Routzong Megan R, Moalli Pamela A, Maiti Spandan, De Vita Raffaella, Abramowitch Steven D
Translational Biomechanics Laboratory, Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
Magee-Womens Research Institute, Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, PA, USA.
Interface Focus. 2019 Aug 6;9(4):20190011. doi: 10.1098/rsfs.2019.0011. Epub 2019 Jun 14.
This study's aim was to determine whether the inclusion of superficial perineal structures in a finite-element simulation of vaginal delivery impacts the pubovisceral muscle and perineal body, two common sites of birth-related injury. The hypothesis, inferred from prevailing literature, was that these structures would have minimal influence (differences less than ±10%). Two models were made using the Visible Human Project's female cadaver to create a rigid, fixed pelvis, musculature held by spring attachments to that pelvis, and a rigid, ellipsoidal fetal head prescribed with an inferior displacement to simulate delivery. Injury site stretch ratios and fetal head and perineal body displacements and angles of progression were compared between the Omitted Model (which excluded the superficial perineal structures as is common practice) and the Included Model (which included them). Included Model stretch ratios were +107%, -9.84% and -14.6% compared to Omitted Model perineal body and right and left pubovisceral muscles, respectively. Included Model peak perineal body inferior displacement was +72.5% greater while similar anterior-posterior displacements took longer to reach. These results refute our hypothesis, suggesting superficial perineal structures impact simulations of vaginal delivery by inhibiting perineal body anterior-posterior displacement, which stretches and inferiorly displaces the perineal body.
本研究的目的是确定在阴道分娩的有限元模拟中纳入会阴浅部结构是否会影响耻骨内脏肌和会阴体，这是两个常见的分娩相关损伤部位。根据现有文献推断，假设是这些结构的影响极小（差异小于±10%）。使用可视人计划的女性尸体制作了两个模型，以创建一个刚性的、固定的骨盆，通过弹簧附件与该骨盆相连的肌肉组织，以及一个规定了向下位移以模拟分娩的刚性椭圆形胎头。在省略模型（按照常规做法排除会阴浅部结构）和纳入模型（包括这些结构）之间比较了损伤部位的拉伸率以及胎头、会阴体的位移和进展角度。与省略模型相比，纳入模型中会阴体和左右耻骨内脏肌的拉伸率分别为+107%、-9.84%和-14.6%。纳入模型中会阴体的最大向下位移增加了+72.5%，而前后位移达到相似程度所需时间更长。这些结果反驳了我们的假设，表明会阴浅部结构通过抑制会阴体的前后位移影响阴道分娩模拟，而这种位移会拉伸并使会阴体向下移位。
