Dominant A1 Direction as an Additional Factor for Deciding Surgical Approach for A1 Bifurcation Aneurysms

Abstract

Background and ObjectivesClipping of the Anterior communicating artery (AcomA) located aneurysms is considered a critical surgical procedure for neurosurgeons worldwide due to the complexity of the surgical area. The present study is conducted to discuss the importance of the geometrical curvatures and the direction of the dominant A1 artery and their impact on aneurysmal growth direction and choice of side selection of the Pterional surgical approach side. MethodsThe present study enrolled 183 patients with ruptured AcomA-located aneurysms. the aneurysms were all treated surgically through a Pterional approach. Because of multiple dominant A1 direction, we divided the artery into 2 segments and based on the second segment direction we categorized the patients into Ascending A1, Descending A1, and Horizontal A1 groups. The ascending group includes the superiorly projecting aneurysms, while the horizontal and descending groups include the anteriorly and inferiorly projecting aneurysms respectively. Contralateral Pterional approach to the dominant A1 was chosen for aneurysms with an ascending artery. However, the ipsilateral Pterional approach was conducted in horizontal and descending A1 dominant groups. ResultsThe aneurysmal growth projection axis always follows the direction of the second dominant A1 segment. Full neck control with satisfactory perforators inspection was achieved through the contralateral approach in most cases of an ascending A1 especially if ipsilateral A2 is posterior to the neck. The A1 segment can be satisfactorily seen from the contralateral exposure before the Aneurysmal neck is exposed in ascending A1 geometries. ConclusionA1 direction is an important additional factor that is to be considered for side selection when deciding Pterional exposure of A1 bifurcation aneurysms. Accessing the contralateral dominant ascending A1 has better visualization of the neck than entering from ipsilateral approach especially if the ipsilateral A2 was posterior to the neck.