J NeuroIntervent Surg Doi

8/9/2019 J NeuroIntervent Surg Doi

1/26

J NeuroIntervent Surg doi:10.1136/jnis.2009.001883

y Hemorrhagic stroke

Combined microsurgical and endovasculartreatment of a giant left middle cerebral

artery aneurysm

1. Ali Zomorodi1,2. Ketan R Bulsara2,3. Allan H Friedman1,4. Michael J Alexander3

+AuthorAffiliations

1. 1Duke University Medical Center, Durham, North Carolina, USA2. 2Yale Department of Neurosurgery, New Haven, Connecticut, USA3. 3Maxine Dunitz Department of Neurosurgery, California, USA1. Correspondence to MichaelAlexander MD Professor and Vice-Chairman Department of

Neurosurgery Cedars-Sinai Medical Center Director, Cedars-Sinai Neurovascular Center

86311 West Third Street, Suite 800E Los Angeles, California 90048;[email protected]

yReceived 29 October 2009

y Revised 25 January 2010y Accepted 1 February 2010y Published Online First 15 June 2010

Next Section

Abstract

Giant fusiform aneurysms ofthe middle cerebral artery (MCA) bifurcation pose significant

treatment challenges. A giant fusiform aneurysm ofthe left MCA in a pediatric patient, whichpersisted despite Hunterian ligation ofthe M1 and double barrel superficial temporal artery

(STA) to M2 bypasses, is reported. The aneurysm was trapped by endovascular coiling ofthefeeding M2 trunk through the STA anastamosis. Hunterian ligation combined with extracranial

intracranial bypass is an effective technique for treating giant fusiform aneurysms ofthe MCAbifurcation for patients who fail balloon test occlusions. However, in certain cases, flow reversal

may not eliminate the aneurysm and continued aneurysm filling may occur through retrogradefilling from the bypass recipient vessels. In these cases, endovascular trapping ofthe aneurysm


2/26

may be undertaken through the bypass graft. The feasibility ofthis management scheme isdemonstrated.

Giant intracranial aneurysms are defined as being larger than 2.5 cm in any dimension. These

aneurysms often have a wide and indefinable neck; contain atheromas, calcification and mural

thrombi; and often incorporate the origin ofcritical perforators or cortical vessels. As a result,direct surgical or endovascular treatment ofthese lesions is often not possible. Ofthe reportedstrategies for indirect treatment ofgiant aneurysms, the most popular consists ofHunterian

ligation with or without extracranialintracranial bypass.13 However, aneurysm regrowth canoccurfollowing this procedure, requiring further treatment.247 We report on a giant fusiform

aneurysm ofthe left middle cerebral artery (MCA) bifurcation which was treated with a doublebypass ofthe superficial temporal arteries (STAs) to the M2 trunks, followed by ligation ofthe

M1 proximal to the aneurysm. Follow-up imaging demonstrated continued filling oftheaneurysm via retrograde filling through one ofthe M2 recipient trunks. Endovascular occlusion

ofthis vessel was undertaken through the bypass, thereby trapping the aneurysm.

Previous SectionNext Section

Case report

A pediatric patient with a past medical history significant for bacterial meningitis presented with2 days ofnon-remitting headaches and emesis. CT scan ofthe brain with and without contrast

demonstrated a giant, partially thrombosed, aneurysm ofthe left MCA. There was no evidence ofsubarachnoid hemorrhage on CT orlumbar puncture. She was transferred to ourfacility for

further management.

CT angiography was performed, demonstrating a giant fusiform aneurysm originating from the

left M1 segment (figure 1). The aneurysm measured approximately 62 mm32 mm46 mm, andincorporated the origin ofboth M2 trunks. Functional MRI demonstrated left brain dominancefor receptive and motor speech. A balloon test occlusion with single photon emission computed

tomography scanning was performed. The patient developed reversible dysphasia and right armweakness after only 90 s ofocclusion, and the single photon emission computed tomography

scan demonstrated a perfusion defect in the left frontal operculum and anterior temporallobe.


