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Yang M, Chen C, Wang Z, Long J, Huang R, Qi W, Shi R. Finite element analysis of female pelvic organ prolapse mechanism: current landscape and future opportunities. Front Med (Lausanne) 2024; 11:1342645. [PMID: 38323034 PMCID: PMC10844411 DOI: 10.3389/fmed.2024.1342645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/05/2024] [Indexed: 02/08/2024] Open
Abstract
The prevalence of pelvic organ prolapse (POP) has been steadily increasing over the years, rendering it a pressing global health concern that significantly impacts women's physical and mental wellbeing as well as their overall quality of life. With the advancement of three-dimensional reconstruction and computer simulation techniques for pelvic floor structures, research on POP has progressively shifted toward a biomechanical focus. Finite element (FE) analysis is an established tool to analyze the biomechanics of complex systems. With the advancement of computer technology, an increasing number of researchers are now employing FE analysis to investigate the pathogenesis of POP in women. There is a considerable number of research on the female pelvic FE analysis and to date there has been less review of this technique. In this review article, we summarized the current research status of FE analysis in various types of POP diseases and provided a detailed explanation of the issues and future development in pelvic floor disorders. Currently, the application of FE analysis in POP is still in its exploratory stage and has inherent limitations. Through continuous development and optimization of various technologies, this technique can be employed with greater accuracy to depict the true functional state of the pelvic floor, thereby enhancing the supplementation of the POP mechanism from the perspective of computer biomechanics.
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Affiliation(s)
- Miyang Yang
- The First Clinical Medical College, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Chujie Chen
- The First Clinical Medical College, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Zhaochu Wang
- Department of Anorectal, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Jiaye Long
- Department of Interventional Radiology, Inner Mongolia Forestry General Hospital, The Second Clinical Medical School of Inner Mongolia University for The Nationalities, Yakeshi, China
| | - Runyu Huang
- The First Clinical Medical College, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Wan Qi
- Department of Radiology, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Rong Shi
- Department of Anorectal, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
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Xue X, Zheng Q, Gao Z, Shen J, Yao T. The influence of the combined impairments and apical mesh surgery on the biomechanical behavior of the pelvic floor system. Front Bioeng Biotechnol 2024; 11:1292407. [PMID: 38260732 PMCID: PMC10800848 DOI: 10.3389/fbioe.2023.1292407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/08/2023] [Indexed: 01/24/2024] Open
Abstract
Objective: The prolapse mechanism of multifactorial impairment of the female pelvic floor system and the mechanics of the pelvic floor after apical suspension surgery are not yet understood, so we developed biomechanical models of the pelvic floor for the normal physiological state (0°) and 90° pathological state. Methods: Under different types and levels of the impairments and uterosacral suspensions, the possible changes in the morphometric characteristics and the mechanical characteristics of suspension and support functions were simulated based on the biomechanical models of the pelvic floor. Results: After the combined impairments, the descending displacement of the pelvic floor cervix and the stress and displacement of the perineal body reached maximum values. After surgical mesh implantation, the stresses of the normal pelvic floor were concentrated on the uterine fundus, cervix, and top of the bladder and the stresses of the 90° pathological state pelvic floor were concentrated on the uterine fundus, uterine body, cervix, middle of the posterior vaginal wall, and bottom of the perineal body. Conclusion: After the combined impairments, the biomechanical support of the bladder and sacrococcyx in the anterior (0°) and 90° pathological state pelvic floor system is diminished, the anterior vaginal wall dislodges from the external vaginal opening, and the posterior vaginal wall forms "kneeling" profiles. The pelvic floor system may evolve with a tendency toward the cervical prolapse with anterior and posterior vaginal wall prolapse and eventually prolapse. After surgical mesh implantation, the cervical position can be better restored; however, the load of combined impairment of the pelvic floor is mainly borne by the surgical mesh suspension, the biomechanical support function of pelvic floor organs and sacrococcyx was not repaired by the physiological structure, and the results of uterosacral suspension alone may be poor.
