Microsurgical Treatment of a Giant Thrombosed Basilar Artery-Superior Cerebellar Artery Aneurysm With the Aid of Double Bypass Superficial Temporal Artery-Posterior Cerebral Artery and Superficial Temporal Artery-Superior Cerebellar Artery: 2-Dimensional Operative Video.

Giant thrombosed posterior circulation aneurysms are rare lesions with a natural history associated with high morbidity and mortality.1-6 The treatment has high risk with either microsurgical or endovascular treatment (ET). While ET allows easier access but high recurrence rate, microsurgical treatment has more difficult access but provides more durable lasting treatment.7-13 A 47-year-old woman presented with left hemiparesis from a right giant thrombosed basilar artery-superior cerebellar artery (BA-SCA) aneurysm buried in the brainstem with surrounding edema. Owing to risk of perforator occlusion and high recurrence rate with ET, we opted for microsurgical clipping with the aid of double protective bypass of superficial temporal artery-posterior cerebral artery (STA-PCA) and STA-SCA. The patient consented to the procedure and publication of her image. Initially, we performed a pterional craniotomy with zygomatic arch removal and exposed the right PCA, right SCA, BA, and aneurysm neck. Then, to perform a safe protective STA-PCA bypass, it was necessary to make a partial temporal lobectomy to avoid injury of a PCA-perforating branch. Subsequently, BA-SCA aneurysm was clipped. After clipping, STA-SCA bypass was performed to prevent possible occlusion of SCA afterward. After initial worsening of left hemiparesis and right oculomotor palsy, the patient recovered with rehabilitation and had no deficits 6 months after surgery. Postoperative imaging confirmed aneurysm exclusion, absence of ischemic lesions, and recovering of brainstem edema. Protective bypasses are a useful technique to improve outcomes in the microsurgical treatment of certain giant posterior circulation aneurysms. This report was approved by the ethics committee of our institution.