Correct understanding of the definition and management strategies for refractory hydrocephalus.

Hydrocephalus refers to the abnormal accumulation of cerebrospinal fluid (CSF) in the central nervous system, typically resulting from an imbalance between CSF production and absorption. Traditional classifications of hydrocephalus do not incorporate management strategies (not classified according to the degree of difficulty of treatment). Clinically, hydrocephalus that is challenging to treat is often categorized as refractory hydrocephalus (RH). However, the absence of a unified definition of RH impedes the standardization of treatment approaches, raising clinical dilemmas. This article explores the definition, etiologies, classification, and management strategies for RH. Based on the literature and the Diagnosis-Related Group payment system principles, RH is clinically defined as progressive hydrocephalus meeting one or more of the following criteria: (1) the absence of significant clinical or radiological improvement within 60 days despite standard interventions, usually due to pathological factors, such as abnormal CSF characteristics, (2) inability to achieve curative surgical treatments attributable to complex anatomy such as abnormal dynamic changes or multiloculated compartments, and (3) failure to respond after two consecutive therapeutic procedures. RH consists of six distinct subtypes, with infectious hydrocephalus being the most common, followed by low-pressure hydrocephalus. Temporary management strategies for RH must be carefully tailored to patient-specific characteristics, considering the risk-benefit analysis of available measures. In cases of infectious RH, achieving CSF sterilization and evaluating the results are crucial. Curative surgery for infectious RH should be performed only after CSF has been completely sterilized to normal levels. In low-pressure RH, a critical focus is identifying and addressing the sites receiving CSF.