外科学专业课 前列腺增生英文预习资料学习课件

BENIGHPROSTATICHYPERPLASIA

(BPH)

——《Smith’SGeneralUrology》，the15thedition

INCIDENCEANDEPIDEMIOLOGY

BPHisthemostcommonbenigntumorinmen,anditsincidenceisage-related,TheprevalenceofhistologicBPHinautopsystudiesrisesfromapproximately20%inmenaged41-50,to50%inmenaged51-60,andtoover90%inmenolderthan80.Althoughclinicalevidenceofdiseaseoccurslesscommonly,symptomsofprostaticobstructionarealsoage–related.Atage55,approximately25%ofmenreportobstructivevoidingsymptoms.Atage75,50%ofmencomplainofadecreaseintheforceandcaliberoftheirurinarystream.

RiskfactorsforthedevelopmentofBPHarepoorlyunderstood.Somestudieshavesuggestedageneticpredisposition,andsomehavenotesracialdifferences. Approximately50%ofmenundertheageof60whoundergosurgeryforBPHmayhaveaheritableformofthedisease.Thisformismostlikelyanautosomaldominanttrait,andfirst-degreemalerelativesofsuchpatientscarryanincreasedrelativeriskofapproximately4-fold.

Etiology

TheetiologyofBPHisnotcompletelyunderstood,butitseemstobemultifactorialandendocrinecontrolled.Theprostateiscomposedofbothstromalandepithelialelements,andeach,eitheraloneorincombination,cangiverisetohyperplasticnodulesandthesympotomsassociatedwithBPH.Eachelementsmaybetargetedinmedicalmanagementschemes.

LaboratoryandclinicalstudieshaveidentifiedtwofactorsnecessaryforthedevelopmentofBPH:dihydrotestosterone(DHT)andaging.A nimalstudiesinthedoghavedemonstratedthatwithaging,theprostatebecomesmoresensitivetoandrogens.Ofinterestisthatprostaticgrowthinagingdogsappearstobemorerelatedtoadecreaseincelldeaththantoanincreaseincell,proliferation.Laboratorystudieshavesuggestedseveraltheoriesinthisarea,including(1)stromal-epithelialinteractions(stromalcellsmayregulatethegrowthofepithelialcellsorotherstromalcellsviaaparacrineorautocrinemechanismbysecretinggrowthfactorssuchasbasicfibroblastgrowthfactorortransforminggrowthfactor-β);(2)agingmayresultinstemcells’undergoingablockinthematurationprocessthatpreventsthemfromenteringintoprogrammedcellsdeath(apoptosis).Theimpactofaginginanimalstudiesappearstobemediatedviaestrogensynergism.Indogs,estrogenshavebeenshowntoinducetheandrogenreceptor,altersteroidmetabolismresultinginhigherlevelsofintraprostaticDHT,inhibitcelldeathwhengiveninthepresenceofandrogens,andstimulatestromalcollagenproduction.

ObservationsandclinicalstudiesinmenhaveclearlydemonstratedthatBPHisunderendocrinecontrol.CastrationresultsintheregressionofestablishedBPHandimprovementinurinarysymptoms.Administrationofaluteinizinghormone-releasinghormone(LHRH)analoginmenreversiblyshrinksestablishedBPH,resultinginobjectiveimprovementinflowrateandsubjectiveimprovementinsymptoms.AdditionalinvestigationshavedemonstratedapositivecorrelationbetweenlevelsoffreetestosteroneandestrogenandthevolumeofBPH.ThelattermaysuggestthattheassociationbetweenagingandBPH,mightresultfromtheincreasedestrogenlevelsofagingcausinginductionoftheandrogenreceptorlevelsinhumanBPH.

Pathology

Asdiscussedabove,BPHdevelopsinthetransitionzone.Itistrulyahyperplasticprocessresultingfromanincreaseincellnumber.Microscopicevaluationrevealsanodulargrowthpatternthatiscomposedofvaryingamountsofstromaandepithelium.Stromaiscomposedofvaryingamountsofcollagenandsmoothmuscle.ThedifferentialrepresentationofthehistologiccomponentsofBPHexplains,inpart,thepotentialresponsivenesstomedicaltherapy.Thusalpha-blockertherapymayresultinexcellentresponsesinpatientswithBPHthathasasignificantcomponentofsmoothmuscle,whilethesewithBPHpredominantlycomposedofepitheliummightrespondbetterto5α-reductaseinhibitors.Patientswithsignificantcomponentsofcollageninthestromamaynotrespondtoeitherformofmedicaltherapy.Unfortunately,onecannotreliablypredictresponsivenesstoaspecifictherapy.

