Unyielding Progress: Treatment Paradigms for Giant Aneurysms

16 Pages·2012·8.42 MB·English

C 2
HAPTER
Unyielding Progress: Treatment Paradigms for
Giant Aneurysms
Laligam N. Sekhar, MD, FACS, Farzana Tariq, MD, Jeffrey C. Mai, MD, PhD, Louis J. Kim, MD,
Basavaraj Ghodke, MD, Daniel K. Hallam, MD, and Ketan R. Bulsara, MD
Despite advances in the management of both ruptured and studies have reported that they represent 20% to 40% of
unruptured aneurysms, the management of giant aneur- cerebral aneurysms.13-15 Although they can be found in any
ysms remains extraordinarily challenging. In this article, we agegroup,themajoritycometoclinicalattentionbetweenthe
reviewtheindicationsfortheirtreatmentandthemicrosurgical fifth and seventh decades of life.10,11 Up to 70% of patients
and endovascular options and propose a treatment algorithm. harboring these aneurysms manifest with symptoms of mass
effect, including headaches and neurological deficits such
as cranial neuropathies.16-19 One-quarter present after sub-
WHAT ARE GIANT ANEURYSMS? arachnoid or intracerebral hemorrhage.1,12,17,20-23 Up to 5%
Aneurysms are classified depending on their size and of patients may present with seizures.15
shape.Aneurysmscanbedefinedassmall(#6mm),medium
NATURAL HISTORY OF GIANT ANEURYSMS
(7-12mm),large(13-24mm),orgiant;giantaneurysmshave
arbitrarily been defined as those $25 mm by a number of The International Study of Unruptured Intracranial
studies, including the International Cooperative Study on Aneurysms provides the best available information to date
Aneurysmspublishedin1966.1,2Giantaneurysmsarefurther regarding the natural history of unruptured intracranial
subdivided by shape into either saccular or fusiform confor- aneurysms (Table 1).24 It confirms that the tendency for rup-
mations, with saccular being the most common.3 Large and ture is substantially higher in giant aneurysms. In addition,
giant aneurysms share similar features, problems, and treat- themortalityobservedoncegiantaneurysmshaverupturedis
ment strategies. greater than that for small or medium aneurysms.18-20 Thus,
Despite the fact that enormous technical advancements whenanunrupturedgiantaneurysmisdiscovered,thenatural
have been made in the fields of neuroradiology, neuro- historygenerally favors treatment,providedthatthepatient’s
anesthesia, neuroendovascular surgery, and microsurgery physiologicalageandmedicalconditionaresuitable.Allvia-
over the past 2 decades, the treatment of giant aneurysms ble microsurgical and endovascular treatment options should
remains a formidable challenge. In particular, giant aneur- be taken into consideration, with careful evaluation of asso-
ysms have a host of specific problems, their large size ciated morbidities factored into the final treatment approach.
notwithstanding. Frequently, calcification, thrombosis, and Accordingly, treatment should be performed in centers with
wallthickeningareobservedinandaroundtheneckorsac.4-6 greatexperience($100aneurysmscasesperyear)andexper-
Thepresenceofmultipleperforators,especiallyinthecaseof tise in both endovascular and microsurgical interventions,
fusiform giantaneurysms, andbranch vesselsarisingdirectly including high-flow bypasses.
