[Vascular anomalies associated with anterior communicating aneurysms].

Using a bifrontal trans-interhemispheric approach, we have performed direct operations on 206 cases of aneurysm of the anterior communicating artery, 44 of which (21.4%) had vascular anomalies associated with the aneurysm. Those anomalies included 27 cases (13.1%) with median artery of the corpus callosum, 20 cases (9.7%) with duplication of the anterior communicating artery and one case (0.5%) with duplication of the A1 portion. Preoperative diagnosis of the duplications was not possible on the basis of angiograms. Moreover, preoperative diagnosis of the median artery using angiography was unambiguous in only 11 of the 27 cases (41%). The majority (81.5%) of the aneurysms of the anterior communicating artery in cases with a median artery of the corpus callosum were found to develop at the trifurcation of the anterior communicating artery, the A2 portion and the median artery of the corpus callosum.