AsBPHnodulesinthetransitionzoneenlarge,theycompresstheouterzonesoftheprostate,resultingintheformationofaso-calledsurgicalcapsule.ThisboundaryseparatesthetransitionzonefromtheperipheralzoneandservesasacleavageplaneforopenenucleationoftheprostateduringopensimpleprostatectomiesperformedforBPH.

Pathophysiology

OnecanrelatethesymptomsofBPHtoeithertheobstructivecomponentofprostateorthesecondaryresponseofthebladdertotheoutletresistance.Theobstructivecomponentcanbesubdividedintothemechanicalandthedynamicobstruction.

Asprostaticenlargementoccurs,mechanicalobstructionmayresultfromintrusionintotheurethrallumenorbladderneck,leadingtoahigherbladderoutletresistance.Priortothezonalclassificationoftheprostate,urologistsoftenreferredtothe“3lobes”oftheprostate,namely,themedianandthetwolaterallobes.ABPHautopsystudyfromthe1930sclassifiedthegrosschangesofBPHinto5categories:(1)isolatedmedianlobeenlargement(30%);(2)isolatedlaterallobeenlargement(15%)；（3）lateralandmedianlobe(trilobar)enlargement(23%),(4)posteriorcommissure(posteriorvesicalliporelevatedbladderneck)hyperplasia(15%);(5)lateralandposteriorcommissurehyperplasia(17%).Prostaticsizeondigitalrectalexamination(DRE)correlatespoorlywithsymptoms,inpartbecausethemedianlobeandposteriorcommissurearenotreadilypalpable.

Thedynamiccomponentofprostaticobstructionexplainsthevariablenatureofthesymptomsexperiencedbypatients.Theprostaticstroma,composedofsmoothmuscleandcollagen,isrichinadrenergicnervesupply.Thelevelofautonomicstimulationthussetsatonetotheprostaticurethra.Useofalpha-blockertherapydecreasesthistone,resultinginadecreaseinoutletresistance.

Theirriativevoidingcomplains(seeblow)ofBPHresultfromthesecondaryresponseofthebladdertotheincreasedoutletresistance.Bladderoutletobstructionleadstodetrusormusclehypertrophyandhyperplasiaaswellascollagendeposition.Althoughthelatterismostlikelyresponsibleforadecreaseinbladdercompliance,detrusorinstabilityisalsoafactor.Ongrossinspection,thickeneddetrusormusclebundlesareseenastrabeculationoncystoscopicexamination.Ifleftunchecked,mucosalherniationbetweendetrusormusclebundlesensues,causingdiverticulaformation.

ClinicalFindings

A.Symptoms:

Asdiscussedabove,thesymptomsofBPHcanbedividedintoobstructiveandirritativecomplaints.Obstructivesymptomsincludehesitancy,decreasedforceandcaliberofstream,sensationofincompletebladderemptying,doublevoiding(urinatingasecondtimewithin2hofthepreviousvoid),strainingtourinate,andpost-voiddribbling.Irritativesymptomsincludeurgency,frequency,andnoctusia.

Theself-administeredquestionnairedevelopedbytheAmericanUrologicalAssociation(AUA)isbothvalidandreliableinidentifyingtheneedtotreatpatientsandinmonitoringtheirresponsetotherapy.TheAUASymptomsScorequestionnaireisperhapsthesinglemostimportanttoolusedintheevaluationofpatientswithBPHandisrecommendedforallpatientsbeforetheinitiationoftherapy.Thisassessmentfocuseson7itemsthataskpatientstoquantifytheseverityoftheirobstructiveorirritativecomplaintsonascaleof0-5.Thus,thescorecanrangeform0to35.Asymptomscoreof0-7isconsideredmild,.8-19isconsideredmoderate,and20-35isconsideredsevere.TherelativedistributionofscoresforBPHpatientsandcontrolsubjectsis,respectively,20%AND83%inthosewithmildscores,57%and15%inthosewithmoderatescores,and23%and2%inthosewithseverescores.

Adetailedhistoryfocusingontheurinarytractexcludesother

possiblecausesofsymptomsthatmaynotresultfromtheprostate,suchasurinarytractinfection,neurogenicbladder,urethralstricture,orprostatecancer.

