Basilar - Semantic Scholar

Neuroradiology Guenther Radenko

E. Klein, MD #{149}Dieter H. Szolar, Karaic, MD #{149}Klaus A. Hausegger,

MD MD

A. Leber,

#{149} Klaus

MD

Basilar Tip Aneurysm: Endovascular with Guglielmi Detachable Coils-Midterm PURPOSE: To determine the safety and effectiveness of Guglielmi detachable coils in the endovascular treatment of ruptured and nonruphired basilar tip aneurysms. MATERIALS AND METHODS: A basilar tip aneurysm was occluded with Guglielmi detachable coils in 21 patients. The aneurysmal diameter was small (less than 12 mm) in 15 patients, large (12-25 mm) in four patients, and giant (more than 25 mm) in two patients. Angiographic follow-up ranged from 6 to 48 months (mean, 26 months); clinical follow-up ranged from 1 to 48 months. RESULTS: Embolization was technically successful in all patients. Cornplete occlusion was achieved in 14 (67%) patients; 90% occlusion was achieved in seven (33%) patients. There was partial reperfusion of the aneurysm in three patients (14%) after 6 months, which necessitated repeated embolization. The clinical results were excellent in 13 patients, good in six, and fair in one. One patient died 2 months after the embolization due to pulmonary complications. A posterior cerebral artery was occluded in five (24%) patients; one of these patients developed a permanent neurologic deficit, one developed a transient neurologic deficit, and three had no clinical symptoms. CONCLUSION: Endovascular treatment of a basilar tip aneurysm with Guglielmi detachable coils seems to be a safe and less invasive altemative to surgical clipping.

B

of the deep location of tip aneurysms, surgical

ECAUSE

basilar treatment

is difficult,

and

there

There

that

is considered

reports for occlusion of basilar tip aneurysms in sebected patients. To our knowledge, however, ours is the first report of the use of GDCs in a nonselected study population. Because of the high surgicab risk associated with the anatomic location of a basilar tip aneurysm, none of the patients in the present

is a

rate

of 7.4%

and

coils

have

been

basilar

tive The 25)

microcoils,

enabling

occlusion of saccuban results of preliminary of the

endovascubar aneurysms

intracranial

been

encouraging.

Index

terms:

Aneurysm,

blockade,

METHODS

From

December

21 patients with

a basilar

tip

with GDCs. was obtained physically

were

1992

to December

(13 women

eight

aneurysm

Written from and

and

were

informed all patients,

mentally

abbe.

1996,

men) treated

consent who were The

patients

aged

31-75 years (mean, 50 years). At the time of presentation, 16 (76%) patients had a subarachnoid hemorrhage, and two (10%) patients had signs of mass effect (sixth nerve palsy in one patient, headache and vertigo in the other). An an-

sebec-

eurysm (14%)

Aneurysm,

#{149}

was patients.

therapy,

found All

incidentally 16 patients

1753.1264

Arteries,

#{149}

in three with a sub-

therapeutic

1753.1264

GDC

Abbreviations: Radiology

AND

Patients

reported

1753.73

in a nonselected

of patients.

MATERIALS

aneurysms. studies (19-

cerebral,

aneurysms

a

occlusion of with GDCs

have

tip

population

and 11.3%, respectively. With the development of the Guglielmi detachable coil (GDC), the indication for treatment of intracranial aneurysms may have changed. The use of GDCs allows a more controlled and precise placement of these soft platinum

a few

GDC

of

The purpose of this study was to determine the safety and effectiveness of GDCs in the endovascubar treatment of ruptured and nonruptured

mortality rate of 9.8% associated with the use of balloons. Morbidity and mortality rates associated with the use of nondetachable (17) to be 4.2%

only

use

were considered to be candifor surgery. We report our results of 4 years of experience with GDC treatment in 21 patients with a ruptured or a nonruptured basilar tip aneurysm.

to be moper-

a morbidity

been

of the

study dates

able or may be associated with a high surgical risk (8-15). Detachable balboons (8-16) and nondetachable microcoils (17,18) have been widely used. However, these devices are associated with a relatively high compbication rate. Higashida et ab (13) reported

have

(22,26,27)

high risk of complications (1-7). Hence, the surgical outcome in patients with a basilar tip aneurysm has been shown (7) to be poorer than the outcome in those with an aneurysm in the anterior circulation. During the past decade, endovascubar treatment has gained acceptance as a therapeutic alternative in the care of patients with an intracranial aneunysm

Treatment Results’

1997;

=

Gughielmi

detachable

coil,

PCA

=

posterior

cerebra!

artery.

