Fetoscopic repair of open spina bifida between 26 0/7 and 27 6/7 gestational weeks and postnatal cerebrospinal fluid diversion.

To assess the rate and risk factors for cerebrospinal fluid (CSF) diversion among cases of prenatal repair of open spina bifida (OSB) performed from 26 0/7 to 27 6/7 gestational weeks, given a traditional cutoff of 25 6/7 weeks. This is a descriptive study of patients who underwent fetoscopic OSB repair (2019-2023) from 26 0/7 to 27 6/7 gestational weeks. Data were collected prospectively and examined as predictors of CSF diversion (ventriculoperitoneal shunt or endoscopic third ventriculostomy) within the first 12 months of life. Of 42 study patients, CSF diversion was required in 12 cases (28.6%). In bivariate analysis, only preoperative ventricular size was associated with the CSF diversion procedure (largest ventricle 14.5 ± 3.0 vs 11.9 ± 2.5 mm, p = .015). Multiple logistic regression showed that cases with preoperative ventriculomegaly ≥15 mm appeared more likely to have CSF diversion (OR 5.23, 95% CI 0.98-28.09, p = .054). Neither level of the lesion nor myeloschisis was associated with CSF diversion. Prenatal OSB repair from 26 0/7 to 27 6/7 gestational weeks was associated with a 28.6% risk of postnatal CSF diversion at 12 months of life. Results are similar to those in which repair is performed ≤25 6/7 weeks. Approximately 40% of patients undergoing prenatal open spina bifida (OSB) repair need CSF diversion at 1 year of life.The upper limit for percutaneous fetoscopic OSB repair has been 25 6/7 gestational weeks; few data exist regarding outcomes of prenatal repair after 25 weeks. OSB repair at 26 0/7-27 6/7 gestational weeks appeared to provide a similar benefit in reducing CSF diversion risk at 1 year of life.