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Virtualplanning7943-SELECTING THEOPTIMALOSTEOTOMYLINESAfterthecraniofacialteamhasdecidedabouttheoptimaltreatmentplanbasedonthevirtualsimulation(step1)andthecomparisonwithreferencevalues(step2)thevirtualosteotomylinescanbedeterminedDissectingthecraniumintomanybonesegmentsmakesitfeasibletosculptacraniuminanydesirableshapeThiswouldhowever,resultinalesssolidreconstructionandrequiremorefixationmaterialInadditionusingmultiplebonesegmentsmightcreateundesirablevisibleorpalpablestepsbetweenthebonesegments ThereforeoneshouldaimtouselargerbonesegmentsandtheuseofmultipleandsmallerbonesegmentsshouldbeavoidedespeciallyinthefacialregionsuchastheforeheadIdeallybonesegmentsfromanotherlocationaremovedtoanewpositioninawaythatthecurvatureandshapeareoptimallyutilizedDuringtheactualsurgeryoncetheosteotomieshavedeterminedthebordersofasegmentthefreedomofthereconstructionislimitedThismakesitnearlyimpossibletofindtheoptimumbetweentheosteotomiesandtheidealpositionofthebonesegmentsSinceosteotomiesareirreversibleandmakingsegmentslargerisnotpossibleadjustingthebonesegmentswillresultinevensmallerormultiplesegmentsasaconsequenceInavirtualenvironmentbonesegmentscanbetranslocatedandmanipulatedinawaythattheircurvaturematchesthenewlyformedshapeThereafter,virtualosteotomiescanbecreated Thisparadoxicalbackwardplanningmakesitpossibletofindtheoptimalpositionofbonesegmentsfirstanddeterminethecorrespondingosteotomieslater4-BACKWARDPLANNINGAnotheradvantageofbackwardplanningisthattheoptimalbone-to-bonecontactcanbepursuedBecause theosteotomiesaredefinedaftera finalpositionof thebone segmentis determined an optimal cuttingpattern canbe strategicallydesignedForexamplecreatingabonesegmentusingaskewedosteotomylinecanresultinasegmentwithmaximalocclusionatitsfinalposition Thebenefitisthat thiswilllead tosolidconstructionless fixationmaterialisneededand therisk
