前交通動脈瘤周囲の血管構築について

Abstract

Fourteen cases of unruptured aneurysm of the anterior communicating artery (AcoA) in which a radical operation was performed through an interhemispheric approach were reviewed in order to investigate the microsurgical anatomy around the AcoA.The aneurysms were classified into 3 types according to the relationship of the aneurysm projection and both A2 portions of the anterior cerebral artery. In Type 1, the aneurysm projects anteriorly to both A2 arteries. In Type 2, the aneurysm projects between the two A2, arteries, and in Type 3, the aneurysm projects posteriorly to both A2 arteries.In this series we found the neck of the aneurysm originating not only in the AcoA, but also in the unilateral A1-A2 junction, and in some cases, in the bifurcation of the unilateral A1 when the other was hypoplastic or aplastic.Thirty-nine perforators were identified on video-tapes recorded during the operative procedure. Nine of these perforators arose from the AcoA, mainly on its posterior or superior surfase. Seventeen recurrent arteries of Heubner could be confirmed, and one third of the total arose from the A1, one third from the A2, and one third from the A1-A2 junction.During neck clipping of Type 1 aneurysms, the perforators arising from the AcoA can be con-firmed easily, and rarely, if ever, interfere with clipping. Conversely, in Type 3 and in some cases of Type 2 aneurysms, great care must be taken to spare these perforators during dissection or neck clipping, because many times the visualization of them is poor and insufficient.The recurrent artery of Heubner does not interfere with clipping in this approach, because it runs out lateraly from the AcoA complex. However in some cases of Type 2 and Type 3 aneurysms, it could be necessary to be aware of the origin and course of this artery and take a side view of the aneurysm, to avoid and preserve it.