CHURCHILLLIVINGSTONEELSEVIERAn imprint of Elsevier Inc. 2006,Elsevier Inc. All rightsreserved.First published 2006No part of this publication may be reproduced, stored in a retrieval system, or transmitted inany form or by any means,electronic, mechanical, photocopying, recording or otherwise,without the prior permission of the Publishers. Permissions may be sought directly fromElsevier's Health Sciences Rights Department, 1600 John F. Kennedy Boulevard, Suite 1800,Philadelphia, PA 19103-2899, USA:phone: (+1) 215239 3804, fax: (+1) 215 2393805, ore-mail:healthpermissions@elsevier.com. You may also complete your request.on-line via theElsevier homepage (http://www.elsevier.com). byselecting 'Support andcontact' and then'Copyright and Permission'.ISBN-13: ISBN-lO:Reprinted 2007British Library Cataloguing in PubUcation DataA catalogue record for this book is available fromthe British LibraryLibrary of Congress Cataloging in PubUcation DataA catalog record for this book is available from theLibrary of CongressNoticeMedical knowledge is constantly changing. Standard safety precautions must be followed butas new research and clinical experience broaden our knowledge, changes in treatment anddrug therapy may become necessary or appropriate. Readers are advised to check the mostcurrent product information provided by the manufacturer of each drug to be administeredto verify the recommended dose, the method and duration of administration, andcontraindications. It is the responsibility of the practitioner, relying on experience andknowledge of the patient, to determine dosages and the best treatment for each individualpatient. Neither the Publisher nor the author assumes any liability for any injury and/ordamage to persons or property arisingfrom this publication.The PubUsherPrinted in ChinaLast digit is the print number: 9 8 7 6 5 4 3 2Working together to growlibrariesin developing countrieswww.elsevier.comI www.bookaid.org I www.sabre.orgELSEVIER Sabre FoundationList of ContributorsCindy L Amundsen MDAssociate Professor of ObstetricsandGynecologyDivision of UrogynecologyDuke University Medical CenterDurham, NC, USAKarl-Erik Andersson MDPhDProfessor of Clinical PharmacologyLund University HospitalLund, SwedenKarl Be PT PhDProfessor of Exercise ScienceNorwegian School of Sport SciencesOslo, NorwayTimothy B Boone MD PhDRussell and Mary HughScott Professor andChairmanScott Department of UrologyBaylor College of MedicineHouston, TX,USAMuriel K Boreham MDAssistant Professor of ObstetricsandGynecologyUniversity of Texas Southwestern MedicalCenterDallas, TX,USALinda Brubaker MDMSAssistant Dean for Clinical and TranslationalResearchProfessor, Department of Obstetrics andGynecologyDirector and Fellowship Director, Division ofFemale Pelvic Medicine and ReconstructiveSurgery,Loyola University MedicalCenterMaywood, IL, USAChristopher R Chapple BSc MDFRCS(Urol)Professor of UrologyThe Royal Hallamshire Hospital&SheffieldHallamUniversitySheffield, UKC SageClaydon MDAssistant Professor of ObstetricsandGynecologyDivision of Female Pelvic Medicine andReconstructionBrody School of MedicineEast Carolina UniversityGreensville, NC, USAFirouz Daneshgari MDDirectorCenter for Female Pelvic Medicine andReconstructiveSurgeryCleveland, OH, USADonna Deng MDClinical InstructorReconstructiveand Female UrologyDavid GeffenSchool of Medicineat UCLALos Angeles, CA, USANaresh V Desireddi MDDepartment of UrologyFeinberg School of MedicineNorthwestern UniversityChicago, IL, USARoger R Dmochowski MDFACSProfessor of Urologic SurgeryVanderbilt University MedicalCenterNashville, TN, USACatherine E DuBeau MDAssociate Professor of MedicineSection of GeriatricsDepartment of MedicineUniversity of ChicagoChicago, IL, USAMichael K Flynn MDMHSAssistant Professor of ObstetricsandGynecologyUniversity of RochesterRochester, NY, USAJason PGilleran MDUniversity of Texas at Southwestern MedicalCenter at DallasUrology, Dallas, TX, USANoelani M Guaderrama MDDepartment of OBGYN, Female PelvicMedicine and ReconstructiveSurgerySouthern California Permante MedicalGroupIrvine, CA, USAAdam PKlausner MDAssistant Professor of Urology ResearchDepartment of UrologyUniversity of Virginia HealthScience CenterCharlottesville, VA, USAGary ELemack MDAssociate Professor of UrologyResidency ProgramDirectorUniversity of Texas Southwestern MedicalCenterDallas, TX, USAviiviiiICONTRIBUTORSMalcolm Lucas MDConsultantUrological SurgeonSwansea NHSTrustMorristonHospitalSwansea, UKCourtenay Moore MDFellowGlickman Urological InstituteCleveland, OH,USACharles W Nager MDProfessorDepartment of Reproductive MedicineDivision of Female Pelvic MedicineandReconstructive SurgeryUniversity of California, San DiegoLa)olla, CA, USAChristine Norton PhD MA RNProfessor of Gastrointestinal Nursing,King's College LondonNurseConsultant,St Mark's Hospital,Harrow, Middlesex, UKAndrew Pickersgill MDConsultant Obstetricianand GynaecologistStepping Hill HospitalStockport, UKChristina) Poon MDClinical InstructorLions' GateHospitalVancouver, BC, CanadaShlomoRazMDProfessor of UrologyCo-Director, Division of Female Urology,Reconstructive Surgery and UrodynamicsUniversiry of CaliforniaLos AngelesLos Angeles, CA, USALarissa Rodriguez MDAssistant Professor of UrologyReconstructiveand Female UrologyDavid GeffenSchool of Medicine at UCLALos Angeles, CA, USAMatthew PRutman MDAssistant Directorof UrologyCo-Director of Incontinence, VoidingDysfunction and UrodynamicsDepartment of UrologyColumbia UniversityNewYork, NY, USAHarriette M Scarpero MDAssistant Professor of Urologic SurgeryVanderbilt University Medical CenterNashville, TN, USAAnthonyJSchaeffer MDDepartment of UrologyFeinberg School of MedicineNorthwestern University MedicalSchoolChicago, IL, USAJoseph I Schaffer MDAssociate Professor of ObstetricsandGynecologyChief of GynecologyDirector, Division of UrogynecologyandReconstructive Pelvic SurgeryUniversity of Texas SouthwesternMedicalCenterDallas, TX, USAAnthony R B Smith MDFRCOGConsultant GynaecologistDepartment of Urological GynaecologySaint Mary's Hospitalfor Women andChildrenManchester, UKWilliam D Steers MDHovey Dabney Professor and ChairDepartment of UrologyUniversity of VirginiaCharlottesville, VA, USARichard Turner-Warwick CBE FRCPFRCSFRCOGEmeritus ConsultantThe Middlesex Hospital &InstituteofUrologyLondon, UKClifford Y Wai MDAssistant Professor of Obstetrics andGynecologyUniversity of Texas Southwestern MedicalCenterDallas, TX,USAKristene E Whitmore MDProfessor of Surgery, Urology and OBGYNDrexelUniversityPhiladelphia, PA, USAPhilippe E Zimmern MDFACSProfessor of UrologyDirector, Bladder andIncontinenceTreatment CenterDepartment of UrologyUniversity of Texas Southwestern MedicalSchoolDallas, TX, USAPrefaceThree years agoPhilippe Zimmern and I askedourselves thequestionisthere a rolefor yet another booklooking atfemale urology and disorders of thefemale pelvic floor? Wecarefullyreviewedexistingpublications anddecidedthattherewas a potential roleforjustsucha booktargetedatclinicians ofalldisciplinesinterestedinthissub-specialtyarea. With this in mind we felt it was important to criticallyreviewall oftheimportant areaswithinthesub-specialtyusingamulti-disciplinaryapproach. Therebymakingthisan internationallyapplicablebook,which will be usefultoclinicians with all levels of interest, experience and expert-ise. As you will seethesectionsonbothurinaryandfecalincontinencearewrittenby expertsfrommany disciplines,covering these topics in detailin what we hope to be a veryreadable and interesting style.We hope that you will agree with thefundamental ethosofthisbookthat themulti-disciplinaryapproachtoman-agement is not only preferable butalso essential to achievethe best results for our patients.Christopher R ChapplePhilippe E Zimmern2006ixForewordIn thepast decadetherehas beena long overduerecogni-tion that collaboration between urologists, obstetrician-gynecologists, colonandrectal surgeons, physiotherapists,physiologists, pharmacologists, and nurse practitioners isessential if weare toenhance our care of womenwithdisorders of the pelvic floor. Theeditors of MultidiscipHnaryManagement of Female Pelvic Floor Disorders have assembled anexperienced, well balancedgroupofauthors fromvariousdisciplines as well as geographicallydiverse institutionstoshare