Dissecting Aneurysm at the Proximal Segment of the Anterior Cerebral Artery Associated with Infraoptic Course Anterior Cerebral Artery

Abstract

A 48-year-old man presented a subarachnoid hemorrhage caused by a rupture of a dissecting aneurysm at the proximal segment (A1 segment) of the right anterior cerebral artery (ACA). He also had an anomalous artery named infraoptic course ACA and an agenesis of the contralateral ACA A1 segment. Balloon occlusion test at the bifurcation of the right internal carotid artery demonstrated that the distal segments of the bilateral ACAs were perfused through the infraoptic course ACA. Therefore, we surgically trapped the A1 segment including the aneurysm. The patient got discharged without any neurological deficit. Natural course of ACA dissecting aneurysms is unclear because of rarity of the disease and treatment strategy is still controversial. Most of the dissecting aneurysms in the A1 segment are surgically treated, because they often present with massive hemorrhage and poor prognosis. In the present case, the contralateral A1 segment was absent but trapping of the dissecting aneurysm could be achieved without vascular reconstruction (e.g., bypass surgery) because of the presence of the infraoptic course ACA.

Unilateral and Bilateral Aplasia of the Anterior Cerebral Artery in the Presence of Their Vascular Sources

“…As for the descriptions of the origin of the left and right ACAs from one ICA, as described by Burbank and Morris [5], and Kawaji et al [23], a persistent POℓA probably assumed the role of the "second" ACA [32,33,52]. Similar descriptions were also found in the articles of Pokhrel and Bhatnagar [40], and Saikia et al [43], but their schema and/or images do not correspond to the text, i.e.…”

“…We think that previously cited frequencies of unilateral ACA aplasia should not be taken as xed values, especially because some authors do not distinguish ACA hypoplasia from aplasia [6,8,17,31,43,54], or aplasia from agenesis [8,16,17,23,42]. Wanibuchi et al [54] described A1 hypoplasia in the text, while they marked the same case as "aplasia" in the table.…”

“…We noticed vascular variations associated with ACA aplasia in the Table 2 as certain authors described. However, some of them were of unique kind, such as the unilateral PCoA aplasia [30,35,48], or the VA aplasia [4], or the persistence of primitive carotid-basilar anastomosesthe trigeminal artery [45], or the hypoglossal artery [15], or the proatlantal intersegmental artery [4], or an unusual course of the ACA in the A1 part [23,36,42]. Another rather interesting fact is that associated vascular variations were not evidenced in the 16/38 literature cases of unilateral ACA aplasia.…”

“…It distributes anteromedial central branches in the A1 part; the proximal medial striate arteries from the previous group of branches supply the anterior hypothalamus, the septum pellucidum, the anterior cerebral commissure, the fornix and the striatum, while the preoptic, supraoptic and the anterior perforating arteries, also from the previous group of branches, supply the corresponding nuclei of diencephalon [9]. However, there were descriptions of many morphologic variations of the ACA, such as the origin of both of the ACAs from one ICA [5,23,40], or A1 aplasia [4,10,15,27,29,37], or hypoplasia [1,8,17,22,27,28,44,49,51,52], or an unusual course [23,36,42], or distibution of variable branches [26,38,51], or a fenestration [11,13,20,38,49,53], or a nonunion with the opposite ACA [38,51], or forming of the so-called azygos pericallosal artery [11,38,47,50], or tripling of the A2 parts [1,11,47,50]. Many authors found an association between pathologic disorders and ACA variations [19,24,…”

The Infraoptic or Infrachiasmatic Course of the Anterior Cerebral Artery Emerging an Elongated Internal Carotid Artery

“…Different authors reported cases of aneurysms associated with infraoptic ACAs [ 20 ]. These were found on the AComA or on the A1 or A2 segments of the ACA [ 4 , 5 , 7 , 8 , 13 , 18 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. An aneurysm on an infraoptic A1 segment of an azygos ACA was also reported [ 14 ].…”