A Rare Embryologic Variation: Anterior Communicating Artery Aneurysm Associated with Carotid–-Anterior Cerebral Artery Anastomosis or Infraoptic Course of the Anterior Cerebral Artery

Abstract

Aneurysms of the complex of the anterior cerebral artery are frequently associated with anatomic variations of the circle of Willis. We describe a case of aneurysmal rupture of the anterior communicating artery, a variant of the anterior cerebral artery. The aneurysm appeared to be situated on this vessel proximal to the infered site of the AcoA. Surgery was performed at the 6th day after hemorrhage. The anterior communicating artery aneurysm was clipped. The post operative course was unventful, with complete recovery. In our case, an extremely rare variation of the proximal tract of the anterior cerebral artery, i.e. an infraoptic course of the proximal precommunicating tract under the optic nerve, with the distal A1 tract anterior to the chiasm and positioned between the optic nerves, is presented.

A Ruptured Anterior Communicating Artery Aneurysm with Infra-optic Course of the Anterior Cerebral Artery: A Case Report and a Short Review

“…Three cases were treated by coil embolization with a simple technique in two cases and with a stent-assisted technique in one case. 3 , 26 , 27) Ruptured ACoA aneurysms with IOA were frequently (44%) associated with other congenital vessel anomalies ( Table 1 ), 3 – 5 , 9 – 23 , 26 – 28 , 30 , 32 , 34) and the present case was the first one of an IOA aneurysm with an anomalous branching of a RAH from the aneurysm.…”

“…As to the surgical approach, 23 of 27 cases of ACoA aneurysms were treated by clipping via a pterional approach and an orbitozygomatic approach. The side of a pterional approach was basically the same side as that of IOA, 4 , 5 , 9 , 10 , 11 , 13 – 16 , 19 , 22 , 23 , 30 , 32 , 34) and relatively high-positioned ACoA aneurysms tended to be operated via an orbitozygomatic approach or an AIH including our case. 4 , 6 , 21) In the present case, complete obliteration of the aneurysm could not avoid the sacrifice of the RAH and resulted in cerebral ischemia in the RAH territory, causing mild cognitive dysfunction.…”

“…Besides, RAH was reported to be multiple in 28% of 2300 cadaveric cases by Bonasia et al 38) Therefore, it is important to carefully evaluate the perianeurysmal anatomical structures before surgical and endovascular treatment. 2 , 39) Surgical clipping via a pterional approach has been reported to be safe, 4 , 5 , 9 , 10 , 11 , 13 – 16 , 19 , 22 , 23 , 30 , 32 , 34) but an AIH is also suggested to be reasonable and effective as to full exposure of the perianeurysmal anatomical structures including potential anomalies of the ACA, ACoA, and its perforators. 7) Alternatively, endovascular treatment of ACoA aneurysms with IOA may be equally feasible depending on their accessibility and morphology, although the importance and limitation of precise detection and preservation of these vessels remain as with surgical treatment.…”