their own knowledge of these frequently inter-relateddisorders.The format ofthe bookislogical, beginningwiththerecognitionthat we must understandnormal anatomyandphysiologyof the pelvic floor before dealing with theabnormal and progressing from diagnosis and managementeventually to a review of statistics for the clinician.The readers will appreciate the balanced approach totreatment options. Women with disorders of the pelvic floorcannot all bemanagedin astandardized fashion. Somecomplaints are best managed non-surgically and others, suchas fistulas, may always require surgical intervention forultimate cure. The editors havepurposefully provided aAt first glance this text might seemto be just anotheraddition to the ever increasing library of texts dealingwithportionsofwhat is termed"femaleurology"or"urogyne-cology,"dependingononesspecialty. It is, however, con-siderably more than that. The well respected editorial board,consisting of 2 urologists, 2 urogynecologistsandan expertinpelvicfloorphysiotherapy, hasput togethera veritablehandbookforafellowship infemalepelvicmedicine andreconstructive surgery. Eachsubject encompassed inthisarea, with thepossible exceptionof female sexual dysfunc-tion, is covered in a succinct but authoritativemannerby acarefully chosen roster of authors. The result, in my opinion,is a comprehensive text which will give the reader a workingknowledge ofthepertinent concepts andcurrent dataincomprehensive approachtopatient care, recognizingthatonlythepatientandher personal doctor shouldmake theultimate decision regarding management.One of the hidden treasures insuchacomprehensivetext authoredbyadiversegroupof people istheset ofbibliographies following all chapters. The truly curiousreaderwill find an endless source of references not only toclassic but also to current literature.Personally, I have had a long interest in caring for womenwithdisordersof thepelvicfloor. Mypatients andIhaveregularly benefitedfrom the on-going work of the men andwomenwho have editedandcontributedto thistext. Thewomen of theworld owe a debt of gratitudetotheeditorsandcontributorsnot onlyfor their pastwork but totheircommitment to providing us this comprehensive, up to dateresource.Bob L Shull MDProfessor of Obstetrics and GynecologyTexas A&M University Health Science CentersScott & White Clinic and HospitalTemple, TX, USAeach area and provide a basis on which to build an individuallibrary or reference file in those areas. Fellows and residentswill find thetextextremely useful, as will those urologistsandgynecologists whose practicesareconcentratedinthisarea. Ifonetookeachofthe 30 chaptersandconstructed2teaching conferences around each, one would have avery impressive and nearly completecurriculum for femalepelvic medicine and reconstructive surgery.AlanJ Wein MD PhD(Han)Professor and Chair of the Division of UrologyUniversity of Pennsylvania HealthSystemPhiladelphia, PA, USAxiPelvic Anatomy for the SurgeonHarrietteMScarpero and Roger R DmochowskiCHAPTER1INTRODUCTIONSignificant advancements incomputer andimagingtech-nology in recent years have enabled more realistic renderingof human pelvic anatomy. Magnetic resonance imaging(MRI) has provided unsurpassed soft tissue visualizationandthe abilitytoseestructures inseveral spatial planes.Dynamic MRI offers the opportunity to see anatomic struc-tures altered by intraabdominal pressure and provides clari-fication of the contents of the prolapse inunclear cases(Fig. 1.1). Usinginteractive rotation of the three-dimen-sional (3D) model of thehumanpelvis, as well as cinefilmsof thepelvic floorandportionsof thelower urinarytract(LUT) during straining and relaxation, we may also improveFigure 1.1A sagittal image froma dynamic MRI of thefemalepelvisduring Valsalva maneuver. Aprominent cystoceleisidentified as thecontents of theanterior compartmentprolapse.our understandingofthepathophysiologicmechanismsofstressincontinence.' Computedtomography(CT) imagescanbereconstructedinthreedimensions, creatingimagesofgreater definition andrealism. Just assimulators havebecome standard inthe fieldsof aviation andaerospace,virtual reality models of the humanmay replace cadavers inthe gross anatomy laboratory.This chapterwillhighlightsomeofthesenewareasofanatomic researchas well as review pelvic anatomy and thesurgical relevance of key anatomic structures. For thepurpose of this chapter, pelvic anatomy is divided into threemainareas: pelvic musculature, ligaments andfascia,andneurovascular supply to thepelvic organs.THEPELVIC FLOORTheterm"pelvic floor" refers to more than just the musclesthatsupportthepelvicviscera. Thevisceraareactuallyacomponent of it. The entity of the "pelvic floor" includes thepelvic viscera, the peritoneumoverlying it, endopelvicfascia,levator ani muscles, coccygeus,obturator internus,piriformis, and perineal membrane/ The muscles, associatedfascia and ligaments and the fascial attachments of theviscera workin concert to support the contents of theabdominopelvic cavity. The load carriedby the pelvic flooris shared by all its components. Damage to the pelvicmuscles by injury, diseaseorsurgery increasestheload onthe fascia and vice versa.Points of origin and insertion of pelvic muscles are on thebonypelviswhichcanthereforebeconsidered the foun-dation on which the pelvic floor is built. Areas of interest tothe pelvicsurgeon onthe bonypelvis includethe pubicsymphysis, pubic rami, ischial spines, ischial tuberosities,and coccyx. The sacrospinous ligaments attach to the ischialspines. Extending laterally fromthe spines is the arcustendineusthatattachesanteriorlytothelower pubicbone.Near its pubicend, thearcus tendineus splits intotwo por-tions: the tendinous arch of thepelvic fascia from which thepubocervical fasciaarises, andthe tendinous archof the;>::lj34CHAPTER1 PELVICANATOMYFORTHESURGEONlevatorani fromwhich thelevatorani musclesarise. Theseareas are pertinent landmarks for manyofour commontransvaginaland transabdominal procedures.Being familiarwiththelocationof thesebonystructures will direct thesurgeontoward other structures of importance suchas liga-mentsandhelpprevent inadvertentinjurytostructuresinclose proximity such as the ureter or neurovascular bundles.PELVIC MUSCULATUREThemuscles of thepelvicfloor consist of a groupcollec-tively known as the levator ani and the coccygeus. Thelevator ani musclesareknownseparatelyas the pubococ-cygeus (PC), iliococcygeus, and puborectalis. These musclestaketheir namesfromtheirpointsof originonthepelvis.They extendtogether as an expansive sheet fromtheinnersurface of the pubic bone, just lateral to the symphysis, to thepelvicsurface of theischialspines(Fig.1.2). Atthepelvicside wall, the levator ani are attached to the arcus tendineus.Posteriorly, theyextendfromtheir origin onbothsides andtravel medially to a midline raphe between the rectumand coccyx. Physiologic studieshave demonstrated that thelevator ani exhibit constant activitywhichallows themtowork as a functional shelf in support of thepelvic viscera.'The pubococcygeus is the most medial of the group. Fromitsoriginat thepubis, itsurroundsthevaginamedial toitandmay haveattachmentstotheurethra. Intheposteriorpelvis it surrounds the anus between theinternal and exter-nal sphincters. Histochemical analysis of the PCmuscles hasidentifiedbothslow-twitch and fast-twitchfibers indicatingFigure1.2The levator animusclesand levator hiatuses.A,urethra; B, urogenital hiatus; C, rectal hiatus; D, pubococcygeus;E, i1iococcygeus; F, coccygeus(adaptedfrom WahleGR,YoungGPH, RazS. Anatomy andpathophysiology ofpelvic support.In:RazS, ed. Femaleurology.Philadelphia: WB Saunders; 1996).that themuscleworkstoprovidestaticvisceral supportaswell as maintaining tone and active closure of urethra,vagina, andrectum." These muscles are theones contractedduring a Kegel exercise, so their strength can be assessed atleast subjectively by palpation while the patient contracts themuscle. ThePCmuscles havea roleinsexual function aswell. Tension or spasm in thesemuscles has been implicatedin the painful disorder of vaginismus as well as thepleasurable rhythmic contractions during orgasm.The origin of the iliococcygeus is theposterior portion ofthetendinous arch and ischial spine. From either side of