B.Signs:

Aphysicalexamination,DRE,andfocusedneurologicexaminationareperformedonallpatients.Thesizeandconsistencyoftheprostateisnoted,eventhoughprostatesize,asdeterminedbyDRE,doesnotcorrelatedwithseverityofsymptomsordegreeofobstruction,BPHusuallyresultinasmooth,firm,elasticenlargementoftheprostate.Induration,ifdetected,mustalertthephysiciantothepossibilityofcancerandtheneedforfurtherevaluation(ie,prostate-specificantigen[PSA],transrectalultrasoound,andbiopsy).

C.LaboratoryFindings:

Aurinalysistoexcludeinfectionorhematuriaandserumcreatininemeasurementtoassessrenalfunctionarerequired.Renalinsufficiencymaybeobservedin10%ofpatientswithprostatismandwarrantsupper-tractimaging.PatientswithrenalinsufficiencyareatanincreasedriskofdevelopingpostoperativecomplicationsfollowingsurgicalinterventionforBPH.SerumPSAisconsideredoptional,butmostphysicianswillincludeitintheinitialevaluation.PSA,comparedwithDREalone,certainlyincreasestheabilitytodetectCaP,itsuseremainscontroversial.

D.Imaging:

Upper-tractimaging(intravenouspyelogramorrenalultrasound)isrecommendedonlyinthepresenceofconcomitanturinarytractdiseaseorcomplicationsfromBPH(eg,hematuria,urinarytractinfection,renalinsufficiency,historyofstonedisease).

E.Cystoscopy:

Cystoscopyisnotrecommendedtodeterminetheneedfortreatmentbutmayassistinchoosingthesurgicalapproachinpatientsoptingforinvasivetherapy.

F.AdditionalTests:

Cystometrogramsandurodynamicprofilesarereservedforpatientswithsuspectedneurologicdiseaseorthosewhohavefailedprostatesurgery.Measurementofflowrate,determinationofpost-voidresidualurine,andpressure-flowstudiesareconsideredoptional.

DifferentialDiagnosis

Otherobstructiveconditionsofthelowerurinarytract,suchasurethralstricture,bladderneckcontracture,bladderstone,orCaP,mustbeentertainedwhenevaluatingmenwithpresumptiveBPH.Ahistoryofpreviousurethralinstrumentation,urethritis,ortraumashouldbeelucidatedtoexcludeurethralstrictureorbladderneckcontracture.Hematuriaandpainarecommonlyassociatedwithbladderstones.CaPmaybedetectedbyabnormalitiesontheDREoranelevatedPSA(seebelow).

Aurinarytractinfection,whichcanmimictheirritativesymptomsofBPH,canbereadilyidentifiedbyurinalysisandculture;however,aurinarytractinfectioncanalsobeacomplicationofBPH.Althoughirritativevoidingcomplaintsarealsoassociatedwithcarcinomaofthebladder,especiallycarcinomainsitu,theurinalysisusuallyshowsevidenceofhematuria.Likewise,patientswithneurogenicbladderdisordersmayhavemanyofthesignsandsymptomsofBPH,butahistoryofneurologicdisease,stroke,diabetesmellitus,orbackinjurymaybepresentaswell.Inaddition,examinationmayshowdiminishedperinealorlowerextremitysensationoralterationsinrectalsphinctertoneorthebulbocavernosusreflex.Simultaneousalterationsinbowelfunction(constipation)mightalsoalertonetothepossibilityofaneurologicorigin.

Treatment

Afterpatientshavebeenevaluated,theyshouldbeinformedofthevarioustherapeuticoptionsforBPH.Itisadvisableforpatientstoconsultwiththeirphysicianstomakeaneducateddecisiononthebasisoftherelativeefficacyandsideeffectsofthetreatmentoptions.

Specifictreatmentrecommendationscanbeofferedforcertaingroupsofpatients.Forthosewithmildsymptoms(symptomscore0-7),watchfulwaitingonlyisadvised.Ontheotherendofthetherapeuticspectrum,absolutesurgicalindicationsincluderefractoryurinaryretention(fallinginleastoneattemptatcatheterremoval),recurrenturinarytractinfectionfromBPH,recurrentgrosshematuriafromBPH,bladderstonesfromBPH,renalinsufficiencyfromBPH,orlargebladderdiverticula.

