Side selection of the pterional approach for superiorly projecting anterior communicating artery aneurysms.

We investigated surgical results based on craniotomy sidedness in patients with superiorly projecting anterior communicating artery (ACoA) aneurysms to evaluate decision-making on the surgical approach based on the anatomical planes of both A2 vessels. Among 99 patients treated surgically, 19 (19.2%) ACoA aneurysms projected superiorly. We analyzed the associations between surgical outcomes and the planes containing both A2 vessels (anterior or posterior displacement of A2 in relation to the aneurysm). Surgery in nine patients was approached from the side of the A2 posterior displacement, while surgery for ten patients was approached from the side of anterior displacement. A higher requirement for gyrus rectus aspiration was found in patients approached from the plane of A2 anterior displacement (p=0.041). All aneurysms were successfully secured without any surgery-related complications, except in two patients. Approaches from the side of posterior displacement of A2 in patients with superiorly projecting ACoA aneurysm allowed the aneurysmal necks to be secured safely and prevented postoperative complications.