SevenAVMs系列--脑室及脑室周围动静脉畸形的显微外科解剖
胼胝体AVM手术解剖及切除策略
脑室体部AVM手术解剖及切除策略
脑室三角部AVM手术解剖及切除策略
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颞角AVM
ThetemporalhornAVMisbasedonthechoroidplexusinthetemporalhorn(Fig.14.7).ThisAVMdiffersfromthemedialtemporalAVMthatliesmedialtothetemporalhornintheuncus,hippocampus,andparahippocampus.TemporalhornAVMsaresurroundedalmostentirelybyependyma.Whentheypresentwithhemorrhage,thebleedingisintraventricularratherthanintraparenchymal.TheirprimarysupplyistheplexalsegmentoftheAChA,whichisenlarged.
ThelPChAcanalsocontributetotheseAVMsthroughthechoroidalfissureandcollateralconnectionsfromtheatrium.Thechoroidalfissureofthemedialtemporallobeformsastalkofarterialsupplytothenidusmedially.VenousdrainageisviatheinferiorChorV,whichexitsthechoroidalfissureviatheinferiorventricularveinandjoinstheBVRintheambientcistern.TemporalhornAVMstypicallyrespectependymalboundariesandspareeloquenthippocampal
structures.
颞角AVM位于颞角脉络丛(图14.7)，与颞叶内侧AVM不同。后者位于颞角内侧的钩回、海马和海马旁回。颞角AVM几乎完全被室管膜包围。当出血时，流出的血液位于脑室而非实质内。它们主要的供血动脉是扩张了的AChA的脉络丛段。lPChA也可以通过脉络裂与来自三角部的侧支连接参与颞角AVM的供血。颞叶内侧脉络裂形成一柄状动脉血供到达内侧血管巢。静脉引流是通过下ChorV，后者在脉络裂经由脑室下静脉，在环池加入BVR。颞角AVM通常具有室管膜边界，不累及功能性的海马结构。
Fig.14.7ThetemporalhornAVM:(a)axialcross-sectionaland(b)superiorviews,withthetemporalhornunroofed.ThisAVMislocatedinthechoroidplexusandchoroidalfissureofthetemporalhorn,suppliedbytheAChAandtoalesserdegreethelPChA,anddrainedbytheinferiorchoroidalandinferiorventricularveins.
图14.7颞角AVM:(a)轴位切面观；(b)上面观，去除颞角顶部。该AVM位于颞角脉络丛和脉络裂，由AChA供血，小部分由IPChA供血，引流入脉络膜下静脉和脑室下静脉。
TemporalHornAVMResection颞角AVM切除术
TemporalhornAVMsareresectedlikebasaltemporalAVMsthroughatemporalcraniotomy(Fig.14.18,step1)andtranscorticalapproachthroughtheinferiortemporalgyrus(ITG).Thepatientispositionedsupine,headturned90degreeslaterally,andthevertexloweredtogainanupwardangletowardthetemporalhorn.Ahorseshoeincisionandthetemporalcraniotomyarebasedovertheear.TheapproachenterslowintheITGandanglesuptotheventricle,stayingbeneath
theopticradiationsinMeyer’sloopthatpassesoverthetemporalhorn(step2).Navigationhelpsaimthistranscorticalroute.Onceentered,thehornisopenedlongitudinallyalongitsaxisforafullviewoftheAVM.TheinferiorChorVandBVR(step3)arenotvisibleuntiltheendofthedissection.
TheAChAisidentifiedproximallyinthechoroidalfissureattheplexalpointanteriorly,andthelPChAsupplyisidentifieddistallyinthechoroidalfissurepastthenidus(step4).TheAChAinputsareinterruptedinitially(step5),butadditionalchoroidalsupplypersistsonthemedialmargin.