from aneurysmal walls contributes substantial complexity to
their management.7 Even when these aneurysms are saccular TREATMENT OPTIONS
in shape, they can grow to encompass a large portion of the The treatment options for giant aneurysms are summa-
parentvesselcircumference.Throughmasseffectalone,giant rized in Table 2. More endovascular options are available
aneurysms can present with compression of adjacent brain, when an unruptured giant aneurysm is discovered. Although
brainstem, and cranial nerves, and such compression can there is increasing experience in the literature with stent-
worsen after treatments such as endovascular coiling.8,9 assisted coiling in the setting of aneurysmal subarachnoid
hemorrhage, the dual antiplatelet therapy required for endo-
INCIDENCE AND PRESENTATION vascular stents currently limits widespread use in acute sub-
arachnoid hemorrhage patients. The presence of antiplatelet
Giant aneurysms represent only 3% to 5% of all
agents substantially complicates the management of cerebro-
intracranialaneurysms,withapredilectionforfemalepatients
of2:1or3:1.10-12Incontrast,inthepediatricpopulation,some spinal fluid diversion and hydrocephalus secondary to sub-
arachnoidhemorrhageandintraventricularblood,specifically
with maintaining externalventriculostomydrainsorinserting
Copyright©2012byTheCongressofNeurologicalSurgeons
0148-396X shunts.
6 ClinicalNeurosurgery (cid:1) Volume59, 2012
ClinicalNeurosurgery (cid:1) Volume 59,2012 TreatmentParadigms forGiantAneurysms
TABLE1. NaturalHistoryofUnrupturedAneurysmsFromthe TABLE2. TreatmentOptionsforUnruptured vsRuptured
International StudyofUnruptured Intracranial Aneurysmsa24 GiantAneurysms
AnnualRateofBleeding,% UnrupturedAneurysms RupturedAneurysms
Anteriorcirculationaneurysms Microsurgical Clipreconstruction Clipreconstruction
exceptPCOM,mm options
7-12 0.5 Deephypothermic Deephypothermic
13-24 2.9 circulatoryarrest circulatoryarrest.
$25 8 Bypasswithproximal Bypasswithproximal
occlusion/trapping/distal occlusion/trapping/distal
Posteriorcirculationaneurysm+
occlusion occlusion
ICA-PCOManeurysm,mm
Endovascular Proximalocclusion/ Proximalocclusion/
7-12 2.9
options trappingaftertest trappingaftertest
13-24 3.7 occlusion occlusion
$25 10
Primarycoilingwithor Primarycoiling,without
aICA,internalcarotidartery;PCOM,posteriorcommunicatingartery. withoutstentplacement stentplacement
Flowdiversiondevice
LEVEL OF EVIDENCE
clipping. However, with some carotid and vertebral aneur-
There are no randomized trials available to compare
ysms,encirclingorfenestratedclipscanbefashionedforclip
various treatment methods. Both microsurgical treatments
reconstruction of the vessel wall. In such cases, a standard
(high-flow bypasses) and endovascular treatments (flow-
craniotomy is usually combined with a skull base approach
diversion stents) have evolved over the last decade, and the
such as an orbital osteotomy to enhance the exposure and to
recommendationspresentedhere arebased on theexperience
reduce brain retraction. Preparations for a bypass procedure
at our center and on other case series of microsurgical18,25-63
must be done in select patients, in the event that the recon-
andendovascular18,31,33,64-76therapies.Becauseoftheconcen- struction technique cannot preserve the patency of $1
trationof giant aneurysm cases in large centers and thetreat-
involved arteries. In situations potentially requiring bypass,
ment preferences of individual surgeons, multiple biases are
patientsareloadedwithaspirin,withitsclinicalactivitymea-
inherent in published case series. Therefore, the level of evi-
sured by a VerifyNow aspirin assay (Accumetrics, Inc, San
dence must be considered to be Class III.
Diego, California).
Wediscussmicrosurgicalclipping,bypasswithaneurysm
Total intravenous anesthesia is usually used to permit
occlusion, deep hypothermic circulatory arrest with aneurysm
neurophysiologic monitoring of motor evoked and somato-
clipping, endovascular proximal occlusion, endovascular coil-
sensory evoked potentials, as well as brainstem auditory
ing without or with high-porosity stents, and flow-diversion
evoked potentials in those cases with the potential for
devices (stents) in the roleofmanagement ofgiantaneurysms.
brainstem involvement. Proximal and distal arterial control
oftheaneurysmissecured,andthepatientisplacedintoburst
MICROSURGICAL CLIP RECONSTRUCTION
suppression with propofol (Diprivan; AstraZeneca plc,
In general, an aneurysm must have a “neck,” even if it London,UnitedKingdom).Temporarytrappingisperformed
is very broad, to be optimally treated with microsurgical before aneurysm dissection, and systolic blood pressure is
FIGURE 1. A and B, a 57-year-old man presented with subarachnoid hemorrhage, Hunt and Hess grade 4, Fisher grade 3/4.