205:191-196

I From the Departments of Radiology (G.E.K., D.H.S., R.K., K.A.H.) and Neurosurgery (K.A.L.), Karl-Franzens Medical School and University Hospital, Auenbruggerp!atz 9, 8036 Graz, Austria. From the 1995 RSNA scientific assembly. Received March 11, 1997; revision requested April 11; revision received June 11; accepted June 12. Address reprint requests to G.E.K. © RSNA, 1997

1 Qi

Findings

in 21 Patients

with

a Basilar

Tip

Age (y)/Sex

Clinical

1/44/F

Incidental finding Mass effect

2/49/F 3/57/M

Finding

Mass effect

6/60/M

Incidental finding Incidental finding Subarachnoid hemorrhage

7/42/M 8/56/F

Subarachnoid Subarachnoid

hemorrhage hemorrhage

9/31/M

Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid Subarachnoid

hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage

4/46/F

5/75/F

10/46/F 11/50/F 12/64/F 13/38/F

14/34/M 15/43/M 16/52/F 17/47/F 18/58/M 19/67/M 20/56/F

21/47/F

Aneurysm

Hunt-Hess Grade

Patient!

Treated

onset

hemorrhage treatment

within

of symptoms.

grading

The

system

Hunt

was used

subarachnoid three patients,

as grade

underwent 4 days

Small Small

26 24

Large

65

90

0

Small

18

0 I

Small Large

58 110

100 100

I

Small

28

I II II H

Small Small Small Small

8 48 8 45

II

Small

43

ifi ifi HI ifi ifi N IV V V

Large Small Giant Giant Large Small Small Small Small

84 40

hemorrhage as grade

and

as grade

The aneurysm

and

as grade

I in

as grade

Initially,

V in two

IV in patients. (less than 12

angiograms

was small

in diameter) in 15 patients, (12-25 mm in diameter) in four

giant

(more

than

in two patients

25 mm

(Table).

patients

sented

in diameter) in

had

diameter the aneurysm

had a wide

4 mm

in diameter).

clinical

diagnosis

rhage

of subarachnoid

was confirmed

mographic

(CT)

the diagnosis confirmed angiography Magnetic

neck (larger

with computed

findings

(Fig

2a),

la,

lb. (MR)

2b, 2c, images,

than

follow-up

4 years.

Outcome

the basis

on

ranged

in patients

of a modified

(23): excellent (neurologically (mild deficit), fair (marked cit), poor (comatose), and

Interventional

from

,,l

necessary.

3c). MR an-

to

classified

intact),

neurobogic

scale good

defi-

dead.

#{149}

anesthesia

12-25

mm;

giant

intact

with

no detectable

was

placed

was

GDC

Therapeutics,

system

microcatheter

Su-

(Target

Calif).

thrombus

The

coaxial

flushed

formation

PCA

between

the

24

Excellent

16 48 47

Excellent Excellent Excellent

30

Good

of PCA

of left PCA

was 25 mm in diameter

deficit;

Excellent Good

25 15 42 6 NA 24

good

mild

=

Good Good Dead

Good

or larger.

deficit;

fair

=

with coils that had the largest relation

of the

size

of the

hemi-

marked

diameter

aneurysm.

in Care

was taken to place the first coil in a basketlike configuration in the aneurysm (Fig lc). embolization

was

performed

with

to fill the remaining

cavity

control

showed

angiograms

the aneurysm densely packed with GDCs (Figs le, if, 2d, 2e, 3d, 3e). After placement and before electrolytic detachment of each GDC, a control angiogram was obtained with

hand

Nycomed,

guide

injection

of iodixanol

Oslo,

catheter

Norway)

(Visipaque;

through

to confirm

the

the correct

site

teries.

artery.

with a of saline and heparin (1,000 IU per 500 mL normal saline) to pre-

solution heparin vent

vertebral

continuously

of!eft

46

and location of the coil, as well as to demonstrate the patency of the adjacent ar-

catheter (Balt, in the cervical seg-

Fremont,

was

PCA

subtraction

catheter placement in the anaccomplished coaxially with

a Tnacker-18

ofleft

Further

was ex-

Fair Excellent Excellent Excellent Excellent Excellent Excellent Excellent

25

aneurysm

intro-

Excellent Excellent

18 6 18 6 NA

smaller coils (Fig id) until

6-F

Outcome*

45 26 26

PCA

of systemic

catheter

a 6-F guide

for

perselective eurysm

Procedure

General

changed

of the dominant

Thirteen procedures were performed with local anesthesia. Sedative and/on analgesic drugs were also administered if deemed

the diagnostic

ment

Glasgow

was

a transfemoral

hemortoand

1 month

was

90

sheath. Computer-assisted measureof the aneurysm was performed to the appropriate size of GDC. Subse-

