BIOMECHANICS OF THE FEMALE PELVIC FLOOR BIOMECHANICS OF THE FEMALE PELVIC FLOOR Edited by LENNOX HOYTE Director, Urogynecology andFemale Pelvic Reconstructive Surgery,USF College ofMedicine, Tampa, FL,UnitedStates of America; MedicalDirector,Urogynecologyand Robotic Surgery, Tampa GeneralHospital, Tampa, FL, United Statesof America MARGOT DAMASER Professor ofMolecularMedicine, Cleveland Clinic LernerCollegeof Medicine, Case Western Reserve University, Cleveland,OH, United Statesof America; LernerResearchInstitute,ClevelandClinic,Cleveland,OH,UnitedStatesofAmerica; Advanced Platform Technology Center, Cleveland VAMedicalCenter, Cleveland, OH, United States of America AMSTERDAM (cid:129) BOSTON (cid:129) HEIDELBERG (cid:129) LONDON NEW YORK (cid:129) OXFORD (cid:129) PARIS (cid:129) SAN DIEGO SAN FRANCISCO (cid:129) SINGAPORE (cid:129) SYDNEY (cid:129) TOKYO Academic Press is an imprint of Elsevier AcademicPressisanimprintofElsevier 125LondonWall,LondonEC2Y5AS,UK 525BStreet,Suite1800,SanDiego,CA92101-4495,USA 50HampshireStreet,5thFloor,Cambridge,MA02139,USA TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UK Copyright©2016ElsevierInc.Allrightsreserved. Exceptions:Chapters2and20,Copyright©2016JohnDelancey.PublishedbyElsevierInc.Allrights reserved. Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronic ormechanical,includingphotocopying,recording,oranyinformationstorageandretrievalsystem, withoutpermissioninwritingfromthepublisher.Detailsonhowtoseekpermission,further informationaboutthePublisher’spermissionspoliciesandourarrangementswithorganizationssuch astheCopyrightClearanceCenterandtheCopyrightLicensingAgency,canbefoundatour website:www.elsevier.com/permissions. ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher (otherthanasmaybenotedherein). Notices Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperience broadenourunderstanding,changesinresearchmethods,professionalpractices,ormedicaltreatmentmay becomenecessary. Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluating andusinganyinformation,methods,compounds,orexperimentsdescribedherein.Inusingsuch informationormethodstheyshouldbemindfuloftheirownsafetyandthesafetyofothers,including partiesforwhomtheyhaveaprofessionalresponsibility. Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors,assume anyliabilityforanyinjuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligence orotherwise,orfromanyuseoroperationofanymethods,products,instructions,orideascontainedin thematerialherein. BritishLibraryCataloguinginPublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress ISBN:978-0-12-803228-2 ForinformationonallAcademicPresspublications visitourwebsiteatwww.elsevier.com PrintedandboundintheUSA Publisher:JoeHayton AcquisitionsEditor:FionaGeraghty EditorialProjectManager:MariaConvey ProductionProjectManager:LisaJones Coverdesigner:MariaInesCruz CONTRIBUTORS S.Abramowitch Universityof Pittsburgh, Pittsburgh, PA,UnitedStates of America A. Akhondi-Asl Departmentof Radiology, Boston, MA, United Statesof America J.B. Alford Universityof South Florida, Tampa, FL, United Statesof America M. Alperin Universityof California, San Diego, CA, UnitedStates of America J.A. Ashton-Miller Universityof Michigan, Ann Arbor,MI, United States of America A. Borazjani Lerner ResearchInstitute, ClevelandClinic, Cleveland, OH, United Statesof America M.A.T. Bortolini Federal University of Sa˜o Paulo, Sa˜o Paulo, Brazil S.Branda˜o Universityof Porto,Porto,Portugal B.Brazile Mississippi State University, Starkville, MS, United Statesof America L. Chen Universityof Michigan, Ann Arbor,MI, United States of America D.Christiansen Mississippi State University, Starkville, MS, United Statesof America C.E. Constantinou Stanford University, Stanford, CA, United States of America T. Da Roza Universityof Porto,Porto,Portugal M. Damaser Professor ofMolecularMedicine,ClevelandClinicLernerCollegeofMedicine,CaseWestern Reserve University;LernerResearch Institute, ClevelandClinic; Advanced Platform TechnologyCenter,ClevelandVAMedicalCenter,Cleveland,OH,UnitedStatesofAmerica J.O.L. DeLancey Universityof Michigan, Ann Arbor,MI, United States of America K. Downing AlbertEinsteinCollegeofMedicine/MontefioreMedicalCenter,Bronx,NY,UnitedStatesof America xi xii Contributors D. Easley University of Pittsburgh,Pittsburgh,PA, United States of America V. Egorov ArtannLaboratories, Trenton, NJ,UnitedStates of America J.Fielding UTSouthwestern,Dallas, TX,UnitedStates of America L. Hoyte Director,UrogynecologyandFemalePelvicReconstructiveSurgery,USFCollegeofMedicine; MedicalDirector,UrogynecologyandRoboticSurgery,TampaGeneralHospital,Tampa,FL, United