thepelvis,theyjoinintoamidline raphejust above the anal-coccygeal body. Thepuborectalisismoremedial thantheiliococcygeus, originates at the posterior surface of the pubisand inserts at themidline to therectum. On contraction, thismuscle is pulledtoward its pubic attachment, effectivelyclosingtheproximal anal canal. Itfurther aidsanal conti-nence bymaintainingthe anorectal angle. There aretwoareas of discontinuitywithin thelevatorani knownas theurogenitalhiatusanteriorly andtheanorectalhiatus poste-riorly. Thevaginaandurethratraversethe more anteriorhiatusand therectum passes through theposterior hiatus.The levator ani muscles share in the mechanisms ofdefecation and urination as well as visceral support. Levatordysfunctionas a result of vaginaldeliverymay leadtolossof pelvicorgansupport, as well as constipation or fecal andurinary incontinence. A test of levator ani muscleresponseto stimulation measured by EMG found diminishedresponse at rest andoncontractioninmultiparouswomenwith a prolonged secondstage of labor,'The coccygeus muscle, which is continuous with theiliococcygeusanteriorly, originates at theischialspinesandsacrospinous ligament and then inserts on the lateral sacrumandcoccyx. Theseattachmentsgiveit atriangularconfig-uration. The coccygeus is more posterior than the levator aniand overlies the sacrospinous ligaments.The obturator muscles, typically considered as muscles ofthe lower extremity, are nonetheless intimately connected tothe muscles of the pelvic floor. Theycompose the lateralpelvis or pelvic side walls. Their origin is the internal surfaceof theobturator membrane, posterior bonymarginsof theobturator foramen, the pubic rami, and ramus ofthe ischium.They insert into the medialsurface of the greater trochanterof the femur. Thearcus tendineus fasciapelvisor "whiteline" that has been previously described is a condensation ofobturator fascia and endopelvic fascia. This pelvic landmarkmay be attenuated or torn, contributing to a defect inante-rior compartment support. Theobturatorforamenwithinthe bony pelvis and the associated obturator canal within themuscle are other important landmarks. The obturatorneurovascular bundle runsthrough theseopeningsand is ofparticular concernin anewer variant of the midurethralpolypropylene sling knownas thetransobturator tape.The piriformis, which lies in the same plane as thecoccygeus, arises from the sacrum and inserts on the greatertrochanter. It has special significancebecause the sacralplexus lies on top of it on its course beneath the coccygeus.Perineal membrane. Below thelevatorani is theper-ineal membranewhichisa densetriangularareaoffasciaintheanterior half of thepelvicoutlet. Itarises fromtheinferiorischiopubic rami andattachesmediallyto theure-thra, vagina, and perineal body. Like the levators above, it ispierced by the vagina and urethra. Some authorsrefer to theperineal membrane asthe urogenital diaphragmbut thistermis incorrect.As classically described, a true urogenitaldiaphragm, consisting of two layersof fascia enclosingthedeep transverse perineal muscle and sphincter urethrae andcreating a closed compartment, does not exist,"Perineum. The anatomy of theperineum is important toany discussion of thepelvic floor because thesemuscles liebeneaththemuscles of thepelvicfloor, and reconstructionof the perineummay be undertaken along with pelvicprolapse surgery. Commonly, theanatomy of theperineumis described as being divided into an upper urogenitaltriangle and a lower anal triangle. The points of the triangleare the pubic symphysis, ischial tuberosity, and tip of coccyx.A linethroughthe anterior ischial tuberositiesforms theshared base of the two triangles.The perineal body is a tendinous structure locatedmidline between theanus and vagina. It is thecentral fixa-tionpoint of theperineum. Themuscles of theurogenitaltriangle include the median bulbocavernosus, right andleft ischiocavernosus, and superficial transverse perinealmuscle(Fig. 1.3). Thebulbospongiosus musclesurroundsthe vaginal introitus and covers the lateral part of thevestibular bulbs. It also attaches to the corpora of the clitorisPELVICFASCIAANDLIGAMENTS Iand theperinealbody. The ischiocavernosusmuscle coversthecruraof theclitoris. The superficial transverseperinealmuscleextends fromtheischial tuberositytotheperinealbody. It can be poorly developed or absent. Adeeptransverse perineal muscleoriginates at the ramusof theischium and joins the urethral and anal sphincters as well astheperineal body. The ischiorectal fossa is a wedge-shapedspace in the anal triangle between the levator ani andobturator internus. This anatomic space is importantbecauseof its relationship tothe pudendal neurovascularbundle. The internal pudendal vessels and nerveare withinthelateral wall oftheischiorectal fossa andtheobturatorinternus muscle. The fascial sheath covering this spacecreates the pudendal or Alcock's canal.PELVIC FASCIA ANDLIGAMENTSThere is often confusion regarding the divisions and namingof various portions of the pelvic fascia known as endopelvicfascia. Thefascia investing thelevatoranimay be referredtoseparatelyas thelevatorfascia. Thelevator-endopelvicfascia can be subdivided further into the pubourethralligaments, urethropelvic ligaments, pubocervical fascia, anduterosacral ligamentcomplex(Fig. 1.4). These subdivisionshelpto distinguishtheimportance of thefascia for specificsupport roles.Manystructurescommonlyreferredtoas ligamentsarereally condensations of levator fascia, so they differ from thetoughconnective tissuecomposing ligament elsewhereinthe body. As visceral ligaments, these condensations are justloosely organized connective tissue, containing considerableamounts of smoothmuscle," The fibers of visceral ligamentsarefarlessregularthanthe fibers oftrue ligaments. Thepubourethral ligaments are the fascial support of themidurethra totheinnersurfaceof theinferior pubis. TheyIschiocavemosus muscleWall ofvaginaDeep perineal muscleAnal canalExtemal anal sphinctermuscleAnococcygealligamentCoccyxUrethral meatusBulbospongiosus muscleIschial tuberositySuperficial transverseperineal musclelevator ani muscleSacrotuberous ligamentGluteus maximus muscleFigure1.3 Muscles of theperineum(fromDelancey JO, Richardson AC. Anatomy ofgenital support.In: BensonJT; ed. Femalepelvic floor disorders. New York: WWNorton; 1992).5zo1=u~en6CHAPTER1 PELVICANATOMYFORTHESURGEONFigure1.4View ofthepelvicmusculature and somepelvic organsinrelationto thefascial layersof thepelvicfloor.supportandstabilizetheurethraandanterior vaginalwall.Theexternal sphincterislocatedjust distal tothese liga-ments. They have beenexamined grossly andhistologicallyand foundto be very consistent structures that demonstratedensecollagen fibers," Laxity or failureof these ligaments ispartiallyresponsibleforstressurinaryincontinence(SUI)as describedbytheintegraltheory"Themidurethralslingreconstitutes these structures to restore continence. Theurethraisalsosupportedon both sides bylevator fascia.Proximallythislateral urethral support is termedtheure-thropelvicligaments whichare the endopelvicfasciathatfuses theperiurethral fascia to thearcustendineus. It is themajor support for the bladderneckandproximal urethra.Again, these areas are contiguous and not truly distant struc-tures. They are specializedareas of the endopelvic fascia.Urethralsupport is not determinedby fasciaalone. Thepelvicmuscles are also responsible. The fascial attachmentsresponsible for urethral support are those of the pubo-urethral ligaments, periurethraltissue, andanterior vaginalwall to arcus tendineus fascia pelvis (paravaginal fascialattachment) (seeFig. 1.4). Themuscularcomponent is theconnection of periurethral tissues to the levator ani muscles.When these attachments are intact, continence is main-tained. During increased abdominal pressure, theurethra iscompressed against this firmsupportive layer as explained bythe"hammocktheory" of continence.l" Weakening of thesesupportscanleadtoanterior wall relaxationanddiminish-ment of the occlusive action of the vaginal support.Connective tissue disorders havebeen implicated as acause and/or contributor to significant pelvicorgan pro-lapse.'! It may alsobe possible that aging and hormonalchanges associatedwithmenopausemayalterthe compo-sitionandstrengthofconnectivetissue.!"