Page 194 - Demo

192Chapter11andflatsurfaceThiswasconcludedclinicallyanddeterminedonthe3DphotoanalysisHowever,whenthepost-opCT-scanwascomparedtotheplanningseveralpointsofimprovementscouldbenotedThemostnoticeabledeviationwastheshapeoftheorbitalbar,whichshowedamuchsmallerangleonthepost-opscanthanintheplanning(seeαFigure7)ThiscouldbeobservedbecausethenasionliesanterioroftheplanningwhilethelateralcantiiweremoreposteriorlocatedDuetothistheplannedanteriordisplacementof13mmwasnotmetandonly8mmwasrealized(Figure8)TherearetworeasonsforthisThefirstoneisthatduringsurgerythepiecesdidnotfitperfectlyinthereconstructionguideBecausewecreatedalidontopoftheguideitwasdifficulttoseamlesslyfitthebonesegmentsintotheguideandsmallinaccuraciescausedbytheosteotomycreatedinterferenceThiscouldbeillustratedinFigure9 Thereforewerecommend tocreateaguide thatonlycoverstheoutsidecontour(andnotthetop)oftheorbitalbar ThesecondreasonisthatwedidnotcutbutbendedthelateralpartsoftheorbitalbarThiswasdonetostimulateosteosynthesisbutthisalsomadeitmoredifficulttoreproducethesteepangleoftheplanning(Figure9)IfwelookatthefrontalpartsoftheforeheadwecanalsoseeadiscrepancybetweenoutcomeandplanningThisisalogicalconsequencebecausewepositionedthefrontalpartsdirectlyontheorbitalbarBothintheplanningasinthescanthefrontalpartsarefollowingthecontourofthebarperfectlyThisisanotherargumentthatthereconstructionoftheorbitalbarshouldbe(more)preciseAnotherrecommendationistocreateoneguideforthereconstructionoftheorbitalbarandtheforeheadInthiscaseweusedthreedifferentguidesforallthepartsbutthiswascumbersometouseduringsurgeryandasingleguidewillprobablymakethereconstructionmoreaccurateEventhoughwewereawarethatwedidnotapprehendtheplannedlateralwideningduringsurgerythepost-opscanshowedapoorerresultthanweexpectedItshouldbenotedhowever,thatweplanned3mmovercompensationNeverthelessthemainlessonisthatweshouldtrytofollowtheplanningmorestrictlyduringsurgery