Computedtomographicangiographyrevealedarupturedgiantaneurysmmeasuring2.8cminthegreatestdimensionwithareas
ofpartial thrombosis andcalcification. C,angiogramrevealeda dominantA1andasmallleftA1.
(cid:1)2012TheCongressofNeurological Surgeons 7
Sekharetal ClinicalNeurosurgery (cid:1) Volume59, 2012
preservedtoenablearepair,whichcanbeaccomplishedwith
monofilament sutures and/or aneurysm clips.
Intraoperatively, direct micro-Doppler insonation,
indocyanine green angiography fluorescence angiography,
or C-arm angiography is then used toconfirm vessel patency
and aneurysm obliteration. Postoperative digital subtraction
angiographyisperformedtoobtainhigh-resolutionimagesto
exclude the possibility of neck remnants not discoverable by
other methods. If a neck remnant is found on this study, an
early follow-up angiogram (2-3 months postoperatively) is
recommended.
CASE EXAMPLE 1
A 57-year-old man presented to the emergency department after
a seizure and collapse and on arrival was found to be following
commands with his left upper extremity, withdrawing on the right
side,andopeningeyestovoice(GlasgowComaScalescore,11).A
noncontrastheadcomputedtomography(CT)disclosedsubarachnoid
hemorrhage, Hunt and Hess grade 4, and Fisher grade 3 to 4 and
revealedagiantanteriorcommunicatingarteryaneurysmmeasuring
2.8 cm along its long axis with regions of partial thrombosis and
acrescenticrimofcalcification(Figure1Aand1B).TheCTangio-
gram showed a dominant right A1 and an atretic left A1 supplying
theaneurysm(Figure1C).Intraoperatively,arightoccipitalexternal
ventriculostomywasplacedusingframelessneuronavigationtoavoid
thefrontalhornofthelateralventricle.Next,asaphenouscraniotomy
with a right temporal craniotomy and basal frontal osteotomy was
performedtogainbilateralaccesstotheaneurysm(Figure2A).After
temporaryclipapplicationonbilateralA1andA2vessels,anendoa-
neurysmectomywasperformed,aidedbyaSonopetultrasonicaspi-
rator (Stryker, Mahwah, New Jersey) and followed by resection of
thedomeandwalloftheaneurysm.Theneckoftheaneurysmwas
closed with 6-0 and 7-0 Prolene (Johnson & Johnson, New Bruns-
wick,NewJersey)monofilament,andthesuturelinewasreinforced
withasingleright-angleFT820Tclip(Aesculap,B.BraunMelsun-
genAG,Melsungen,Germany;Figure2B).Thefrontalsinuseswere
exenteratedandsealedwithautologousabdominalfatgraftandvas-
cularized pericranium. Postoperative CT angiography (Figure 3A)
FIGURE 2. A, surgery drawing showing exposure (bifrontal andcerebralangiography(Figure3Band3C)demonstratedcomplete
and right temporal craniotomy and basal frontal osteotomy; occlusion of the aneurysm with preservation of bilateral anterior
((cid:1) Copyright L.N. Sekhar). B, the suture line along the cerebralarterycirculation.
neck of the aneurysm is reinforced with a right-angle During the postoperative phase, symptomatic vasospasm was
FT820Tclip. treatedwithhypervolemic,hemodilution,andhypertensivetherapy.
