Intracranialduralarteriovenousfistulas(dAVFs)areagroupofacquiredpathologicalvascularmalformationsthataredefinedbyanabnormalconnectionbetweenanarteryandavein,bypassingthecapillarybed.Theshuntingthatisconfinedtotheduraissuppliedbybranchesoftheexternalcarotidartery,tentorialbranchesoftheinternalcarotidartery,meningealbranchesofthevertebralartery,andrarely,thepialbranchesofthecerebralarteries.
颅内硬脑膜动静脉瘘是一种由动脉和静脉之间绕过毛细血管床而异常连接的获得性病变。硬脑膜局部是由颈外动脉的分支,颈内动脉的小脑幕支,椎动脉的脑膜支和极少部分脑动脉的软膜支供血。
ThedAVFsandmorespecificallythefistulasthemselvesarelocatedwithinthewallsoftheduralvenoussinus.Theymaydevelopduetoduralvenousthrombosis,infection,previoussurgery,ortrauma,althoughmanycasesareidiopathic.Inflammatorychangesfromtheseconditionscancauseangiogenesis,demonstratedbyhighconcentrationsofvascularendothelialgrowthfactor(VEGF)foundnearfistulas.Asubsetofthesefistulasdirectlyconnectstoacortical(leptomeningeal)vein.
硬脑膜动静脉瘘（dAVFs），确切地说瘘管本身位于硬脑膜静脉窦壁，其形成可能是由于硬脑膜静脉窦的血栓、感染、前期的手术或外伤,但多数情况下是自发性的。炎症可以使瘘管周围聚集高浓度的血管内皮生长因子，最终导致血管再生。这些瘘管的一部分可直接与大脑皮层（或软膜）静脉相通。
Someresearchershavealsoproposedembryologictheoriesthatimplicateabnormalrecanalizationoftheprimitivedirectconnectionsbetweenthearteriesandveinsinresponsetoaninflammatoryreactionorvenoussinusocclusion.
一些研究者也提出了胚胎发育理论，其涉及动静脉的炎性反应或静脉窦闭塞引起的动静脉胚胎期原始连接的异常再通。
Thefrequencyofarteriovenousmalformations(AVMs)inthegeneralpopulationisapproximately0.15%,andanestimated10%to15%ofthesearedAVFs.MultipleclassificationsystemsfordAVFsexist.Thesesystemsarebasedonthelesions’venousdrainagepatternsasthisfactordictatesthebehaviorofthelesion.DjindjianandTheNeurosurgicalAtlasbyAaronCohen-Gadol,M.D.MerlandfirstclassifieddAVFsaccordingtotheirvenousangioarchitecturein.In,Cognardfurtherclassifiedbothcranialandspinalarteriovenousfistulasaccordingtotheirvenousoutflowwithprognosticandtreatmentimplications.
动静脉畸形在普通人群中的发病率约为0.15%，其中大约10%～15%为dAVFs。硬脑膜动静脉瘘具有多个分类系统，这些分类系统都是基于病变的引流静脉模式而制定，从而决定了病变的表现形式。年，Djindjian和Merland根据静脉血管架构首次将dAVFs进行分型。年，Cognard根据dAVF的静脉流向相关的预后因素及治疗并发症，进一步将颅内和脊髓的dAVF进行分类。
BordensimplifiedtheCognardclassification,emphasizingthatthemajorfactorinpredictinganaggressiveclinicalcourseisthepresenceofcorticalvenousdrainage.Unlikevenoussinuses,corticalveinsarenotprotectedbytheduraandcannotwithstandarterialpressures.Therefore,dAVFswithcorticalvenousdrainage(BordentypesIIandIII)haveahigherriskofruptureandhemorrhage.ThehemorrhagefromdAVFscanbeparenchymal,subarachnoid,orsubduralinnature.
Borden简化了Cognard分类,强调皮层引流静脉是预测一个临床诊疗结局的主要因素。不同于静脉窦，皮层静脉不受硬脑膜的保护，不能承受动脉压。因此，具有皮层静脉返流(Borden分型II和III型)的硬脑膜动静脉瘘可能有更高的破裂或出血的风险，其出血特点可能为脑实质出血，蛛网膜下腔出血或硬膜下出血。
表1:硬脑膜动静脉瘘分型
Borden分型
Cognard分型
I型:流入硬脑膜静脉窦或脑膜静脉
I型:顺行流入硬脑膜静脉窦
IIa型:硬脑膜静脉窦逆流
II型:流入硬脑膜静脉窦+皮层静脉返流
IIb型:顺行流入硬脑膜静脉窦+皮层静脉返流
IIa+b型:硬脑膜静脉窦出现逆流+皮层静脉返流
III型:仅有皮层静脉返流
III型:仅有皮层静脉返流，无静脉扩张
IV型:皮层静脉返流伴静脉扩张
V型:流入髓周静脉
Intracranialhemorrhageandneurologicdeficitislikelyin2%oftheBordenclassificationtypeI,39%oftypeII,and79%oftypeIIIdAVFs.
硬脑膜动静脉瘘Borden分型I型其脑出血和神经功能缺陷约占2%，II型约39%，III型约占79%。
