- Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
- Department of Radiology, Ankara University Hospitals, Sihhiye, Ankara, Turkey
- Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
Correspondence Address:
Mustafa K. Başkaya
Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
DOI:10.4103/2152-7806.94928
Copyright: © 2012 Aktüre E. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.How to cite this article: Erinç Aktüre, Anıl Arat, Niemann DB, Salamat MS, Mustafa K. Başkaya. Bilateral A1 fenestrations: Report of two cases and literature review. Surg Neurol Int 16-Apr-2012;3:43
How to cite this URL: Erinç Aktüre, Anıl Arat, Niemann DB, Salamat MS, Mustafa K. Başkaya. Bilateral A1 fenestrations: Report of two cases and literature review. Surg Neurol Int 16-Apr-2012;3:43. Available from: http://sni.wpengine.com/surgicalint_articles/bilateral-a1-fenestrations-report-of-two-cases-and-literature-review/
Abstract
Background:Bilateral fenestration of the A1 segment of anterior cerebral artery (ACA) is an uncommon anomaly. Our objective is to describe two cases with this anomaly and to review the literature.
Case Description:A 50-year-old woman presented with subarachnoid hemorrhage from a ruptured A1 aneurysm. Angiography revealed bilateral A1 segment fenestration as well as an aneurysm on the proximal end of fenestration on the right side. The second case is that of an 86-year-old woman who was found to have bilateral fenestration of A1 segment at autopsy.
Conclusion:Bilateral A1 fenestration is an uncommon anomaly that may be associated with an aneurysm. In surgical clipping of such cases, extreme caution should be exercised to inspect both arms of the fenestration since both may have multiple perforators as demonstrated in our autopsy specimen. This will be the first published pictorial demonstration of these perforators arising from the arms of fenestration.
Keywords: A1 segment, aneurysm, anterior cerebral artery, bilateral fenestration, central nervous system
INTRODUCTION
Fenestrations of the cerebral arteries most commonly occur in the anterior communicating artery, the vertebral artery, the basilar artery, and the middle cerebral artery.[
CASE REPORTS
Case 1
A 50-year-old woman with family history of ruptured aneurysms presented with subarachnoid hemorrhage. Computed tomography (CT) angiography performed at our institution revealed a small aneurysm at the proximal end of fenestrated right A1 segment and bilateral fenestrations of the A1 segments [Figure
Figure 1
Volume rendered 3-dimensional computerized tomographic angiography (3D CTA) images show bilateral A1 fenestrations (a) (arrows) and saccular aneurysm involving proximal end of the right A1 fenestration (b) (arrowhead). Postoperative digital subtraction angiography shows complete obliteration of the aneurysm involving proximal end of the right A1 fenestration (c) (arrowhead). 3D views of the left carotid circulation obtained from rotational angiogram show the left-sided fenestration (d) (arrow)
Case 2
An 86-year-old woman with a history of Alzheimer's disease, depression, and hypertension passed away at a nursing home due to complications related to dementia. She did not have any known history of neurovascular diseases or complaints. Her autopsy revealed incidental bilateral fenestrations of A1 segments. The anomalous cerebral vessels (A1 segments, anterior communicating artery, and A2 segments) were isolated for further microscopic examination by cutting A1s proximally and A2s distally [
Figure 2
Postmortem specimen showing bilateral A1 fenestrations. Note that one large perforator originates from the large arm of the left fenestration on the left side and two from the large arm of the fenestration on the right side. Also, note very prominent right recurrent artery of Heubner on the right and again very prominent anterior communicating artery perforator. Inlet picture on left bottom corner shows magnified view of two of the perforating branches (arrowheads) originating from the small arm of the left A1 fenestration after the specimen is stained with luxol fast blue to overcome the transparency
DISCUSSION
Fenestration is the separation of the arterial lumen into two distinct channels, each having its own endothelial, muscular, and adventitial layers. Distally, these two channels merge into a single arterial lumen again. The fenestration of the A1 segment of the ACA is an uncommon entity which was first described by Fawcett and Blachford in 1905. They found its incidence to be 0.14% in 700 brains.[
Fenestrations of the cerebral vessels are associated with other vascular anomalies and saccular aneurysms.[
The origin of the A1 perforators in a fenestrated A1 segment is important in both endovascular and open surgical approaches for the treatment of associated aneurysms. The A1 segment generally supplies the optic chiasm, anterior third ventricle and hypothalamus, medial third of the anterior commisure, caudate head, globus pallidus, anterior limb of internal capsule, and rostral thalamus.[
CONCLUSION
We demonstrated two cases of bilateral fenestrations of the A1 segment of the ACA which is an uncommon variant. The fenestration of the A1 segment is known to be associated with aneurysms, and the fact that the perforators can arise from either limb is important in the planning of the management of such aneurysms.
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