Biomechanics of the Female Reproductive System: Breast and Pelvic Organs: From Model to Patient (Biomechanics of Living Organs)

“Biomechanics of the Female Reproductive System: Breast and Pelvic Organs.From Model to Patient” is the first book to cover biomechanical studies of thewoman’s reproductive system. Clinicians and scientists gathered to propose a bookpresenting the main results and studies completed over the last decade to increasethe understanding of women’s reproductive physiology, diseases, and treatment andimprove the design of medical devices and clinical interventions, including surgicalprocedures.International key opinion leaders in medical, mechanical engineering, biomedical engineering,physics, and computer sciences have described, discussed, and presentedexisting approaches, methodologies, and results. We hope this book will providethe reader with a comprehensive overview of the state-of-the-art research, development,and perspectives in biomechanical modeling and numerical simulation of thewomen’s reproductive system. From a medical perspective, spreading this culture ofsoft tissue biomechanics and their evolution with aging and damage could improvethe knowledge and understanding of pathologies such as genital prolapse, pelvic pain,and pelvic organ dysfunction. One step beyond the modeling and prediction value ofthe models that could be developed could solve medical issues and improve patientcare regarding these pathologies in an area lacking technologies, medical software,and devices. The primary motivation of every researcher in biomedical engineeringis to improve the quality of the treatment and the patient’s life. We hope our effortswill contribute to this. Front Cover Biomechanics of the Female Reproductive System: Breast and Pelvic Organs Copyright Contents Contributors Editor's biography of 2022 Foreward Preface Note of the series editors Part 1 Backgrounds: anatomy, physiology, and physio-pathology 1 Pelvic floor functional anatomy 1.1 Overview 1.2 Levator ani 1.2.1 Levator ani muscle and its three subdivisions 1.2.1.1 Overall anatomy of the levator ani muscle 1.2.2 Levator ani lines of action 1.2.2.1 Hiatal closure and the perineal complex 1.2.2.2 Perineal membrane 1.2.3 Levator ani muscle injury 1.2.3.1 Levator ani muscle injury associated with prolapse 1.2.3.2 How does childbirth cause injury? 1.3 Connective tissue supports of the pelvic organs 1.3.1 Overview 1.3.2 Apical supports: Level I 1.3.2.1 Cardinal and uterosacral ligaments 1.3.2.2 Tissue composition of cardinal and uterosacral ligaments 1.3.2.3 Ligament geometry 1.3.2.4 Ligament changes with prolapse 1.3.3 Anterior compartment: Level II 1.3.3.1 Fascial and levator arches 1.3.3.2 Alteration in pelvic sidewall anatomy due to injury 1.3.4 Anterior compartment: Level III 1.3.5 Structural failure sites in anterior vaginal wall prolapse 1.3.6 Anatomy and structural failure sites in posterior compartment prolapse 1.3.6.1 Anatomy of the posterior vaginal wall support as it applies to rectocele 1.3.6.2 How does posterior vaginal wall support fail? References 2 Epidemiology & pathophysiology of pelvic organ prolapse & urinary incontinence in women 2.1 Epidemiology of pelvic organ prolapse 2.1.1 Prevalence & incidence 2.1.2 Risk factors 2.1.2.1 Age & obesity 2.1.2.2 Race & ethnicity 2.1.2.3 Childbirth, parity & mode of delivery 2.1.2.4 Hysterectomy 2.2 Pathophysiology of pelvic organ prolapse 2.2.1 Anatomical structure, support & function 2.2.1.1 Pelvic floor anatomy & supports 2.2.1.1.1 Levator ani 2.2.1.1.2 Arcus tendineus levator ani & fascia pelvis 2.2.1.1.3 Perineal membrane (urogenital diaphragm) 2.2.1.1.4 Perineal body 2.2.1.1.5 Uterosacral-cardinal ligament complex 2.2.1.2 Pelvic floor support mechanisms 2.2.2 Physiological mechanisms of POP 2.2.2.1 Pelvic floor defects 2.2.2.2 The integral theory 2.2.2.3 Changes in collagen & smooth muscle of the vagina & supportive tissues 2.2.2.4 Age & obesity 2.2.2.5 Pregnancy, parity, & postpartum pelvic floor muscle trauma 2.2.3 Clinical diagnosis & evaluation 2.2.4 Treatment & management 2.3 Epidemiology of urinary incontinence 2.3.1 Prevalence, incidence, & remission 2.3.2 Risk factors 2.3.2.1 Age & obesity 2.3.2.2 Race 