Relevant anatomical structures for the endoscopic third ventriculostomy (ETV) approach and their maintained integrity following ETV, such as massa intermedia, mammillary bodies, basilar artery, clivus, and the extent of Liliequist's membrane, also play an important role in outcome estimation. ETV is an effective treatment option for adult patients with noncommunicating hydrocephalus. The ETV success score (ETVSS) attempts to predict ETV success and failure in the treatment of childhood hydrocephalus by taking age cause of hydrocephalus. ETV has been reported to be an effective treatment for communicating hydrocephalus in certain patients. Communicating hydrocephalus is caused by decreased intracranial compliance which increases systolic pressure and fluid transmission into the brain parenchyma rather than cerebrospinal fluid (CSF) absorption. ETV success and complication avoidance during/following the operative procedure depends on precise preoperative planning, and is usually based on magnetic resonance imaging (MRI).