Giant dolichoectatic basilar trunk aneurysms have an unfavorable natural history and are associated with high morbidity, but their neurosurgical treatment is complex and challenging.
Flow reversal reconstruction with fourth-generation bypass and proximal vertebral artery clip occlusion is performed via orbitozygomatic craniotomy with the Kawase approach under rapid ventricular pacing.
Fourth-generation bypass is an innovative, technically challenging, and clinically effective tool in the treatment armamentarium for giant dolichoectatic basilar trunk aneurysms.
