Presigmoid Transpetrosal Approach for Superficial Temporal Artery to Distal Posterior Cerebral Artery Bypass and Trapping of Aneurysm

Background and importance Aneurysms of the posterior cerebral artery (PCA) are uncommon, estimated at less than 1% of all cerebral aneurysms, and less than half occur distal to the P1/2 junction. Unfortunately, the conventional bypass approach for PCA aneurysms-primarily occipital artery to distal PCA cortical branches-has a history of unsatisfying results. Clinical presentation A 42-yr-old female presented with Fisher 3 Hunt-Hess 2 subarachnoid hemorrhage secondary to ruptured distal PCA aneurysm. She was initially evaluated by the endovascular service, but due to recent subarachnoid hemorrhage, endovascular treatment with flow diversion and/or vessel sacrifice was felt to be relatively contraindicated and the patient was referred for surgical evaluation for possible bypass. The patient subsequently underwent surgery for trapping of aneurysm and concomitant superficial artery to distal PCA bypass. Conclusion A novel approach for the treatment of a ruptured distal PCA aneurysm is described, consisting of posterior transpetrosal exposure and division of the tentorium with superficial temporal artery to P3 bypass.