3/26

View larger version:

y In a new windowy Download as PowerPoint Slide

Figure 1

CT angiography ofthe brain demonstrating a giant left middle cerebral artery bifurcationaneurysm. The aneurysm occupies the middle cranialfossa. It incorporates the two M2 trunks.

Based on these findings a double bypass ofthe STA to MCA was performed with proximal M1

occlusion. The two M2 trunks were identified exiting the aneurysm, and the M1 could bevisualized entering the aneurysm. The two M2 trunks were isolated and the two branches ofthe

STA were anastamosed to them in an end to side fashion using a 10-0 suture. Good flow throughthe grafts was confirmed with the Doppler, and the M1 segment was then clipped with a straight

Yasargil clip, distal to the anterior temporal branch, with immediate softening ofthe aneurysm.

Immediately postoperatively, the patient had right upper and lower extremity paresis anddysphasia. A CT angiogram obtained immediately postoperatively showed patency ofboth STA

branches with backfilling ofthe aneurysm. The patient's dysphasia resolved by the time ofherdischarge on postoperative day 5, and her strength had improved to 4/5. At herfirst postoperative

visit, she had normal speech and motorfunction.


4/26

Six months after the bypass, the patient had an MRI and MR angiography which demonstratedpersistent prominent filling ofthe aneurysm. A CT angiogram was obtained (figure 2). This

study showed persistent filling ofa 3.1 cm3.8 cm area ofthe aneurysm in a retrograde fashionthrough one ofthe M2 trunks, with thrombosis ofthe remainder ofthe aneurysm. Both grafts

were patent.



Figure 2

CT angiography obtained approximately 6 months after double superficial temporal artery

(STA)M2 bypass and clip ligation ofthe M1 segment. The aneurysm continues to fill in a

retrograde fashion. It receives supply in a retrograde fashion through the frontal branch oftheSTA via the superior M2 trunk. The two bypasses are widely patent (arrows). There is no

antegrade filling ofthe M1 beyond the clip.

The patient was referred for endovascular treatment. The patient's left common femoral arterywas accessed and a 6 French introducer sheath placed (the right side could not be accessed due to

scarring). Intravenous heparin (5000 units) was administered to obtain an activated clotting time

>250 s. A 6 French Guider catheter (Boston Scientific, Natick, Massachusetts, USA) wasadvanced into the left common carotid, and a common carotid angiogram was obtained (figure3). This demonstrated occlusion ofthe M1 branch just proximal to the aneurysm, with retrograde

filling ofthe aneurysm from the frontal branch ofthe STA anastamosis to the inferior M2 trunk.At this point, using roadmap assistance, a 0.010 microcatheter (Boston Scientific) was advanced

over a microwire (Boston Scientific) into the main trunk ofthe STA. Intra-arterial nitroglycerin(100 g) was delivered into the STA, and the frontal branch ofthe STA was selected. The

microcatheter was then advanced through the anastamosis into the inferior trunk ofthe M2 just


5/26

distal to the aneurysm. Superselective injections were performed through the catheter (figure 4).This demonstrated a large lenticulostriate perforator originating from the M2 vessel just distal to

the aneurysm. The microcatheter was positioned between the outflow region ofthe aneurysm andthe lenticulostriate artery. A polymer coated and bare platinum GDC (Matrix2 and GDC-10;

Boston Scientific) were deployed at this point. The microcatheter was then withdrawn into the

frontal branch ofthe STA, and an additional 50 g ofnitroglycerin were administered throughthe microcatheter to prevent spasm ofthe graft and recipient vessel. The final images wereevaluated and the introducer sheath was removed. Hemostasis was obtained with a 6 French

Perclose device.



Figure 3

Magnified anteroposterior (A) and lateral (B) views ofthe left common carotid injection. Noteocclusion ofthe M1 segment by the clip. A jet ofcontrast enters the aneurysm through the

superior M2 trunk (large arrow). Alarge perforating vessel originates from the superior M2trunk, just distal to the aneurysm (small arrow). Both bypass grafts are patent (arrowheads). The

parietal division ofthe superficial temporal artery (STA) is anastamosed to the inferior M2 trunk,and fills most ofthe distal middle cerebral artery (MCA) distribution. The frontal division ofthe

STA is anastamosed to the superior M2 trunk. It supplies the aneurysm and the frontal opercularbranches ofthe MCA.