A.WatchfulWaiting:

VeryfewstudiesonthenaturalhistoryofBPHhavebeenreported.Theriskofprogressionorcomplicationsisuncertain.However,inmenwithsymptomaticBPH,itisclearthatprogressionisnotinevitableandthatsomemenundergospontaneousimprovementorresolutionoftheirsymptoms.

RetrospectivestudiesonthenaturalhistoryofBPHareinherentlysubjecttobias,relatedtopatientselectionandthetypeandextentoffollow-up.VeryfewprospectivestudiesaddressingthenaturalhistoryofBPHhavebeenreported.Onesmallseriesdemonstratedthattheprogressiontourinaryretentionoccurredinapproximately10%ofsymptomaticmen,while50%ofpatientsshowedmarkedimprovementorresolutionofsymptoms.Recently,alargerandomizedstudycomparedfinasteridewithplaceboinmenwithmoderatelytoseverelysymptomaticBPHandenlargedprostatesonDRE.Patientsintheplaceboarmofthestudyhada7%riskofdevelopingurinaryretentionover4years,

Asmentionedabove,watchfulwaitingistheappropriatemanagementofmenwithmildsymptomscores(0-7).Menwithmoderateorseveresymptomscanalsobemanagedinthisfashioniftheysochoose.Neithertheoptimalintervalforfollow-upnorspecificendpointsforinterventionhavebeendefined.

B.MedicalTherapy

1.Alphablockers：Thehumanprostateandbladderbasecontainsalpha-adrenoreceptors,andtheprostateshowsacontractileresponsetocorrespondingagonists.Theconctractilepropertiesoftheprostateandbladderneckseemtobemediatedprimarilybythesubtypeα1areceptors.AlphablockadehasbeenshowntoresultinbothobjectivedegreesofimprovementinthesymptomsandsignsofBPHinsomepatients.Alphablockerscanbeclassifiedaccordingtotheirreceptorselectivityaswellastheirhalf-life.

Phenoxybenzamineandprazosinhavecomparableefficacywithrespecttosymptomaticrelief,butthehigherside-effectprofileofPhenoxybenzamine,associatedwithitslackofalpha-receptorspecificity,precludesitsuseinBPHpatients.Dosetitrationisnecessarywithprazosin,withtypicaltherapystartedat1mgatbedtimefor3nights,thenincreasedto1mgtwiceaday,whichistitratedupto2mgtwiceadayifnecessary.Athigherdoses,littleadditionalsymptomaticimprovementisobservedandside-effectprofilesworsen.Typicalsideeffectsincludeorthostatichypotension,dizziness,tiredness,retrogradeejaculation,rhinitis,andheadache.

Long-actingalphablockersmakeonce-a-daydosingpossible,butdosetitrationisstillnecessary.Terazosinisinitiatedat1mgdailyfor3daysandincreasedto2mgdailyfor11daysandthento5mgperday.Dosagecanbeescalatedto10mgdailyifnecessary.Therapywithdoxazosinisstartedat1mgdailyfor7daysandincreasedto2mgdailyfor7days,andthento4mgdaily.Dosagecanbeescalatedto8mgdailyifnecessary.Sideeffectsaresimilartothosedescribedforprazosin.

Themostrecentadvanceinaloha-blockertherapyisrelatedtotheidentificationofsubtypesofalpha-1-receptors.Selectiveblockadeoftheα1areceptors,whicharelocalizedintheprostateandbladderneck,resultsinfewersystemicsideeffects(orthostatichypotension,dizziness,tiredness,rhinnitis,andheadache),thusobviatingtheneedfordosetitration.Tamsulosinisinitiatedat0.4mgdailyandcanbeincreasedto0.8mgdailyifnecessary.

Severalrandomized,double-blind,placebo-comtrolledtrials,individuallycomparingterazosin,doxazosin,ortamsulosinwithplacebo,havedemonstratedthesafetyandefficacyofalloftheseagents.Comparativetrialsofvariousalphablockersareongoing.

2.5α-Reductaseinhibitors：Finasterideisa5α-reductaseinhibitorthatblockstheconversionoftestosteronetodihydrotestosterone.Thisdrugaffectstheepithelialcomponentoftheprostate,resultinginareductioninthesizeoftheglandandimprovementinsymptoms.Sixmonthsoftherapyarerequiredtoseethemaximumeffectsonprostatesize(20%reduction)andsymptomaticimprovement.

