Case Report

Therapeutic Clip Occlusion of the Anterior Choroidal
Artery Involved with Partially Thrombosed Fusiform
Aneurysm: A Case Report
Sherif Rashad, MD,* Hidenori Endo, MD,† Ahmed Elsayed Sultan, MD,*‡x
Hiroaki Shimizu, MD,jj Miki Fujimura, MD,* Kenichi Sato, MD,‡
Yasushi Matsumoto, MD,‡ and Teiji Tominaga, MD*

Background: We describe a rare case with partially thrombosed fusiform anterior
choroidal artery (AchA) aneurysm successfully treated with therapeutic occlusion
of the AchA. Clinical presentation: A 58-year-old man presented with transient
mild hemiparesis of the right side. Magnetic resonance imaging (MRI) showed an
ischemic lesion in the posterior limb of the left internal capsule. Digital subtraction
angiography (DSA) revealed a left internal carotid artery saccular aneurysm
(14.5-mm diameter) arising from the supraclinoid segment. The left AchA was not
detected in the initial DSA, and MRI showed the aneurysm to be partially thrombosed. The second DSA performed 2 weeks after the onset showed recanalization
of the thrombosed portion of the aneurysm with the left AchA apparently arising
from its tip. The aneurysm was diagnosed as a partially thrombosed fusiform
AchA aneurysm. Results: Open surgery was performed and a titanium clip was
applied to the base of the fusiform aneurysm under motor evoked potential monitoring, which remained unchanged after clipping. Occlusion of the aneurysm was
confirmed by Doppler ultrasound and intraoperative fluorescence angiography.
Furthermore, Doppler ultrasound and fluorescence angiography showed that the
blood flow supplying the pyramidal tract was reconstituted by the retrograde collateral flow from the choroidal segment. The aneurysm was completely obliterated in
postoperative DSA, which demonstrated retrograde filling of the AchA through the
posterior circulation. The patient manifested transient weakness of the right side
postoperatively, which was completely recovered after short-term rehabilitation.
Conclusions: This case illustrates the unique clinical course of a rare partially thrombosed fusiform AchA aneurysm, successfully treated with therapeutic clip occlusion
of the AchA under the multimodal monitoring. Key Words: Fusiform aneurysm—
thrombosed aneurysm—anterior choroidal artery—ischemic stroke—proximal
occlusion.
Ó 2015 by National Stroke Association

From the *Department of Neurosurgery, Tohoku University
Graduate School of Medicine, Sendai, Japan; †Department of Neurosurgery, Kohnan Hospital, Sendai, Japan; ‡Department of Neuroendovascular Therapy, Kohnan Hospital, Sendai, Japan; xDepartment
of Neurosurgery, Faculty of Medicine, Alexandria University, Alexandria, Egypt; and jjDepartment of Neurosurgery, Akita University
Graduate School of Medicine, Akita, Japan.

Received January 29, 2015; revision received April 11, 2015;
accepted April 17, 2015.
Address correspondence to Hidenori Endo, MD, Department
of Neurosurgery, Kohnan Hospital, 4-20-1 Nagamachi-minami,
Taihaku-ku, Sendai 982-8523, Japan. E-mail: hideendo@gmail.com.
1052-3057/$ - see front matter
Ó 2015 by National Stroke Association
http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.04.024

Journal of Stroke and Cerebrovascular Diseases, Vol. 24, No. 8 (August), 2015: pp e227-e230

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Anterior choroidal artery (AchA) aneurysms represent
approximately 2% of cerebral aneurysms.1 The most common cerebral aneurysms are the saccular type, which
arise from the bifurcation of the AchA from the internal
carotid artery (ICA). Aneurysms arising from the distal
segments of the AchA are rarely reported.2 Fusiform
AchA aneurysms are also rare; in fact, Lehecka et al3
recently reported that fusiform AchA aneurysms comprised only 2% of the AchA aneurysm in the Kuopio
series. Safety and efficacy of surgical treatment for these
fusiform AchA aneurysms are unclear. Here, we report
a case of a partially thrombosed fusiform AchA aneurysm
with ischemic onset successfully treated with proximal
clip occlusion under multimodal monitoring. We discuss
the anatomic collateral circulation for AchA territory and
the importance of intraoperative monitoring during therapeutic occlusion of AchA.