6/26



Figure 4

Lateral view ofmicrocatheter injection in the superior M2 trunk. The microcatheter was

advanced through the anastamosis ofthe frontal branch ofthe STA into the superior M2 trunk.Superselective injection demonstrates jet ofcontrast filling the giant aneurysm. A prominent

perforating lenticulostriate vessel is seen to originate from the proximal M2 trunk after itemerges from the aneurysm. The microcatheter was advanced distal to this vessel in order to

preserve it prior to coiling ofthe M2 trunk.

A post-procedure angiogram was obtained demonstrating endovascular occlusion ofthe left

inferior M2 trunk just distal to the aneurysm (figure 5). There was minimalflow into theaneurysm, which was expected to thrombose after reversal ofheparin. The lenticulostriate vessel

originating from the M2 trunk remained patent. After the procedure, the patient remained at herneurologic baseline, and was discharged home on post-procedure day 1. A 6 month follow-up

cerebral angiogram was planned.


7/26



Figure 5

Late phase magnified anteroposterior (A) and lateral (B) views ofthe left common carotid

injection. There is minimal slow filling ofthe aneurysm (asterisk). There is slowed anterogradeflow through the frontal branch ofthe superficial temporal artery. There is delayed anterograde

opacification ofthe lenticulostriate vessel (arrow) identified in figures 3 and 4.


Discussion

Giant aneurysms account for only 5% ofall intracranial aneurysms but comprise a growing

proportion ofaneurysms treated at major referral centers.810 In general, these aneurysms carrya significant risk ofmajor morbidity, with estimated mortality rates as high as 80% at 5 years if

untreated.810 Treatment ofthese lesions is best undertaken by a multidisciplinary teamconsisting ofexperienced cerebrovascular surgeons, neurointerventional radiologists,

neuroanesthsiologists and critical care specialists.

Giant fusiform aneurysms ofthe MCA in particular pose a significant treatment challenge. Direct

surgical clipping is often not possible for these lesions as they incorporate cortical andperforating branches, and often harbor intraluminal thrombus and calcified atheromas which

make clip closure difficult.11Aneurysmectomy is an attractive option as it allows definitivetreatment ofthe lesion with exacting reconstruction ofthe vessel.12 However, in practice, this

approach requires prolonged occlusion ofthe vessel with a high risk ofresultant ischemiccomplications. While these risks can be decreased through the use ofhypothermic circulatory

arrest, this technique carries its own risks which can be significant.11Aneurysm trapping is notfeasible for MCA aneurysms, as this would risk occlusion ofthe important lenticulostriate

vessels originating from this segment. For patients who fail physiologic tests ofvessel occlusion,


8/26

Hunterian ligation with distal bypass is a well established technique for the treatment oftheselesions.1261314 The hemodynamic changes induced by the bypass procedure alone may cause

thrombosis or stabilization ofthe aneurysm while retrograde flow can supply the perforators.31516 Unfortunately, continued growth or even rupture ofaneurysms following Hunterian ligation

and distal bypass has been reported to occur. 247

Despite the tremendous advances in endovascular techniques, direct endovascular treatment ofgiant aneurysms is not always feasible as these aneurysms often do not have a definable neck,

and often harborlarge mural thrombi. Balloon assisted or stent assisted coiling is possible.However, coil compaction and recanalization ofthe aneurysm is a common phenomenon,

occurring in up to 90% ofcases in some series.17 Endovascular occlusion ofthe parent vessel, orendovascular trapping, are both attractive options that have been used on select patients who pass

balloon test occlusions (reviewed by Gonzalez and colleagues18). Endovascular parent vesselocclusion or trapping has also been used with great success in combination with surgical

bypass.21921 However, to our knowledge, there are no reports ofendovascular treatmentundertaken through a bypass graft.

