Bubbles and Troubles: A Case of Azygous ACA with Bilateral ICA Aneurysm, Besides the Usual Distal ACA Aneurysm

Abstract

Azygous ACA is one of the rare anatomic variants of anterior cerebral artery. Predisposition to aneurysm development is attributed to the alteration in flow dynamics. Such hemodynamic alteration is most commonly seen in the anterior circulation, causing distal ACA aneurysm to be the most commonly associated vascular pathology. Although neurosurgical literature is replete with anatomical reports of such cases, there has been no case reports where bilateral ICA aneurysms are also present with the distal ACA aneurysm. In this case, the presence of hypoplastic left A1 segment might predispose the other segments of Circle of Willis to hemodynamic alterations. Thus, whenever one comes across an azygous ACA in association with an additional anomaly he should be vigilant enough to look for other pathologies beyond the commonly encountered distal ACA aneurysm. The presence of azygous ACA also poses a technical challenge due to the risk of ischemic insult to anterior regions of bilateral hemispheres during temporary clipping of the single A2 trunk. In addition to it, the presence of a hypoplastic A1 segment also makes the approach to the giant aneurysm in ICA segment more technically demanding as cross flow is not adequate. So, the presence of multiple anatomic anomalies not just increases the number of vascular pathologies but also enhances the challenges that the surgeon has to face in planning the strategic approach to tackle all the lesions.