Case Report
A 58-year-old man presented with complaints of transient mild weakness followed by numbness of the right
side of the body. Diffusion-weighted imaging and
T2-weighted imaging showed a high-intensity lesion in
the posterior limb of the left internal capsule (Fig 1, A).
Digital subtraction angiography (DSA) revealed an aneurysm (14.5-mm diameter) arising at the supraclinoid
segment of the left ICA (Fig 1, B). The aneurysm was
interpreted as a saccular type of the nonbranching site

S. RASHAD ET AL.

of the left ICA with an accompanying bleb at its tip.
DSA showed a thin posterior communicating artery that
originated proximally relative to the aneurysm. The
AchA was not clearly visible, suggesting that occlusion
of the AchA occurred at the onset of the cerebral infarction. Magnetic resonance imaging (MRI; Fig 1, C) showed
the aneurysm to be partially thrombosed without surrounding hemorrhage.
Second MRI (Fig 1, D) done after 2 weeks showed
recanalization of the thrombosed part of the aneurysm,
which was confirmed by the second DSA (Fig 1, E). The
second DSA showed that the recanalization of the thrombosed part with the AchA being visible (Fig 1, E). Furthermore, injection of contrast media from the microcatheter
placed inside of the aneurysm showed an AchA arising
from the tip of the aneurysm (Fig 1, F). Thus, the aneurysm was diagnosed as a partially thrombosed fusiform
AchA aneurysm. We decided to perform surgery to prevent recurrent ischemic stroke and future bleeding.
Open surgery was performed under the motor evoked
potential (MEP) monitoring. A left frontotemporal craniotomy was performed. The left sylvian fissure was widely
split to expose the whole aneurysm (Fig 2, A). Several perforators, which had not been identified by the second
DSA (Fig 2, B), originated from the aneurysmal sac.
MEP temporarily decreased in amplitude during temporary clipping of these perforators, suggesting that these
perforators supplied the pyramidal tract through the
anterior perforated substance (Fig 3). The AchA was

Figure 1. Preoperative imaging: (A) Axial T2WI showed a high-intensity lesion in the posterior limb of the left internal capsule. (B) Left internal carotid angiography (lateral view) revealed an aneurysm (14.5-mm diameter) arising at the supraclinoid segment. (C) Initial MRI showed the thrombus within the aneurysm
(arrow). (D) MRI done after 2 weeks showing the recanalization of the thrombosed part of the aneurysm (arrowhead). (E) Second angiography (lateral view)
showed an enlargement of the aneurysm (16.1-mm diameter) and an AchA arising from its tip. (F) Aneurysmography confirmed an AchA arising from the
tip of the aneurysm. Abbreviations: AchA, anterior choroidal artery; MRI, magnetic resonance imaging; T2WI, T2-weighted imaging.

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Figure 2. Intraoperative view: (A) Whole appearance of the aneurysm. (B) Several perforators originating from the aneurysmal sac (arrow). (C) AchA arising
from the tip of the bleb (arrowhead). Arrow indicates the same perforators as shown in (B). (D) Two titanium clips applied to the base of the aneurysm. (E) Drawing
showing the collateral flow to the pyramidal tract after the clip application. Black arrow and arrowhead indicating the same arteries as shown in (B) and (C). (F)
Postoperative angiography of the left vertebral artery showing retrograde filling of the AchA through the posterior circulation (double arrow). (G) Postoperative
DWI showing slight high-intensity lesions in the left AchA territory. Abbreviations: AchA, anterior choroidal artery; DWI, diffusion-weighted imaging.

seen arising from the tip of the aneurysm, which was
compatible with the findings of the second DSA (Fig 2,
C). The MEP remained unchanged by temporary occlusion of this artery. These findings suggested that this fusiform aneurysm was an enlarged AchA itself. The artery
arising from the aneurysmal tip was the transition between the cisternal segment and the choroidal segment,
the distal portion of which supplied the choroid plexus.
A titanium clip was applied to the base of the fusiform
aneurysm that corresponded to the origin of the AchA
under MEP monitoring, which remained unchanged after
the clipping (Fig 2, D). Occlusion of the aneurysm was
confirmed by Doppler ultrasound and intraoperative

fluorescence angiography. Doppler ultrasound and intraoperative fluorescence angiography showed that the
blood flow to the perforators supplying the pyramidal
tract was reconstituted by the retrograde collateral flow
from the choroidal segment (Fig 2, E). Postoperative
DSA showed complete obliteration of the aneurysm
with retrograde filling of the AchA through the posterior
circulation (Fig 2, F). Postoperative diffusion-weighted
imaging showed slight high-intensity lesions in the left
AchA territory, resulting in transient mild weakness of
the right side of the body (Fig 2, G). The patient required
short-term rehabilitation and was discharged 1 month
after surgery with complete recovery of the right
hemiparesis.

