RESUMEN
A 58-year-old female was admitted to our hospital because of weakness of the right lower extremity and dysesthesia of the right upper extremity. From her clinical symptoms the patient was tentatively diagnosed as having a sort of cerebral infarction and treated with administration of urokinase and antiplatelet agents. However, angiographical examination revealed a unruptured aneurysm of the A1 portion of the left anterior cerebral artery. Preoperative angiogram showed that the dome of the aneurysm compressed one of the neighboring perforating artery which arose from adjacent to the neck of the aneurysm. The patient underwent neck clipping of aneurysm successfully. During the operation, the perforator was hardly adhered to the dome of the aneurysm. So, careful dissection was made only around the neck and the perforator was spared. Her symptoms were disappeared immediately after surgery. The perforator was demonstrated with better filling in the postoperative angiogram than that in the preoperative angiogram. The pathomechanisms of cerebral ischemia caused by unruptured aneurysm were reviewed on the literature. Most of the cases were caused by release of fragmental thrombi from a large aneurysm. There was a very exceptional case whose symptoms had seemed to be related to the direct compression of the neighboring perforator by the aneurysm. The compressed perforator in this case was seemed to be corresponded with the medial proximal striate artery stated by Yasargil.