In this case, a giant MCA aneurysm was treated with Hunterian ligation and double STAM2

bypass. Even though a low flow bypass was used, retrograde filling ofthe aneurysm through oneofthe recipient M2 branches resulted in continued aneurysm growth. The responsible M2 branch

was catheterized through the STA graft, and embolized with GDC coils. Special care was takento ensure adequate heparinization prior to catheterizing the bypass graft, and prophylactic

nitroglycerin was administered to prevent vasospasm from catheter manipulation. Additionally,in this case, microcatheter injections demonstrated a large lenticulostriate vessel originating from

the M2 branch just distal to the aneurysm, and this branch was carefully preserved during thisprocedure. This case demonstrates that it is possible to advance a microcatheter through the site

ofan STAMCA anastamosis. Furthermore, it demonstrates that endovascular trappingfollowing extracranialintracranial bypass is possible, and important perforators can be identified

and preserved with this technique.


Acknowledgments

The authors thank Michelle Vallati for her editorial assistance.


Footnotes

y Competing interests None.y Patient consent Obtained.y Provenance and peer review Not commissioned; externally peer reviewed.

Previous Section


9/26

References

1. 1. Drake CG

. Giant intracranial aneurysms: experience with surgical treatment in 174 patients. ClinNeurosurg 1979;26:1295.

[Medline]

2. 1. Drake CG,2. Peerless SJ,3. Ferguson GG

. Hunterian proximal arterial occlusion for giant aneurysms of the carotid circulation. J

Neurosurg 1994;81:65665.

[Medline][Web ofScience]

3. 1. Gerber S,2. Dormont D,3. Sahel M,4. et al

. Complete spontaneous thrombosis of a giant intracranial aneurysm. Neuroradiology1994;36:31617.

[Medline]

4. 1. Barnett DW,2. Barrow DL,3. Joseph GJ

. Combined extracranialintracranial bypass and intraoperative balloon occlusion forthe treatment of intracavernous and proximal carotid artery aneurysms. Neurosurgery1994;35:927.

[Medline]

5. 1. Chang SD,


10/26

2. Marks MP,3. Steinberg GK

. Recanalization and rupture of a giant vertebral artery aneurysm after hunterian

ligation: case report. Neurosurgery 1999;44:111720.

[Medline]

6. 1. Drake CG,2. Peerless SJ

. Giant fusiform intracranial aneurysms: review of 120 patients treated surgically from

1965 to 1992. J Neurosurg 1997;87:14162.

[CrossRef][Medline]

7. 1. Lee KC,2. Joo JY,3. Lee KS,4. et al

. Recanalization of completely thrombosed giant aneurysm: case report. Surg Neurol1999;51:948.

[Medline]

8. 1. Barrow DL,2. Alleyne C

. Natural history of giant intracranial aneurysms and indications for intervention. ClinNeurosurg 1995;42:21444.

[Medline]

9. 1.

Murayama Y,2. Nien YL,

3. DuckwilerG,4. et al

. Guglielmi detachable coil embolization of cerebral aneurysms: 11 years' experience. JNeurosurg 2003;98:95966.


11/26


10.1. Youmans JR2. Peerless SJ,3.

Wallace MD,4. Drake CG

. Giant intracranial aneurysms. In: Youmans JR, ed. Neurological surgery. Philadelphia:WB Saunders, 1990;174263.

11.1. Wilkins RH,2. Rengachary SS3. Batjer HH,4. Kopitnik TA,5.

Purdy PD,6. et al

. Giant intracranial aneurysms. In: Wilkins RH, Rengachary SS, eds. Neurosurgery. New

York: McGraw-Hill, 1996;236176.

12.1. Ceylan S,2. Karakus A,3. Duru S,4. et al

. Reconstruction of the middle cerebral artery after excision of a giant fusiform

aneurysm. Neurosurg Rev 1998;21:18993.

[Medline]

13.1. Lawton MT,2. Spetzler RF

. Surgical strategies for giant intracranial aneurysms. Acta Neurochir Suppl

1999;72:14156.

[Medline]

14.1. Spetzler RF,2. Roski RA,3. Schuster H,


12/26

4. et al. The role of ECIC in the treatment of giant intracranial aneurysms. Neurol Res1980;2:34559.

[Medline]

15.1. Cantore G,2. Santoro A,3. Da Pian R

. Spontaneous occlusion of supraclinoid aneurysms after the creation of extra-

intracranial bypasses using long grafts: report of two cases. Neurosurgery 1999;44:21619.

