HCRN Core Data Project: Characterizing Patient Populations in the Hydrocephalus Clinical Research Network (HCRN)

Inclusion Criteria: Information for all neurosurgical hydrocephalus patient events will be obtained from each HCRN Clinical Center and will be placed continuously into the Core Data Project. The first calendar year will be 2008, and data collection will continue for the duration of the existence of the HCRN. Neurosurgical hydrocephalus patient events include any operation for the treatment of documented hydrocephalus including the following: * Ventriculoperitoneal shunt * Ventriculoatrial shunt * Ventriculopleural shunt * Arachnoid cyst shunts * Subdural shunts * Lumboperitoneal shunts * Shunts replaced after treatment of infection * Shunts exposed during an operations but not revised * Endoscopic third ventriculostomies * Ommaya reservoir(s) * Ventricular access devices/reservoirs * Subgaleal shunts. Exclusion Criteria: The following temporary cerebrospinal fluid (CSF) diversion procedures will not be included in the Core Date Project: • External ventricular drain(s)