!" Immunohisto-chemical staining of periurethralfascia fromcontinent andincontinent postmenopausal women with pelvic organprolapse demonstrated differences and reductions of thetypesof collagen foundinincontinent womencompared tocontinent. Theinvestigatorstheorizethatthese alterationsindicate analteration inmetabolism of connective tissueintheperiurethral regionleading toa significant decreaseincollagen inpostmenopausal women." Inastudytoassesswhether menopausewasassociated withconnectivetissueweakening, theuterosacralligament resiliencewas assessedin hysterectomy specimens. It was significantlyreduced withvaginal delivery, menopause, and older age."The genital tract (ovary, uterus, cervix, and vagina) isattached on eachside tothepelvicsidewalls by endopel vicfascia. In relation to a specificorgan, the fasciais oftenreferredtoas themesentery of theorgan. Themesenteriesnot only support the organs but also carry their blood supply.Themesenteryof theovarycontaining its vascular pedicleis found at its craniolateral aspect and is known as theinfundibulopelvic ligament. Other mesenteries referred to asligaments includethe broad ligament which, asthe nameimplies, isa wideexpansiveligamentoneithersideof theuterus that attaches to the pelvic side wall. The broadligament contains the fallopian tubes, ligament of the ovariesand uterus, and the uterine vasculature. The round ligamentis an additional uterine support found within the broadligament. The mesenteries blend into fibrous sheets thatbecome thecardinal and uterosacral ligaments. The cardinalligament is found at the base of the broad ligament. Itcontains veins and the uterine artery and supports the uterusalong withtheround ligament, ovarianligament, and utero-sacral ligament. In all, there are six ligamentous supports ofthe pelvicviscera: the broad, round, uterosacral, cardinal,ovarianand infundibulopelvic. Theoriginof the cardinalligament is thegreater sciatic foramen. The uterosacralliga-ment arises from the second through fourth sacral vertebrae.Both surround the cervix and suspend it to the pelvicsidewall. They extend downwardfromthe cervix to suspendthe upper vagina as well.There is no real separationbetweenthe cardinal anduterosacralligaments. The entire support apparatus is con-tinuousfromtheuppermost cardinal-uterosacral complextothe pubocervical fascia. Thecellularmake-upof theseligaments is amixture of smoothmuscle and connectivetissue. Therehasbeenhistologicexaminationof some ofthesetissues. Thecardinal ligament, forinstance, hasbeenshownto beprimarilyperivascularconnectivetissue run-ningparallel totheuterine vessels.'? Ina small histopatho-logic evaluationofthe uterosacral ligament, investigatorscouldnot consistentlyidentifynormal ligamentoustissue,particularlyinthe posthysterectomypelves."Thelackofsolid ligamentous tissuesuggests that this structure may notbe a reliable fixedstructure for prolapse repair but thisremains to be determined by larger studies.VASCULARANDNEUROLOGICSUPPLYTOALLPELVICORGANSContinuous with the cardinal-uterosacral complexbuthaving its own anatomic distinction is the pubocervicalfascia. It is theendopelvicfascia lower inthepelvis wherethe vagina meets the pelvic wall. Thepubocervical fasciaattachesthe vaginalaterallytothearcus tendineusof thefasciapelvis andsupportsthe bladdertothe same. Poste-riorlyit blends withthecardinal ligamentsandis encoun-teredwhendissectinglaterallybeneaththe vaginal wallatthelevel of thebladder during anterior vaginalwall surgery.Defects inthis fasciaproduce anterior compartment pro-lapse. In description of anterior compartment prolapse, theterm "paravaginal defects" refersspecificallyto detachmentof the pubocervical fasciafromthe arcus tendineus. Thearcustendineusmayitself detachfromthepubis orischialspine. In 71 retropubic operations, thearcus tendineus fasciapelvis was noted to be detached fromthe ischial spineover the pubis in a significant majorityof cases (97.6%versus2.8%).19Theanatomyof vaginal support has been describedinterms of levelsof support, aconceptwhichhelps concep-tualize therole of eachligament (Fig. 1.5).20 Level I supportat the vaginal apexisprovidedbythe upper divisions ofendopelvic fascia, collectively knownas paracolpium. Thesefibers extendverticallyandposteriorlytowardthesacrum.In level II the midportion of the vagina is connected laterallyto thepelvicwalls by theparacolpium. Thisstructural layeris intimately related to the anterior vaginal wall andstretches the vagina transversely between bladder andrectum. At levelIII, thedistal vaginais attached directly tothe surrounding organsand muscle without any interveningfascia.Just beneathandadjacenttothevaginaintheposteriorcompartment is a layer of fibromuscular tissueknownas therectovaginal septum(Denonvillier's fascia). It is a fascialcontinuationof the peritoneal cavitybetweentheapexofFigure1.5Levels of vaginal support (fromreference2).the vagina and anterior rectum. Moredistinctly, it isthefusion of theposterior vaginal fascia and the prerectal fascia.Ittooblends withthe cardinal-uterosacral complexsupe-riorly andfuseswiththeperineal body inferiorly. Laterallythefusedlayersareknownas pararectal fascia. Monoclonaland polyclonal antibody tissue analysis of fetaland newbornpelvic specimenshasrevealedthat therectogenitalseptumis formedbymesenchymeinthe earlyfetal period. Thereis apparent coinnervationof the rectal musclelayers andadjacent longitudinal muscle fibersofthe septum. Thesetissue findings support a functional correlation betweenrectumandrectogenital septum; therefore, careful dissec-tioninthis area duringpelvicsurgerycouldlimit neuraldamage and defecatory disturbance."VASCULAR ANDNEUROLOGIC SUPPLYTOALL PELVIC ORGANSTheblood supplyof the levator ani, coccygeus, andpiri-formis is theinferior gluteal artery. The innervation of thelevator muscles is a bit controversial. In a recent study,detailedpelvicdissections of female cadaverswereunder-takentoelucidatetheperipheralinnervation of thefemalelevator ani muscles.Nerve biopsy specimens wereobtainedto confirmthegross findings. Theauthors point out thatdespite "specific and exhaustive attempts to locate pudendalnerve branches to thelevators, none could be demonstratedin any cadaver.'t" Instead the levator ani were found tobeinnervatedbyanerve that originatesfromthe thirdtofifthsacral foramina which they termed the "levator aninerve." Thesefindingscontradict the belief that the pelvicfloor muscles areinnervatedbybranchesof the pudendalnerve.n-25The authors found that the pudendal nerve inner-vated the external anal sphincter, external urethral sphincter,perineal muscle, clitoris, andperineal skin."Another important finding from these dissections was thatthe levator ani nerve crossesthecoccygeal musclepreciselyat the point traditionallyconsideredsafefor sacrospinousligament fixation sutures, namely two fingerbreadths medialtothe ischial spine. Therefore, sacrospinousligament fixa-tion (SSLF) wouldhave a highpotential fornerveinjury orentrapment. The authors postulate that injury to thelevatorani nerve and subsequent pelvic floor denervation andatro-phy could be another explanation for the high occurrence ofanterior vaginal wall prolapse reported afterSSLF.nThe autonomic inferior hypogastric plexus (IHP) (leftand right pelvic plexuses)is the major nerve supply to pelvicorgans.26,27 It is located on pelvic side walls bilaterallybeneath thefascia and medial to thevasculature and extendsfromthe sacrumtothegenital organs at the level of thelower sacralvertebrae." It is composed of parasympatheticfibers from sacralnerve rootsS3-4 (nervi erigentes or pelvicsplanchnic) and occasionally S2 (sacral splanchnic nerves)as7zof=u~C/')81CHAPTER1 PELVICANATOMYFORTHESURGEONwell as some sympathetic fibersfromTII-12/Ll-2 from thelumbosacral trunk (hypogastric nerve). The IHPis believedto supply all the pelvic viscera. The posterior portionsupplies the rectum to the level of the internal anal sphinctervia the inferior mesenteric plexus branches, the bladder andurethral sphincter viavesical branch andthe uterus andupper thirdof thevagina. It may also be supplementedbyautonomic supply from the ureter and arteries. In one studyoffemalecadavers, sacral splanchnicnerves werederivedfromeither S1or