2.3.2.3 Pregnancy, parity & mode of delivery 2.3.2.4 Hysterectomy 2.4 Pathophysiology of urinary incontinence 2.4.1 Anatomical structure, support & function 2.4.1.1 Lower urinary tract anatomy & supports 2.4.1.1.1 Urinary bladder 2.4.1.1.2 Urethra 2.4.1.1.3 Pelvic floor muscles & the external urethral sphincter 2.4.1.2 Lower urinary tract function 2.4.1.2.1 The female urethral sphincter mechanism 2.4.2 Physiological mechanisms of UI 2.4.2.1 Stress UI 2.4.2.1.1 Urethral hypermobility 2.4.2.1.2 Intrinsic sphincter deficiency 2.4.2.2 Urge UI 2.4.2.2.1 Detrusor overactivity 2.4.2.3 Mixed UI 2.4.2.4 Overflow incontinence 2.4.3 Clinical diagnosis & evaluation 2.4.4 Treatment & management References 3 Current surgical treatments for women's genital prolapse 3.1 Introduction 3.2 Signs and symptoms of genital prolapse 3.3 Surgical indications and alternative treatments 3.3.1 Pelvic floor physiotherapy 3.3.2 Pessaries 3.3.3 Surgery 3.4 Surgical techniques 3.4.1 Pelvic floor support 3.4.2 General surgical principles 3.4.3 Apical suspensions 3.4.3.1 Sacrocolpopexy 3.4.3.2 Uterosacral ligaments suspension 3.4.3.3 Sacrospinous ligament suspension 3.4.4 Level 2 suspensions 3.4.5 Restauration of organ support: level 3 3.4.5.1 Anterior prolapses (cystoceles) 3.4.5.2 Posterior prolapses (rectoceles) 3.4.6 Obliterative procedures 3.4.7 Autologous vs synthetic mesh 3.5 Surgical strategies 3.6 Mechanical consequences of the different management options 3.6.1 Expectant management 3.6.2 Autologous surgeries 3.6.2.1 Suspensions 3.6.2.2 Plications 3.6.2.3 Colpectomy 3.6.3 Mesh surgery 4 Physiology and physiopathology of pregnancy and delivery 4.1 Introduction 4.2 Changes in biomechanical intrinsic characteristics during pregnancy 4.2.1 Changes in joint mobility in women 4.2.2 Changes in spinal curve in women 4.2.3 Change in pelvic organ mobility 4.2.3.1 Clinical considerations 4.2.3.2 Ultrasound considerations 4.3 Pathophysiological process 4.3.1 Hormonal considerations 4.3.2 Conjunctive tissue's remodeling 4.3.3 Data from animal experimentation 4.4 Association with the mode of delivery and the risk of perineal trauma at childbirth 4.4.1 Mode of delivery 4.4.2 Perineal trauma 4.5 Biomechanics of spontaneous normal delivery 4.5.1 Delivery of the head 4.5.2 Delivery of the shoulder 4.6 Peripartum biomechanical considerations 4.6.1 Physiological changes 4.6.1.1 Hormonal changes 4.6.1.2 Changes to muscles and connective tissue 4.6.2 Powers 4.6.2.1 Contractions 4.6.2.2 Maternal pushing 4.6.2.3 Fundal pressure 4.6.3 Passages 4.6.3.1 Type of pelvis 4.6.3.2 Birth canal 4.6.4 Passenger 4.6.4.1 Fetal size 4.6.4.2 Malpositions and malpresentations 4.6.4.3 Fetal head shape 4.6.5 Birth position 4.6.6 Practitioner 4.6.6.1 Manual perineal protection 4.6.6.2 Operative vaginal delivery 4.6.6.3 Other interventions 4.6.6.4 Shoulder delivery 4.7 Model development, testing, and validation 4.8 Conclusion 4.9 List of Abreviations References Part 2 Mechanical properties – constitutive laws – experimental characterizations 5 Inverse problems in the characterization of soft connective tissue: perspective for reproduction system 5.1 Introduction 5.2 Common sources of inverse problem in soft tissue biomechanics 5.2.1 Elastography of soft tissue biomechanics 5.2.1.1 Subject the tissues to a deformation 5.2.1.2 Measure the displacement fields 5.2.1.3 Compute the mechanical properties 5.2.1.4 Applications in the pelvic system 5.2.2 Nondestructive invasive techniques 5.2.3 Nonagreed standard testing of soft tissue biomechanics 5.3 The finite element model updating method 5.3.1 Useful definitions and concepts 5.3.1.1 Deformation tensors 5.3.1.2 Stress tensors 5.3.1.3 Constitutive equations 5.3.2 Forward problem 5.3.2.1 Strong form 5.3.2.2 Weak form 5.3.3 Inverse problem 5.3.3.1 Definition of the cost function 5.3.3.2 The adjoint method 5.3.3.3 Minimization of the cost function and resolution of the inverse problem 5.3.4 Applications to the pelvic system 5.4 Sequential methods 5.5 The virtual fields method 5.5.1 General introduction 5.5.2 Applications to soft tissues 5.6 Conclusions and future directions emerging field of pelvic biomechanics References 6 Mechanical properties of women pelvic soft tissues 