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Affiliation(s)
- Xianglu Xue
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
| | - Qiuyu Zheng
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
| | - Zhenhua Gao
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Jihong Shen
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Tingqiang Yao
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
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Das S, Hendriks GAGM, van den Noort F, Manzini C, van der Vaart CH, de Korte CL. 3D ultrasound strain imaging of puborectal muscle with and without unilateral avulsion. Int Urogynecol J 2023; 34:2225-2233. [PMID: 37058159 PMCID: PMC10506943 DOI: 10.1007/s00192-023-05498-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/29/2023] [Indexed: 04/15/2023]
Abstract
INTRODUCTION AND HYPOTHESIS The puborectal muscle (PRM), one of the female pelvic floor (PF) muscles, can get damaged during vaginal delivery, leading to disorders such as pelvic organ prolapse. Current diagnosis involves ultrasound (US) imaging of the female PF muscles, but functional information is limited. Previously, we developed a method for strain imaging of the PRM from US images in order to obtain functional information. In this article, we hypothesize that strain in the PRM would differ from intact to the avulsed end. METHODS We calculated strain in PRMs at maximum contraction, along their muscle fiber direction, from US images of two groups of women, which consisted of women with intact (n1 = 8) and avulsed PRMs (unilateral) (n2 = 10). Normalized strain ratios between both ends of the PRM (avulsed or intact) and the mid region were calculated. Subsequently, the difference in ratio between the avulsed and intact PRMs was determined. RESULTS We observe from the obtained results that the contraction/strain pattern of intact and undamaged PRMs is different from PRMs with unilateral avulsion. Normalized strain ratios between avulsed and intact PRMs were statistically significant (p = 0.04). CONCLUSION In this pilot study, we were able to show that US strain imaging of PRMs can show differences between intact PRMs and PRMs with unilateral avulsion.
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Affiliation(s)
- Shreya Das
- Medical Ultrasound Imaging Center, Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10 (767), PO Box 9101 (766), 6500 HB, Nijmegen, The Netherlands
| | - Gijs A G M Hendriks
- Medical Ultrasound Imaging Center, Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10 (767), PO Box 9101 (766), 6500 HB, Nijmegen, The Netherlands
| | - Frieda van den Noort
- Robotics and Mechatronics, Technical Medical Center, University of Twente, Enschede, The Netherlands
| | - Claudia Manzini
- Department of Reproductive Medicine and Gynecology, University Medical Center, Utrecht, The Netherlands
| | - C H van der Vaart
- Department of Reproductive Medicine and Gynecology, University Medical Center, Utrecht, The Netherlands
| | - Chris L de Korte
- Medical Ultrasound Imaging Center, Department of Medical Imaging, Radboud University Medical Center, Geert Grooteplein Zuid 10 (767), PO Box 9101 (766), 6500 HB, Nijmegen, The Netherlands.
- Physics of Fluids, TechMed Center, University of Twente, Enschede, The Netherlands.
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Xue X, Wang H, Xie J, Gao Z, Shen J, Yao T. Two-dimensional biomechanical finite element modeling of the pelvic floor and prolapse. Biomech Model Mechanobiol 2023:10.1007/s10237-023-01729-y. [PMID: 37294482 DOI: 10.1007/s10237-023-01729-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 05/20/2023] [Indexed: 06/10/2023]
Abstract
We developed the pelvic floor model in physiological and pathological states to understand the changes of biomechanical axis and support that may occur from the normal physiological state to the prolapse pathological state of the pelvic floor. Based on the physiological state model of the pelvic floor, we model the uterus to the pathological state position by balancing intra-abdominal pressure (IAP) and uterine pathological position load. Under combined impairments, we compared the patterns of changes in pelvic floor biomechanics that may be induced by different uterine morphological characteristic positions under different IAP. The orientation of the uterine orifice gradually changes from the sacrococcygeal direction to the vertical downward of vaginal orifice, and a large downward prolapse displacement occurs, and the posterior vaginal wall shows "kneeling" profile with posterior wall bulging prolapse. When the abdominal pressure value was 148.1 cmH2O, the descent displacement of the cervix in the normal and pathological pelvic floor system was 11.94, 20, 21.83 and 19.06 mm in the healthy state, and 13.63, 21.67, 22.94 and 19.38 mm in the combined impairment, respectively. The above suggests a maximum cervical descent displacement of the uterus in the anomalous 90° position, with possible cervical-uterine prolapse as well as prolapse of the posterior vaginal wall. The combined forces of the pelvic floor point in the direction of vertical downward prolapse of the vaginal orifice, and the biomechanical support of the bladder and sacrococcygeal bone gradually diminishes, which may exacerbate the soft tissue impairments and biomechanical imbalances of the pelvic floor to occur of POP disease.
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Affiliation(s)
- Xianglu Xue
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, No.727, Jingming South Road, Chenggong District, Kunming, 650500, China
| | - Haifeng Wang
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Kunming, 650032, China
| | - Jiachen Xie
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, No.727, Jingming South Road, Chenggong District, Kunming, 650500, China
| | - Zhenhua Gao
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Kunming, 650032, China
| | - Jihong Shen
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Kunming, 650032, China
| | - Tingqiang Yao
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, No.727, Jingming South Road, Chenggong District, Kunming, 650500, China.
