Safety and Performance of the Polaris® 24 Adjustable Valve System in Hydrocephalus Patients' Treatment

Inclusion Criteria: * Patient implanted with the Polaris® 24 adjustable valve system for the following reasons: * Primo implant of a valve shunt-based derivation system, or as a * Replacement of another valve -based shunt system, or * Endoscopic ventriculostomy (EVT) failure * Patient having given his/her informed consent prior to inclusion in this study, as per local regulations Exclusion Criteria: * Confirmed or suspected infections along the length of the shunt (meningitis, ventriculitis, peritonitis, septicemia or bacteremia) or any infection present in any part of the body * Patient on anticoagulant therapy, or presenting with bleeding diathesis, or with haemorrhagic CSF, as the presence of blood in the system could lead to an obstruction in the system * Ventriculo-atrial shunts in patient suffering from congenital cardiopathies or other malformations of the cardio-pulmonary system