The right occipital ventriculostomy was later converted to a right
occipital ventriculoperitoneal shunt. The patient was subsequently
then elevated approximately 20% above baseline to enhance dischargedhomeonpostoperativeday53aftera2½-weekcourseof
collateral arterial flow while temporary clips are in place. in-patientrehabilitation.At3monthspostoperatively,thepatienthad
Adenosine-induced flow arrest can also be used only if complete resolution of his hemiparesis and was independent in his
toleratedbythepatienttoenhancedissectionoftheaneurysm, activities of daily living (modified Rankin Scale [mRS] score, 2)
with partialimpairment ofhisshort-termmemory.
to aid in the placement of permanent clips, or to ameliorate
bleeding in the operative field.
DEEP HYPOTHERMIC CIRCULATORY
Theaneurysmcanbedirectlypuncturedtoemptyblood
ARREST TECHNIQUE
if there is no thrombus inside, or suction decompression
(DallasTechnique77)canbeperformedwithproximalinternal The deep hypothermic circulatory arrest (DHCA) tech-
carotid artery (ICA) aneurysms. When thrombus, calcifica- nique has been used to treat giant aneurysms at some
tion,orextensiveatheromaispresent,theaneurysmsacmust centers45,47,78-85;theseniorauthor(L.N.S.)hasexperiencewith
be opened distal to the neck to facilitate its removal; this is a more limited number of patients.86 Its popularity for the
calledanendoaneurysmectomyprocedure.Theorificesofthe treatment of giant aneurysms of the anterior circulation has
inflow and theoutflow vessels mustthen be cleared ofather- waned in recent years owing to the success of current neuro-
omaorthrombus.Itisimperativethatsufficientneckmustbe protective agents and the refinement of bypass techniques
8 (cid:1)2012TheCongressofNeurological Surgeons
ClinicalNeurosurgery (cid:1) Volume 59,2012 TreatmentParadigms forGiantAneurysms
FIGURE3. A(axial),postoperativecomputedtomographicangiographyshowingcompleteocclusionoftheaneurysm.BandC,
postoperative angiogram showing complete exclusion of the aneurysm with no residual, along with patent bilateral anterior
cerebralarterycirculation.
that minimize the need for prolonged temporary occlusion. the day before surgery, and during the operation, the brain is
TheDHCAtechniquestillhasbenefitsforposteriorcirculation subjected to burst suppression before temporary clip applica-
aneurysms, particularly those involving the basilar tip. The tion. Blood pressure is kept normotensive or slightly hyper-
primary difficulty with DHCA is unpredictable recovery after tensive (elevated by 20%) during temporary occlusion of
circulatory arrest, with good results reported in about 63% to unruptured aneurysms. Intravenous heparin, usually 2000 to
75%ofpatients.61,69Othersignificantcomplicationsarerelated 3000 U, is administered during the bypass, with activity
to postoperative brainhemorrhage. To be suitable for circula- monitored by activated clotting times.
toryarrest,theaneurysmmusthaveaneckorthesurgeonmust The aneurysm is generally explored after all prepara-
be able to recreate a neck through the removal of thrombus, tions are made for the bypass to see if it can be directly
atheroma, coils, etc, to enable clipping. A direct saphenous clipped. If not, the bypass proceeds under temporary clip
vein graft bypass into the basilar artery after DHCA with occlusion and burst suppression. After completion of the
debulkingofagiantbasilaraneurysmhasalsobeenperformed bypass,luminalpatencyisconfirmedbyuseofintraoperative
by the senior author.81 micro-Doppler and either indocyanine green angiography or
standard intraoperative angiography. The aneurysm is then
BYPASS FOR GIANT ANEURYSMS treated during the same session; otherwise, the bypass may
occlude or the aneurysm may rupture as a result of increased
Various bypass and reconstructive techniques for giant
aneurysms have been iteratively refined over the preceding intra-aneurysmal pressure in the presence of altered flow
dynamics. Aneurysmal treatment may consist of proximal
decade.28,37-43,50,51,55,58,83,87 These techniques include local
occlusion only or trapping. Occasionally, distal occlusion of
revascularization such as direct vessel reimplantation, side-
to-side vessel anastomosis, low-flow extracranial-intracranial theaneurysmcanbedoneinunrupturedcasestopreservethe
bypass (including superficial temporal artery or occipital patency of branch vessels or perforators arising from the
arteryvesselsassources),andhigh-flowextracranial-intracra- aneurysm neck area.
