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CASE REPORT |
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Ruptured ACoM aneurysm with anomalous origin of bilateral ACA from the cavernous segment: Case report and literature review
Manjul Tripathi1, Tejasvi Singh1, Aman Batish1, Chirag K Ahuja2, Sandeep Mohindra1
1 Department of Neurosurgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
2 Department of Radiodiagnosis, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
| Date of Submission | 09-Jun-2021 |
| Date of Decision | 11-Aug-2021 |
| Date of Acceptance | 13-Oct-2021 |
| Date of Web Publication | 30-Jan-2023 |
Correspondence Address:
Sandeep Mohindra,
Department of Neurosurgery, Post Graduate Institute of Medical Education and Research, Chandigarh
India
 Source of Support: None, Conflict of Interest: None DOI: 10.4103/jpn.JPN_129_21
 Abstract | | |
Anterior communicating artery (ACoM) and anterior cerebral artery (ACA) are the most common locations of anomalous variations and aneurysm formation. Infraoptic origin of ACA is an extremely rare anatomical variant. This case report illustrates an extremely rare anatomical variation of bilateral infraoptic origin of ACA with ruptured ACoM aneurysmal subarachnoid hemorrhage. The authors detail this case in the light of the available literature and operative nuance in its management. For the treatment of a complex situation, accurate understanding of the anatomic variations, intraoperative three-dimensional orientation, proper imaging study, and extremely careful technique are essential.
Keywords: Aneurysm, anomalous, anterior communicating artery, subarachnoid hemorrhage
How to cite this URL:
Tripathi M, Singh T, Batish A, Ahuja C, Mohindra S. Ruptured ACoM aneurysm with anomalous origin of bilateral ACA from the cavernous segment: Case report and literature review. J Pediatr Neurosci [Epub ahead of print] [cited 2023 May 30]. Available from: https://www.pediatricneurosciences.com/preprintarticle.asp?id=368793 |
| Introduction | |  |
Only 5% of all aneurismal cases are children.[1] Among children with non-traumatic intracranial hemorrhage, aneurysms are the responsible etiology in 13% of the cases.[2] Pediatric intracranial aneurysms have a lesser propensity to bleed compared with adult counterparts.[2] In pediatric population, multiple factors attribute to aneurysmogenesis, viz., connective tissue disorders, polycystic kidney disease, sickle cell anemia, alpha-1 antitrypsin deficiency,[3] etc. Frequently, such aneurysms have associated vascular anomalies such as triplicated anterior cerebral artery (ACA) (in 2–13% of the cases[4]) and cardiac anomalies (coarctation of aorta and valvular defects). An infraoptic origin of ACA is a rarer anomaly with approximately 60 cases reported till date.[5],[6] These anatomic variations pose a surgical challenge and recognition in the preoperative period helps in minimizing operative misadventures. The authors present a pediatric case of aneurysmal subarachnoid hemorrhage, who had bilateral aberrant ACA with infraoptic course.
| Case Details | | |
A 9-year-old boy presented spontaneous intraventricular bleed. At presentation, he was unconscious, without any focal neurological deficit. Imaging revealed dense intraventricular hemorrhage with ventriculomegaly [[Figure 1]A]. Laboratory work-up was unremarkable. Emergency cerebrospinal fluid diversion was performed to relieve intracranial pressure (ICP). Post-shunting, the patient gained consciousness. CT angiography [[Figure 1]B-D] revealed a complex lobulated ruptured anterior communicating artery (ACoM) aneurysm (arrowhead) with triplication of A2 segment (arrows) with infraoptic course of bilateral ACAs (curved arrows). Digital subtraction angiography was attempted for better delineation of the aberrant anatomy, which revealed coarctation of the aorta. The catheter could not be negotiated beyond the stenosed segment of descending aorta. The patient was optimized for surgery, and successful clipping of posteriorly directed ACoM aneurysm was performed through pterional craniotomy [[Figure 2]A-D]. Intraoperatively, both ACAs were seen having infraoptic course, with no intradural internal carotid artery (ICA) segment. Post-operative course was uneventful, and the patient was discharged without any residual neurological deficit. | Figure 1: Axial non-contrast CT (A) showing intraventricular hemorrhage with ventriculomegaly. CT angiography (B-D) demonstrating the ACOM aneurysm (arrowhead), triplication of A2 segment of ACAs (arrows) along with the elongated infraoptic course of ACA-A1 segment (curved arrows). ACA = anterior cerebral artery; ACoM = anterior communicating artery; CT = computed tomography
