Endoscopic third ventriculostomy, HydrocephalusNeuroendoscopy Predictive valueThird ventricle

OBJECTIVE: Preoperative third ventricle deformation (known as 'bowing') is associated with higher endoscopic third ventriculostomy (ETV) success. In children, the effect of bowing has not to date been systematically studied. Aim of of this study is to determine the effect of bowing on ETV success in adult and child patients. PATIENTS AND METHODS: In this retrospective, monocentric study were included 135 (70 adults and 65 children) of 157 patients who underwent ETV between 2008-2016, with mean follow-up 4.3 years. Presence and extent of bowing and its impact on ETV outcome were evaluated. Third ventricular anatomy was assessed on pre- and postoperative MR imaging. RESULTS: In patients > 6 months old, the ETV success rate was 91% in bowing-positive cases and 47.6% in bowing-negative cases. Among patients < 6 months old, ETV was successful in 37% of those with bowing and 36.4% of those without. Presence of bowing strongly indicates ETV success in patients older than 6 months (p < 0.000 5), including children of 7 months and older (p 0.001). This relationship was not confirmed in pediatric patients up to 6 months old (p 1.000). The extent of bowing does not influence ETV success (p 0.559). Bowing correction strongly correlates with ETV success (p < 0.000 5). CONCLUSION: We confirmed significant correlation between bowing and ETV success in patients over 6 months old. This relationship was not determined in those younger than 6 months and therefore we do not recommend bowing in ETV indication criteria for this patient cohort.