France)

giograms (Fig 3a), and/or CT angiograms were obtained in all patients who did not have a subarachnoid hemorrhage. The study protocol included angiographic follow-up at 6 months and 1,2 (Fig 30, and 4 years after treatment. The clinical

90

digital

Paris,

3b,

100 100

intraarterial

quently,

of basilar tip aneurysm was with findings from four-vessel

(Figs resonance

90

neurologically

the

In all patients,

100 100 100

for the purpose

through

ducer ment select

a narrow neck (4-mm or smaller); in twelve patients,

nine

90

of the cerebral vessels were obtained by using a 6-F catheter (Simmons II or Headhunter; Cordis, Miami, Fla) in-

large patients,

The aneurysm

100 100 100

60 20 70 16

of right

None None None None Occlusion None Occlusion None None None Occlusion None None None None Occlusion None

patients, condition

intravenously anticoagulation.

patients,

mm

and

in eight medical

None None Occlusion None

90

100 100 100

diameter

=

100 90

185 172 100

Angiographic Follow-up (rno)

Complicationst

who were either in or uncooperative. Heparin (Heparin Immuno; Immuno, Vienna, Austria) (5,000 IU) was administered

Hess

the

II in four

ifi in five patients,

two patients,

used poor

endoof the

to classify

Occlusion (%)

0 0 0

Small

arachnoid vascular

GDCs

Length

(cm)

aneurysm had a diameter of less than 12 mm; large aneurysm t PCA = posterior cerebral artery. t NA = not available. A modified Glasgow scale was used to report outcome: excellent paresis, aphasia, or other deficit; poor = comatose. *

with Coil

Aneurysm Size*

two

The percentage of occlusion initially achieved was determined on angiograms, with

iOO% indicative

of complete

occlu-

sion of the aneurysm. Complete occlusion was defined as occlusion of the aneurysmal sac and neck; 90% occlusion was defined as an occlusion of the aneurysmal sac,

with

a small,

residual

open

part

of the

neck.

catheters. The negotiation of the aneurysm was accomplished with a platinum-tipped 0.016-inch

steerable

guide

wire

(Taper;

was used in all cases. Care was taken not to touch the wall of the dome of the aneurysm with the tip of either the guide wire or the microcatheter. A various number (range, 1-14; mean, 3) of GDCs (Target Therapeutics) of various sizes (2-10 mm in diameter, 8-40 cm in

length) were implanted by using a pneviousby described technique (19,22-24). The synthesis have

where.

and

been

physical

described

GDC

properties (28)

implantation

in detail

of GDCs else-

was started

RESULTS

Tar-

get Therapeutics). Roadmapping was helpful during this part of the procedure and

Superselective catheter placement in the aneurysm with the GDC microcatheter and GDC embolization were technically

possible

The

findings,

therapeutic

results,

(if any)

are summarized

plications the Table. An eurysm

initial was

clinical

in all 21 (100%)

patients.

examination and

com-

in

100% occlusion of the anachieved in 14 (67%) pa-

tients. Nine of these patients aneurysm with a small neck,

had an whereas

October

1997

, :

d.

e.

Figure eral

1.

Vertebral

projections

angiograms

show

a). (c) Frontal

a barge

smaller-diameter

projection coils.

cluded

point,

at this

in the (e) frontal

five patients wide neck. (33%)

basilar

the

tip

central

(f) lateral

aneurysm

part

all of whom

show

with seven had

a

an

aneurysm with a wide neck; 90% occlusion of the aneurysm was achieved at initial treatment. In three of these patients, 6-month follow-up angiograms showed that the remnant of the aneurysmab

neck

had

increased

in size

owing to compaction of the coils. The aneurysm itself remained the same; that is, coil compaction resulted in a recurrence without a change in morphobogy of the original aneurysm. Repeated treatment was necessary in cases

of recurrence.