6.1 Introduction 6.2 Vagina 6.2.1 Overview 6.2.2 Contributions from collagen and elastic fibers 6.2.3 Contributions from smooth muscle cells 6.2.4 Contributions from the nonfibrous ground matrix 6.2.5 Summary 6.3 Uterus 6.3.1 Overview 6.3.2 Contributions from collagen and elastic fibers 6.3.3 Contributions from smooth muscle cells 6.3.4 Contributions from the nonfibrous ground matrix 6.3.5 Summary 6.4 Uterosacral ligaments 6.4.1 Overview 6.4.2 Mechanical contributions from collagen and elastic fibers 6.4.3 Contributions from contractile smooth muscle cells 6.4.4 Contributions from the nonfibrous ground matrix 6.4.5 Summary 6.5 Levator ani 6.5.1 Introduction 6.5.2 Contributions from collagen and elastic fibers 6.5.3 Contributions from skeletal muscle cells 6.5.4 Contributions from the nonfibrous ground matrix 6.5.5 Summary References 7 Mechanical properties of breast tissue 7.1 Introduction 7.2 Mechanics of breast tissue 7.2.1 A brief introduction to continuum mechanics 7.2.2 Constitutive models 7.2.2.1 Constitutive model considerations 7.2.2.2 Popular constitutive models for breast tissues 7.2.3 Constitutive model coefficient determination 7.2.3.1 Elastography 7.2.3.1.1 US strain imaging 7.2.3.1.2 Linear and nonlinear finite element ultrasound elastography (FE-USE) 7.2.3.1.3 Ultrasound shear wave elastography and computer tomographic elastography 7.2.3.1.4 Magnetic resonance shear wave elastography (MR-SWE) 7.2.3.1.5 Mechanical imaging 7.2.3.2 Measurement of mechanical properties of ex-vivo tissue specimens 7.2.3.2.1 Indentation 7.2.3.2.2 Whole breast biomechanical model based optimization 7.2.4 Constitutive model coefficients 7.3 A community's use of mechanics 7.4 Final remarks and future directions 7.4.1 Final remarks 7.4.2 Future directions References 8 Evolution of mechanical properties with pathology & aging: application to pelvic tissues? 8.1 Introduction 8.2 Mechanical properties of tissues 8.3 The mechanical importance of tissue composition and microstructure 8.3.1 Collagen 8.3.1.1 Pathologies specific to collagen 8.3.1.2 Impact of aging on collagen 8.3.2 Elastin 8.3.2.1 Pathologies specific to elastin 8.3.2.2 Impact of aging on elastin 8.3.3 Glycosaminoglycans 8.3.3.1 Pathologies specific to glycosaminoglycans 8.3.3.2 Impact of aging on glycosaminoglycans 8.3.4 Smooth muscle 8.3.4.1 Pathologies specific to smooth muscle 8.3.4.2 Impact of aging on smooth muscle 8.3.5 Skeletal muscle 8.3.5.1 Pathologies specific to skeletal muscle 8.3.5.2 Impact of aging on skeletal muscle 8.3.6 Pathologies directly affecting multiple aspects of pelvic tissue mechanics 8.3.7 Pathologies and aging of pelvic tissues 8.3.8 Pelvic floor disorders 8.3.8.1 Stress urinary incontinence 8.3.8.2 Pelvic organ prolapse 8.3.9 Pregnancy and childbirth 8.4 Conclusion References 9 Mechanical properties of pelvic implants: interaction between implants and tissue 9.1 Motivation 9.1.1 Current issues with prosthetic meshes for pelvic organ prolapse repair 9.1.2 Why mechanics matter 9.1.3 Hypotheses 9.1.4 Outline of this chapter 9.2 Mechanical and physical properties of prosthetic meshes 9.2.1 Textile meshes as hierarchical structures 9.2.2 Non-linear stress-strain relationship 9.2.3 Anisotropy 9.2.4 Viscoelasticity 9.2.5 Preconditioning 9.3 Experimental mechanical characterization of prosthetic meshes 9.3.1 Physiologically relevant test conditions 9.3.2 Mechanical behavior: a broad term 9.3.3 Mechanical behavior at the lower length scales 9.3.4 Structural mechanical behavior 9.3.5 Local mesh-tissue interaction 9.3.6 Experimental observations: what can we learn for the mechanical evaluation and design of meshes? 9.3.7 What would an ideal mesh look like? 9.4 Numerical modeling of pelvic implants 9.4.1 Structural simulations 9.4.2 Meso-/microstructure-inspired modeling approaches 9.4.3 Meso-/microstructural and multi-scale models 9.5 Alternative materials: electrospun networks 9.6 What are the needs? References 10 Constitutive models of soft connective tissues under large strain: application to pelvic tissue? 