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Fidalgo DS, Jorge RMN, Parente MPL, Louwagie EM, Malanowska E, Myers KM, Oliveira DA. Pregnancy state before the onset of labor: a holistic mechanical perspective. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01853-3. [PMID: 38758337 DOI: 10.1007/s10237-024-01853-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024]
Abstract
Successful pregnancy highly depends on the complex interaction between the uterine body, cervix, and fetal membrane. This interaction is synchronized, usually following a specific sequence in normal vaginal deliveries: (1) cervical ripening, (2) uterine contractions, and (3) rupture of fetal membrane. The complex interaction between the cervix, fetal membrane, and uterine contractions before the onset of labor is investigated using a complete third-trimester gravid model of the uterus, cervix, fetal membrane, and abdomen. Through a series of numerical simulations, we investigate the mechanical impact of (i) initial cervical shape, (ii) cervical stiffness, (iii) cervical contractions, and (iv) intrauterine pressure. The findings of this work reveal several key observations: (i) maximum principal stress values in the cervix decrease in more dilated, shorter, and softer cervices; (ii) reduced cervical stiffness produces increased cervical dilation, larger cervical opening, and decreased cervical length; (iii) the initial cervical shape impacts final cervical dimensions; (iv) cervical contractions increase the maximum principal stress values and change the stress distributions; (v) cervical contractions potentiate cervical shortening and dilation; (vi) larger intrauterine pressure (IUP) causes considerably larger stress values and cervical opening, larger dilation, and smaller cervical length; and (vii) the biaxial strength of the fetal membrane is only surpassed in the cases of the (1) shortest and most dilated initial cervical geometry and (2) larger IUP.
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Affiliation(s)
- Daniel S Fidalgo
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal.
- Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), R. Dr. Roberto Frias, 4200-465, Porto, Portugal.
| | - Renato M Natal Jorge
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
- Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), R. Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Marco P L Parente
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
- Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), R. Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Erin M Louwagie
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Ewelina Malanowska
- Department of Gynaecology, Endocrinology and Gynaecologic Oncology, Pomeranian Medical University, Szczecin, Poland
| | - Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA
| | - Dulce A Oliveira
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
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Fidalgo DS, Samimi K, Oyen ML, Skala MC, Jorge RMN, Parente MPL, Malanowska E, Oliveira DA, Myers KM. Development of a multilayer fetal membrane material model calibrated using bulge inflation mechanical tests. J Mech Behav Biomed Mater 2024; 150:106344. [PMID: 38160642 DOI: 10.1016/j.jmbbm.2023.106344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
The fetal membranes are an essential mechanical structure for pregnancy, protecting the developing fetus in an amniotic fluid environment and rupturing before birth. In cooperation with the cervix and the uterus, the fetal membranes support the mechanical loads of pregnancy. Structurally, the fetal membranes comprise two main layers: the amnion and the chorion. The mechanical characterization of each layer is crucial to understanding how each layer contributes to the structural performance of the whole membrane. The in-vivo mechanical loading of the fetal membranes and the amount of tissue stress generated in each layer throughout gestation remains poorly understood, as it is difficult to perform direct measurements on pregnant patients. Finite element analysis of pregnancy offers a computational method to explore how anatomical and tissue remodeling factors influence the load-sharing of the uterus, cervix, and fetal membranes. To aid in the formulation of such computational models of pregnancy, this work develops a fiber-based multilayer fetal membrane model that captures its response to previously published bulge inflation loading data. First, material models for the amnion, chorion, and maternal decidua are formulated, informed, and validated by published data. Then, the behavior of the fetal membrane as a layered structure was analyzed, focusing on the respective stress distribution and thickness variation in each layer. The layered computational model captures the overall behavior of the fetal membranes, with the amnion being the mechanically dominant layer. The inclusion of fibers in the amnion material model is an important factor in obtaining reliable fetal membrane behavior according to the experimental dataset. These results highlight the potential of this layered model to be integrated into larger biomechanical models of the gravid uterus and cervix to study the mechanical mechanisms of preterm birth.
