BackgroundDue to the compressive effect of the brain masses, hydrocephalus treatment is mainly achieved by shunting and discharge of fluid. However, some reports have shown the potential adverse effects of this method and its potential contraindications that result in focusing on preventive approaches like endoscopic third ventriculostomy (ETV). Hence, in the present study, the authors undertook a study to examine the hypothesis that preoperative ETV could reduce the likelihood of hydrocephalus and the need for shunting in patients undergoing surgery for posterior fossa tumors. MethodsIn the current cross-sectional study, 40 consecutive patients were scheduled for surgery to remove posterior fossa masses using ETV preoperatively (n = 23) or were considered as the controls with no preoperative ETV (n = 17). Afterward, these patients were followed up for 2 months after surgery regarding hydrocephalus and the need for shunt insertion. The postoperative change in the ventricular-cranial ratio (VCR) was also compared in 2 groups. ResultsOf 23 patients in the ETV group, none required postoperative shunting due to the lack of evidence supporting hydrocephalus; however, 7 patients were found to require shunting in the non-ETV group. Notably, the value of VCR significantly reduced in both groups with no significant difference. ConclusionETV protocol before the surgical removal of posterior fossa tumors can effectively reduce the rate of postoperative hydrocephalus, decreasing the need for postoperative shunting.