Endoscopic third ventriculostomy in idiopathic normal pressure hydrocephalus. Efficacy and possible positive...

Current best practice for the treatment of idiopathic normal pressure hydrocephalus (iNPH) involves ventriculoperitoneal shunt implantation, which is associated with several long-term complications. Throughout the last two decades endoscopic third ventriculostomy (ETV) has emerged as an alternate therapeutic modality. This modality promises a lower incidence of surgical and postoperative complications. This review focuses on patients with iNPH treated via ETV, compares the efficacy of ETV between individual studies and summarizes predictive measures of ETV success.

The development of the protocol was guided by the Preferred Reporting Items for Systematic Review and MetaAnalysis Protocols 2015 statement. Relevant literature was selected using complex registers and in several bibliographical databases. A total of 17 original articles comparing the efficacy of ETV were selected for the review, 12 of which were used to analyze positive predictors of ETV therapy.

A total of 282 patients with iNPH underwent ETV, with an average efficacy 63.7 %. Positive predictors of ETV treatment were the presence of pathological outflow resistance (R_out) in the ventricular compartment during cerebrospinal fluid (CSF) dynamic tests, hyperdynamic CSF flow, functional stenosis of the Sylvian aqueduct and/or bowing of the third ventricle on magnetic resonance imaging (MRI). Further positive predictors included short duration of symptoms and a predominantly gait-centric clinical presentation.

Endoscopic treatment of patients with iNPH remains controversial and shunt surgery remains the treatment of choice. The analyzed studies show that a subset of patients profit from ETV. Further studies with robust randomized cohorts comparing ETV to shunting are necessary.