Severalrandomized,double-bling,placebo-controlledtrialshavecomparedfinasteridewithplacebo.Efficacy,safety,anddurabilityarewellestablished.However,symptomaticimprovementisseenonlyinmenwithenlargedprostates(>40cm3).Sideeffectsincludedecreasedlibido,decreasedejaculatevolume,andimpotence.SerumPSAisreducedbyapproximately50%inpatientsbeingtreatedwithfinasteride,butindividualvaluesmayvary,thuscomplicatingcancerdetection.

Arecentreportsuggeststhatfinasteridetherapymaydecreasetheincidenceofurinaryretentionandtheneedforsurgicalinterventioninmenwithenlargedprostatesandmoderatetoseveresymptoms.However,optimalidentificationofappropriatepatientsforprophylactictherapyremainstobedetermined.

3.Combinationtherapy：Thefirstrandomized,doouble-blind,placebo-controlledstudyinvestigatingcombinationalpha-blockerand5α-reductaseinhibitortherapywasrecentlyreported.Thiswasafour-armVeteransAdministrationCooperativeTrialcomparingplacebo,finasteridealone,terazosinalone,andcombinationfinasterideandterazosin.Over1200patientsparticipated,andsignificantdecreasesinsymptomscoreandincreasesinurinaryflowrateswereseenonlyinthearmscontainingterazosin.However,onemustnotethatenlargedprostateswerenotanentrycriterion;infact,prostatesizeinthisstudywasmuchsmallerthanthatinpreviouscontrolledtrialsusingfinasteride(32versus52cm3).Additionalcombinationtherapytrialsareongoing.

4.Phytotherapy：Phytotherapyreferstotheuseofplantsorplantextractsformedicinalpurposes.TheuseofPhytotherapyinBPHhasbeenpopularinEuropeforyears,anditsuseintheUnitedStatesisgrowingasaresultofpatient-drivenenthusiam.Severalplantextravtshavebeenpopularized,includingthesawpalmettoberry,thebarkofPygeumafricanum,therootsofEchiniceapurpureaandHypoxisrooperi,pollenextract,andtheleavesofthetremblingpopular.Themechanismsofactionofthosephytotherapiesareunknown,andtheefficacyandsafetyoftheseagentshavenotbeentestedinmulticenter,randomized,double-blind,placebo-controlledstudies.

C.conventionalsurgicaltherapy

1.Transurethralresectionoftheprostate(TURP)：ninety-fivepercentofsimpleprostatectomiescanbedoneendoscopically.Mostoftheseproceduresinvolvetheuseofaspinalanestheticandrequirea1-to2-dayhospitalstay.SymptomscoreandflowrateimprovementwithTURPissuperiortothatofanyminimallyinvasivetherapy.ThelengthofhospitalstayofpatientsundergoingTURP,however,isgreater.MuchcontroversyrevolvesaroudpossiblehigherratesofmorbidityandmortalityassociatedwithTURPincomparisonwiththoseofopensurgery,butthehigherratesobservedinonestudywereprobablyrelatedtomoresignificantcomorbiditiesintheTURPpatientsthaninthepatientsundergoingopensurgery.Severalotherstudiescouldnotconformthedifferentinmotalitywhenresultswerecontrolledforageandcomobidities.RisksofTURPincluderetrogradeejaculation(75%),impotence(5-10%),andincontinence(<1%).Complicationsincludebleeding,urethralstrictureorbladderneckcontracture,perforationofprostatecapsulewithextravasation,andifsevere,TURsyndromeresultingfromahypervolemic,hyponatremicstateduetoabsorptionofthehypotonicirrigatingsolution.ClinicalmanifestationsoftheTURsyndromeincludenausea,vomiting,confusion,hypertension,bradycardia,andvisualdisturbances,theriskoftheTURsyndromeincreaseswithresectiontimesover90min.treatmentincludesdiuresisand,inseverecases,hypertonicsalineadministration.

2.Transurethralincisionoftheprostate：menwithmoderatetoseveresymptomsandasmallprostateoftenhaveposteriorcommissurehyperplasia(elevatedbladderneck).Thesepatientswilloftenbenefitfromanincisionoftheprostate.ThisprocedureismorerapidandlessmorbidthanTURP.Outcomesinwell-selectedpatientsarecomparable,althoughalowerrateofretrogradeejaculationwithtransurethralincisionhasbeenreported(25%).ThetechniqueinvolvestwoincisionsusingtheCollinsknifeatthe5and7o’clockpositions.theincisionsarestartedjustdistaltotheureteralorificesandareextendedoutwardtotheverumontanum.