The

aneurysm

in

two of these patients was large; the third patient had a small aneurysm. In the other four patients with a small aneurysm that was 90% occluded after initial treatment, the residual filling was unchanged at follow-up and was considered to be too small for repeated embolization. There was no Volume

205

Number

#{149}

1

(straight

aneurysm

in the use of GDCs arrow)

with

(straight

to occlude

an outpouching

arrow)

complete

occlusion

change

a large of the

in the

is still

occlusion

bobization with an

and initial

with

GDCs

(mean,

34 months),

unchanged.

In the

patients

written. angiomonths who

(mean,

In clinical ruptured patients ography

repeated

aneurysm. were followed at 6-48 months

Fourteen up with (mean,

toms

of repeated

tient

who

in

was

were

no clinical

had

of these angi25

who died had no

treated

2 symp-

In the pa-

recently,

findings

signs

there

of repeated

of hemorrhage

In the

up. The in seven patients.

11 patients

grade

II-IV

clinical patients Three

months

of pulmonary after

showed follow-

outcome was excellent and good in four patients with an initial

I had an excelat the 6-month

follow-up. Of the two grade V hemorrhage, outcome at follow-up,

died

a Hunt

subarachnoid

Hunt and Hess grade bent clinical outcome a

at fobwith

the aneurysm at the 6-month

improvement

un-

with

ocobtained

bleeding.

was

and Hess hemorrhage,

bleeding

in all 16 patients

angiograms

The patient after treatment

low-up.

30 months).

terms,

prevented

(b) lat-

arrow

(arrow).

none In

derwent repeated treatment, occlusion of the aneurysm remained stable at angiographic follow-up at 18-47 months

and

(curved

bleeding. The patients with signs of a mass effect (ii - 2) and those without symptoms (n = 3) were followed up at 6-45 months (mean, 24 months);

underfollow-up

the occlusion

(a) Frontal

aneurysm

vertebral

months). months

the second patient, 100% occlusion, was

at the time this article was 12 patients, who underwent graphic follow-up at 24-48

of the

(e, 0 Postembolization

at 6-month

treated too recently to have gone 6-month angiographic

tip aneurysm.

dome

first coil, which acts as a frame for the subsequent The outpouching (curved arrow) is completely

perfused.

of the aneurysm

basilar

right

follow-up angiography in 12 (86%) of the 14 patients with a completely occluded aneurysm after initial treatment. One of the two remaining patients died 2 months after the em-

was

#{149}1’

f.

of steps

(arrow) after delivery of the large-diameter shows incomplete occlusion of the aneurysm.

of the

projections

had an aneurysm In the remaining

patients,

the sequence

shows the aneurysm (d) Frontal projection

but

and

show

#{149}!

the

patients one had

with

a

a good and the other complications 2

embolization.

Radiology

Of

the

193

#{149}

a.

b.

c.

Figure 2. Ruptured basilar tip aneurysm. (a) Axial CT scan shows subarachnoid hem-

orrhage

and the aneurysm

(arrow).

(b, c)

Ver-

tebral angiograms obtained in the (b) frontal and (c) lateral projections show a small basilar tip aneurysm (straight arrow) with a welldefined neck (curved arrows). (d, e) Postembolization vertebral angiograms obtained in the (d) frontal and (e) lateral projections show complete occlusion of the aneurysm with GDCs

(arrow).

two patients with sixth nerve palsy, one had an improved outcome, and the other, who had a large aneurysm accompanied by headache and yentigo, had a worsened outcome with neurologic deficit. Outcome in the three

asymptomatic

patients,

a

in whom

the aneurysm was detected incidentally, remained unchanged. There were postoperative and therapy-related complications in five patients, namely, occlusion of one of the PCAs after treatment. In one patient, the PCA was reopened by means of intraarterial fibrinolytic therapy; however, a permanent neurologic deficit resulted. In another patient, a transient neurobogic deficit resulted, but the 6-month clinical outcome was good. In a third patient, there was flow reduction in one PCA because the GDCs caused partial compromise of the origin of the PCA. The patient was clinically asymptomatic, and normal perfusion of the formerly compromised PCA was evident at the 6-month follow-up. The other patients were clinically asymptomatic; the PCA had normal perfusion by way of the anterior circulation through the posterior communicating artery. The overall morbidity and mortality rate was 5% (one patient) and 5% (one patient), respectively. Thene was 0% mortality at 30 days after performance of the procedure. 194

Radiology

#{149}

d.

e.

after detachment, which can result in occlusion of parent vessels (13,15). Therefore, only patients with an inoperable basilar tip aneurysm or who were