[Medline]

16.1. Day AL,2. Gaposchkin CG,3. Yu CJ,4. et al

. Spontaneous fusiform middle cerebral artery aneurysms: characteristics and aproposed mechanism of formation. J Neurosurg 2003;99:22840.

[Medline]

17.1. Hayakawa M,2. Murayama Y,3. DuckwilerGR,4. et al

. Natural history of the neck remnant of a cerebral aneurysm treated with the Guglielmi

detachable coil system. J Neurosurg 2000;93:5618.


18.1. Gonzalez NR,2. GuckwilerG,3. Jahan R,4. et al


13/26

. Challenges in the endovascular treatment of giant intracranial aneurysms.Neurosurgery 2006;59:11314.

19.1. Ewald CH,2.

Kuhne D,3. Hassler WE

. Bypass-surgery and coil-embolisation in the treatment of cerebral giant aneurysms.Acta Neurochir (Wien) 2000;142:7317.

[Medline]

20.1. Hacein-Bey L,2. Connolly ES Jr,3.

Mayer SA,4. et al

. Complex intracranial aneurysms: combined operative and endovascular approaches.Neurosurgery 1998;43:130412.

[Medline]

21.1. Hoh BL,2. Putman CM,3.

Budzik RF,4. et al

. Combined surgical and endovascular techniques of flow alteration to treat fusiform andcomplex wide-necked intracranial aneurysms that are unsuitable for clipping or coil

embolization. J Neurosurg 2001;95:2435.

[Medline]

_________________________________________________________________________

J NeuroIntervent Surg doi:10.1136/jnis.2009.001883

y Hemorrhagic stroke


14/26

Combined microsurgical and endovascular

treatment of a giant left middle cerebral

artery aneurysm1. Ali Zomorodi1,2. Ketan R Bulsara2,3. Allan H Friedman1,4. Michael J Alexander3

+AuthorAffiliations

1. 1Duke University Medical Center, Durham, North Carolina, USA2. 2Yale Department of Neurosurgery, New Haven, Connecticut, USA3.

3Maxine Dunitz Department of Neurosurgery, California, USA

1. Correspondence to MichaelAlexander MD Professor and Vice-Chairman Department ofNeurosurgery Cedars-Sinai Medical Center Director, Cedars-Sinai Neurovascular Center86311 West Third Street, Suite 800E Los Angeles, California 90048;

[email protected]

y Received 29 October 2009y Revised 25 January 2010y Accepted 1 February 2010y Published Online First 15 June 2010

Next Section

Abstract

Giant fusiform aneurysms ofthe middle cerebral artery (MCA) bifurcation pose significanttreatment challenges. A giant fusiform aneurysm ofthe left MCA in a pediatric patient, which

persisted despite Hunterian ligation ofthe M1 and double barrel superficial temporal artery(STA) to M2 bypasses, is reported. The aneurysm was trapped by endovascular coiling ofthe

feeding M2 trunk through the STA anastamosis. Hunterian ligation combined with extracranial

intracranial bypass is an effective technique for treating giant fusiform aneurysms ofthe MCAbifurcation for patients who fail balloon test occlusions. However, in certain cases, flow reversalmay not eliminate the aneurysm and continued aneurysm filling may occur through retrograde

filling from the bypass recipient vessels. In these cases, endovascular trapping ofthe aneurysmmay be undertaken through the bypass graft. The feasibility ofthis management scheme is

demonstrated.


15/26

Giant intracranial aneurysms are defined as being larger than 2.5 cm in any dimension. Theseaneurysms often have a wide and indefinable neck; contain atheromas, calcification and mural

thrombi; and often incorporate the origin ofcritical perforators or cortical vessels. As a result,direct surgical or endovascular treatment ofthese lesions is often not possible. Ofthe reported

strategies for indirect treatment ofgiant aneurysms, the most popular consists ofHunterian

ligation with or without extracranialintracranial bypass.13 However, aneurysm regrowth canoccurfollowing this procedure, requiring further treatment.247 We report on a giant fusiformaneurysm ofthe left middle cerebral artery (MCA) bifurcation which was treated with a double

bypass ofthe superficial temporal arteries (STAs) to the M2 trunks, followed by ligation oftheM1 proximal to the aneurysm. Follow-up imaging demonstrated continued filling ofthe

aneurysm via retrograde filling through one ofthe M2 recipient trunks. Endovascular occlusionofthis vessel was undertaken through the bypass, thereby trapping the aneurysm.


