We provide intraoperative problems and their preventive measures during the pterional approach to the basilar top aneurysm. We focus on the surgical techniques to obtain a wider operative field through the pterional approach. The surgical difficulties depend on various factors, including the size, location, and direction of the basilar top aneurysm. In particular, the interrelationship between the location of the internal carotid artery and the basilar top aneurysm is an important factor to be fully assessed preoperatively.