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 | Figure 2: (A) Intraoperative view after right pterional craniotomy and sylvian dissection showing right optic nerve, third nerve, and right middle cerebral artery in optico-occulomotor space. There is no internal carotid artery. (B) MCA continuing in the sylvian fissure. (C) Bilateral ACA traversing through interoptic space. (D) Aneurysm in interhemispheric fissure with application of the temporary clip on A1. ACA = anterior cerebral artery; A1 = A1 segment of anterior cerebral artery; A2 = A2 segment of anterior cerebral artery; AN = neck of aneurysm; LT = lamina terminalis; ON = optic nerve; MCA = middle cerebral artery
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| Discussion | | |
Frequently encountered ACA variants include hypoplasia of A1 segment (2–3%),[7 azygous ACA (<2%)],[[8] and triplicated ACA (3%).[7] Infraoptic origin and course of ACA is a rare variation, with a few reports available in the literature[7] [Table 1]. If unilateral, it has a predilection for right side. Bilateral infraoptic ACA is exceedingly rare.[9] It is essentially considered to be an anastomotic communication between ICA and anterior circulation; as in a few cases, an ipsilateral supraoptic hypoplastic A1 has also been noted.[10] The anomalous ACA arises from low lying/proximally placed ICA bifurcation, usually at the level of ophthalmic artery. A few instances of infraoptic ACA originating extradurally, proximal to ophthalmic artery have also been reported.[11] | Table 1: Literature review of clinical cases of bilateral infraoptic origin of anterior cerebral artery with associated anomalies and management details
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In its proximal part, it courses horizontally and medially, passes beneath the optic nerve, and finally ascends vertically to meet the ACoM. Usually, the infraoptic ACA ascends anterior to the optic chiasm; however, variants traveling through the chiasm have also been observed.[12],[13] Definitive embryological basis of an anomalous infraoptic A1 is unclear. Aberration during development of primitive ophthalmic artery has been considered as the most probable etiology.[14] However, this theory does not explain infraoptic ACA arising proximal to the origin of ophthalmic artery. Persistence of communication between primitive dorsal and ventral ophthalmic artery[15] or persistent communication of ACA and primitive maxillary artery[16] is other plausible explanation.
Infraoptic ACA has been largely reported in adult population with no description of similar case in pediatric population.[17] ACoM has been the commonest site of aneurysm associated with infraoptic ACA. It has been reported to be associated with azygous ACA, fused pericallosal artery, moyamoya disease, coarctation of aorta, abnormal gyrus segmentation, hypoplastic vertebral artery, suprasellar craniopharyngioma, and bicuspid aortic valve.[18],[19],[20] Our case had an associated coarctation of aorta. To the best of our knowledge, no case has been reported to have bilateral infraoptic ACA with triplicated A2 and coarctation of aorta.
Preoperative recognition of infraoptic ACA is essential in operative planning for obtaining proximal control during clipping of ACoM aneurysm. Endovascular coiling of ACoM aneurysm associated with infraoptic ACA is easier owing to large caliber of A1 and relatively straight course in comparison to supraoptic A1. However, associated coarctation of aorta may pose difficulty for endovascular catheterization, when femoral route is undertaken.
Such cases highlight the need of an expert evaluation of the preoperative angiogram to avoid any surgical misadventure and surprise. An intraoperative discovery of infraoptic ACA may confuse the novice operating surgeon in differentiating ACA from ICA. In such a case, proximally placed ICA bifurcation will also present complete middle cerebral artery starting from skull base and follow its usual sylvian fissure course. Prebifurcation branches of supraclinoid ICA (ophthalmic, superior hypophyseal, posterior communicating, and anterior choroidal artery) have cavernous origin.
| Conclusion | | |
Bilateral anomalous infraoptic ACA is an extremely rare entity. A higher likelihood of intracranial aneurysm formation has been associated with it. It is imperative to recognize it on preoperative imaging for better operative or endovascular planning for the treatment of associated aneurysms.
Acknowledgements
Nil.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1]
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