Open Spinal Dysraphism Without Hindbrain Herniation—Natural History and Postnatal Outcome

Bedei I.; Kik C.C.; Axt-Fliedner R.; DeKoninck P.L.J.; Ventura W.; Köhler S.; Schulze M.; Struffert T.; Kolodziej M.; Diehl D.; Sass B.; Spoor J.K.H.; Keil C. · Prenatal Diagnosis (2025) · DOI: 10.1002/pd.6855

Resumen

Objective: To report the natural history of fetuses with open spinal dysraphism (OSD) without hindbrain herniation (HBH) during second-trimester evaluation. Methods: A multicenter retrospective cohort study was conducted across three prenatal centers to evaluate fetuses with OSD. We reviewed cases with postnatally confirmed OSD without prenatal HBH at 19–27 weeks. Standardized prenatal evaluation consisted of repetitive ultrasound and magnetic resonance imaging. Postnatal outcome measures involved imaging, intraoperative findings and neurological function tests. Results: Among 280 fetuses with OSD, evaluated at a median gestational age of 21 weeks, a total of 12 (4%) lacked HBH. Moderate ventriculomegaly was observed in 33% of cases without HBH. Corpus callosum anomalies were not detected. Postnatally, HBH was present in 50%, while the shunt rate remained low (20%). In 80%, postnatal motor function (MF) was equal to or better based on the anatomical level. In 33%, MF after birth declined in comparison to the first fetal functional assessment in the second trimester. Conclusion: Fetuses with OSD and absent HBH in the second trimester demonstrate a low postnatal shunt rate. MF was frequently impaired at the initial second-trimester assessment, and in about a third of cases, postnatal MF seemed to have worsened. These findings may inform counseling and question the place of fetal surgery for this subgroup.