Changes in third ventricular size in pediatric patients undergoing endoscopic third ventriculostomy.

PURPOSE: Optimal methods of evaluating radiographic data following endoscopic third ventriculostomy (ETV) are not yet known. This study analyzes imaging parameters, including third ventricular width and cross-sectional area (CSA), in pediatric ETV patients.
METHODS: Hydrocephalic pediatric patients treated by ETV at the senior authors' institution from 2004 to 2011 were stratified clinically (successful versus unsuccessful outcome) and retrospectively reviewed. Measured from pre- and post-operative imaging studies, third ventricular parameters included maximal width and mid-sagittal CSA, while lateral ventricular parameters included the ratio of greatest frontal horn width to co-linear skull internal diameter and the frontal-occipital horn ratio.
RESULTS: Ten successful ETV patients (mean age 10.6 years; range 11 months to 19.8 years) obtained imaging at least 2.75 months following surgery, while four unsuccessful ETV patients (mean age 9.8 years; range 4 months to 17.3 years) underwent imaging before repeat intervention. Third ventricular width showed an average decline of 0.32 cm and 17.4 % in the successful ETV cohort, but average increases of 0.35 cm and 21.0 % in the ETV failure group. Successful ETV patients exhibited mean decreases of 1.85 cm(2) and 19.7 % in third ventricular mid-sagittal CSA, while unsuccessful ETV patients showed mean increases of 1.17 cm(2) and 17.3 % per patient. These differences were statistically significant. Measures of lateral ventricular size showed similar trends, but with lower magnitude.
CONCLUSIONS: Third ventricular imaging parameters (width and mid-sagittal CSA) exhibited more pronounced responses to ETV than lateral ventricular measurements in pediatric hydrocephalic patients.