Dissectiondownthechoroidalfissurefromproximaltodistalinterruptsthesechoroidalfeeders,requiringananteriorattackandsomeAVMmobilizationlaterally(step6).Thechoroidalfissureispreferentiallyopenedinferiorly,throughthetelachoroideabetweenthechoroidplexusandthefimbriaofthefornix(teniafimbriae),avoidingthetailofthecaudateandtheinferiorthalamusonthesuperiorside.ThefinalstagesofdissectionreachthevenousconnectionstotheBVRandremaininginputsfromthelPChA(step7).Althoughnotstrictlyeloquent,butlikeotherventricularAVMs,temporalhornAVMsareadjacenttothethalamus,caudatenucleus(tail),fornix(fimbria),andhippocampus(Fig.14.19).
颞角AVM切除像颞底AVM一样通过颞部开颅(图14.18,第1步)、通过颞下回(ITG)经皮质入路。病人取仰卧位，头向侧方偏转90°，降低顶点以获得一朝向颞角的向上的角度。以耳上为基底的马蹄形切口、颞部开颅。入路在颞下回下部，角度对着脑室，保持在Meyer’s环内的视放射之下。Meyer’s环从上面越过颞角(第2步)。导航有助于确定该入路。一旦进入颞角，沿其轴纵向打开，以完整看到AVM。直到切除结束才能够看到下ChorV和BVR(第3步)。在脉络裂近端丛点之后辨认AChA，在脉络裂远端病变之后可见lPChA供血(第4步)。先阻断AChA供血血管(第5步),但是另外的自脉络丛的供血血管在内侧缘，从近端向远端继续分开脉络裂阻断这些脉络丛供血血管。需要向前用力，将一部分AVM移向外侧(第6步)。优先通过脉络丛和穹窿伞（伞带）之间的脉络膜，从下方打开脉络裂，避开上面的尾状核尾部和丘脑下部。最后一步切除的是汇入BVR的引流静脉和残留的来自lPChA的供血血管(第7步)。虽然没有严格意义上的语言功能，但是像其它脑室AVM一样，颞角AVM与丘脑、尾状核(尾部)、穹窿（伞）和海马相邻(图14.19)。
Fig.14.18(opposite)ResectionstrategyfortemporalhornAVMs.(a)Step1,exposingtheAVMwithahorseshoescalpincision(inset,dashedline),temporalcraniotomy(inset,solidline),andtranscorticalapproachthroughtheinferiortemporalgyrus.(b)AVMboxshowingarterialsupplyfromtheAChAandlPChA,venousdrainagemediallytotheBVR,andproximitytothedominanthemisphere’shippocampus.(c)Step2,enteringthetemporalhornwithatranscorticalapproach
throughtheITG;step3,identifyingdrainingchoroidalandventricularveins(theBVRisnotvisibleuntillater);step4,identifyingtheAChAinthechoroidalfissureanteriorly;andstep5,interruptingtheanteromedialfrontintheproximalchoroidalfissure.(d)Step6,dissectingalongthechoroidalfissurefromproximaltodistal(coronalcross-sectionalview).(e)Step7,mobilizingtheAVMoutofthechoroidalfissuretodividethelPChAsupplyandidentifytheBVRinambientcistern.
图14.18颞角AVM的切除策略。(a)第1步，显露AVM：马蹄形头皮切口(嵌入图，虚线)，颞部开颅（嵌入图，实线），通过颞下回经皮层入路。(b)AVM盒示意来自AChA和lPChA的动脉供血，静脉向内侧引流到BVR，以及邻近优势半球的海马。(c)第2步，通过ITG经皮质入路进入颞角。第3步，辨认脉络丛和脑室的引流静(BVR直到后来才能看到)。第4步，辨认前方脉络裂内的AChA。第5步，从近端脉络裂阻断AChA的前内面。(d)第6步，沿脉络裂由近及远分离(冠状断面观)。(e)第7步，将AVM移出脉络裂，以切断lPChA供血，辨认环池内的BVR。
Fig.14.19This19-year-oldmanpresentedina