Statesof America K. Knight University of Pittsburgh,Pittsburgh,PA, United States of America R.K. Kotarinos UniversityofSouthFlorida,MorsaniCollegeofMedicine,Tampa,FL,UnitedStatesofAmerica J.A. Kruger University of Auckland,Auckland, New Zealand X. Li University of Sheffield, Sheffield, United Kingdom J.Liao MississippiState University,Starkville, MS, United States of America C. Lisle KnowledgeVis, LLC, Maitland; University of CentralFlorida, Orlando,FL, United States of America V. Lucente The Institute forFemale PelvicMedicine &Reconstructive Surgery, Allentown,PA,United Statesof America J.Luo University of Michigan,Ann Arbor, MI,UnitedStates of America S. Madill Schoolof Physical Therapy,University of Saskatchewan,Saskatchewan, Canada T. Mascarenhas University of Porto, Porto, Portugal H.C. Ming SingaporeGeneralHospital; Duke-National Universityof Singapore, Singapore P.A. Moalli University of Pittsburgh,Pittsburgh,PA, United States of America M.P. Nash University of Auckland,Auckland, New Zealand Contributors xiii R.Natal Jorge Universityof Porto,Porto,Portugal P.M.F. Nielsen Universityof Auckland, Auckland, New Zealand M. Parente Universityof Porto,Porto,Portugal S.S.Patnaik Mississippi State University, Starkville, MS, United Statesof America P.L.Ryan Mississippi State University, Starkville, MS, United Statesof America A. Sarvazyan Artann Laboratories, Trenton, NJ, United Statesof America D.C. SimkinsJr. Universityof South Florida; Formerics, LLC, Tampa,FL, United Statesof America C.H. van der Vaart UniversityMedical CenterUtrecht, Utrecht, Netherlands H.van Raalte Princeton Urogynecology, Princeton,NJ,UnitedStates of America S.K. Warfield Departmentof Radiology, Boston, MA, United Statesof America B.Weed Mississippi State University, Starkville, MS, United Statesof America X. Yan Universityof Auckland, Auckland, New Zealand EDITORS’ BIOGRAPHY Lennox Hoyte, MD, MSEECS is Professor of Obstetrics and Gynecology at the University of South Florida (USF). He is the founding Division andFellowshipdirectorofFemalePelvicMedicine and Reconstructive Surgery (FPMRS) at USF. BoardcertifiedinOB/Gyn,andfellowship-trained in FPMRS, he received a BSEE from WPI, an MSEECS from MIT, and his MD from Stanford University. He completed OB/Gyn residency training at Brigham and Womens Hospital/Mass General Hospital, Fellowship training in FPMRS at Loyola University, and Surgical Planning at Harvard. He performs advanced robotic and vagi- nal surgery to correct prolapse, and treats women with all types of pelvic floor dysfunction. He invents and commercializes medical devices for simplifying surgery and enhancing patient safety. He has received 4 patents, with several more pending.Hespentadecadedesigningandbuildingadvancedcomputercircuits,andtools for automating their design and production. This prepared him for a research career in MRIbased3Dpelvicreconstruction.Dr.Hoytehaspublishedalargenumberofpeer- reviewed manuscripts, including the first to demonstrate differences in 3D pelvic floor structure between normal women, and those with prolapse and urinary incontinence. His current research is geared to developing imaging markers to predict the success of different surgical approaches to correct pelvic organ prolapse. xv xvi Editors’Biography Margot Damaser, PhD is Professor of Molecular Medicine at the Cleveland Clinic Lerner College of Medicine with appointment as Staff in the Department of Biomedical Engineer- ing and the Glickman Urological and Kidney Institute of the Cleveland Clinic. She also has an appointment as Senior Research Career Scientist in the Advanced Platform Technology Center of the Louis Stokes Cleveland Department of Veterans Affairs Medical Center. She received an A.B. in Engineering Science from Harvard and Radcliffe Colleges and a PhD in Bioengineering from the University of California at Berkeley and San Francisco. She completed two postdoc- toral fellowships, at Lund University, Lund, Sweden, and in the Department of Urology at the Hospital of the University of Pennsylvania, Philadelphia,PA.Thefocusofher20yearresearch careerhasbeenonimprovingknowledgeofpelvicfloorfunctionandbiomechanicsand translating thisknowledgeto improvediagnosis andtreatmentof pelvicfloor disorders. ShehashadresearchfundingfromNIH,VA,privatefoundations,andcorporations.She hasfivepatentspendingandover120peer-reviewedpublications.Sheisconsideredan internationallyrecognizedexpertinthefieldsoflaboratory-basedandpreclinicalinves- tigationsinpelvicfloordisorders,aswellasdevelopmentofnoveltherapiesandmethods of diagnosing dysfunction. FOREWORD This