Is the age of the Cerebral Bypass Gone?Jonathan White, M.D.Associate Professor of Neurosurgery UT Southwestern Medical Center Dallas, TexasHistorical Indications For Bypass:nVascular replacement:uComplex aneurysmsuTumorsnIschemiauMoya Moya diseaseuAtherosclerosisHistorical use of bypass?nFukushima 1986-2006n100 patients, Saphenous veinnAneurysm, Menigioma, carotid body, glomus, othernThree types of bypassuPetrous to paraclinoiduCervical external to petrousuCervical external to M2Things ChangeTraditional ways no longer needed:Better Technology?Tumors:nBetter microsurgerynMicroscopenUltrasonic aspiratorTumors: Gamma KnifeAneurysms?nBetter microscopenBetter clipsnIntra-operative angiographynAnesthesianBetter surgeons?nBetter surgical trainingAneurysms: Coils and StentsWhat about Ischemia?Results of Bypass Studies: Bypass does not worknN Engl J Med. 313 (19):1191-2000, 1985, Nov 7.n714 Medical and 663 STA-MCA bypass patientsnFollowed 56 monthsnNo difference overall between groupsnSome surgical subgroup did worse:uMCA stenosis, carotid occlusion with TIAAngioplasty and StentDoes new technology and information eliminate the need for traditional techniques?Gamma Knife?Gamma knife resultsnPoor control with large volume tumorsnRisk of vascular injury Aneurysm Coiling?UT Southwestern 2002-200695 aneurysms greater then 2.0 CM 17 were treated by primary endovascular Only 9 (53%) completely occluded 12 (71%) required re-treatmentIschemic disease: Flaws of previous bypass trialsnPre operative strokes considered surgical failurenSelection bias good surgical candidates not randomizednMedical failure cases did not crossnNot enough power to identify subgroups which may benefit from bypassIschemia: Need to measure at risk tissuenYonas, J NSG 1993uXe CT; compared 5% vs 50% drop in flow with diamoxu68 patients for 24 monthsu4.4% vs 36% stroke risk in low flow PtsnGrubb, JAMA 1998uPET evidence of high oxygen extraction, 31 monthu11/39 (28%) vs 2/42 (5%) ipislateral stroke riskSTA-MCA bypass for ischemia:STA-MCA bypassSTA-MCA bypassSTA-MCA bypassSTA-MCA BypassSTA-MCA resultsnJapanese EC-IC Bypass trial (JET)u1st 206 patients, surgery group has significantly fewer strokesnStanford study of Moya Moya patientsuDecreased future risk of strokeuRegression of Moya Moya collateralsnCoss trialuHigh risk group randomizedTraditional techniques still have role.nCarotid replacementuComplex aneurysmuSkull based tumornIschemic diseaseuMeasure blood flow to find at risk tissueuSelect proper patientsConcluding Case:Combined TechniquesCombined techniquesCombined TechniquesCombine past and future