Anatomical Surgical Trajectory for Endoscopic Transcortical Third Ventriculostomy: A Neuronavigation-Guided Cadaveric...

Endoscopic third ventriculostomy (ETV) is a widely used surgical treatment for obstructive hydrocephalus. While the anatomical landmarks of the third ventricular floor are well described, the organization of white matter (WM) tracts along the transcortical ETV corridor and their correlation with neuronavigation and endoscopy remain insufficiently clarified. This study aimed to anatomically map the transcortical ETV trajectory from cortical entry to the third ventricular floor using stepwise cadaveric dissections integrated with neuronavigation and clinical correlation.

Stepwise WM dissections were performed in 8 formalin-fixed human brains. Dissections were conducted with and without navigation guidance, extending from cortical entry points to the ventricular floor. Real-time tracking and endoscopic visualization were employed to document anatomical structures and their relationships to the corridor. The anatomically defined trajectory was subsequently applied in a pediatric cohort undergoing neuronavigation-guided transcortical ETV.

Neuronavigation-guided cortical entry points were localized between the superior and middle frontal gyri, avoiding eloquent cortical regions. Stepwise dissections demonstrated the orderly traversal of U-fibers, superior longitudinal fasciculus, arcuate fasciculus, fronto-aslant tract, corona radiata, and callosal fibers before ventricular entry. Endoscopic correlation confirmed the midline tuber cinereum, just anterior to the mammillary bodies, as the optimal perforation site. In the clinical series, this trajectory was associated with favorable radiological and clinical outcomes without permanent neurological deficits.

Defining the transcortical ETV route on the basis of a detailed WM anatomy and neuronavigation enables a reproducible and anatomically defined surgical pathway. This integrated anatomical framework supports standardized surgical planning and offers practical value for pediatric neuroendoscopic practice.