Tim van Mieghem

Objectives To determine simple prenatal imaging parameters that can easily be acquired to predict the need for postnatal CSF diversion (PCD) surgery in fetuses undergoing open fetal surgery for open spina bifida (OSB). Methods All fetuses with OSB that underwent open fetal surgery between June 2017 and June 2021 with available follow‐up outcomes were included. Imaging parameters including clivus‐supraocciput angle (CSA) on magnetic resonance imaging, transcerebellar diameter (TCD) and lateral ventricle size (Vp) on ultrasound (US), were collected pre‐ and postoperatively. The requirement for PCD surgery was determined at 1 year of age. The predictive strength of each parameter was determined by Receiver Operating Characteristic curve analysis. Results Among 36 babies eligible for the analyses, 41.7% required PCD by one year of age. Pre‐operative Vp (AUC 0.71; 95% confidence interval [CI] 0.54–0.88; p = 0.03), TCD (AUC 0.72; 95% CI 0.55–0.89; p = 0.02) and CSA (AUC 0.72; 95% CI 0.51–0.93; p = 0.04) were fair predictors for PCD surgery. After fetal surgery, TCD (AUC 0.93; 95% CI 0.83–1.00; p < 0.0001) and CSA (AUC 0.94; 95% CI 0.83–1.00; p = 0.0005) were outstanding predictors of PCD, whereas post‐operative Vp was a fair predictor (AUC 0.71, 95% CI 0.54–0.88, p = 0.03). Conclusion Post‐operative CSA and TCD were outstanding predictors for the need for PCD surgery.