S2sympatheticganglia, incontrast tomales in which all sacral sympathetic ganglia wereinvolved.i"The location of the IHP within the pelvis mayvarybetween gender and between individuals of the same gender.Infemales, the IHP nerve fiberswere identified infourlocationsandatotal of 60 locations wereobservedin49female hemipelves. In57% of cases, theIHPwas foundinthe uterosacral ligament. It was found parametrially in30%of cases. It was found pararectallyand inthe foldbetweenthebladder anduterusin2%and 11 %ofcasesrespecrively;"The medialpositionof theIHPhas important implica-tionsfor surgical procedures. MoredetailedknowledgeofIHP locationcanpredict areasof concernfor iatrogenicinjuryduringpelvic surgery. The sacral promontory is themost superior region where operative injury mayoccur.Operations such as aortocavallymph node dissections, colo-rectal surgery, andabdominosacralcolpopexiesmay injurethesuperiorhypogastricplexus."Dissectionofthemeso-rectumor retrorectal spacerisks thesuperiorhypogastricplexus and pelvic and sacral splanchnic nerves. Pelvic lymphnodedissections aroundtheinternal iliac artery can injuretheIHPitselfas well as dissection along themiddlerectalartery. Injuryto theanteriorIHPmay occurduringinter-vention near the distal ureter, uterine or inferior vesicalarteries, and Denonvillier's fascia.Pelvicnerve damageisawell-known complication ofradical hysterectomy that mayleadtobladder, anorectal,and sexual dysfunction. Delineation of theanatomicdistri-bution of important pelvic plexuses can help preventinadvertent injury and resultant neurogenic dysfunction.Fromdissection ofnervebrandinganddistributionofthepelvicplexus of 12 femalecadavers, thepelvicplexusandsubsidiaryplexusesarelaidcloselytothe lateral walls ofthepelvicorgans. Thepelvicplexusandtheuterosacral-cardinal ligaments are closely related."In radical hysterectomy as it is classicallydescribed,branches of the pelvic plexus may be divided. Modificationssuchas preservationofthelateral 1-2emofthecardinalligamenthas beenshown toreducetheincidenceofpost-operative urinary dysfunction compared to hysterectomyrequiring transection of the cardinal ligament flush with thepelvic side wall anduterosacral ligament flushwith therectum.30,31 The cardinal ligament and uterosacral ligamentcontain considerable nerve tissue, includingmajor nervetrunks, ganglia, and free nerve fibers."The nerve content ishigher at the originonthe pelvicsidewallsthan at theirinsertion intotheuterus. Ina follow-upstudyby thesameinvestigators, different nerve types within the uterosacralligament andcardinal ligament wereidentifiedandquan-tifiedwith neuropeptidemarkers." Thecontent of nervefibers isdifferent between the ligaments, andtotal nervecontent ishigher inthe uterosacral ligament. Theutero-sacral ligamenthada greater amount of sympathetic nervecomparedwithcardinal ligament. Sympatheticandpara-sympathetic nervecontent was similarin thecardinal liga-ment. The sensory and sensorimotor components of thecardinal ligament werelessthanthose of the uterosacralligament. Larger diameter trunks were found in greaternumbers inthe uterosacral ligament andlikelyrepresentnervesupplytomore distant pelvic organs supplied by theIHP(bladder, large bowel, and uterinebody). Radical hys-terectomy modifications that focus on less radical tran-section ofthe uterosacral ligament may reduce surgicalmorbidity."Surgical techniquemaycontinuetoevolveasour knowledge of the autonomic nervous systeminthepelvis grows.The genital organs within the female pelvis (ovaries,fallopian tubes, uterus, and vagina) do not all have commonembryology; therefore, their bloodsupplyandinnervationdiffer. Despite their differences, theinternal iliacarteryorhypogastric arteryisthe mainbloodsupplytothe pelvisand pelvic viscera. The ovary receives parasympathetic fibersfrom the vagus nerve and syrnpathetics from TI0, the lessersplanchnics, via the inferior hypogastric plexus. Ovarianarteries aredirect branches fromtheventral aorta. Thereis anastomotic connection to the uterine artery. Venousdrainage is accomplished by a pampiniformplexus thatcoalesces into a single ovarian vein. Ovarian venous drainageis not symmetric. The right ovarian vein drains directly intothe vena cava and the left into the left renal vein. The fallop-ian tubes receive a dual blood supply from the ovarian arterywhichsupplies the lateral third anduterinearterywhichsuppliesthemedial two-thirds. Thefallopian tubesreceiveparasympathetic and sympathetic innervation along theovarian and uterine arteries.Theuterus receives vascular supply fromthe uterineartery, abranchofthe anteriortrunkoftheinternal iliacartery. There are contributions aswell fromthe ovarianarteryandvaginalartery. Theuterinearteryalso suppliesthe cervix and givescontributions to the vagina. Thesevessels runina circuitouspathwithinthebroadligament.The pelvic ureter is in close proximity to the uterus and itsvasculature. Attention toits location is necessaryduringmanypelvicprocedurestoavoid ureteral injury. Neartheinfundibulopelvic ligament, the ureter is crossed bythegonadal vein. The ureter crosses the cardinal ligamentat itslowest portion andtravelscaudally. Inthis areait issur-roundedby the uterine venous plexus and uterine artery. Itthenpasses thesupravaginal portion of thecervixapproxi-mately1.5em fromit oneithersidetoreachthebladder.Thevenous drainageof theuterusis a plexus withseverallevels converging intoa main vein withinthemyometrium.This uterine plexus communicates with ovarian and vaginalplexuses as well. Innervationtotheuterusarises fromtheinferior hypogastric plexus. The vaginal blood supply travelslaterally within the cardinal ligaments and through the para-vaginal suspensory ligaments to the vagina. The main arteryis thevaginal branchoftheinternal iliacarterybut theremay be vaginal arteries thatarise from the uterine artery orinferior vesical artery. Additionally there is a vaginal arterialplexus that extendstoa midlinevaginal artery, sometimesreferredtoas theazygous arteryofthevagina. A vaginalvenous plexus communicatesthrough the cardinalligamentwiththevenous systemofthebladder, rectum, andpara-vaginal tissues.Thenervesupplytothevagina is extensive. Of greatestimportance are thepudendalnerve(S2-4)andtheinferiorhypogastricplexus. Sensoryafferentstotheskinandsub-cutaneoustissues of thelower two-thirdsof thevagina arevia thepudendal nerve. Efferent motor somaticsupplyisnot significant to thevaginal wall since thereis no striatedmuscle. Visceral nerve supply for the upper vagina, muscu-lature, and glands arises from the inferior hypogastric plexus.Afferent fibers transmit noxious stimuli from the peritoneumand pouch of Douglas, cervix and upper thirdof the vaginatothenerverootsS2-4. Efferentfibers supplythesmoothmuscle and glands of the vagina. Sympathetic nerves accom-panysacral nervesof thehypogastric plexus. Parasympa-thetic fibers are carried by the pudendal nerve in the inferiorhypogastric plexus to the lower portion of the vagina.Thearterial supplytothebladder includes a varietyofvessels. Superior vesical arteries (1-4)arise from the umbil-ical arteryto supplytheupper bladder. Themiddlevesicalarterymay arise from the umbilical arteryor as a branch ofthesuperiorvesicleartery andsupplies thebladderbody.The vaginal artery maysupplythe inferiorbladder neck.Additional supply may be given by the obturator or inferiorgluteal arteries. Most arteriesto thebladder arise from theumbilical artery trunk of the internal iliac artery, except theinferior vesical artery which is its own branch off the inter-nal iliac. Venous return is by a vesical plexus. Innervation ofthe bladder can be divided into that to the bladder itself andthat to the bladder outletThe bladderis innervated by thepelvic plexus found just lateral to the rectum. The plexus hasinputfromS2-4spinal segmentsbythepelvicsplanchnicnerveandinput fromTIG-L2segments bythe presacralnerve. The detrusor receivesparasympatheticinput fromthe pelvic nerve. Sympathetic input is carriedon thehypo-RESEARCHINANATOMY Igastricnerve. Thefemaleurethrareceivesarterial supplyfrom branchesof thevaginalartery. Venous drainageis viathe pelvic venous plexus.According torecent studiesof thelower urinary tract infetuses, the anatomy of the urethral sphincter differs