cutting-edge textbook of female pelvic floor biomechanics brings an integrated, multidisciplinaryfocustothestudyoffemalepelvicfloordisorders.Withcontributions from recognized experts in the fields of biomedical, structural, materials, and tissue engineering, as well as anatomy, imaging, visualization, biochemistry, tissue ultrastruc- ture,pelvicsurgery,andradiology,thebookisdesignedtogarnernewinsightsintothe femalepelvicfloor.Whilethisinnovativetextbookencouragesnovelsolutionstofemale pelvic floor dysfunction, it also serves as a primer on pelvic floor biomechanics. Thus,unlikepreviousbooksonthepelvicfloor,thetextcoversawiderangeoftopics vital to understanding the biomechanics of the pelvic floor, including physiology, anatomy, ultrastructure, medicine, engineering analysis, imaging, and visualization. Theimpactofpregnancyandchildbirthonpelvicfloorbiomechanicsiscoveredindetail. Central to such a biomechanical analysis is the need to generate realistic biomechanical models and this, too, is extensively covered. Each chapter builds on the previous ones, suchthatareadercanreadthebookinitsentiretyfromfronttoback,asonemightina course on biomechanics. I am confident that readers of this book will see opportunities to evaluate theories aboutchildbirthinjuryinsilicothus,bypassingtheethicalandlogisticcomplexitiesaris- ing from in vivo attempts to study the effects of labor, and maternal and fetal variables on pelvic floor outcomes in large cohorts of women. In addition, readers will be able to use the concepts presented herein to test patient-specific scenarios for surgical repair of prolapse. Inshort,thisbookfillsanimportantgapinourknowledgebaseoffemalepelvicfloor disorders.Itisrequiredreadingforthosewhowishtofullygrasprelevantbiomechanics and make an important contribution to the field of female pelvic floor dysfunction. CHARLES J. LOCKWOOD, MD Professor of Obstetrics, Gynecology, and Public Health Senior Vice President, USF Health Dean, Morsani College of Medicine University of South Florida xvii PREFACE Thereareinfacttwothings,scienceandopinion;Thefirstbegetsknowledge,thesecond ignorance. Hippocrates, Laws, BookIV Thisbookonthebiomechanicsofthepelvicfloordisordersthatyouarereadingmarksa milestone in the development of this exciting new field. It signals the transition from opinion to science. The path between these two points of view is not always an easy one to take and depends on developing novel tests that can provide relevant measure- ments so that competing hypotheses can betested. The important new workpresented here on understanding the mechanical nature of the pelvic floor marks a distinct shift from a historically observation-based approach to these problems that have dominated the field during the last century. Early in the 20th century, outstanding observational research was conducted that resulted in two landmark books: Joseph Halban’s and Julius Tandler’s Anatomy and Etiology of Genital Prolapse in Women [1] and R.H. Paramore’s the Statics of the FemalePelvicViscera[2].Thesetwoworkscontain,inthefirstcase,theresultsofmetic- ulousdissectionsanddocumentationoftheanatomyseeninscoresofcadaverswithpro- lapse.Inthesecondcase,Paramoreprovidesathoughtfulanddetailedtheoreticalanalysis ofthebiomechanicalfactorsinvolvedinnormalsupportandaconsiderationofhowthey arealteredinwomenwithprolapse.Unfortunately,theonlytoolsavailablefortheseearly investigators were acute observation, clear thinking, and simple devices for measuring distancesandpressure.Theobservationsmadebythesepioneersareimportant,butsci- entificallytestingtheideasthattheyandsubsequentinvestigatorsproposedwasnotpos- sible at that time. Greatstridesoccurwhenarelevantbasicsciencedisciplineislinkedtoaclinicalprob- lem.Forexample,therevolutionininfertilitytreatmentsthatoccurredwithdevelopment ofinvitrofertilizationoccurredbyapplyinginsightsmadeincellbiology,endocrinology, andgenetics;sciencesthatareattheessenceoffertilization,implantation,andembryogen- esis. For the pelvic floor and its disorders, the primary basic science is biomechanics; the understanding of complex structuralinteraction between biological tissues. Certainly cell andmolecularbiologyandgeneticshavearoletoplay,buttheydependonidentifyingthe relevant disease processes and questions that are involved in structural failure. Threemajordevelopmentshaveallowedpelvicfloorsciencetoadvance.Firstisthe availabilityofadvancedimagingintheformofMRIandultrasound,secondistheability toconstructmeasureableanatomicallyaccurategeometricmodelsfromrealwomen,and third the advent of computational methods including finite element modeling so that xix