Fetoscopic two-layer closure for open neural tube defects: prospective study of obstetric, surgical and perinatal outcomes in the first 50 cases

Fetoscopic repair for open neural tube defects (ONTDs) has gained acceptance among leading groups, although it remains controversial owing to the lack of a standardized neurosurgical technique. In 2018, our group described a new fetoscopic two-layer procedure with an exteriorized uterus for ONTD reconstruction. This study aimed to report obstetric, surgical and perinatal outcomes for the first 50 cases since the implementation of this technique and to provide comparative data with open fetal surgery studies.

This was a single-center, observational, prospective study conducted between February 2017 and September 2024. Patients scheduled for fetoscopic repair of ONTD using the two-layer technique with uterine exteriorization were included, and variables such as maternal characteristics, prenatal diagnosis, surgical technique, obstetric outcome, perinatal outcome and complications were evaluated. We compared these with the outcomes of the Management of Myelomeningocele Study (MOMS) cohort and a post-MOMS cohort.

Fetoscopic repair of ONTD was performed successfully in all 50 (100%) cases, with no conversions to hysterotomy repair. Of these, 48 cases resulted in a live birth, one in stillbirth and one pregnancy was terminated. Presurgical ultrasound identified myelomeningocele in 29 (58.0%) and ventriculomegaly in 27 (54.0%) cases. The mean ± SD gestational age at surgery was 25.0 ± 1.1 weeks, and the mean procedure duration was 178 ± 37.6 min. In 42 (84.0%) cases, the repair was performed using a two-layer technique. Complications included preterm prelabor rupture of membranes in 24/49 (49.0%) cases and chorioamniotic membrane separation in 11/49 (22.4%). Among the live births, delivery occurred at a median gestational age of 36.0 (interquartile range (IQR), 33.9-37.2) weeks, with 14/48 (29.2%) delivering at term. Median birth weight was 2510 (IQR, 2178-2816) g, and no cases of neonatal death were reported. Postnatal motor function was equal or better than the presurgery motor level in 26/34 (76.5%) cases. No case of cerebrospinal fluid leakage at the spinal repair site was reported. Comparison with the MOMS and post-MOMS studies showed a higher gestational age at delivery, improved motor outcome and less respiratory distress syndrome than in the post-MOMS cohort. Vaginal delivery occurred in 47.9% of cases in our cohort, in contrast to the MOMS and post-MOMS cohorts, in which all deliveries were by Cesarean section.

The hybrid two-layer closure of ONTDs is a safe procedure, yielding obstetric and perinatal outcomes comparable with those of open surgery. However, it may not be suitable for all types of defect. Long-term data are required to allow for comprehensive comparisons and to determine whether this technique should be recommended over other current surgical options. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.