Introduction: The anterior communicating artery (ACOA) complex accounts for 30% of intracranial aneurysms. The ACOA is the single most common artery to give rise to such pathology. Side selection for best approaching these aneurysms can be confusing and depends on preoperative radiological understanding of the spatial configuration of the whole complex.
Methods: Twenty patients with ACOA aneurysms confirmed by CTA, referred to Alexandria University, Egypt between 2005 to 2008 were the subjects of this study. Angioarchitechture of the complex delineated by CTA focused on the aneurysm’s site, size, shape, projection direction, surgical neck and its height from skull base. Measurements and spatial configuration of parent arteries were analyzed and correlated with the intraoperative anatomy.
Results: All Aneurysms were saccular in nature. 90% originated at the junction of a dominant A1 segment with the ACOA. 10% from ACOA itself. 95% were small in size (55% less than 5mm). 5% were large. Most common projections were anterior and superior. Hypoplastic A1 was found in 16 patients. Absent A1 in 2 patients, fenestrated ACOA in 2 patients and a third A2 in 2 patients. Also, Left dominant A1 in 50%, right dominant A1 in 40% and equal sized A1 in 10% of cases. CTA correlated well with intraoperative findings but had limitations delineating aneurysms near the skull base. Small perforators were poorly delineated if at all. Absent A1s were less than 0.2mm intraoperatively. Anterior/inferior projecting aneurysms were approached from the dominant A1side.Superior/posterior aneurysms were approached from the side at which the proximal A2 segment was posteriorly displaced regardless to the side of the dominant A1 artery.
Conclusions: Side selection of the Pterional approach based on CTA provided a safe and adequate angle for viewing the aneurysmal neck, anticipating potential exposure requirements such as gyrus rectus resection or A2 dissection and mobilization.
Patient Care: This research will improve patient care by adding to the understanding of surgical aspects of securing intracranial aneurysms.
Learning Objectives: By the conclusion of this session, participants should be able to;
1) Identify components of the Anterior communicating artery complex.
2) Appreciate variable aneurysm projections shown by CTA images.
3) Appreciate advantages provided by CTA for determining side of Pterional approach for approaching Anterior communicating aneurysms