"Modified Half Pterional Transylvian and Half Subtemporal Approach" for Microsurgical Clipping of Superior Cerebellar Artery Aneurysm Treated With Previous Endovascular Flow-Diverting Stent: 2-Dimensional Operative Video.

The incidence of aneurysm persistence or recurrence after successful endovascular flow diversion ranges from 6% to 25%.(1-8) The understanding of microsurgical anatomy and its application to complex skull base and revascularization techniques are critical for treating posterior circulation aneurysms that have undergone prior flow diversion.(9-13) We describe the case of a 46-year-old woman who previously underwent endovascular flow diversion for an unruptured right superior cerebellar artery (SCA) aneurysm with persistent aneurysm filling over a 4-year period. Because the superior cerebellar artery originated from the neck of the aneurysm and she had prior thromboembolic complications from flow diversion, repeat endovascular treatment was deemed less favorable than microsurgical clipping. The patient underwent a cranio-orbital pterional craniotomy, Hakuba "peeling" of the temporal dura propria from the lateral wall of the cavernous sinus, and anterior clinoidectomy. The oculomotor nerve was exposed throughout its cisternal segment and the tentorium cut to widen the oculomotor-tentorial window.(14-16) A posterior clinoidectomy was performed with an ultrasonic bone claw.(17) The SCA, posterior cerebral artery, and basilar trunk were identified, and the aneurysm was clipped. Postoperative imaging showed a submillimeter remnant of the aneurysm which was left to maintain patency of the SCA. The technical considerations and literature on outcomes for microsurgical treatment of previously flow-diverted posterior circulation aneurysms are reviewed. The case presentation, operative nuances, and postoperative course with imaging are reviewed with detailed anatomic and cadaveric diagrams to orient the viewer. The patient and family provided informed consent for the procedure and verbal consent for the publication of this submission.