Usefulness of 4K Indocyanine Green Videoangiography for Basilar Artery Identification During Endoscopic Third Ventriculostomy in Adults With Secondary Hydrocephalus: Technical Note and Four-Case Series

BACKGROUND AND OBJECTIVES: Endoscopic third ventriculostomy (ETV) achieves favorable outcomes in adults with secondary hydrocephalus, with reported success rates of approximately 78.8%. However, inflammation caused by tumor, infection, or previous surgical intervention frequently leads to thickening of the tuber cinereum (TC), observed in nearly half of such cases. When the TC becomes opaque, the basilar artery (BA) and its perforating branches cannot be visualized, substantially increasing the risk of catastrophic vascular injury during fenestration.To address this challenge, we used intraoperative indocyanine green (ICG) videoangiography to visualize the BA complex through the thickened TC. METHODS: We retrospectively reviewed adult patients with secondary hydrocephalus who underwent ETV with endoscopic ICG videoangiography between November 2018 and June 2025 (n = 4). RESULTS: In all cases, flexible neuroendoscopy revealed a markedly thickened TC, prompting a switch to a rigid 4K ICG endoscope. Intravenous ICG administration enabled real-time identification of the BA and its branches despite the opaque TC. CONCLUSION: ICG videoangiography provided clear vascular delineation in all 4 cases, and no BA or branch injuries occurred. These findings demonstrate that 4K ICG videoangiography offers reliable, real-time vascular guidance and serves as a valuable adjunct to enhance the safety of ETV in patients with thickened third ventricular floors.