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Nadhif MH, Irsyad M, Ocviyanti D. Biomechanically Compliant Gynecologic Training Simulator. Simul Healthc 2023; 18:135-143. [PMID: 35363667 DOI: 10.1097/sih.0000000000000654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Pap smear training is commonly conducted using simulators before practicing with humans. Unfortunately, existing simulators do not well simulate the biomechanical properties of pelvic tissues, and this may negatively impact the training outcome. In this study, we used finite element analysis (FEA) to identify a material that most accurately simulates pelvic tissues in terms of biomechanical properties for fabricating gynecologic training simulators. The selected material was then used to fabricate a vagina and cervix model using a hybrid technique of fused deposition modeling and molding to qualitatively confirm the structural integrity of the simulator. METHODS The vagina and cervix were reconstructed in a 3-dimensional feature according to geometrical parameters reported in the literature. The biomechanical compliance of the simulators was investigated by comparing 5 materials-RTV615, Dragon Skin 10, Dragon Skin 30, Dragon Skin FX-Pro, and Ecoflex 00-30-and a pelvic tissue model (control) using 2 FEA modules. The structural mechanics module simulated the insertion and opening of a vaginal speculum, and the (1) horizontal opening of the vagina and peak von Mises stress at the anterior and (2) posterior walls of the vagina were obtained. The explicit dynamics module estimated (1) the fracture stress during punch biopsies and (2) maximum perpendicular deformation of the cervix before break. The most biomechanically compliant material was subsequently used to fabricate the simulator using the hybrid technique. RESULTS From the FEA, the horizontal opening of the vagina, peak von Mises stress at the anterior wall of the vagina, peak von Mises stress at the posterior wall of the vagina fracture stress, and maximum perpendicular deformation of the cervix before break were obtained; the results of Dragon Skin 10 and the control were most similar. Therefore, the simulator was fabricated using the material. A qualitative evaluation of the simulator by the naked eye verified its structural integrity. CONCLUSIONS Of the materials studied, the FEA results showed that Dragon Skin 10 was the most accurate material for simulating pelvic tissues in terms of the biomechanical properties in a gynecologic training simulator. The simulator was also successfully fabricated using the hybrid technique. Further studies may also involve experimental testing to support the simulation results.
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Affiliation(s)
- Muhammad Hanif Nadhif
- From the Medical Physics Department (M.H.N.), and Medical Technology Cluster (M.H.N., M.I.), Indonesian Medical Education and Research Institute (IMERI), Faculty of Medicine; and Department of Obstetrics and Gynecology (D.O.), Faculty of Medicine/Ciptomangunkusumo Central Hospital, Universitas Indonesia, Jakarta, Indonesia
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Fang F, Zhao Z, Xiao J, Wen J, Wu J, Miao Y. Current practice in animal models for pelvic floor dysfunction. Int Urogynecol J 2023; 34:797-808. [PMID: 36287229 DOI: 10.1007/s00192-022-05387-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 08/31/2022] [Indexed: 11/29/2022]
Abstract
INTRODUCTION AND HYPOTHESIS The objective was to explore the current practice of using animal models for female pelvic floor dysfunction (PFD). METHODS By applying PFD and animal models as the keywords, we made a computerized search using PubMed, Ovid-Medline and Ovid-Embase from 2000 to 2022. The publications on the construction and application of animal models for PFD were included, and the results are presented in narrative text. RESULTS Studies on PFD primarily use rodents, large quadrupeds, and nonhuman primates (NHPs). NHPs are closest to humans in anatomy and biomechanics of the pelvic floor, followed by large quadrupeds and rodents. Rodents are more suitable for studying molecular mechanism, histopathology of PFD, and mesh immune rejection. Large quadrupeds are adaptable to the study of pelvic floor biomechanics and the development of new surgical instruments for PFD. NHPs are suitable for studying the occurrence and pathogenesis of pelvic organ prolapse. Among modeling methods, violent destruction of pelvic floor muscles, regulation of hormone levels, and denervation were used to simulate the occurrence of PFD. Gene knockout can be used to study both the pathogenesis of PFD and the efficacy of treatments. Other methods such as abdominal wall defect, vaginal defect, and in vitro organ bath system are more frequently used to observe wound healing after surgery and to verify the efficacy of treatments. CONCLUSIONS The rat is currently the most applicable animal type for numerous modeling methods. Vaginal dilation is the most widely used modeling method for research on the pathogenesis, pathological changes, and treatment of PFD.
