Endoscopic third ventriculostomy versus shunt under 2 years in triventricular hydrocephalus: A multicenter prospective study

The International Infant Hydrocephalus Study (IIHS) is an international, prospective, multicenter study to compare ETV and shunt in infants (<24 months old) with symptomatic triventricular hydrocephalus from aqueductal stenosis. IIHS utilized a prospective comprehensive cohort design, which contained both a randomized and non-randomized (parental preference) arm. Patients were followed prospectively for time to treatment failure, defined as the need for repeat CSF diversion procedure (shunt or ETV) or death due to hydrocephalus. The primary outcome was the Health Utilities Index score at the age of 5 years. Patient recruitment started in 2005 and concluded in 2013; hence 5-year primary outcome data collection has not been completed yet (as per April 2016). A preliminary survival analysis was performed to compare time to failure for ETV vs. shunt. A total of 158 patients were included (median age at surgery 3.6 mths, 115 ETV, 43 shunts) across 27 centers in 4 continents. Only 52 patients (32.9%) were randomized. Actuarial success rates for ETV vs. shunt at 6 months were 66% vs. 88%. The 6-month ETV success rate of 66% was slightly higher than would have been predicted by the ETV Success Score (57%). Patients younger than 6 months of age appeared to do relatively worse with ETV than older patients. These initial results suggest that shunting has a superior success rate compared to ETV, although the success rate for both was relatively high. We will await the results of the important primary outcome of health status at 5 years of age.