Transpetrosal Approach to a Ruptured Distal Basilar Perforating Artery Aneurysm

Abstract

Basilar perforating artery aneurysms are rare and underreported vascular anomalies in the cerebrovascular literature. Various open and endovascular treatment approaches can be employed to treat these aneurysms based on several patient- and aneurysm-specific factors. Some authors have even advocated for conservative, nonoperative management. Here, we report a case of a ruptured distal basilar perforating artery aneurysm secured by an open transpetrosal approach. A 67-year-old male presented to our institution with a Hunt-Hess grade 2, modified Fisher grade 3 subarachnoid hemorrhage (SAH). Initial cerebral digital subtraction angiography (DSA) did not identify an intracranial aneurysm or other vascular lesions. However, the patient had a re-rupture event several days after presentation. DSA at this time revealed a posteriorly projecting distal basilar perforating artery aneurysm. Initial attempts with endovascular coil embolization were unsuccessful. Thus, an open transpetrosal approach was taken to gain access to the middle and distal basilar trunk to secure the aneurysm. This case underscores the unpredictability of basilar perforating artery aneurysms and the challenges encountered when considering active treatment. We demonstrate an open surgical approach with an intraoperative video for definitive management after failed attempted endovascular treatment.

Keywords: basilar artery aneurysm; basilar perforating aneurysm; cerebrovascular surgery; operative video; transpetrosal approach.

Figure 1. Axial computed tomography of the head demonstrating extensive diffuse subarachnoid hemorrhage involving the premedullary and prepontine cisterns extending into the basal cisterns (A) and evidence of early obstructive hydrocephalus (B)

Figure 2. Computed tomography angiography of the head (mean intensity projection) without evidence of basilar perforator aneurysm in the sagittal (A) nor the coronal (B) plane

Figure 3. Three-dimensional reconstructions from digital subtraction angiography post-bleed day 1 demonstrating angiographic occult perforator aneurysm arising from the distal basilar artery near its junction with the right superior cerebellar artery (A) and a similar angled reconstruction created during digital subtraction angiography following re-rupture (B) as well as lateral view of the aneurysm (C)

Figure 4. Small area of diffusion-weighted restriction in the right anterior portion of the rostral pons (A); right anterior oblique view of the basilar artery during postoperative digital subtraction angiography showing complete aneurysmal obliteration (B)