Persistent carotid-basilar anastomoses are unusualembryological vascular remnants (1). The mostcommon embryonic communication between thecarotid and vertebrobasilar systems is a persistenttrigeminal artery (PTA). This has been observed in 0.1-0.2 % of cerebral angiograms, usually as an inciden-tal finding (2). Although the presence of PTA isgenerally thought to be of uncertain significant, thesearteries and their variants have been identified as a rarecause of cranial nerve dysfunction (3, 4). In manyprevious reports, there was an association with cerebralaneurysm in 14-22 % of patients with PTA (5-9).Aneurysms of a persistent trigeminal artery itself areexceedingly rare and endovascular treatment of theseaneurysms has not been attempted so much. We reporta case of endovascular treatment for a persistent

trigeminal artery aneurysm presenting as isolated sixthnerve palsy.

CASE REPORT

A 49-year-old female presented with diplopia whichwas worsen on looking towards the left side for 3months. On examination, she had isolated sixth nervepalsy on the left eye (Fig. 1). The other cranial nerveswere intact. There was no focal abnormality in theperipheral neurological system. She initially had brainmagnetic resonance imaging and magnetic resonanceangiography (MRA), which showed the unrupturedaneurysm in the cavernous segment of the left internalcarotid artery (ICA) (Fig. 2). She underwent four-vessel cerebral digital subtraction angiography, whichrevealed the saccular aneurysm at the bifurcation of thecavernous segment of the ICA and PTA (Fig. 3A & B).We planned endovascular treatment of the aneurysm.Under the general anesthesia, she underwent endovas-cular treatment of the PTA aneurysm using Guglielmidetachable coils via the left ICA. The coils were placedinside the aneurysm which was successfully occludedwith preserving PTA (Fig. 3C & D). The patienttolerated the procedure well. Immediately after

Neurointervention 2, August 2007 113

Case Report

1Department of Radiology and 2Neurosurgery, Samsung MedicalCenter, Sungkyunkwan University School of Medicine, Seoul, Korea

Received July 10, 2007; accepted after revision August 10, 2007.Correspondence to: Pyoung Jeon, MD, Department of Radiology,Samsung Medical Center, Sungkyunkwan University School ofMedicine, 50 Ilwon-dong, Kangnam-gu, Seoul 135-710, KoreaTel. 82-2-3410-6433, 2548 Fax. 82-2-3410-6414 E-mail: pyoung.jeon@samsung.comNeurointervention 2007;2:113-116

Endovascular Treatment for a PersistentTrigeminal Artery Aneurysm Presenting as

Isolated Sixth Nerve Palsy

Ki-Hun Kwon, MD1,2, Keon Ha Kim, MD, Pyoung Jeon, MD, Hong Sik Byun, MD, Ph.D., Jong Soo Kim, MD, Ph.D.2, Seung-Chyul Hong, MD, Ph.D.2

The trigeminal artery is the most common persistent carotid-basilar anastomotic channelobserved in adult life, and its occurrence probably represents a defect in cerebrovascular devel-opment. It can be associated with other congenital abnormalities such as cerebral aneurysms,but only rarely do aneurysms of the persistent trigeminal artery itself arise. Endovascular treat-ment of these aneurysms has not been attempted so much. We report a case of endovasculartreatment for a persistent trigeminal artery aneurysm causing isolated sixth nerve palsy.

Key Words : Persistent trigeminal artery; Aneurysm; Endovascular treatment

procedure, she was well recovered without othercomplications and had only isolated sixth nerve palsyshowed preoperatively. After one month of procedure,she was subjectively improvement of her diplopia andshowed a little limitation of lateral gaze on the left sidein the neurological examination.

DISCUSSION

Four types of primitive carotid-basilar anastomoses(trigeminal, otic, hypoglossal, and proatlantic interseg-mental arteries) can be observed on the 24th day of anembryo (5-8, 10). These anastomoses disappeargradually when the basilar artery and the posteriorcommunicating artery (PcoA) begin to develop. ThePcoA finally becomes the main supplying artery ascarotid-basilar communicating artery on the 32nd dayof embryo. Twenty-five percent of all PTAs are associ-ated with cerebral vascular diseases including arteri-ovenous malformation, carotid-cavernous fistula,moyamoya disease, Sturge-Weber syndrome, and so on(5, 11-13).

Based on the review of 261 cases with PTA in theliterature between 1950 and 2003, PTA associated withaneurysm was presented in 39 cases (14). Of these,aneurysm was located at the bifurcation of the

cavernous segment of the ICA and PTA in 17 cases, atthe trunk of the PTA in 10, and at the junction of theICA with the basilar artery in 5. In the remaining 7cases, the location of aneurysms was not described indetail. Most cases of PTA do not cause clinicalsymptoms. Clinical symptoms such as ocular motornerve dysfunction can be developed by the mass effectfrom the aneurysm in the cavernous sinus. The PTAalso can be associated with a higher incidence ofvertebrobasilar insufficiency and brain stem infarction(7, 15).

The PTA can take a lateral or medial course. When itarises from the posterolateral aspect of the intracav-ernous portion of the ICA, it runs underneath theabducent nerve and continues caudally between thetrigeminal and abducent nerves to join the distal basilarartery. When it arises from the posteromedial aspect, itruns caudally through the sella turcica and pierces theclival dura at the dorsum sellae to join the basilarartery. Cranial nerve displacement or distortion is lesslikely in this variation (2, 16). In our case, the sourceimages of MRA showed the course of a PTA andconfirmed that a saccular aneurysm of the left PTA waslocated at the lateral aspect of the cavernous segment ofthe left ICA, which was might be the cause of isolatedsixth nerve palsy. It was very difficult surgically to

114 Neurointervention 2, August 2007

Ki-Hun Kwon, et al.