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Affiliation(s)
- Fei Fang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, West China Second University Hospital, Sichuan University, West China Campus, Chengdu, 610041, Sichuan Province, China
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan Province, China
| | - Zhiwei Zhao
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan Province, China
| | - Jingyue Xiao
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan Province, China
| | - Jirui Wen
- Deep Underground Space Medical Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan Province, China
| | - Jiang Wu
- Deep Underground Space Medical Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan Province, China
| | - Yali Miao
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, West China Second University Hospital, Sichuan University, West China Campus, Chengdu, 610041, Sichuan Province, China.
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Xie J, Li S, Yao T, Shen J. A 2D equivalent mechanical model of the whole pelvic floor and impairment simulation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3659. [PMID: 36305715 DOI: 10.1002/cnm.3659] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/28/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
We developed a complete 2D equivalent mechanical model of the pelvic floor based on magnetic resonance imaging (MRI) images of a 35-year-old healthy woman. This model can simulate anterior vaginal prolapse (AVP) due to soft tissue impairment. Thus, we can study the mechanism of prolapse formation from a mechanical perspective and improve the assessment and treatment of the condition in clinical practice. Based on 2D MRI image parameter measurements and computer-aided design methods, the 2D equivalent mechanical model of the whole pelvic floor in the sagittal plane was accurately reconstructed, which includes all necessary tissues of the pelvic floor system. Material parameters were mainly from the literature. We simulated the impairment by reducing the tissue's mechanical properties, and numerical simulations predicted the mechanical response and morphological changes of the healthy and impaired pelvic floor in different states. In six intra-abdominal pressure (IAP) states (8.4-208.9 cmH2 O), the maximum cervical descent in the impaired pelvic floor was 0.3-18.521 mm, which was much greater than that in the healthy pelvic floor (0.14-6.55 mm). Once the impairment occurred (0%-25%), there was a significant increase in maximum displacement, stress, and cervical descent (30.9-36.5 mm, 0.56-1.12 MPa, 4.6-12.1 mm), and a clinically similar prolapse shape occurred. Simple supine and standing will not cause prolapse. The formation of prolapse is closely related to vaginal tissue impairment. In the standing position, the main forces on the healthy pelvic floor system are distributed horizontally posteriorly and inferiorly, reducing the burden in the vertically downward direction.
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Affiliation(s)
- Jiachen Xie
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
| | - Song Li
- Department of Urology, First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Tingqiang Yao
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
| | - Jihong Shen
- Department of Urology, First Affiliated Hospital of Kunming Medical University, Kunming, China
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Xu Y, Liu H, Hao D, Taggart M, Zheng D. Uterus Modeling from Cell to Organ Level: towards Better Understanding of Physiological Basis of Uterine Activity. IEEE Rev Biomed Eng 2020; 15:341-353. [PMID: 32915747 DOI: 10.1109/rbme.2020.3023535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The relatively limited understanding of the physiology of uterine activation prevents us from achieving optimal clinical outcomes for managing serious pregnancy disorders such as preterm birth or uterine dystocia. There is increasing awareness that multi-scale computational modeling of the uterus is a promising approach for providing a qualitative and quantitative description of uterine physiology. The overarching objective of such approach is to coalesce previously fragmentary information into a predictive and testable model of uterine activity that, in turn, informs the development of new diagnostic and therapeutic approaches to these pressing clinical problems. This article assesses current progress towards this goal. We summarize the electrophysiological basis of uterine activation as presently understood and review recent research approaches to uterine modeling at different scales from single cell to tissue, whole organ and organism with particular focus on transformative data in the last decade. We describe the positives and limitations of these approaches, thereby identifying key gaps in our knowledge on which to focus, in parallel, future computational and biological research efforts.
