クリッピングのために前床突起の削除を行った真の後交通動脈瘤の手術  [in Japanese] Surgical Treatment of True Posterior Communicating Artery Aneurysm with Removal of the Anterior Clinoid Process  [in Japanese]

An aneurysm arising from the posterior communicating artery itself is named true posterior communicating artery aneurysm (true PcomA), of which the incidence is less than 5% of aneurysms arising around the origin of the posterior communicating artery (Pcom). We successfully operated on a case with true PcomA with removal of the anterior clinoid process. The patient is a 66-year-old male who suddenly developed consciousness disturbance. Emergency head CT showed subarachnoid hemorrhage, and he was referred to our center for surgical treatment. His consciousness became clear after admission. Cerebral angiography revealed left true PcomA projecting inferomedially. He had undergone by-pass surgery for aortitis syndrome with artificial vessels 33 years earlier. The bilateral subclavian arteries were occluded, and bilateral vertebral arteries were not seen on aortography. The vertebrobasiler system was filled from the anterior circulation via the Pcoms. We took a left pterional approach, removed the anterior clinoid process and incised the dural ring to provide wide working space, because the aneurysm was below the internal carotid artery and the optic nerve, the dome of which adhered to the base of the middle cranial fossa. After we dissected the adhesion between the aneurysm and the Pcom, the proximal neck was found to be located 3-4 mm from the origin of the Pcom. The aneurysm was clipped with Yasargil's titanium clip. The postoperative course was uneventful, and the patient was discharged with no neurological deficit. We consider that hemodynamic stree may play an important role in the development of true PcomA associated with occlusion of major vessels.