Case report

A pediatric patient with a past medical history significant for bacterial meningitis presented with2 days ofnon-remitting headaches and emesis. CT scan ofthe brain with and without contrast

demonstrated a giant, partially thrombosed, aneurysm ofthe left MCA. There was no evidence ofsubarachnoid hemorrhage on CT orlumbar puncture. She was transferred to ourfacility for

further management.

CT angiography was performed, demonstrating a giant fusiform aneurysm originating from the

left M1 segment (figure 1). The aneurysm measured approximately 62 mm32 mm46 mm, andincorporated the origin ofboth M2 trunks. Functional MRI demonstrated left brain dominance

for receptive and motor speech. A balloon test occlusion with single photon emission computed

tomography scanning was performed. The patient developed reversible dysphasia and right armweakness after only 90 s ofocclusion, and the single photon emission computed tomographyscan demonstrated a perfusion defect in the left frontal operculum and anterior temporallobe.


16/26



Figure 1

CT angiography ofthe brain demonstrating a giant left middle cerebral artery bifurcationaneurysm. The aneurysm occupies the middle cranialfossa. It incorporates the two M2 trunks.

Based on these findings a double bypass ofthe STA to MCA was performed with proximal M1

occlusion. The two M2 trunks were identified exiting the aneurysm, and the M1 could bevisualized entering the aneurysm. The two M2 trunks were isolated and the two branches ofthe

STA were anastamosed to them in an end to side fashion using a 10-0 suture. Good flow throughthe grafts was confirmed with the Doppler, and the M1 segment was then clipped with a straight

Yasargil clip, distal to the anterior temporal branch, with immediate softening ofthe aneurysm.

Immediately postoperatively, the patient had right upper and lower extremity paresis anddysphasia. A CT angiogram obtained immediately postoperatively showed patency ofboth STA

branches with backfilling ofthe aneurysm. The patient's dysphasia resolved by the time ofherdischarge on postoperative day 5, and her strength had improved to 4/5. At herfirst postoperative

visit, she had normal speech and motorfunction.


17/26

Six months after the bypass, the patient had an MRI and MR angiography which demonstratedpersistent prominent filling ofthe aneurysm. A CT angiogram was obtained (figure 2). This

study showed persistent filling ofa 3.1 cm3.8 cm area ofthe aneurysm in a retrograde fashionthrough one ofthe M2 trunks, with thrombosis ofthe remainder ofthe aneurysm. Both grafts

were patent.



Figure 2

CT angiography obtained approximately 6 months after double superficial temporal artery

(STA)M2 bypass and clip ligation ofthe M1 segment. The aneurysm continues to fill in a

retrograde fashion. It receives supply in a retrograde fashion through the frontal branch oftheSTA via the superior M2 trunk. The two bypasses are widely patent (arrows). There is no

antegrade filling ofthe M1 beyond the clip.

The patient was referred for endovascular treatment. The patient's left common femoral arterywas accessed and a 6 French introducer sheath placed (the right side could not be accessed due to

scarring). Intravenous heparin (5000 units) was administered to obtain an activated clotting time

>250 s. A 6 French Guider catheter (Boston Scientific, Natick, Massachusetts, USA) wasadvanced into the left common carotid, and a common carotid angiogram was obtained (figure3). This demonstrated occlusion ofthe M1 branch just proximal to the aneurysm, with retrograde

filling ofthe aneurysm from the frontal branch ofthe STA anastamosis to the inferior M2 trunk.At this point, using roadmap assistance, a 0.010 microcatheter (Boston Scientific) was advanced

over a microwire (Boston Scientific) into the main trunk ofthe STA. Intra-arterial nitroglycerin(100 g) was delivered into the STA, and the frontal branch ofthe STA was selected. The

microcatheter was then advanced through the anastamosis into the inferior trunk ofthe M2 just