DISCUSSION Vertebrobasilar aneurysms for 5%-i5% of all intracranial rysms

account aneu-

(5). Basilar

tip aneurysms are the type (51%) of aneurysm in the posterior circulation (29,30). Aneurysms of the posterior circulation, particularly basilar tip aneurysms, are

most

common

difficult

to treat

high morbidity 7,31). Hence,

niques

have

alternative

have

surgically

and several

gained therapy

tachable

of intracranial

ever,

such

balloons

the irregular

acceptance

shape

aneurysms.

rupture.

possible

et al in large de-

for treatHow-

do not adapt to of the aneurysm,

thereby causing stress on the wall during balloon inflation

ing in a relatively

as an

Higashida

embolization

in (1tech-

who

reported results who underwent

balloon

ment

result

in patients

this aneurysm.

(10-13,15) have series of patients

and

mortality rates endovascular

high

aneurysm and result-

risk of aneurysm

Another shortcoming displacement of the

is the balloon

otherwise

unable

to undergo

surgery

were selected for endovascular balloon embolization. With the development of steerable microcatheter guide-wire systems, superselective catheter placement in an aneurysm and delivery of microcoils have become possible. The nontraumatic placement of the tip of the microcatheter in the aneurysm and the implantation of microcoils should eliminate

the complications

with

the use of detachable

such

as rupture

that

of the aneurysm.

Casasco et al (17) reported nies of 71 cases of aneurysm platinum-fiber

occur

balloons,

microcoibs.

a large setreated with An

incom-

plete occlusion was reported in 11 (15%) of the 71 cases. Two of these patients died because of a repeated hemorrhage. In six patients, there were ischemic cornplications;

in four

patients,

there

was

October

1997

4

a.

b

C.

! 1

-.-.--“

-d. Figure in the grams graphic

3.

Nonruptured

(b) frontal obtained projection

basilar

tip aneurysm.

the most important advantage of the GDC: The coil is detached only when the correct position is demonstrated at angiognaphy. In case of inadvertent placement, the GDC can be withdrawn and reinserted. A further advantage

and

softness

is

of the coils,

which enables the filling of outpouchings in the aneurysm and minimizes the risk of rupture. Additionally, during electrolytic detachment of the GDC, ebectrothrombosis occurs adjacent to the coil, which accelerates the occlusion.

Volume

205

(a) MR angiogram

shows

the basilar

tip aneurysm

and (c) lateral projections show a small, wide-necked basilar tip aneurysm in the (d) frontal and (e) lateral projections show complete occlusion of the obtained at 2-year follow-up shows persistent occlusion of the aneurysm

occlusion of the parent vessel. These two types of complications were the result of the fact that these microcoils are nondetachable, which seems to cause pnobbems especially in the treatment of a wide-necked aneurysm. When conventional microcoils are used, ischemic complications can result after inadvertent placement of the last coil. Conversely, the attempt to avoid inadvertent placement can result in incomplete occlusion of the aneurysm. With the development of the GDC, the disadvantages of nondetachable microcoils and detachable balloons can be minimized (32). Controlled delivery is

the flexibility

--

-.,----

Number

#{149}

1

Implantation with

the

was

largest

started

diameter

with relative

(arrow). aneurysm (arrow).

a GDC

(arrows).

neck

to achieve a basand to bridge the aneurysm neck with a mesh of coils. The remaining cavity was filled with smaller-diameter coils, which were placed in the network of the first coil;

due

this

A 98%

placement

the

prevented

parent

artery.

Problems

with

occur

the

neck

into

GDC

and/or

can

implantation

an

features a wide aneurysm

of aneuin

the normal branch arteries oniginate near the neck on are incorporated in the aneurysm can cause difficulties (to the point of impossibility) in the tight packing of the aneurysm. In these cmcumstances, there is a risk that the coils will bulge into the parent artery on cornpromise the adjacent origin of the parent artery, and only loose packing and a

which

sometimes

incomplete

occlusion

of the

be achieved. Consequently, complete occlusion is possible in a banger percentage of small-necked aneurysms than wide-necked aneuaneurysm

rysms

can

(33).

caused

A further

complication

is the

by

to arterial Guglielmi

100%

95%

reported cases

of basilar

was

of wide-necked

occlusion

in one case of a in their series of aneurysm.

achieved

in

of a wide-necked

more

necessary.

an initial in seven aneurysm.

peated canalization.

