脑动静脉畸形.ppt

CEREBRALARTERIOVENOUS MALFORMATIONSAVM: a TLA for the CNSIncidencen0.52%￿at autopsynSlight male preponderance (1.09 to 1.94)nCongenital lesions (although rarely familial)EmbryologynFirst half of third week of gestationäepiblastic cells migrate to form mesodermämesodermal cells differentiate to arterial and venous vessels on the surface of the embryonic nervous systemEmbryologynFirst half of third week of gestationäepiblastic cells migrate to form mesodermämesodermal cells differentaite to arterial and venous vessels on the surface of the embryonic nervous systemnSeventh gestational weekävessels sprout branches & penetrate developing brainäreach the gray-white interface, either loop back to pial surface or traverse entire neural tube, thus epicerebral & transcerebral circ'näeventually connect arterial and venous systems by around the twelfth week Pathology & Pathophysiologynabsence of normal capillary systemPathology & Pathophysiologynabsence of normal capillary systemnusual function displacedPathology & Pathophysiologynabsence of normal capillary systemnusual function displacednasymptomatic at birthPathology & Pathophysiologynabsence of normal capillary systemnusual function displacednasymptomatic at birthnvessels change with timenmay develop aneurysmsnparenchymal changes within and around the lesionPathology & Pathophysiologynabsence of normal capillary systemnusual function displacednasymptomatic at birthnvessels change with timenmay develop aneurysmsnparenchymal changes within and around the lesionnsite frequency is proportional to brain volumePathology & Pathophysiologynabsence of normal capillary systemnusual function displacednasymptomatic at birthnvessels change with timenmay develop aneurysmsClinical presentationn95%￿have symptoms by age of 70 yearsClinical presentationn95%￿have symptoms by age of 70 yearsnpeak presentation second to fourth decadeClinical presentationn95%￿have symptoms by age of 70 yearsnpeak presentation second to fourth decade–high output failure, neonate, vein of Galen–hydrocephalus, first decade–headache, hemorrhage, seizures, 2nd & 3rdClinical presentationnfactors contributing to symptoms–vessel walls, flow and pressuresClinical presentationnfactors contributing to symptoms–vessel walls, flow and pressures–enlargement and encroachmentClinical presentationnfactors contributing to symptoms–vessel walls, flow and pressures–enlargement and encroachment–dural sinusesClinical presentationnfactors contributing to symptoms–vessel walls, flow and pressures–enlargement and encroachment–dural sinuses–ischaemiaClinical presentationnfactors contributing to symptoms–vessel walls, flow and pressures–enlargement and encroachment–dural sinuses–ischaemia–cardiac outputClinical presentationHemorrhagenAVM–rupture not a function of sizenAneurysm–rupture related to aneurysm sizeHemorrhagenAVM–rupture not a function of size–no marked increase with exercise, pregnancy, traumanAneurysm–rupture related to aneurysm size–increase with trauma exercise, end pregnancyHemorrhagenAVM–rupture not a function of size–no marked increase with exercise, pregnancy, trauma–arteriovenous, therefore less severenAneurysm–rupture related to aneurysm size–increase with trauma exercise, end pregnancy–arterial, therefore more severeHemorrhagenAVM–rupture not a function of size–no marked increase with exercise, pregnancy, trauma–arteriovenous, therefore less severe–mortality 6 to 13.6%nAneurysm–rupture related to aneurysm size–increase with trauma exercise, end pregnancy–arterial, therefore more severe–mortality 30-50%HemorrhagenAVM–rupture not a function of size–no marked increase with exercise, pregnancy, trauma–arteriovenous, therefore less severe–mortality 6 to 13.6%–lower rebleed mortality rate (1%)nAneurysm–rupture related to aneurysm size–increase with trauma exercise, end pregnancy–arterial, therefore more severe–mortality 30-50%–higher rebleed mortality rate (13%)HemorrhagenAVM–rupture not a function of size–no marked increase with exercise, pregnancy, trauma–arteriovenous, therefore less severe–mortality 6 to 13.6%–lower rebleed mortality rate (1%)–vasospasm rarenAneurysm–rupture related to aneurysm size–increase with trauma exercise, end pregnancy–arterial, therefore more severe–mortality 30-50%–higher rebleed mortality rate (13%)–vasospasm commonHemorrhage - AVMnNonetheless, risk of major, incapacitating, or fatal hemorrhage in untreated lesion is 40 to 50% Hemorrhage - AVMnNonetheless, risk of major, incapacitating, or fatal hemorrhage in untreated lesion is 40 to 50%nYearly risk of initial hemorrhage ~3%nRebleed in first subsequent year 6-18%, reducing to ~3% again thereafternPediatric prognosis worse than adult Spetzler & Martin Grading SystemCriteriaScoreSize of Nidus Small (<3cm)1Medium (3-6cm)2Large (>6cm)3Eloquence of Adjacent Brain No0Yes1Deep Vascular Component No0Yes1Treatment OptionsHSurgical ResectionTreatment OptionsHSurgical ResectionHEndovascular EmbolisationTreatment OptionsHSurgical ResectionHEndovascular EmbolisationHStereotatic RadiosurgeryTreatment OptionsHSurgical ResectionHEndovascular EmbolisationHStereotatic RadiosurgeryHMultimodal TherapyTreatment OptionsHSurgical ResectionHEndovascular EmbolisationHStereotatic RadiosurgeryHMultimodal TherapyHConservative ManagementNormal Perfusion Pressure Breakthrough TheoryR.F. Spetzler et alNormal perfusion pressure breakthrough theoryLoss of autoregulation and carbon dioxide reactivity in presence of large arteriovenous malformation.Normal perfusion pressure breakthrough theoryLoss of autoregulation and carbon dioxide reactivity in presence of large arteriovenous malformation.Normal hemispheric vessels are chronically maximally dilated to attempt to divert flow from the AVMNormal perfusion pressure breakthrough theoryLoss of autoregulation and carbon dioxide reactivity in presence of large arteriovenous malformation.Normal hemispheric vessels are chronically maximally dilated to attempt to divert flow from the AVMObliteration of the AVM diverts all flow to these maximally dilated vessels which have lost their normal control mechanismsNormal perfusion pressure breakthrough theoryLoss of autoregulation and carbon dioxide reactivity in presence of large arteriovenous malformation.Normal hemispheric vessels are chronically maximally dilated to attempt to divert flow from the AVMObliteration of the AVM diverts all flow to these maximally dilated vessels which have lost their normal control mechanismsResults in loss of protection of the capillary bed, with edema and hemorrhagenArterial inflowMathematical ModelsnArterial inflownNidusMathematical ModelsnArterial inflownNidusnVenous OutflowMathematical ModelsAnaesthesia Technique。