Is the endoscopic third ventriculostomy success score an appropriate tool to inform clinical decision-making?

Introduction: The endoscopic third ventriculostomy success score (ETVSS) is a model, which provides each patient with a prediction of the outcome of endoscopic third ventriculostomy. The objective of this study was to determine if there is clinical value to the use of the ETVSS in the decision for ETV. Methods: Prospectively collected data on all ETV procedures with the Republic of Ireland in children <= 16 years of age, totalling 112, from 2008 to 2014 was analysed. The percentage chance of success at six months was retrospectively calculated according to the ETVSS. A multivariable model, comprising the risk factors from the ETVSS - age, aetiology and previous shunt - was created and its performance compared to that of the ETVSS. Results: The ETVSS achieved an AUC of 0.61 (95% CI: 0.49-0.71) with a sensitivity and specificity of 50% and 76%, respectively, at its optimal cutoff. The ETVSS was not significantly well calibrated in this cohort and there was a limited net benefit on decision curve analysis in comparison with the strategy of performing ETV in all patients. The multivariable model achieved an AUC of 0.67 (95% CI: 0.56-0.78), was well calibrated and was associated with a superior net benefit over that of the ETVSS. Conclusion: The ETVSS represents the future of patient risk stratification with an easy to use, individualised approach for each patient. The ETVSS has performed adequately in this study. However, through the addition of novel risk factors, the continuous updating of the model and recalibration where needed, the ETVSS can become a tool that the paediatric neurosurgeon cannot do without.