3.Opensimpleprostatectomy：Whentheprostateistoolargetoberemovedendoscopically,anopenenucleationisnecessary.Whatconstitutes”toolarge”issubjectiveandwillvarydependinguponthesurgeon’sexperiencewithTURP.Glandsover100gareusuallyconsideredforopenenucleation.Openprostatectomymayalsobeinitiatedwhenconcomitantbladderdiverticulumorabladderstoneispresentorifdorsallithotomypositioningisnotpossible.

Openprostatectomiescanbedonewitheitherasuprapubicorretropubicapproach.Asimplesuprapubicprostatectomyisperfomedtransvesicallyandistheoperationofchoiceindealingwithconcomitantbladderpathology.Afterthebladderisopened,asemicircularincisionismadeinthebladdermucosa,distaltothetrigone.Thedissectionplaneisinitiatedsharply,andthenbluntdissectionwiththefingerisperformedtoremovetoremovetheadenoma.Theapicaldissectionshouldbedonesharplytoavoidinjurytothedistalsphinctericmechanism.Aftertheadenomaisremoved,hemostasisisattainedwithsutureligatures,andbothaurethralandasuprapubiccatheterareinsertedbeforeclosure.

Inasimpleretropubicprostatectomy,thebladderisnotentered.Ratheratransverseincisionismadeinthesurgicalcapsuleofthepostate,andtheadenomaisenucleatedasdescribedabove.Onlyaurethralcatheterisneededattheendoftheprocedure.

D.minimallyInvasiveTherapy

1.Lasertherapy：manydifferenttechniquesoflasersurgeryfortheprostatehavebeendescribed.Twomainenegysourcesoflasershavebeenutilized-Nd:YAGandholmium:YAG.

Severaldifferentcoagulationnecrosistechniqueshavebeendescribed.Transurethrallaser-inducedprostatectomy(TURP)isdonewithtransrectalultrasoundguidance.TheTURPdeviceisplacedintheurethra,andtransrectalultrasoundisusedtodirectthediviceasitisslowlypulledfromthebladdernecktotheapex,Thedepthoftreatmentismonitoredwithultrasound.

Mosturologistsprefertousevisuallydirectedlasertechniques.VisualcoagulativenecrosistechniqueshavebeenpopularizedbyKabalin.Undercystoscopiccontrol,thelaserfiberispulledthroughtheprostateatseveraldesignatedareas,dependingonthesizeandconfigurationoftheprostate.fourquadrantandsextantapproacheshavebeendescribedforlaterallobes,withadditionaltreatmentsdirectedatenlargedmedianlobes.Coagulativetechniquesdonotcreateanimmediatevisualdefectintheprostaticurethra,butrathertissueissloughedoverthecourseofseveralweeksandupto3monthsfollowingtheprocedure.

Visualcontactablativetechniquesaremortime-consumingproceduresbecausethefiberisplacedindirectcontactwiththeprostatetissue,whichisvaporized.Animmediatedefectisobtainedintheprostaticurethra,similartothatseenduringTURP.

Interstitiallasertherapyplacesfibersdirectlyintotheprostate,usuallyundercystoscopiccontrol.Ateachpuncture,thelaserisfired,resultinginsubmucosalcoagulativenecrosis.Thistechniquemayresultinfewerirritativevoidingsymptoms,becausetheurethralmucosaissparedandprostatetissueisresorbedbythebodyratherthansloughed.

Advantagesoflasersurgeryinclude:(1)minimalbloodloss,(2)RareinstancesofTURsyndrome,(3)abilitytotreatpatientsreceivinganticoagulationtherapy,and(4)abilitytobedoneasanoutpatientprocedure.disadvantagesinclude:(1)lackofavailabilityoftissueforpathologicexamination,(2)longerpostoperativecatheterizationtime,(3)moreirritativevoidingcomplaints,and(4)highercostoflaserfibersandgenerators.

Large-scale,multicenter,randomizedstudiswithlong-termfollow-upareneededtocomparelaserprostatesurgerywithTURPandotherformsofminimallyinvasivesurgery.

2.Transurethralelectrovaporizationoftheprostate：transurethralelectrovaporizationusesthestandardresectoscopebutreplacesaconventionalloopwithavariationofagroovedrollerball.Highcurrentdensitiescauseheatvaporizationoftissue,resultinginacavityintheprostaticurethra.Becausethedevicerequiresslowersweepingspeedsovertheprostaticur