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Affiliation(s)
- Daniel S Fidalgo
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal; Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
| | | | - Michelle L Oyen
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Melissa C Skala
- Morgridge Institute for Research, Madison, WI, USA; Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Renato M N Jorge
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal; Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Marco P L Parente
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal; Mechanical Department (DEMec), Faculty of Engineering of University of Porto (FEUP), Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Ewelina Malanowska
- Department of Gynaecology, Endocrinology and Gynaecologic Oncology, Pomeranian Medical University, Szczecin, Poland
| | - Dulce A Oliveira
- Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), R. Dr. Roberto Frias 400, 4200-465, Porto, Portugal
| | - Kristin M Myers
- Department of Mechanical Engineering - Columbia University, New York, NY 10027, USA
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Fidalgo DS, Pouca MCPV, Oliveira DA, Malanowska E, Myers KM, Jorge RMN, Parente MPL. Mechanical Effects of a Maylard Scar During a Vaginal Birth After a Previous Caesarean. Ann Biomed Eng 2021; 49:3593-3608. [PMID: 34114131 DOI: 10.1007/s10439-021-02805-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/31/2021] [Indexed: 01/12/2023]
Abstract
Caesarean section is one of the most common surgeries worldwide, even though there is no evidence supporting maternal and perinatal long-term benefits. Furthermore, the mechanical behavior of a caesarean scar during a vaginal birth after caesarean (VBAC) is not well understood since there are several questions regarding the uterine wound healing process. The aim of this study is to investigate the biomechanical Maylard fiber reorientation and stiffness influence during a VBAC through computational methods. A biomechanical model comprising a fetus and a uterus was developed, and a chemical-mechanical constitutive model that triggers uterine contractions was used, where some of the parameters were adjusted to account for the matrix and fiber stiffness increase in the caesarean scar. Several mechanical simulations were performed to analyze different scar fibers arrangements, considering different values for the respective matrix and fibers stiffness. The results revealed that a random fiber arrangement in the Maylard scar has a much higher impact on its mechanical behavior during a VBAC than the common fibers arrangement present in the uninjured uterine tissue. An increase of the matrix scar stiffness exhibits a lower impact, while an increase of the fiber's stiffness has no significant influence.
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Affiliation(s)
- D S Fidalgo
- INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering/DEMec, Faculty of Engineering, University of Porto, Porto, Portugal.
| | - M C P Vila Pouca
- INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering/DEMec, Faculty of Engineering, University of Porto, Porto, Portugal
| | - D A Oliveira
- INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering/DEMec, Faculty of Engineering, University of Porto, Porto, Portugal
| | - E Malanowska
- Department of Gynaecology, Endocrinology and Gynaecologic Oncology, Pomeranian Medical University, Szczecin, Poland
| | - K M Myers
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - R M Natal Jorge
- INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering/DEMec, Faculty of Engineering, University of Porto, Porto, Portugal
| | - M P L Parente
- INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering/DEMec, Faculty of Engineering, University of Porto, Porto, Portugal
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Fidalgo DS, Areias B, Sousa LC, Parente M, Jorge RN, Sousa H, Gonçalves JM. Minimally invasive transforaminal and anterior lumbar interbody fusion surgery at level L5-S1. Comput Methods Biomech Biomed Engin 2020; 23:384-395. [PMID: 32096422 DOI: 10.1080/10255842.2020.1731482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
This paper presents a finite element analysis to investigate the biomechanical changes caused by transforaminal (TLIF) and anterior lumbar interbody fusion (ALIF) at the L5-S1 level, applying two different implants: T_PAL (TLIF) and SynFix (ALIF). The main objective is to determine which one is more stable for patients. Numerical simulations of segmental motion show that, in the early postoperative phase, displacements and rotation angles obtained in ALIF are greater than the corresponding ones obtained in TLIF, as well as the principal stress values on the ligaments. So, TLIF performed with T_PAL is more stable than ALIF, especially during the recovery phase.
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Affiliation(s)
- D S Fidalgo
- INEGI/DEMec, FEUP, Universidade do Porto, Porto, Portugal
| | - B Areias
- INEGI/DEMec, FEUP, Universidade do Porto, Porto, Portugal
| | - L C Sousa
- INEGI/DEMec, FEUP, Universidade do Porto, Porto, Portugal
| | - M Parente
- INEGI/DEMec, FEUP, Universidade do Porto, Porto, Portugal
| | - R N Jorge
- INEGI/DEMec, FEUP, Universidade do Porto, Porto, Portugal
| | - H Sousa
- Centro Hospitalar de Vila Nova de Gaia/Espinho, Vila Nova de Gaia, Portugal
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