than

one

complete of 33

and

embobization

was

et al (27) cases

in

aneurysm. aneu-

occlusion

(21%)

a

in three

aneurysm

McDougall

two and

achieved

two cases of a small-necked In three cases of a wide-necked rysm,

initial

aneurysm,

was

coils

of a small-

bifurcation

occlusion

cases

of the

in

two

angioangio-

aneunysmal

flow. et al (22)

necked aneurysm and wide-necked aneurysm 23 cases

obtained

vertebral (f) Frontal

compaction

occlusion

cases

of anatomic Specifically,

because

aneurysm.

rysmal

bulging

angiograms

of a remnant

development

to the

size of the aneurysm ket-like configuration

(b, c) Vertebral

(d, e) Postembolization with GDCs (arrow).

reported

with of basilar

GDCs tip

Six patients required retreatment because of partial neIn

three

of these

patients,

the repeated treatment was successful. Bavinzski et al (26) reported 100% occbusion in seven (33%) of 13 patients. In one case, repeated treatment was performed. All of these previous studies, however, involved a selected group of patients. Unlike in the studies cited in the preceding paragraph, we performed endo-

Radiology

.

195

vascular treatment in a nonsebected population of patients with a basilar tip aneurysm; therefore a comparison of our results with those of surgical series (1-7,31)

may

be more

valid.

In our

series

of 21 patients with a basilar tip aneunysm, an initially complete occlusion was achieved in 14 (67%) patients, and 90% occlusion was achieved in seven (33%) patients. In other studies (22,26, 27,33), the highest percentage of corn-

plete

occlusions

with

a small-necked

was reported aneurysm.

in patients Because

of recurrence of partial perfusion of the aneurysmab neck after 6 months, repeated treatment was necessary in three of the patients in our series. The goal of any treatment for an intracranial aneurysm is to avoid bleeding, to prevent repeated bleeding in a ruptured aneurysm, and to improve neurobogic symptoms due to mass effect in a patient with an unruptured aneurysm. In 16 of 21 patients, a basilar tip aneurysm caused subarachnoid hemorrhage before treatment. There was no repeated hemorrhage after treatment, which suggests that an incomplete occlusion (in five patients with a ruptured aneurysm, an initial 90% occlusion was achieved) may protect the aneurysm against repeated rupture (22,23,26,34). Two patients in our series presented with symptoms due to mass effect. Clinical improvement of the symptoms was observed in one of these patients; however, GDC embolization resulted in protection against bleeding in both patients. Three other asymptomatic patients, whose aneurysms were found incidentally, were treated successfully to prevent rupture. Another disadvantage in treating patients with a wide-necked basilar tip aneurysm is the risk of compromising an adjacent origin of the PCA. The cause for occlusion of the PCA can be either mechanical compression of the origin at an attempted tight packing of the aneurysm or thrombus formation when the intraaneurysmal thrombus shifts to the origin of the parent vessel. The occbusion of one PCA was the most important complication in our series. Occlusion of a PCA occurred in five (24%) patients, and only one of these patients had worsened clinical symptoms intraoperatively; therefore, intraarterial fibninolytic therapy was started immediately. Despite successful reopening of the artery, the patient developed a permanent neurologic deficit. Guglielmi et al (22) reported one complication (permanent hemianopsia) in a patient with a wide-necked basilar bifurcation aneurysm with bilateral ocdusion of the PCAs. In their series of patients with a posterior circulation aneurysm, the

196

Radiology

#{149}

morbidity and mortality rates were both 7%. McDougall et al (27) reported one patient with a repeated hemorrhage after treatment and thrOmbOsis of the distal part of the basilar artery and of the P-i segment of the PCA, which resulted in a permanent neurologic deficit. In one patient, the coil migrated into the P-i segment of the PCA but did not compromise the parent artery. In summary, occlusion by means of endovascular

coils

is a promising

alter-

native therapy in patients with an intracranial aneurysm that should not be treated with surgical clipping because of increased risk to the patient. Surgical clipping of a basilar bifurcation aneurysm is difficult and is associated with high morbidity and mortality rates. Our midterm results indicate that occlusion with GDCs is a less invasive and safe alternative therapeutic method for the treatment of patients with such an aneurysm and that this method should be used preferentially. Moreover, this endovascular approach is not only less invasive than other procedures, but it is also associated with a shorter period of hospitalization. In addition, patients with a poor medical condition can be treated. Long-term follow-up studies, however, are needed before the present results can be confirmed. U

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aneurysms.

October

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1997