Distal Basilar Perforator Artery Aneurysm: Case Report

OBJECTIVE AND IMPORTANCE: Distal basilar artery aneurysms represent 5 to 8% of intracranial aneurysms. It is crucial to preserve all of the basilar apex perforating vessels when dissecting in this region. This report is the first to describe a rostral basilar perforating artery that was the anatomic origin of a cerebral aneurysm. CLINICAL PRESENTATION: A 56-year-old woman presenting with subarachnoid hemorrhage underwent initial four-vessel cerebral angiography that did not demonstrate the source of her hemorrhage. A follow-up cerebral angio-gram 9 days later suggested a small aneurysm in the region of the left superior cerebellar artery. INTERVENTION: A left pterional craniotomy was performed. An aneurysm arising from the origin of a distal basilar perforating artery was identified and obliterated with a small vascular clip. Flow was preserved in the perforating vessel, and the patient had an excellent outcome. CONCLUSION: The findings in the report illustrate the novel anatomic principle that a distal basilar perforating vessel can serve as the anatomic origin of a cerebral aneurysm. Knowledge of this entity would be helpful in avoiding complications at surgery, including perforator injury or aneurysmal rupture in such cases.