Easy Dissection of the Interhemispheric Fissure for Treatment of the Anterior Communicating Artery Aneurysm by the Pterional Approach

Abstract

When the fundus of an aneurysm is superiorly or posteriorly directed or the anterior communicating artery (ACoA) is located far from the sphenoidal plane, wide dissection of the interhemispheric fissure is needed to expose the ACoA aneurysm. When the thickened arachnoid membrane covering the dorsal surface of the ipsilateral optic nerves is dissected through the pterional approach, the dissection must not be performed beyond the midline of the optic chiasm. As a result, the undissected arachnoid membrane becomes tense and is easily cut down toward the interhemispheric fissure. We have used this technique in 24 patients in whom the ACoA aneurysm projected superiorly or posteriorly. The gyrus rectus was resected in four patients with ruptured aneurysm because the aneurysmal domes were partially buried in the ipsilateral gyri recti. In the remaining patients, the aneurysmal dome was fully exposed without gyrus rectus resection. The present technique is helpful to dissect the interhemispheric fissure easily and widely by the pterional approach and to expose the ACoA aneurysm adequately.