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The histological microstructure and in vitro mechanical properties of the human female postmenopausal perineal body. Menopause 2020; 26:66-77. [PMID: 29994970 DOI: 10.1097/gme.0000000000001166] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The perineal body connects muscles from the pelvic floor and is critical for support of the lower part of the vagina and proper function of the anal canal. We determined mechanical parameters and volume fractions of main components of the human female postmenopausal perineal body. METHODS The specimens were taken from 15 fresh female cadavers (age 74 ± 10, mean ± standard deviation). Seventy-five specimens from five regions of the perineal body were processed histologically to assess volume fractions of tissue components using stereological point testing grid. Fifteen specimens taken from the midline region were loaded uniaxially with 6 mm/min velocity until tissue rupture to determine Young's modulus of elasticity, ultimate stresses, and strains. RESULTS The perineal body was composed of collagen (29%), adipose cells (27%), elastin (7%), smooth muscle (11%), and skeletal muscle (3%). The residual tissue (19%) constituted mostly peripheral nerves, lumina of blood vessels, fibroblasts, and fibrocytes. Young's modulus of elasticity at midline region was 18 kPa (median) at small and 232 kPa at large deformations, respectively. The ultimate stress was 172 kPa and the ultimate strain was 1.4. CONCLUSIONS We determined the structural and mechanical parameters of the perineal body. The resultant data could be used as input for models simulating pelvic floor prolapse or dysfunction.
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Babayi M, Azghani MR, Hajebrahimi S, Berghmans B. Three-dimensional finite element analysis of the pelvic organ prolapse: A parametric biomechanical modeling. Neurourol Urodyn 2018; 38:591-598. [PMID: 30499117 DOI: 10.1002/nau.23885] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 10/17/2018] [Indexed: 11/12/2022]
Abstract
AIMS To evaluate the role of soft tissue and ligaments damage and level of pelvic muscles activation versus intra-abdominal pressure, on pelvic organ prolapse. METHODS This was a computational modeling based on the finite element analysis. Three pelvic muscles, four pelvic ligaments, and three organs (urethra, vagina, and rectum) were simulated. The model was subjected to total 41 472 analysis cases including three intra-abdominal pressures, two damaging levels for the ligaments, three damaging levels for the muscles, and four intentional levels of activation for muscles. RESULTS Increased intra-abdominal pressures caused significant statistical increase of the pelvic organ prolapse (P = 0.000) up to 10 mm downward. Ligaments' defect had no statistically-significant effect on prolapse of the organs (P = 0.981 for rectum, P = 0.423 for urethra, and P = 0.752 for vagina). Damage in the pelvic floor muscles and low intentional level of activation also deteriorated the prolapse (P = 0.000). CONCLUSION Increase of the intra-abdominal pressure (IAP) as may be existed during pregnancy or physical activity increased the organ prolapse. Damages of the ligaments caused less effects on the prolapse. Loss of the passive properties of the muscles which is probable after delivery or aging moderately deteriorated the prolapse disorder. However, activation of the pelvic floor muscles prevented the prolapse. Different recruitments of the muscles, specifically the pubococcygeus (PCM), could compensate the possible defects in other tissues. Targeted pelvic floor muscle training (PFMT) could also be effective in older adults due to considerable role of the pelvic muscles' intentional activation.
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Affiliation(s)
- Masumeh Babayi
- Department of Biomechanics, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - Mahmood-Reza Azghani
- Department of Biomechanics, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - Sakineh Hajebrahimi
- Research Center for Evidence-Based Medicine, Urology department, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Bary Berghmans
- School for Public Health and Primary Care, Maastricht University, Maastricht, The Netherlands
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Evaluating residual strain throughout the murine female reproductive system. J Biomech 2018; 82:299-306. [PMID: 30458959 DOI: 10.1016/j.jbiomech.2018.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 01/10/2023]
Abstract
Mounting evidence suggests that cells within soft tissues seek to maintain a preferred biomechanical state. Residual stress is defined as the stress that remains in a tissue when all external loads are removed and contributes to tissue mechanohomeostasis by decreasing the transmural gradient of wall stress. Current computational models of pelvic floor mechanics, however, often do not consider residual stress. Residual strain, a result of residual stress can be quantitatively measured through opening angle experiments. Therefore, the objective of this study is to quantify the regional variations in opening angles along the murine female reproductive system at estrus and diestrus, to quantify residual strain in the maintenance state of sexually mature females. Further, evidence suggests that hydrophilic glycosaminoglycan/proteoglycans are integral to cervical remodeling. Thus, variations in opening angles following hypo-osmotic loading are evaluated. Opening angle experiments were performed along the murine reproductive system in estrus (n = 8) and diestrus (n = 8) and placed in hypo-osmotic solution. Measurements of thickness and volume were also obtained for each group. Differences (p < 0.05) in opening angle were observed with respect to region and loading, however, differences with respect to estrous stage were not significant. Thickness values were significant (p < 0.05) with respect to region only. The effects of both estrous cycle and region resulted in significant differences (p < 0.05) in observed volume. The observed regional differences indicate variation in the stress-free state among the reproductive system which may have implications for future computational models to advance women's reproductive health.
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