Temporal profile of microvascular disturbances in

LangenbecksArchSurg(2003)388:323–330DOI10.1007/s00423-003-0411-5MUSCULOSKELETALSOFTTISSUECONDITIONINGK.D.SchaserL.ZhangN.P.HaasT.MittlmeierG.DudaH.J.BailTemporalprofileofmicrovasculardisturbancesinrattibialperiosteumfollowingclosedsofttissuetraumaReceived:25May2003Accepted:8July2003Publishedonline:8October2003
Springer-Verlag2003Thepaperwaspresentedatthe2ndMus-culoskeletalSymposium“SignificanceofMusculo-SkeletalSoftTissueonPre-Pper-ativePlanning,SurgeryandHealing”,13–14February2003,Berlin,GermanyK.D.Schaser())·L.Zhang·N.P.Haas·G.Duda·H.J.BailDepartmentofTraumaandReconstructiveSurgery,Charit,CampusVirchow,HumboldtUniversity,AugustenburgerPlatz1,13353Berlin,Germanye-mail:[e-mail].:[phone]Fax:[phone]T.MittlmeierDepartmentofTraumaandReconstructiveSurgery,UniversityofRostock,Rostock,GermanyAbstractBackgroundandaims:Bonedevascularizationduetoim-pairedperiostealperfusionfollowingfracturewithseveresofttissuetrau-mahasbeenproposedtoprecedeandunderlieperturbedbonehealing.Theextentandtemporalrelationshipofperiostealmicrocirculatorydeteriora-tionsaftersevereclosedsofttissueinjury(CSTI)arenotknown.Wehypothesizedthatperiostealmicro-circulationisadverselyaffectedandthemanifestationoftrauma-initiatedmicrovascularimpairmentinperios-teumissubstantiallyprolongedfol-lowingCSTI.Materialandmethods:Usingthecontrolled-impactinjurydevice,weinducedstandardizedCSTIinthetibialcompartmentof35isoflurane-anesthetizedrats.Follow-ingthetraumatheratswereassignedtofivegroups,differingintimeofanalysis(2h,24h,48h,1and6weeks).Non-injuredratsservedascontrols.Beforethemetaphyseal/di-aphysealperiosteumwassurgicallyexposed,intramuscularpressurewithintibialcompartmentwasmea-sured.Usingintravitalfluorescencemicroscopy(IVM)westudiedthemicrocirculationofthetibialperios-teum.Wecalculatedtheedemaindex(EI)bymeasuringtheskeletalmusclewet-to-dryweightratio(EI=injuredlimb/contralaterallimb).Results:Microvasculardeteriorationsofperi-ostealmicrohemodynamicscausedbyisolatedCSTIwerereflectedbyper-sistentdecreaseinnutritiveperfusion,markedlyprolongedincreaseinmi-crovascularpermeabilityassociatedwithincreasinglysustainedleukocyterollingandadherencethroughouttheentirestudyperiod,mostlypro-nounced48hafterthetrauma.Peaklevelincapillaryleakagecoincidedwiththemaximumleukocyteadher-ence,tissuepressure,andedema.Microcirculationoftibialperiosteumincontrolratsdemonstratedahomo-geneousperfusionwithnocapillaryorendothelialdysfunction.Conclusion:IsolatedCSTIinabsenceofafractureexertslong-lastingdis-turbancesinperiostealmicrocircula-tion,suggestingadelayedtemporalprofileinmanifestationofCSTI-inducedperiostealmicrovasculardysfunctionandinflammation.Theseobservationsmayhavetherapeuticimplicationsintermsofpreservingperiostealintegrityandconsideringtheinteractionofskeletalmuscledamageandperiostealmicrovascularinjuryduringmanagementofmus-culoskeletaltrauma.KeywordsPeriosteum·Closedsofttissuetrauma·Intravitalfluorescencemicroscopy·Microcirculation·Leukocyte–endothelialcellinteraction324IntroductionApartfromitsbiologicalrelevance,suchascontainingprecursorcellsofosteoblasts[1],anotherprincipalfunctionoftheperiosteumanditsmicrovasculatureistosupplyoxygenatedbloodandnutrientstothecorticalbone[2,3,4].Inaddition,extensivecharacterizationofinitialstagesinfracturehealinghasidentifiedtheperiosteumasthekeystructureforinitiatingandmedi-atingtheveryfirststepsoffracturehealing.Amongothers,thesemayincludehemostasis,generationandresorptionofthefracturehematoma,migrationofosteo-blastandchondroblastprecursorcells,formationofperiostealcallusandremodeling,andrevascularizationoftheinjuredbone[1,5].Thetriggereventofthishealingcascadeistheperiostealmicrovasculartrauma,whichsubsequentlycausesischemia,inflammation,andnutri-tivedysfunction.Thepathogeneticinfluenceoftrauma-inducedcellularandmicrovascularchangesintheperi-osteumisunderlinedbytheclinicalobservationthatextensivesofttissueinjuryandperiostealstrippingtypicallyprecedesdelayedfracturerepairandfrequentlyresultsinanon-unionormanifestpseudarthrosis[6,7,8,9,10].Despitethiscriticaldecreaseinextra-osseousnutritionalbloodflowtothebone,whichappearstobeacausativefactor,thepreciseextentandtemporalrelation-shipofmicrocirculatorydeteriorationsandpost-traumaticinflammationinperiosteumcausedbyisolatedandsevereclosedsofttissueinjury(CSTI)isnotknown.Therefore,wehypothesizedthatintheabsenceofafracturetheperiostealmicrocirculationisadverselyaffectedbyasevereCSTI.Wefurtherhypothesizedthat,consistentwiththedelayedhealingresponseoffractureswithseveresofttissuedamage,themanifestationoftrauma-initiatedmicrovascularimpairmentissubstantiallyprolonged,andiscausedbypersistentlyenhancedcapillaryandendo-thelialdysfunction,andincreasedmicrovascularperme-abilityandleukocyteactivityintheperiosteum.MaterialandmethodsAnimalpreparationandclosedsofttissueinjuryFollowingapprovaloftheexperimentalprotocolbythelocalcommitteeofanimalresearch,35spontaneouslybreathingmaleSDratswereanesthetizedwithisoflurane(1.6vol%)ina2:1mixtureofN2O/O2(0.4and0.2l