bygender. The continence mechanism is composed of detrusor,trigone, and urethral sphincter muscle with distinctivehistologicfeatures inbothsexes."Infemales, theexternalurethral sphincter covers theventral surfaceof theurethrain ahorseshoe shape. Inferiorly, the sizeof the externalsphincter increases and envelops the distal vagina. Thelevator ani muscles do not support the proximal urethra andmay not actively controlcontinence."Thebloodsupplytothe anorectumisprovidedbytheinferior hemorrhoidal artery and a perineal artery, bothbranches of the pudendal artery. The superior hemor-rhoidal, acontinuationof the inferior mesenteric artery,supplies the rectum above theanorectaljunction. The mid-dle rectal artery, whichmayarisefromthe internal iliacarteryor internal pudendal artery, is also a contributor. Thevenous drainage followsarterial supply. Thesympatheticinnervationtothe anorectumisthesuperior andinferiorhypogastric plexuses. Parasympathetic innervation is carriedon the second, thirdand fourthsacral spinal nerves. Sensoryand motor innervation are distributed on several peripheralnerves.RESEARCH IN ANATOMYSeveral MRI studiesofthe pelvicfloorhavebeenunder-takentodescribe bothnormal andabnormal pelvicflooranatomy.35-40 The levator ani anatomy and endopelvicfasciaand urethra have been examined with MRI to detectanatomic variations innulliparous women. Certainly, theestablishment of normal variation in healthy women is impor-tant prior todescriptionof differences related totrauma,injuryor aging. Evenin20healthycontinent nulliparouswomen with normal pelvic examinations and normalurodynamic results, there wasconsiderable difference inMRI findings that werenot attributableonlytotechnicallimitations inmeasuringtechnique. Therewas anabsenceof visible insertion of thelevatorani insidethepubic bonebilaterally in 10% of all women, which contradicts the classicdescription of normalanatomyin textbooks. The variationsobserved clearly point out the need for further studiesbefore standardizing an imaging technique for assessment ofthe pelvic floor,"Sincevaginaldeliveryisconsidered amajorriskfactorfor levator ani damage and the development of SUI, aninteresting study utilizing MRI from nulliparous women andvaginally primiparous womenwas undertaken. The authorsproposed that the comparisonof images would describethe appearanceandoccurrenceof abnormalityinlevator9zof::u~V'JCHAPTER1 PELVICANATOMYFOR THESURGEONmusclesinnulliparous womenandinwomenafter theirfirst vaginal birth."Additionally, imagesof continent andincontinent women were compared. Abnormalityin levatormuscles wasfound in both continent and incontinent womenbut was demonstratedonlyinwomenwhohaddeliveredvaginallyandnot nulliparous women. Within the primi-parousgroup,28%ofincontinentwomendemonstratedadefect inthe levator ani, compared to 11%of continentwomen, making stress incontinent primiparous womentwiceas likely tohave a muscleabnormality. Theauthorsconcludethat thesefindingsare thefirst scientific evidencein support of vaginal birthas a source of levator ani muscledamage. Furthermore, the MRI images have providedvisu-alization of the type of pelvic floor injury that occurs duringvaginal birth. Theysuggest that further research with apopulation-based study is needed, as well as additionalresearchto identify induced CTrupture inthe vaginalsupports that playa role in pelvic floor dysfunction. Anotherinterestingconcept put forth inthis study isusingMRIand electromyography as complementary techniques inorder to also assesspelvic nerve injury. This may help definethe relationship between nerve injury and MRI-visibleabnormalities."Three-dimensionalMRIhas beenusedtoassess levatorani morphologic features among different grades of prolapseandcomparisonwas madewithnulliparous asymptomaticwomenascontrols." The authors were able to identifypatterns of change in the levator ani but alterations in levatoranimorphologywerenot dependentonthegradeofpro-lapse. Additionally, not all women with pelvic organprolapse (POP) had abnormal levator morphology. What didseemtochangewithincreasinggradeofprolapsewas thegapbetweenlevator andpubicsymphysisandthe levatorhiatus. Furtherstudyof MRI inPOPmayfind it a usefulpredictor as to which patients might develop recurrentprolapse after surgery."One limitation of current MRItechnique is that, at pres-ent,studiesareall performed inthesupinepositionwhichmayor may not introduce distortion. Technical advances inMRIare needed beforeimages of satisfactory detail can beobtainedin standingsubjects. The choiceof slice thicknessforimagesonMRI isacompromise. Thinnerslicesofferhigher spatial but poorer imageresolutionwhereasthickerslicesoffer the converse. There isalsothe possibilityofsubjective bias in reading the scans."MRI has been employed to examine the structural regionsoftheurethrainnulliparous womenandwas determinedto be successful at showing the normal appearance andlocationincontinent, nulliparouswomen." This mayhelpwithfuture investigationstodescribestructural abnormal-ities that might be associated with urinary incontinence.Three-dimensional reconstructionfromserial histologicsections allows for precise description of morphometry andappreciation of spatial relationships of one structure toanother. Suchan investigationhas beenundertakenofthehypogastricplexusofa humanfetus." Serialpelvichisto-logicsections weredigitizedfromslidesdirectly. Usingareconstructionprogram, the image treatment andrecon-struction were performed manually. Results allowed the HPto be visualizedand studied in threedimensions. Althoughthe technique is time consuming, advancing technology maysimplifyandstreamlinethe technique. Studying anatomyand embryology may be dramatically changed by these revo-lutionary imaging/computer technologies.t"Another intriguing modern investigation in humananatomy is the Visible Human Project through the NationalLibrary of Medicine." Established in 1989, this undertakingsought tobuilda digital imagelibraryofvolumetricdatarepresentingthecompleteadult anatomyofbothsexes. Itdefines the anatomy of the adult human in threedimensionsand at highresolution(Fig. 1.6). Thevisible humanfemaledataset was releasedin1995 andcontains 5189 anatomic10Figure1.6Transverseand three-dimensional images created fromthefemalehuman databaseproject."images." It is currently used as a tool to teach anatomy andinthefutureit maybecombinedwithsurgical andanes-thesiology simulators to create a virtualoperating room." Itcouldthenbe usedtoteachsurgicalskills tophysicians inREFERENCES1.StenzlA, Kolle D, EderR, et al. Virtual reality of thelower urinarytractin women. Int UrogynecolJ1999;10:248-253.2. Wei J1, Delancey JOl. Functional anatomy of thepelvic floor andlower urinarytract. ClinObstet Gynecol 2004;47(1 ):3-17.3. Parks AG, PorterNH, MelzakJ. Experimental study of thereflexmechanismcontrollingmusclesof thepelvic floor. DisColonRectum1962;5:407-414.4. Koelbl H, StrasseggerH, RissPA, et al. Morphologic andfunctional aspectsof pelvicfloormusclesin patientswithpelvicrelaxationand genuinestress incontinence. Obstet Gynecol1989;74:789-793.5. Shafik A, EI-Sibi O.Studyof thelevator ani musclein themultipara:roleof levatordysfunctionin defecationdisorders. J ObstetGynecol 2002;22(2): 187-192.6. Mirilas P, SkandalakisJEUrogenital diaphragm: an erroneousconcept castingitsshadow overthesphincter urethrae anddeepperineal space.J AmColi Surg2004;198(2): 279-290.7. WaltersM, Weber AM. Anatomy of thelower urinarytract,rectumand pelvicfloor. In: WaltersMD, KarramMM, eds.Urogynecology andreconstructivepelvicsurgery. St louis:Mosby; 1999.8. Vazzoler N, SoulieM. EscourrouG, et al.Pubourethral ligamentsinwomen: anatomicand clinical aspects. SurgRadiol Anat2002;24(1 ):33-37.9. PetrosPE, UlmstenU. Anintegraltheory anditsmethod forthediagnosis and management of femaleurinaryincontinence. ScandJUrol Nephrol SuppI1993;153:1-93.10. Delancey JO.Structural support of theurethraas it relatestostress urinaryincontinence: thehammock hypothesis. AmJObstetGynecol 1994;170(6):1713-1720.11. CarleyME, SchafferJ. Urinaryincontinence andpelvic organprolapsein womenwithMarfanorEhlersDanlossyndrome.AmJObstet GynecoI2000;182(5):1021-1023.12. UlmstenU. Connective tissue factorsin theaetiology of femalepelvicdisorders.AnnMed1990;22(6):403.13. FalconerC, Ekman-Ordeberg