Parente Marco P L, Calvo Begoña, Mascarenhas Teresa, Jorge Renato M Natal
a INEGI, Faculty of Engineering , University of Porto , Porto , Portugal.
b Aragón Institute of Engineering Research , University of Zaragoza , Zaragoza , Spain.
Comput Methods Biomech Biomed Engin. 2017 Aug;20(11):1249-1259. doi: 10.1080/10255842.2017.1349762.
Vaginal childbirth is the leading cause of pelvic floor muscles injury, which contributes to pelvic floor dysfunction, being enhanced by fetal malposition. Therefore, the aim of the present study is to verify the influence of mediolateral episiotomies in the mechanics of the pelvic floor with the fetus in occiput posterior position when compared to the occiput anterior position. Numerical simulations of vaginal deliveries, with and without episiotomy, are performed based on the Finite Element Method. The biomechanical model includes the pelvic floor muscles, a surface to delimit the anterior region of the birth canal and a fetus. Fetal malposition induces greater extension of the muscle compared to the normal position, leading to increases of stretch. The faster enlargement may be responsible for a prolonged second stage of labor. Regarding the force required to achieve delivery, the difference between the analyzed cases are 35 N, which might justify the increased need of surgical interventions. Furthermore, episiotomy is essential in reducing the damage to values near the ones obtained with normal position, making the fetal position irrelevant. These biomechanical models have become extremely useful tools to provide some understanding of pelvic floor function during delivery helping in the development of preventative strategies.
经阴道分娩是盆底肌肉损伤的主要原因，而盆底肌肉损伤会导致盆底功能障碍，胎儿胎位异常会加剧这种情况。因此，本研究的目的是验证与枕前位相比，枕后位胎儿时会阴侧切术对盆底力学的影响。基于有限元方法，对有侧切术和无侧切术的阴道分娩进行了数值模拟。生物力学模型包括盆底肌肉、界定产道前部区域的表面和胎儿。与正常胎位相比，胎儿胎位异常会导致肌肉更大程度的伸展，从而导致拉伸增加。更快的扩张可能是第二产程延长的原因。关于实现分娩所需的力，分析病例之间的差异为35牛，这可能解释了手术干预需求增加的原因。此外，侧切术对于减少对接近正常胎位时所获数值的损伤至关重要，使胎儿胎位变得无关紧要。这些生物力学模型已成为极其有用的工具，有助于了解分娩过程中的盆底功能，从而有助于制定预防策略。
