Finite element modeling of maximum stress in pelvic floor structures during the head expulsion (FINESSE) study

Abstract

Introduction and hypothesis Several studies have assessed birth-related deformations of the levator ani muscle (LAM) and perineum on models that depicted these elements in isolation. The main aim of this study was to develop a complex female pelvic floor computational model using the finite element method to evaluate points and timing of maximum stress at the LAM and perineum in relation to the birth process. Methods A three-dimensional computational model of the female pelvic floor was created and used to simulate vaginal birth based on data from previously described real-life MRI scans. We developed three models: model A (LAM without perineum); model B (perineum without LAM); model C (a combined model with both structures). Results The maximum stress in the LAM was achieved when the vertex was 9 cm below the ischial spines and measured 37.3 MPa in model A and 88.7 MPa in model C. The maximum stress in the perineum occurred at the time of distension by the suboocipito-frontal diameter and reached 86.7 MPa and 119.6 MPa in models B and C, respectively, while the stress in the posterior fourchette caused by the suboccipito-bregmatic diameter measured 36.9 MPa for model B and 39.8 MPa for model C. Conclusions Including perineal structures in a computational birth model simulation affects the level of stress at the LAM. The maximum stress at the LAM and perineum seems to occur when the head is lower than previously anticipated.

Design, Realization, and Assessment of a High-Fidelity Physical Simulator for the Investigation of Childbirth-Induced Pelvic Floor Damage

“…In fact, appropriate and safe clinical tools to measure these parameters in vivo are not currently available. In contrast, the behavior of the PF during fetal descent has been deeply investigated in the literature through multiple finite element simulations [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33]. In these simulations, the PF muscles, bones and either the FH or the entire fetal body are replicated, changing the constitutive parameters values to investigate different clinical scenarios.…”

Birth and Regulation of head Extension to Guide Manual perineal Assistance (BREGMA) study

“…In addition to the reduction in perineal tension, both techniques also aim to regulate fetal head extension using the exed middle nger or the ulnar border of the dominant hand respectively [13][14][15][16]. This component is considered to be important for the effectiveness of MPP because as the head descends it starts to extend [17].…”

Maternal birth trauma and its consequences: time to raise awareness

“…The understanding of the pathophysiology of obstetric pelvic floor trauma has grown in recent years, with evidence from imaging techniques well described in the paper in this edition by H.P. Dietz [1] and modelling studies of the pelvic floor during labour and head expulsion in a paper by Cechova H [2].…”