A BFig. 1. The photography of eyeball movements. It reveals isolated sixth nerve palsy on the left eye. Left side gaze (A), Right side gaze(B).

A B

Fig. 2. The source images of magneticresonance angiography show that asaccular aneurysm of the left persistenttrigeminal artery is located at the lateralaspect of the cavernous segment of theleft internal carotid artery (A, B).

approach the cavernous segment of the ICA whichlocated deeply in front of the brainstem and close to thecranial nerves and perforating vessels. Therefore, weperformed endovascular treatment for the PTAaneurysm.

In conclusion, although the PTA aneurysm is inciden-tal in most cases, it can occasionally cause cranialnerve dysfunction including, as in this case, isolatedsixth nerve palsy. This is the second case report inliterature describing endovascular coiling of such ananeurysm. In case of the therapeutic challenge to thePTA aneurysm, endovascular treatment should beconsidered as the first line management.

References1. Suttner N, Mura J, Tedeschi H, Ferreira MA, Wen HT, de

Oliveira E, et al. Persistent trigeminal artery: a unique anatomicspecimen analysis and therapeutic implications. Neurosurgery2000;47:428-433; discussion 433-424

2. Salas E, Ziyal IM, Sekhar LN, Wright DC. Persistent trigeminalartery: an anatomic study. Neurosurgery 1998;43:557-561; discus-sion 561-552

3. Ballantyne DL, Reiffel RS, Harper AD. A systematic learningprogram for microvascular technique. Plast Reconstr Surg1980;65:80-82

4. Zingale A, Chiaramonte I, Mancuso P, Consoli V, Albanese V.Craniofacial pain and incomplete oculomotor palsy associatedwith ipsilateral primitive trigeminal artery. Case report. JNeurosurg Sci 1993;37:251-255

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Endovascular Treatment for a Persistent Trigeminal Artery Aneurysm Presenting as Isolated Sixth Nerve Palsy

A B

C DFig. 3. The pre- (A, B) and postoperative (C, D) angiography of the left internal carotid artery. Anteroposterior view (A, C), Lateral view(B, D).

5. Brick JF, Roberts T. Cerebral arteriovenous malformation coexis-tent with intracranial aneurysm and persistent trigeminal artery.South Med J 1987;80:398-400

6. Ikushima I, Arikawa S, Korogi Y, Uehara H, Komohara Y,Takahashi M. Basilar artery aneurysm treated with coil emboliza-tion via persistent primitive trigeminal artery. CardiovascIntervent Radiol 2002;25:70-71

7. Palmer S, Gucer G. Vertebrobasilar insufficiency from carotiddisease associated with a trigeminal artery. Neurosurgery1981;8:458-461

8. Rossitti S, Raininko R. Absence of the common carotid artery in apatient with a persistent trigeminal artery variant. Clin Radiol2001;56:79-81

9. Osborn AG. Diagnostic neuroradiology, 1994:129-13210. Sutton D. Anomalous carotid-basilar anastomosis. Br J Radiol

1950;23:617-61911. Loevner L, Quint DJ. Persistent trigeminal artery in a patient with

Sturge-Weber syndrome. AJR Am J Roentgenol 1992;158:872-

87412. Suzuki S, Morioka T, Matsushima T, Ikezaki K, Hasuo K, Fukui

M. Moyamoya disease associated with persistent primitive trigem-inal artery variant in identical twins. Surg Neurol 1996;45:236-240

13. Wolpert S. The trigeminal artery and associated aneurysms.Neurology 1966:610-614

14. Li MH, Li WB, Pan YP, Fang C, Wang W. Persistent primitivetrigeminal artery associated with aneurysm: report of two casesand review of the literature. Acta Radiol 2004;45:664-668

15. Ito Y, Watanabe H, Niwa H, Hakusui S, Ando T, Yasuda T, et al.The protective effect of a persistent trigeminal artery on brainstem infarctions: a follow-up case report. Intern Med 1998;37:334-337

16. Piotin M, Miralbes S, Cattin F, Marchal H, Amor-Sahli M,Moulin T, et al. MRI and MR angiography of persistent trigeminalartery. Neuroradiology 1996;38:730-733

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신경중재치료의학 2007;2:113-116

외전신경마비를 유발한 지속성 원시 삼차신경동맥 동맥류의 혈관내치료

1성균관대학교 의과대학 삼성서울병원 영상의학과2성균관대학교 의과대학 삼성서울병원 신경외과

권기훈1,2·김건하·전 평·변홍식·김종수2·홍승철2

삼차신경동맥은 성인에서 발견되는 가장 흔한 소멸되지 않은 경동맥-기저동맥 연결통로로서 이것이 남아있다

는것은뇌혈관발달에결함이있을수있다는것을암시한다. 이것은뇌동맥류와같은다른선천적기형과관계가

있을 수있는데, 지속성 원시 삼차신경동맥 그 자체에서 뇌동맥류가 생기는 것은 드물다. 또한 이러한 뇌동맥류가

증상을 일으키는 것은 매우 드물며, 이에 대한 혈관내치료는 거의 보고된 바가 없다. 저자들은 외전신경마비를 유

발한지속성원시삼차신경동맥동맥류의혈관내치료를경험하고보고하는바이다.

Key Words : Persistent trigeminal artery; Aneurysm; Endovascular treatment