10.1 Introduction 10.2 Mechanical formulation 10.2.1 Theoretical framework: large deformation 10.2.2 Hyperelasticity and non-linear elastic modeling 10.2.3 Characterizing soft biological tissues: a challenging task 10.2.3.1 Initial state: impact on the mechanical parameters 10.2.3.2 Incompressibility assumption 10.2.3.3 Homogeneous deformation 10.3 Isotropic modeling 10.3.1 Isotropic models: simplification of the SED and stress computation 10.3.2 Quick application 10.3.3 The elephant in the room: why and when to use an isotropic SED? 10.4 Anisotropic modeling 10.4.1 Stress penalty 10.4.2 Strain penalty 10.4.3 Anisotropic representation: how to carefully open the Pandora's box? 10.5 Conclusion References Part 3 Clinical imaging, investigations tools, and characterization 11 Medical imaging and patient-specific modeling of women pelvic system: application to magnetic resonance images 11.1 Introduction 11.2 Materials and methods 11.2.1 Magnetic resonance imaging 11.2.2 Geometry representation 11.2.3 Pelvic organs modeling using virtual image correlation 11.2.4 Generic 3D geometry 11.2.5 Virtual image 11.2.6 Objective function and optimization 11.2.7 Pelvic floor modeling for simulation 11.3 Applications and discussion 11.4 Conclusions Acknowledgments References 12 Quantitative assessment of pelvic mobility in women using MRI image analysis 12.1 Introduction 12.2 Method for quantifying pelvic mobility 12.2.1 Dynamic MRI protocol 12.2.2 POP-Q method 12.2.3 Full field measurement method 12.2.4 Displacement analysis 12.3 Method for quantifying pelvic mobility 12.3.1 Physiological pelvic mobilities 12.3.2 Pathological mobilities 12.3.3 Mobility analysis for evaluation of surgical techniques 12.4 Inter-organs displacements 12.5 Discussion 12.6 Conclusion References 13 Patient-specific biomechanical modeling for applications in breast cancer diagnosis and treatment 13.1 Introduction 13.1.1 Breast anatomy 13.1.2 Breast cancer 13.1.3 Breast cancer diagnosis and treatment 13.2 Anatomical modeling 13.2.1 Segmenting medical images of the breast 13.2.2 Constructing anatomical models from segmentations 13.3 Applications 13.3.1 Assisting image registration for pre-operative treatment planning 13.3.2 Multimodal image registration for supporting diagnostic imaging 13.3.3 Predicting tumor positions during treatment procedures 13.3.4 Predicting cosmetic outcomes following breast cancer treatment 13.4 Challenges and opportunities Acknowledgments References 14 Ultrasound elastography: in vivo assessment of tissue stiffness 14.1 Introduction 14.2 Principles of elastography 14.2.1 Introduction 14.2.2 Static elastography / strain elastography (SE) 14.2.3 Dynamic elastography / shear wave elastography (SWE) 14.3 Clinical applications for breast and cervix 14.3.1 Breast elastography for tumor detection 14.3.1.1 Strain elastography (SE) of breast 14.3.1.2 Shear wave elastography (SWE) of breast 14.3.2 Cervical elastography 14.3.2.1 Cervical elastography for the prediction of preterm delivery or successful induction of labor 14.3.2.2 Cervical elastography for intraepithelial neoplasia (CIN) and cancer diagnostics 14.4 Conclusion References Part 4 From biomechanical models to medical devices, and patients treatments 15 Numerical simulation of vaginal delivery 15.1 Introduction 15.2 The three phases of a vaginal birth 15.3 Interest to perform a childbirth training simulator 15.4 A real-time childbirth simulation 15.4.1 Geometrical representations of the organs 15.4.2 Modeling of bony pelvis and pelvic floor 15.4.2.1 Bony pelvis 15.4.2.2 Pelvic floor A strategy to obtain a real-time childbirth simulation 15.4.3 Modeling of uterus 15.4.4 Modeling of fetus 15.4.5 The complete delivery simulation coupled to a haptic device 15.4.6 Conclusion 15.5 Accurate childbirth simulations 15.5.1 Stresses applied on pelvic floor muscles 15.5.2 Uterine pressures applied on fetal head 15.5.3 Conclusion 15.6 Conclusion & perspective Acknowledgments References 16 Numerical models for breast surgery and reconstruction 16.1 Introduction 16.2 Previous work on breast biomechanical modeling to aid registration and surgical planning 16.3 Towards surgical guidance 16.4 Symmetric biomechanically guided prone-to-supine breast image registration for surgical and radiotherapy planning 16.5 Multiscale mechano-biological finite element modeling of oncoplastic breast surgery: numerical