G, BlomgrenB, et al. Paraurethralconnective tissueinstress-incontinent womenafter menopause.ActaObstet Gynecol Scand1998;77(1 ):95-100.14. FalconerC, Ekman-OrdebergG, UlmstenU, et al. Changesinparaurethral connective tissue at menopause are counteractedbyestrogen. Maturitas1996;24(3):197-204.15. Goepel C, Hefler l, Methfessel HD, et al. Periurethral connectivetissue statusof postmenopausal womenwithgenital prolapsewithand without stressincontinence.ActaObstet Gynecol Scand2003;82:659-664.16. Reay JonesNH, HealyJC, KingLJ, et al. Pelvic connective tissueresilience decreases withvaginal delivery, menopauseanduterineprolapse. Br JSurg2003;90(4):466-472.17. Range Rl, WoodburneRT. Thegross andmicroscopic anatomy ofthetransverse cervical ligaments. Am JObstet Gynecol1964;90:460-467.18. ColeE, leuPB, Gomelsky A, et al. Histopathological evaluationoftheuterosacral ligament: is thisa dependable structure for pelvicreconstruction?JUrol Abstract 2004; 171(4):304-305.19. Delancey JO. Fascial andmuscularabnormalities in womenwithurethral hypermobility and anterior vaginal wall prolapse. AmJObstet Gynecol 2002;187(1 ):93-98.REFERENCES Itraining or to allowpracticing physicians to gain skill in newtechniques, to give researchers clinical insight into thediseases theyinvestigateor perhaps as a tool toeducateapatient about a disease state or possible treatment.20. Delancey JO. Anatomic aspects of vaginal eversionafterhysterectomy. AmJObstet Gynecol 1992;166:1717-1724.21. Aigner F. Zbar Ap, ludwikowski B, et al. Therectogenital septum:morphology, function, and clinical relevance. DisColonRectum2004;47(2):131-140.22. BarberMD, Bremer RE, Thor KB, et al. Innervationof thefemalelevator ani muscles. AmJObstet Gynecol 2002;187:64-71.23. Wall ll. Themusclesof thepelvicfloor. ClinObstet Gynecol193;36:910-925.24. RetzkySS, RogersRM, RichardsonAC. Anatomy of femalepelvicsupport. In:Brubaker l,Saclarides 1, eds. The femalepelvicfloor: disorders of functionandsupport. Philadelphia: FA Davis;1996.25. Delancey JO. Surgical anatomy of thefemalepelvis. In:Rock JA,ThompsonJp, eds. TeLinde'soperative gynecology. Philadelphia:Lippincott-Raven; 1997.26. Mundy AR. Ananatomicexplanationfor bladder dysfunctionfollowingrectal anduterine surgery. Br JUrol 1982;54:501-504.27. Hockel M, Konerding MA, Heussel CPOLiposuction-assistednerve-sparing extendedradical hysterectomy: oncologicrationale,surgical anatomy, and feasibility study. AmJ Obstet Gynecol1988;178:971-976.28. BaaderB, HerrmannM. Topography of thepelvic autonomicnervous systemanditspotential impact onsurgical interventioninthepelvis. Clin Anat 2003;16:119-139.29. Tong XK, HuoRJ. Theanatomic basisand preventionof neurogenicvoiding dysfunctionfollowingradical hysterectomy. SurgRadiolAnat 1991;13(2):145-148.30. ForneyP. Theeffectsof radical hysterectomy onbladder physiology.AmJ Obstet Gynecol 1980;138:374-382.31. Piver SM, RutledgeF. Smith JP. Five classesof extendedhysterectomy forwomenwithcervical cancer. Obstet Gynecol1974;44:623-644.32. Butler-Manuel SA,Buttery lDK, AHernRp, et al. Pelvic nerveplexustraumaat radical hysterectomy andsimplehysterectomy:thenervecontent of theuterine supportingligaments. Cancer2000;89:834-841.33. Butler-Manuel SA, Buttery lDK, AHernRp, et al. Pelvicnerveplexustraumaat radical hysterectomy andsimplehysterectomy:quantitative study of nerve typesin theuterine supportingligaments. JSocGynecol Investig 2002;9(1 ):47-56.34. Yucel S, BaskinlS.Ananatomic descriptionof themaleandfemaleurethralsphincter complex.JUrol 2004;171 (5):1890-1897.35. Tunn R, Delancey JO, HowardD, et al. Anatomic variations in thelevator ani muscle, endopelvic fasciaandurethra innulliparasevaluatedbymagnetic resonanceimaging.AmJObstet Gynecol2003; 188:116-121.36. SinghK, JakabM, Reid WM, et al. Three-dimensional magneticresonanceimaging assessment of levator ani morphologic featuresin different gradesof prolapse.AmJObstet Gynecol2003;188(4):910-915.37. Umek WH, KearneyR, MorganDM, et al. Theaxiallocationofstructural regionsin theurethra: a magnetic resonancestudy innulliparous women. Obstet Gynecol 2003;102(5Pt1): 1039-1045.38. Parikh M, RasmusssenM, Brubaker l,et al. Threedimensionalvirtual realitymodel of thenormal femalepelvicfloor. AnnBiomedEng 2004;32(2):292-296.11zoE:uwVl12CHAPTER1 PELVICANATOMYFORTHESURGEON39. Delancey JOl. Kearney R. ChouQ. et al. The appearance oflevator ani muscleabnormalities in magnetic resonanceimagesafter vaginal delivery.Obstet Gynecol 2003;101:46-53.40. Hounnou GM. Uhl JF, Plaisant O. et al. Morphometry bycomputerizedthree-dimensional reconstructionof thehypogastricplexus of a humanfetus. Surg Radiol Anat2003;25:21-31.41. UnitedStatesNational Libraryof Medicine. National Institutes ofHealth. Available onlineat: www.nlm.nih.gov/research/visible/visible_human.html42. Centerfor HumanSimulation, University of Colorado. Availableonlineat:www.uchsc.eduThe Physiology of Micturitionand Urine StorageWilliamD Steersand AdamP KlausnerCHAPTER2INTRODUCTIONThelower urinary tract is composedof thebladder andanoutlet that includesthebladder neck, urethra, andexternalurethralsphincter. Thesestructuresforma functional unitthat switches between urinestorageandreleasedependingon the status of the nervoussystem. Urine storagerequires alow bladder pressure that does not exceedoutlet resistance.Urinerelease requires intact innervation, adequate detrusorcontractility, and coordinated relaxation of thebladder out-let and pelvic floor. Failure to meet these basic requirementscanproduce residual urine, urinaryincontinence, hydro-nephrosis, urinarytract infections, calculi or deteriorationof bladder and renal function. Both passive and active mech-anisms participate in the maintenance of continence. Urinarycontinence relies on an active relaxation of the bladder bodyandmaintenance of tonebythebladderneckandurethra.Continence also relies on the passive, viscoelastic propertiesof thesetissues and their pelvic supports.The nervoussystem,themuscular andconnective tissuecomponents of the detrusor, urethra, and pelvic floor, as wellas theurotheliumitself all playsignificantrolesinbladderfunction. The role of the nervous systemin the lowerurinarytract is unique. Central neural inputiscrucialforbladder functionincontrast to itsmodulatory roleinotherviscera.This neural input isthe result ofintegrationandcoordination of autonomic and somatic pathways, and theseneural networkscanrapidlyreorganizefollowinginjury ordisease. Suchuniqueneurophysiologicpropertiesaccentu-atethe importanceofunderstandinghowreflexpathwayscontrol bladder and urethral function. Apart from thenervous system, thebladder, urethra, and supporting tissueshaveunique, intrinsicproperties which contributeto thecontinence mechanism.In addition, there is a growingbodyof evidencewhichdemonstratesthattheurotheliumfunc-tions as a mechano-and chemosensor and that intraluminalcontentscan influence urine storageand release. By gaininga comprehensive understanding of voiding and storagemechanisms, theclinician can formulatea rational planforthe treatment and prevention of urinary incontinence.ANATOMYBladder. The urinary bladder is a hollow viscus composedof coarse bundles of smoothmuscle fascicles. Connectivetissue andextracellular matrixconsistingofcollagen andelastin are interspersed between the muscle fascicles. Inaddition, intramural gangliaandinterstitialcellsmaycon-trol discrete bladder regions andformfunctional modules.'Thereis not aone-to-onerelationshipbetweenfreenerveendingsand smooth musclecells. Rather, excitation spreadsthroughout an interconnected syncytiumof cells. Gapjunctions composed of connexin43 may enhancecouplingand facilitatethe initiation, maintenance, and modulation ofdetrusor contractions. Indeed, this arrangement may explainhow the bladder sustains a contraction even with progressiveshortening of fiber length. With overactive states, it has beenpostulatedthatincreasedcouplingbetweencellsproducesinvoluntary contractions.' Furthermore, the electrochemicalexcitability of smooth muscle cells increases with someoveractive conditions.Urethra. The urethra is composed of epitheliumsur-rounded by lamina propria and a thin layer of circularsmoothmuscle. Beneaththis, athicklongitudinal layer ofsmooth musclerunsalong