nial bypasses using the radial artery or the saphenous vein
grafts.The purposeofrevascularizationcanbeto replace the CASE EXAMPLE 2
parent vessel (in which case a high-flow bypass is used) or This 47-year-old man presented with a 1-month history of
a branch vessel (in which case a local anastomosis or a low- progressive right hemiparesis, intermittent right facial weakness,
flow extracranial-intracranial bypass is used). and dizziness. A preoperative magnetic resonance imaging scan
Bypass techniques require the same preparation as showed a 35 · 25 · 23-mm basilar tip aneurysm, partially throm-
extensive clip reconstruction. Cerebral angiography with bosed,withseveremidbraincompression(Figure4Aand4B).Cere-
external carotid runs is used to assess suitable superficial bral angiography showed a very complex aneurysm, encompassing
2708ofthebasilarapex,withtheleftposteriorcerebralarteryarising
temporal artery or occipital sources and to the suitability of
from the neck (Figure 4C and 4D), rendering the aneurysm unsuit-
the external carotid artery for graft implantation. If a high-
ableforendovasculartreatment.Theabsenceofadefinedneckand
flow bypass is intended, bilateral upper-extremity radial and
an essentially fusiform conformation of the aneurysm further
ulnar artery mapping with an ultrasonic Allen test is
excluded the possibility of clip reconstruction under coverage of
performed, along with bilateral saphenous vein mapping to DHCA. Terminal basilar occlusion, Hunterian ligation, also was
ensure that vessels of suitable caliber are available for consideredbutwashandicappedbytheabsenceofsufficientcollat-
harvesting. Patients are placed on aspirin 325 mg at least eralsfromtheposteriorcerebralartery(Figure4Eand4F).Previous
(cid:1)2012TheCongressofNeurological Surgeons 9
Sekharetal ClinicalNeurosurgery (cid:1) Volume59, 2012
FIGURE 4. A (axial view) and B
(sagittal view), preoperative
magnetic resonance imaging
scan showing 35 · 25 · 23-mm
basilar tip aneurysm, partially
thrombosed, with severe mid-
brain compression. C and D,
angiography showing a complex
aneurysm encompassing 2708 of
thebasilarapex(C),withtheleft
posterior cerebral artery arising
from the neck (D). E and F,
absent collaterals from the pos-
terior communicating artery
showninanangiogramintheleft
internalcarotidarterylateralview
(E) and right internal carotid
arterylateral view(F).
experience from the Steinberg et al26 series showed that terminal proximalposteriorcerebral artery.Atranspetrosalapproachandfar
basilar occlusion is successful in 96% of cases with 2 posterior lateral approach were performed during the first stage (Figure 5A)
communicating arteries (PCOMs) .1 mm in diameter and 74% of for exposure, followed by the bypass (Figure 5B and 5D) and ter-
cases with a single PCOM .1 mm in diameter. This has been minal basilar artery occlusion during the second stage (Figure 5C).
confirmed in a more recent series from the Columbia Presbyterian Theaneurysmrupturedbetweenthe2operations,butultimately,the
Hospital.88 basilar artery occlusion was successfully performed. The patient
We opted to construct an artificial PCOM artery by means of underwent significant deterioration in the immediate postoperative
a radial artery graft bypass connecting the vertebral artery to the phase but gradually improved after 10 days. After 2 months, he
10 (cid:1)2012TheCongressofNeurological Surgeons
ClinicalNeurosurgery (cid:1) Volume 59,2012 TreatmentParadigms forGiantAneurysms
FIGURE5. A,initialviewoftheaneurysmaftertranspetrosalapproachandfarlateralapproachwereperformedinthefirststageof
the operation ((cid:1) Copyright L.N. Sekhar). B, radial artery graft harvest and left V3 segment of the vertebral artery to the left
posterior cerebral artery (PCA) bypass ((cid:1) Copyright L.N. Sekhar). C, terminal basilar artery occlusion performed in the second
stage of the operation ((cid:1) Copyright L.N. Sekhar). D, angiogram performed on postoperative day 2 showing radial artery graft
bypassleftfromV3toleftPCA.E(axialview)andF(sagittalview),postoperativecomputedtomographicangiographydoneat
day 23showinga smallaneurysmremnantatthebase.