18/26

distal to the aneurysm. Superselective injections were performed through the catheter (figure 4).This demonstrated a large lenticulostriate perforator originating from the M2 vessel just distal to

the aneurysm. The microcatheter was positioned between the outflow region ofthe aneurysm andthe lenticulostriate artery. A polymer coated and bare platinum GDC (Matrix2 and GDC-10;

Boston Scientific) were deployed at this point. The microcatheter was then withdrawn into the

frontal branch ofthe STA, and an additional 50 g ofnitroglycerin were administered throughthe microcatheter to prevent spasm ofthe graft and recipient vessel. The final images wereevaluated and the introducer sheath was removed. Hemostasis was obtained with a 6 French

Perclose device.



Figure 3

Magnified anteroposterior (A) and lateral (B) views ofthe left common carotid injection. Noteocclusion ofthe M1 segment by the clip. A jet ofcontrast enters the aneurysm through the

superior M2 trunk (large arrow). Alarge perforating vessel originates from the superior M2trunk, just distal to the aneurysm (small arrow). Both bypass grafts are patent (arrowheads). The

parietal division ofthe superficial temporal artery (STA) is anastamosed to the inferior M2 trunk,and fills most ofthe distal middle cerebral artery (MCA) distribution. The frontal division ofthe

STA is anastamosed to the superior M2 trunk. It supplies the aneurysm and the frontal opercularbranches ofthe MCA.


19/26



Figure 4

Lateral view ofmicrocatheter injection in the superior M2 trunk. The microcatheter was

advanced through the anastamosis ofthe frontal branch ofthe STA into the superior M2 trunk.Superselective injection demonstrates jet ofcontrast filling the giant aneurysm. A prominent

perforating lenticulostriate vessel is seen to originate from the proximal M2 trunk after itemerges from the aneurysm. The microcatheter was advanced distal to this vessel in order to

preserve it prior to coiling ofthe M2 trunk.

A post-procedure angiogram was obtained demonstrating endovascular occlusion ofthe left

inferior M2 trunk just distal to the aneurysm (figure 5). There was minimalflow into theaneurysm, which was expected to thrombose after reversal ofheparin. The lenticulostriate vessel

originating from the M2 trunk remained patent. After the procedure, the patient remained at herneurologic baseline, and was discharged home on post-procedure day 1. A 6 month follow-up

cerebral angiogram was planned.


20/26



Figure 5

Late phase magnified anteroposterior (A) and lateral (B) views ofthe left common carotid

injection. There is minimal slow filling ofthe aneurysm (asterisk). There is slowed anterogradeflow through the frontal branch ofthe superficial temporal artery. There is delayed anterograde

opacification ofthe lenticulostriate vessel (arrow) identified in figures 3 and 4.


Discussion

Giant aneurysms account for only 5% ofall intracranial aneurysms but comprise a growing

proportion ofaneurysms treated at major referral centers.810 In general, these aneurysms carrya significant risk ofmajor morbidity, with estimated mortality rates as high as 80% at 5 years if

untreated.810 Treatment ofthese lesions is best undertaken by a multidisciplinary teamconsisting ofexperienced cerebrovascular surgeons, neurointerventional radiologists,

neuroanesthsiologists and critical care specialists.

Giant fusiform aneurysms ofthe MCA in particular pose a significant treatment challenge. Direct

surgical clipping is often not possible for these lesions as they incorporate cortical andperforating branches, and often harbor intraluminal thrombus and calcified atheromas which

make clip closure difficult.11Aneurysmectomy is an attractive option as it allows definitivetreatment ofthe lesion with exacting reconstruction ofthe vessel.12 However, in practice, this

approach requires prolonged occlusion ofthe vessel with a high risk ofresultant ischemiccomplications. While these risks can be decreased through the use ofhypothermic circulatory

arrest, this technique carries its own risks which can be significant.11Aneurysm trapping is notfeasible for MCA aneurysms, as this would risk occlusion ofthe important lenticulostriate

vessels originating from this segment. For patients who fail physiologic tests ofvessel occlusion,


