Infundibular Dilations and Subarachnoid Hemorrhage: to Treat or Not to Treat?

Abstract

Infundibular dilations are funnel-shaped widenings at the origin of a cerebral artery, most commonly the posterior communicating artery. Controversy exists as to whether an infundibulum represents a normal anatomic variant or a lesion with the potential for rupture and subarachnoid hemorrhage (SAH). We reviewed all reported cases of infundibular dilations and SAH in the world literature and present an illustrative case. Most infundibula in the context of SAH were associated with an aneurysm either on or near an infundibulum. However, there have been 7 reports in which the infundibulum could have been the primary site of rupture and no associated aneurysm was identified. Close review reveals significant limitations of those 7 reports. The literature, and our own experience, do not support the treatment of infundibula, even in SAH patients. Treatment should be directed toward an associated aneurysm, not the infundibulum.