demonstratedamildhemiparesisanddysphasiayetwasindependent cerebralartery(Figure6F).Thepatientrecoveredwellandreturned
for activities of daily living (mRS score, 3) and continuing to tohispreviouswork.
improve.HisCTangiographydemonstratedasmallaneurysmrem-
nantnearthebase(Figure5E,5F),whichisstillbeingfollowedup.
CASE EXAMPLE 4
This 40-year-old doctor presented with severe visual loss and
CASE EXAMPLE 3 headache with a left homonymous hemianopsia on examination.
This 21-year-old man with a rare neurocutaneous vascular Cerebral angiography disclosed a giant ICA aneurysm involving the
syndrome, cutis marmorata telangiectatica saphenous, involving terminalICAsegment.CollateralsfromthecontralateralICAwerepoor
the right side of his body underwent endovascular occlusion of becauseofasmallcaliberanteriorcerebralarteryontheipsilateralside
a giant right ICA aneurysm at 9 years of age. He subsequently (Figure7Aand7B).Thepatientunderwentaradialarterygraftfromthe
presentedwithasymptomaticandprogressivegrowthofagiantright externalcarotidarterytotheMCA(Figure7E),andthentheaneurysm
vertebral artery aneurysm spanning the distal V3 and V4 segments wasclipoccludedinsuchawaythatflowwaspreservedtotheanterior
withawaistingbetweenwheretherightposteriorinferiorcerebellar choroidal artery (Figure 7F). The patient suffered mild hemiparesis,
artery (PICA) originated (Figure 6A and 6B). Additionally, there whichresolvedcompletelyafter3days.Hewasabletoreturntowork
was a small aneurysmal dilatation of the right PCOM, which went asaphysicianandcontinuestoworkfull-timeafter7years.Latefollow-
onto supply the entire rightmiddle cerebral artery territory. Abal- uphasdemonstratedthathisgrafthasremainedpatentbyCTangiog-
loontestocclusionofrightvertebralarterywasperformed,whichthe raphywithoutevidenceofaneurysmalrecurrence(Figure7Eand7F).
patienttoleratedclinically,buttherightPICAfailedtofillfromthe
contralateral vertebral arteryinjection. RESULTS OF BYPASSES FOR ANEURYSMS
WeoptedtoperformarightoccipitalarterytoPICAbypasswith It is difficult to directly compare outcomes from an
proximal occlusion of the right vertebral artery aneurysm (Figure
endovascular (stent-assisted) series with a microsurgical
6C-6E).Thepatientmadeanexcellentrecoveryfromthisprocedure;
bypass series because they are often performed in discrete,
however, to augment collateral circulation in the hopes of reducing
thelikelihoodofdevelopingfurtheraneurysms,heunderwentasub- nonoverlapping subsets of patients harboring giant aneur-
sequentradialarterybypass(extractedfromthepatient’sunaffected ysms. However, some general information can be gleaned
arm) from the right external carotid artery to the right middle from a review of the senior author’s series of bypasses for
(cid:1)2012TheCongressofNeurological Surgeons 11
Sekharetal ClinicalNeurosurgery (cid:1) Volume59, 2012
FIGURE6. AandB,3-dimensionalangiographyshowingagiantrightvertebralarteryaneurysm,whichinvolvesthedistalV3and
V4 segments, with a waisting between where the right posterior inferior cerebellar artery (PICA) originates ((cid:1) Copyright L.N.