21/26

Hunterian ligation with distal bypass is a well established technique for the treatment oftheselesions.1261314 The hemodynamic changes induced by the bypass procedure alone may cause

thrombosis or stabilization ofthe aneurysm while retrograde flow can supply the perforators.31516 Unfortunately, continued growth or even rupture ofaneurysms following Hunterian ligation

and distal bypass has been reported to occur. 247

Despite the tremendous advances in endovascular techniques, direct endovascular treatment ofgiant aneurysms is not always feasible as these aneurysms often do not have a definable neck,

and often harborlarge mural thrombi. Balloon assisted or stent assisted coiling is possible.However, coil compaction and recanalization ofthe aneurysm is a common phenomenon,

occurring in up to 90% ofcases in some series.17 Endovascular occlusion ofthe parent vessel, orendovascular trapping, are both attractive options that have been used on select patients who pass

balloon test occlusions (reviewed by Gonzalez and colleagues18). Endovascular parent vesselocclusion or trapping has also been used with great success in combination with surgical

bypass.21921 However, to our knowledge, there are no reports ofendovascular treatmentundertaken through a bypass graft.

In this case, a giant MCA aneurysm was treated with Hunterian ligation and double STAM2

bypass. Even though a low flow bypass was used, retrograde filling ofthe aneurysm through oneofthe recipient M2 branches resulted in continued aneurysm growth. The responsible M2 branch

was catheterized through the STA graft, and embolized with GDC coils. Special care was takento ensure adequate heparinization prior to catheterizing the bypass graft, and prophylactic

nitroglycerin was administered to prevent vasospasm from catheter manipulation. Additionally,in this case, microcatheter injections demonstrated a large lenticulostriate vessel originating from

the M2 branch just distal to the aneurysm, and this branch was carefully preserved during thisprocedure. This case demonstrates that it is possible to advance a microcatheter through the site

ofan STAMCA anastamosis. Furthermore, it demonstrates that endovascular trappingfollowing extracranialintracranial bypass is possible, and important perforators can be identified

and preserved with this technique.


Acknowledgments

The authors thank Michelle Vallati for her editorial assistance.


Footnotes

y Competing interests None.y Patient consent Obtained.y Provenance and peer review Not commissioned; externally peer reviewed.

Previous Section


22/26

References

1. 1. Drake CG

. Giant intracranial aneurysms: experience with surgical treatment in 174 patients. ClinNeurosurg 1979;26:1295.

[Medline]

2. 1. Drake CG,2. Peerless SJ,3. Ferguson GG

. Hunterian proximal arterial occlusion for giant aneurysms of the carotid circulation. J

Neurosurg 1994;81:65665.


3. 1. Gerber S,2. Dormont D,3. Sahel M,4. et al

. Complete spontaneous thrombosis of a giant intracranial aneurysm. Neuroradiology1994;36:31617.

[Medline]

4. 1. Barnett DW,2. Barrow DL,3. Joseph GJ

. Combined extracranialintracranial bypass and intraoperative balloon occlusion forthe treatment of intracavernous and proximal carotid artery aneurysms. Neurosurgery1994;35:927.

[Medline]

5. 1. Chang SD,


23/26

2. Marks MP,3. Steinberg GK

. Recanalization and rupture of a giant vertebral artery aneurysm after hunterian

ligation: case report. Neurosurgery 1999;44:111720.

[Medline]

6. 1. Drake CG,2. Peerless SJ

. Giant fusiform intracranial aneurysms: review of 120 patients treated surgically from

1965 to 1992. J Neurosurg 1997;87:14162.

[CrossRef][Medline]

7. 1. Lee KC,2. Joo JY,3. Lee KS,4. et al

. Recanalization of completely thrombosed giant aneurysm: case report. Surg Neurol1999;51:948.

[Medline]

8. 1. Barrow DL,2. Alleyne C

. Natural history of giant intracranial aneurysms and indications for intervention. ClinNeurosurg 1995;42:21444.

[Medline]

9. 1.

Murayama Y,2. Nien YL,

3. DuckwilerG,4. et al

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