Aim:This study aimed to analyze the success rates of repeat endoscopic third ventriculostomy (re-ETV) procedure according to ventriculostomy orifice closure types in patients who have undergone a second neuroendoscopic surgery for non-communicating hydrocephalus.Material and Methods:The study included 74 patients who underwent re-ETV procedure due to dysfunctional ventriculostomy orifice. Ventriculostomy closure patterns are classified into three types: Type-1 is defined as the complete closure of the orifice with non-transparent gliosis or scar tissue. Type-2 represents the closure or narrowing of the orifice by newly formed translucent membranes. Type-3 pattern is defined as the blockage of CSF flow due to newly formed reactive membranes in the basal cisterns, with an intact ventriculostomy orifice.Results:The frequency of the ventriculostomy closure patterns was found as follows. Type-1: 17 cases (22.97%); Type-2: 30 cases (40.54%); and Type-3: 27 cases (36.48%). The success rate of the re-ETV procedure according to closure types was 23.52% in Type-1 cases, 46.66% in Type-2 cases, and 37.03% in Type-3 cases. A significantly higher rate of Type-1 closure pattern was observed in the myelomeningocele associated hydrocephalus cases (P < 0,01).Conclusion:In cases where ETV failure occurs, an endoscopic exploration with reopening of the ventriculostomy orifice is a preferable treatment option. Therefore, identifying patients who may benefit from the re-ETV procedure is essential. Type-1 closure pattern was observed to have a higher frequency in cases where hydrocephalus was associated with myelomeningocele, and the success rate of re-ETV seems to be lower in those cases.