Sekhar). C, initial view of the aneurysm after far lateral approach is performed ((cid:1) Copyright L.N. Sekhar). D, surgery drawing
showingtheoccipital-PICAanastomosisandproximalocclusionandclippingofaneurysm.E,postoperativeangiogramshowing
occipitaltoPICAbypassandsaphenousveingraft(SVG)bypass.F,postoperativeangiogramafterthesecondoperationshowing
theexternalcarotidartery (ECA)torightmiddlecerebralartery(MCA)radialarterygraft(RAG).
12 (cid:1)2012TheCongressofNeurological Surgeons
ClinicalNeurosurgery (cid:1) Volume 59,2012 TreatmentParadigms forGiantAneurysms
FIGURE 7. A, preoperative angio-
gramrevealinganeurysminvolving
the terminal internal carotid artery
(ICA).B,angiogramrevealingpoor
collateral flow from the contralat-
eral ICA. C, surgery drawings
showing radial artery graft (RAG)
from the external carotid artery
(ECA)tothemiddlecerebralartery
(MCA; (cid:1) Copyright L.N. Sekhar).
D, surgery drawing revealing pres-
ervation of the anterior choroidal
artery through the clip reconstruc-
tion ((cid:1) Copyright L.N. Sekhar). E,
postoperative angiogram showing
the patent RAG from the ECA to
MCA. F, postoperative angiogram
showing patent anterior choroidal
arteryflow.
aneurysms. From 1988 to 2011, 182 bypasses were per- (Table 4). Giant aneurysms made up only 14% of the total
formed in 172 patients. A careful analysis of results and group. In addition, ruptured aneurysms formed 32% of the
complications (Table 3) was performed in the patients oper- group, with some patients presenting with poor Hunt and
atedonduringthelast6yearsatHarborviewMedicalCenter Hessgrades preoperatively. Theoutcomes after surgerywere
(cid:1)2012TheCongressofNeurological Surgeons 13
Sekharetal ClinicalNeurosurgery (cid:1) Volume59, 2012
TABLE3. Complications ofAneurysmOperationsWith TABLE 5. Outcomesof90 PatientsOperatedonWith 104
BypassesDoneatHarborviewMedicalCenterDuringthePast BypassesatHarborviewMedicalCenterOverthePast6Years
6Years (2005-2011)a
Stroke,n/N(%) 6/104(5.7) Rupturedaneurysms,n(%)
Completerecovery,n/N(%) 3/6(50) PreoperativeHuntandHess
Hematoma(epidural,subdural,Intraparenchymal),% 4 1-3 22(69)
Infection(local/systemic),n(%) 6(5) 4-5 10(31.2)
Deaths,n(%) 5(4.8) Follow-upmRS
Bypassrelated,n(%) 1(0.9) 0-3 23(72)
Diseaserelated(subarachnoidhemorrhage),n(%) 3(2.8) 4-6 9(28)
Othercauses,n(%) 1(0.9) Unrupturedaneurysms,n(%)
Correctionneeded(surgicalorendovascular),n(%) 10 PreoperativemRS
Graftpatencyaftercorrection,n(%) 98 0-3 55(95)
4-5 3(5)
strongly correlated to the preoperative Hunt and Hess grade Follow-upmRS
for ruptured giant aneurysms or the mRS scores for unrup- 0-3 55(95)
tured giant aneurysms (Table 5). Cavernous and ophthalmic 4-6 3(5)
aneurysms,agroupthatmaybeeligiblefortreatmentwiththe aACA,anteriorcerebralartery;mRS,modifiedRankinScale.
Pipeline Embolization Device, formed a small cohort of 23
patients with excellent outcomes (Table 6).