Discussion

Figure 3. MEP findings: MEP amplitude decreased down to 80% subsequent to transient increase after the 3-minute temporary clip occlusion of
the perforator. MEP gradually recovered after clip release. Abbreviations:
MEP, motor evoked potential.

AchA aneurysms are rare, only representing 2%-5% of
all intracranial aneurysms.3 Whereas most of the AchA
aneurysms are small and saccular, the occurrence of large,
giant, or fusiform AchA aneurysms is much rarer.
Lehecka et al3 presented their series of 99 AchA aneurysms, which only included 3 large (3%) and 2 fusiform
(2%) AchA aneurysms. This shows the rarity of the presented case which is a fusiform large and partially thrombosed AchA aneurysm. To our knowledge, there is
only one similar case with such unique features in the
literature.4
Management of AchA aneurysms by open or endovascular surgery is usually problematic, as occlusion of the
AchA carries a high morbidity.5-8 Occlusion of the AchA
during surgical treatment will lead to contralateral
hemiplegia or hemiparesis, hemianesthesia, and hemianopia, which is referred to as the AchA syndrome.5-7

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S. RASHAD ET AL.

In the present case, therapeutic occlusion of AchA was
necessary to occlude the aneurysm considering the
morphology of the aneurysm. However, reconstruction
of AchA by bypass surgery during therapeutic
occlusion of AchA was generally considered difficult
because of the aneurysm’s deep location and its small
diameter. Furthermore, perfora-ting branches that arise
from the AchA may indicate the difficulty of such a
surgery.
Trapping of the aneurysm in the present case was
avoided as important perforators arose from the aneurysm itself. Proximal occlusion was adopted as the alternative treatment strategy, based on the existence of
collateral circulation for AchA territory from the posterior
choroidal artery. Takahashi et al9 demonstrated retrograde filling of AchA on angiogram in cases with occlusion of proximal AchA or the ICA. In the present case,
this collateral flow was enough to supply vital structures
in the AchA territory without filling or enlarging the
aneurysm on postoperative angiogram.
Shih et al4 reported a pediatric case with dissecting
aneurysm of the AchA, which was also successfully
treated with proximal clip occlusion. However, validity
of the therapeutic occlusion of AchA was not discussed
in their report. In the present case, the blood flow in the
AchA and its perforators was confirmed by Doppler ultrasound and intraoperative fluorescence angiography after the clip application. Furthermore, MEP changes were
observed when a clip was applied to the perforators
arising from the aneurysm, whereas no changes were
observed with proximal occlusion. If ischemic complication was expected from the result of these monitoring,
surgical strategy could be changed to wrapping or partial
clipping. Among these monitoring, the MEP is the most
important monitoring for successful treatment. Suzuki
et al studied intraoperative MEP for 108 patients with
ICA aneurysms who underwent surgical clipping.
Among them, 4 of 19 patients with transient MEP changes
after clipping or during temporary occlusion of the
affected artery manifested transient hemiparesis postoperatively.10 One patient with MEP disappearance developed infarction in the internal capsule and experienced
severe hemiplegia. They concluded that MEP monitoring
is a reliable method for detecting ischemia in the AchA
territory. In the present case, the patient manifested transient mild hemiparesis after surgery, although MEP did
not disappear after aneurysmal clipping. Postoperative
MRI showed a small infarction in the AchA territory.
This might be because of insufficient collateral blood
flow from posterior circulation immediately after aneurysmal clipping. The collateral blood flow would sufficiently develop after surgery, which was confirmed by
postoperative angiography.
Although this approach could not be generalized to all
AchA aneurysms, this case is an excellent demonstration
of the importance of the various monitoring tools used

11-14

in the modern aneurysm surgery,
and how the
interpretation of their data can alter the treatment
decision to achieve the best results.

Conclusion
We report a rare case with partially thrombosed fusiform aneurysm successfully treated with proximal clip
occlusion. Various monitoring tools are necessary for
the therapeutic occlusion of AchA.

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