study towards surgical planning and cosmetic outcome prediction 16.6 Conclusion Dedication Acknowledgments References 17 A numerical model for prolapse surgery 17.1 Introduction 17.2 Material and methods 17.2.1 Generation of the patient-specific FEM 17.2.1.1 Integration of non-observable anatomical structures: suspensions system 17.2.1.2 Boundary conditions 17.2.1.3 Material properties of the constitutive tissues 17.2.2 Generation of a patient-specific FEM for pathology 17.2.3 Generation of a surgical techniques model 17.3 Results 17.3.1 Validation of the PS model 17.3.2 Validation of the PathoS model 17.3.3 Evaluation of surgical techniques 17.3.4 Patient-specific model of surgical techniques 17.4 Discussion 17.5 Conclusion References 18 Augmented reality biomechanical simulations for pelvic conditions diagnoses 18.1 Introduction 18.2 Simulation of deformable structures 18.2.1 FE models and constitutive law 18.2.1.1 Linear elastic model 18.2.1.2 Corotational formulation 18.2.2 Implicit time integration 18.2.2.1 Preconditioner 18.2.3 Time-stepping and collision detection 18.2.3.1 Collision detection 18.2.3.2 Contact mapping 18.2.4 Constraint-based simulation 18.2.4.1 Contact and friction models 18.2.4.2 Constraint solving and mechanical coupling Step 1 Step 2 Step 3 Step 4 Step 5 18.2.4.3 Compliance and mechanical coupling 18.3 Registration of biomechanical models 18.3.1 Geometrical binding 18.3.1.1 Outliers and geometrical filtering Unique pairing Filtering with distance Filtering with normals 18.3.2 Constraints definition 18.3.2.1 Bilateral constraints 18.3.2.2 Unilateral constraints 18.3.3 Constraint solving 18.3.3.1 Outliers and mechanical filtering Force clipping Image compliance 18.4 Applications 18.4.1 Data acquisition 18.4.2 Contour tracking 18.4.3 Boundary condition 18.4.4 Evaluation 18.5 Conclusion References 19 Towards patient-specific treatment in gynecologic surgery: recent development and perspectives 19.1 Introduction 19.2 Research investigation needs 19.2.1 Mechanical properties of pelvic tissue 19.2.2 Nondestructive characterization of the mechanical properties of pelvic tissue 19.2.3 Medical image analysis 19.2.4 Numerical simulation of women's reproductive system treatment 19.3 Perspectives: Use of numerical simulation for treatment improvement in gynecology 19.3.1 Numerical simulator for training 19.3.2 Numerical simulation for a better understanding of physiology and pathology 19.3.3 Numerical tools for risks or pathology evaluation and prevention 19.3.4 Numerical tools for treatment planification 19.3.5 Numerical tools for treatment assistance 19.3.6 Towards a new generation of treatment References Index Back Cover Biomechanics of the Female Reproductive System: Breast and Pelvic Organs: From Models to Patients synthesizes complementary advances in women's reproductive biomechanics, medical imaging analysis, patient-specific characterization, and computational finite element models. The book discusses the biomechanical aspects related to the breast and female pelvic floor system at each step of development. The table of contents also covers certain events and diseases, including cancers, delivery, aging, breast, hysterectomy or prolapse surgery. It presents the main biomechanical experimental results obtained and models developed this last decade to highlight the importance of accounting for patient-specific history and aging characteristics to consider damage growth effect and impact. As part of Elsevier's Biomechanics of Living Organs series, this book provides an opportunity for students, researchers, clinicians and engineers to study the main topics related to the biomechanics of the women's reproductive system in a single book written by a global base of experts. Introduces fundamental aspects of breast and pelvic floor Anatomy, Physiology and Physiopathology Covers the most recent imaging techniques (such as image analysis reconstruction, elastography, tagged MRI, nondestructive inverse methods) developed to characterize patient-specific anatomy and mechanical properties characteristics Discusses the main computational studies performed this last decade for modeling the delivery process and potential induced injury