the entire urethrallength. Moredistally, the urethraissurroundedbyahorseshoe-shapedmass of striated muscle termed the external urethral sphinc-ter (EUS). Restingtone ismyogenic since nerve-blockingagentssuchas tetrodotoxin, guanethidine, andatropinefailto abolishcontractile activity of urethral smooth musclestrips. Figure 2.1depicts asagittal sectionofthe humanfemale urethra.External urethralsphincter. Striatedmuscleextendsover the distal two-thirds of the female urethra. Thismusclehas been termedthe EUS and isderivedfromthe pub-orectalis muscle; 87% of themusclefibers are TypeI whichproduceslow, nonfatigable contractions. However, signifi-cant racial differences may exist in thetypesof fibers whichmakeuptheEUS. TheEUS receivessomatic innervationN15CHAPTER2 THEPHYSIOLOGYOFMICTURITIONANDURINESTORAGEsystem, and an efferentlimb, which provides motor outflowtothebladder and urethra. By definition, afferentreferstoinput to a dendriteorsoma ofa neuron. Efferent referstoaxonal transmission froma neuron. The lower urinarytractreceives afferent andefferent innervationfromthepelvic,hypogastric, andpudendal nerves aswell fromthe sym-pathetic chain (Fig. 2.2). Direct nerve pathways to the lowerurinary tract derive from both the spinal cord and the brain.Spinal pathways can be classified as parasympathetic, sym-patheticor somatic. Brainpathways originatemainlyfromthe pons; however, the cerebral cortex and diencephalon alsoinfluencemicturition.Figure 2.1 Sagittal sectionthrough thehuman female urethra. Thediagramdepicts thelayersofcircular andhorizontal smoothmuscleas well as thesupportingstructures that comprise theurethra.z~ fromthe pudendal nerve andprevious investigators haveU found that pudendal nerve block reducesmaximal urethral~ pressure in female volunteers.'16Urethral support system. The pubourethral liga-ments fix the midurethra and suburethral vaginal wall to thepubic symphysis. Thesuburethral vaginal wall serves as thefloor for theurethraand, inwomenwithbladder descent,facilitates bladder neck closure by mechanical compression.Arise inurethral pressureoccursprior toariseinintra-abdominal pressure, indicating an active role for this supportsystem. In addition to active urethral tone, the passive tissueproperties of the bladder and outlet participate in this process.Theendopelvicfascia andlevatorani, by providingpelvicsupport, also facilitateurine storageinwomen. However,recent work has revealed that the levator ani muscles are notinnervatedbythepudendal nerve aspreviouslybelieved.Rather, sacral rootsS3-5give rise to a separate levator aninerve." Therefore, demonstrationofpudendal neuropathyon electrophysiologic studies may approximate, but notdefine, neurologicdamage tothelevatorssincethisnervedoesnot providetheir neural input. Structural damagetothesetissuesor their innervationallows lessresistancetodeformation during abdominal straining. Thus, urethralclosure would not be assured.LOWER URINARVTRACT INNERVATIONReflex pathwaystothe lower urinarytract consist of anafferent limb, that relays information to thecentral nervousFigure 2.2 Autonomic andsomatic innervationof thelowerurinary tract.Sympathetic (yellow)preglionic outflow emergesfrom thethoracolumbar spinal cord, enters thesympathetic chain(SC) andthen travels viathelumbar splanchnicnervetotheceliacplexus (CP) andsuperior hypogastric plexus (SHP).Thehypogastric nervethenconveys thesepreganglionic andpostganglionic fibers tothepelvic plexus(PP) or thebladder andurethra.Parasympathetic (green) preganglionic outflow tothelower urinary tract arisesinthesacral spinal cordS2-4 andrunsinthepelvicnervetothepelvic plexus or tobladder wall ganglioniccells. Somatic (brown)neural output totheexternal urethralsphincter andthepelvic floor originates fromthesacral cordsegment S2-4 andrunsinthepudendal nerve.Spinal pathways to thelower urinary tractParasympatheticsAFFERENT PATHWAYS. Parasympathetic sensory neuronsresideinthe S2-4dorsal root ganglia. Thesebipolarcellssend long processes to the urinary smooth muscle andepithelium. Low-thresholdmyelinated(A8) andunmyeli-nated (C) afferent fibers convey mechanical or noxious(nociceptive)stimuli to thedorsal horn of thespinal cordYThemechanoceptiveafferents responsibleforinitiationofmicturition travel in the pelvic nerve.' The presence of urineinthe urethraprobablyactivates additional afferents thatreinforce the micturition reflex."This reflex may explain thecommon coexistence of detrusor overactivity and stressincontinence, also called"stress hyperreflexia" (Fig. 2.3).Bladder and urethral afferents enter the dorsalhorn of thespinalcordand project laterally towardthesacralparasym-patheticnucleus (SPN).9 Overlapof bladder andurethralafferents suggests that these regions coordinate vesico-sphinctericreflexes,"Second-orderneurons relayafferentinput to supraspinal sitesincludingthe hypothalamusandpons."The hypothalamus coordinates autonomic activitybetweenmultipleorgan systems." The pons controls vis-ceral functions, including micturition and defecation.In addition to providing information to thecentral nerv-ous system on the status of thelower urinary tract, afferentscan directly influence bladder and urethral function.Electrical, chemical, andmechanical stimulation of bladderafferentsresultsinanalteration of smooth muscle contrac-tility, bloodflow, andimmuneresponse. ThesealterationsUrethraFigure 2.3 Stresshyperreflexia.In this diagram, thepresence ofurine intheurethra(voluntary or involuntary) triggers afferentswhichreinforce themicturitionreflex.LOWERURINARYTRACTINNERVATION Iare mediated through the release of neuropeptides fromperipheral nerve terminals.!'EFFERENT PATHWAYS. Parasympathetic outflow to thebladder and urethra originates in the sacral parasympatheticnucleus (SPN). The SPN is located in the intermediolateralcell columnof the S2-4sacral spinal cord. This nucleuscontainsthecholinergicpreganglionicneuronsresponsiblefor micturition, defecation, vaginal relaxation, andclitoralengorgement. Injuriesto theseregionscan result in the triadof bladder, bowel, and sexual dysfunction. Preganglionicsexitthespinal cordin theventral spinal nervesto formthepelvic nerve andthensynapseonpostganglionicneuronsin pelvicganglia. The pelvicgangliaresideon either side oftherectumandvaginaandinthewalls of thebladderandurethra.PHARMACOLOGYANDTHERAPEUTICTARGETS. Nerves inthe humanbladder contain anassortment of neurotrans-mittersincludingacetylcholine, noradrenaline, andneuro-peptides." Preganglionicparasympatheticefferentscontainacetylcholineas well as enkephalins(ENK), galanin,chole-cystokinin(CCK), and nitricoxide (NO).13-16 Cholinergicefferents activate nicotinic receptors on postganglionicneuronsinthe pelvic plexus. Thesepostganglionicnervesrelease acetylcholine which excites muscarinic receptors(M3/M2) expressed by bladder and urethral smooth musclesaswell asbythe urotheliumitself. Thus, antimuscarinicdrugs provideuseful therapyfordetrusoroveractivityandincrease bladder compliance."The muscarinic receptorresponsiblefor humanbladdercontractionistheM3sub-type." Although this subtype predominates, the M2 receptoris mainly responsible for turning off cAMP-mediatedrelaxation mechanisms of the detrusor." Oxybutynin,tolterodine, andtrospiumarenonselectiveantimuscarinics.Newer antimuscarinics darifenacin andsolafenacinact pre-dominantlyonM3receptors. Unfortunately, M3receptorsare also expressed by thegut and salivary glands. Thus, sideeffectsof dry mouthandconstipationstill occurwithM3antagonists (Ikeda, Kobayashi et al. 2002).Nonadrenergic noncholinergic (NANC) transmitters,most notably adenosine triphosphate (ATP), act in conjunc-tionwithacetylcholine to contract detrusor smooth muscle.Antimuscarinics often fail to abolish bladder overactivitybecause of their inability to block noncholinergic excitatorytransmission to the bladder," Purinergic transmission (ATP)providesa greatershareof excitatoryinput tothebladderwith agingor after pelvic surgerywith presumedpartialdenervation"Intheurethra, cholinergictransmissionappearstoplayonly a modulatory role in smooth muscle relaxation.Cholinergicinnervationof the urethra is not completelyunderstood. However, electrical stimulationof the ventralen~o..,-oZN17CHAPTER2 THEPHYSIOLOGYOFMICTURITIONANDURINESTORAGENZo.-.E-