Acta Neurochir (2012) 154:1153–1155 DOI 10.1007/s00701-012-1384-3
LETTER TO THE EDITOR
Ruptured aneurysm arising from the corkscrew basilar artery Yong Cheol Lim & Joonho Chung
Received: 26 April 2012 / Accepted: 3 May 2012 / Published online: 16 May 2012 # Springer-Verlag 2012
Dear Editor, With advancements in modern imaging techniques and microangiography, the specific need to understand the variations and variability of vascular anatomy has increased. Herein, we report a rare case of a patient with a ruptured aneurysm arising from a markedly tortuous basilar artery (BA) with agenesis of the left internal carotid artery (ICA). To ensure safe performance of either neurological microsurgery or neurointervention, knowledge of these anatomic variations of the cerebral artery is important. To the best of our knowledge, this is the first reported case involving a patient with a ruptured aneurysm arising from a corkscrew BA. A 41-year-old woman with no remarkable medical history abruptly developed a severe headache and demonstrated sequential mental change. On arrival at our hospital, she showed a deep stuporous mentality (Hunt-Hess grade 4). Her brain computed tomography (CT) scan showed subarachnoid hemorrhage, intraventricular hemorrhage, and pontine hemorrhage. Findings on CT angiography revealed a markedly tortuous, abnormal configuration of the BA with absence of the ICA (Fig. 1a). Absence of the carotid canal, which was observed on a skull base CT scan, confirmed agenesis of the left ICA. Cerebral angiograms showed ter-
Y. C. Lim Department of Neurosurgery, Ajou University School of Medicine, Suwon, Republic of Korea J. Chung (*) Department of Neurosurgery, Inha University School of Medicine and Hospital, 7-206, 3-Ga, Shinheung-dong, Jung-gu, Incheon 400-711, Republic of Korea e-mail:
[email protected]
mination of the left common carotid artery into the ECA, with no identifiable remnant of the ICA. Branches of the left ECA were normal. Collateral circulations to the left anterior and middle cerebral artery were provided by the patent anterior and posterior communicating arteries. Findings on an angiogram of the left vertebral artery (VA) showed a ruptured aneurysm of the BA trunk arising from a corkscrew-like dysplastic BA (Fig. 1b). The neck of the aneurysm was relatively wide and was believed to be a fusiform-like dilatation rather than a saccular type aneurysm (Fig. 1c). Because the patient was in poor condition and the aneurysm was located in the BA trunk [1], endovascular coil embolization was performed in order to secure the aneurysm (Fig. 1d). The patient survived, but remained vegetative at his 6-month clinical follow-up; no follow-up angiography was performed. Only one previous case involving a corkscrew BA has been reported [3]. Moser et al. reported an incidental finding of a corkscrew BA without other congenital anomalies in a 6-year-old child [3], suggesting the plausibility of the hypothesis that the long BA might be the cause of the tortuosity and overexpression of an angiogenic growth factor. In addition, they presented some speculative queries regarding the question of whether patients with a tortuous BA are predisposed to development of acquired lesions, such as aneurysms. In this case, it might support the possibility that patients with a tortuous BA might have aneurysms. In addition, it is the first case involving a corkscrew BA combined with another anomaly, agenesis of the ICA. Congenital absence of the ICA is a rare vascular anomaly. Kunishino et al. reported that the anomaly was based on atresia or involution of the third aortic arches and distal portion of dorsal aortas in the 20-to-24-mm stage [2]. Formation of the BA occurs at the 7-12-mm stage, and
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Acta Neurochir (2012) 154:1153–1155
Fig. 1 a Findings on computed tomography angiogram revealed a markedly tortuous, abnormal configuration of the basilar artery with absence of the internal carotid artery. b Findings on an angiogram of the left vertebral artery showed a ruptured aneurysm of the basilar artery trunk arising from a corkscrew-like dysplastic basilar artery. c
The neck of the aneurysm was relatively wide and was believed to be a fusiform-like dilatation rather than a saccular type aneurysm. d Endovascular coil embolization was performed in order to secure the aneurysm
completion of the circle of Willis is observed at the 24mm stage; therefore, it appears that collateral circulation via the circle of Willis reflects agenesis of the ICA during early embryonic development, i.e., after development of the BA but prior to completion of the circle of Willis [4]. Therefore, in this case, agenesis of the ICA
was only an incidental finding and did not show correlation with the corkscrew BA. Development of the adult basilar trunk occurs at 4 weeks of gestation, after fusion on the anterior surface of the neural tube, from the paired ventral longitudinal neural system. Multiple variations can occur, depending on the quality of
Acta Neurochir (2012) 154:1153–1155
the fusion process and the actual contribution of the regional segmental artery remnants to the posterior fossa supply. Thus, it might be more reliable to suggest congenital development of the tortuous BA. In patients recognized as having a corkscrew BA, keeping an eye on following intracranial vascular abnormalities, such as aneurysms, may be the best approach.
Acknowledgements This work was supported by INHA University Hospital Research Grant. Conflicts of interest None.
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References 1. Chung J, Park H, Lim YC, Hyun D-K, Shin YS (2011) Endovascular treatment of basilar artery trunk aneurysms. Acta Neurochir 153:2137–2145 2. Kunishio K, Yamamoto Y, Sunami N, Asari S (1987) Agenesis of the left internal carotid artery, common carotid artery, and main trunk of the external carotid artery associated with multiple cerebral aneurysms. Surg Neurol 27:177–181 3. Moser FG, Sarnat HB, Maya MM, Menkes JH (2007) Corkscrew basilar artery as an incidental finding on neuroimaging. Pediatr Neurol 37:375–377 4. Worthington C, Olivier A, Melanson D (1984) Internal carotid artery agenesis: correlation by conventional and digital subtraction angiography, and by computed tomography. Surg Neurol 22:295–300