(beforeorduringcraniotomyandduringdissection),ischemic
COMPLICATIONS AND OUTCOMES OF MICRO- stroke (major or minor), thrombosis of a branch or parent
SURGERY FOR GIANT ANEURYSMS artery postoperatively, and incomplete clipping with recur-
Potential complications during the microsurgical treat- rence. A review of multiple series of cases published in the
ment of giant aneurysms include intraoperative rupture literature shows that an excellent to good outcome (mRS
score, 0-3) was obtained in 58% to 84% of the patients, and
a mortality rate of 14% to 22% was observed.25-43,48,52-61
TABLE4. ResultsofOperationsforAneurysmPatientsTreated Rebleeding was observed in 0% to 3%, and retreatment was
Witha BypassatHarborviewMedicalCenterFrom 2005to required in up to 1% of cases.50
2011a
Totalpatients(aneurysms),n 90(94aneurysms)
ENDOVASCULAR TREATMENTS:
Totalbypasses,n 104
Ruptured,32n(%) 32(34.7) PROXIMAL OCCLUSION
HuntandHessgrade1-3,n 22 Proximal occlusion of the aneurysm via endovascular
HuntandHessgrade4-5,n 10 embolizationisaviableoptionforthosegiantaneurysmsthat
Unruptured,n(%) 60(65.2) have sufficient collateral circulation. Specifically, this option
Previouslytreated,n(%) 18(19.5) is very useful for intracavernous ICAs and selects large and
Surgery,n 9 giant vertebral artery aneurysms with few perforators and no
Endovascular,n 9 major branches. Preoperatively, aspirin 325 mg is given by
Location,n(%) mouth;heparinisgivenintravenouslytoachievetheactivated
ICA 32(34.7)
Cavernous 12
Ophthalmic/paraclinoid 11 TABLE 6. OutcomesofCavernous andParaophthalmic
Others 9 Aneurysms Treated WithBypassesatHarborviewMedical
MCA,n(%) 28(30.4) Center From2005 to2011a
Anteriorcerebralartery,n(%) 17(18.4) Total,23(of90total)
Posteriorcirculation,n(%) 15(16.3) Unruptured,18(78.2%)
Sizeofaneurysms,n(%) Ruptured,5(21.7%)
0-13mm 50(54.3) HuntandHessgrade1-3,3
12-24mm 28(30.4) HuntandHessgrade4-5,2
$25mm 13(14.1) Completeocclusionoftheaneurysm,100%
Bypasstypes,n(%) Patencyofbypass,100%
Extracranial-intracranialbypasses 69(66.3) Follow-upoutcomes
Intracranialgraft 12(11.5) mRS0-3=22(95.6%)
Intracranial-reimplantation 23(22.1) mRS4-6=1(4.4%)
aICA,internalcarotidartery;MCA,middlecerebralartery. amRS,modifiedRankinScale.
14 (cid:1)2012TheCongressofNeurological Surgeons
ClinicalNeurosurgery (cid:1) Volume 59,2012 TreatmentParadigms forGiantAneurysms
FIGURE 8. A and B, complex basilar trunk aneurysm
filling predominantly through a right vertebral artery
(VA) injection. C, postoperative angiogram showing
VA to posterior cerebral artery bypass using a saphe-
nousveingraft(SVG).D,postoperative3-dimensional
angiogramshowingpersistentfillingoftheaneurysm
through the opposite VA. E, endovascular coiling of
the residual aneurysm via the left VA. Note the coils
placed. F, endovascular coiling of the residual aneu-
rysm via the left VA. G, 1-year follow-up angiogram
showingpatentbypassgraftandcompletelyoccluded
aneurysm.
clotting time (ACT) .250sec. Both transcranial Doppler hypotension. Balloon test occlusion for approximately
and cerebral angiography are performed preoperatively and 15 minutes is performed in each patient before permanent
during the procedure to study intracranial collateral circula- endovascular occlusion. A patient is considered to be a suit-
tion in both the presence and absence of induced relative able candidate for permanent occlusion if the following
(cid:1)2012TheCongressofNeurological Surgeons 15