Prenatal diagnosis and postnatal outcome of closed spinal dysraphism.

Objective: To evaluate the prenatal diagnosis of closed dysraphism (CD) and its correlation with postnatal findings and neonatal adverse outcomes. Methods: A retrospective cohort study including pregnancies diagsnosed with fetal CD by prenatal ultrasound (US) and magnetic resonance imaging (MRI) at a single tertiary center between September 2011 and July 2021. Results: CD was diagnosed prenatally and confirmed postnatally in 12 fetuses. The mean gestational age of prenatal imaging was 24.2 weeks, in 17% the head circumference was ≤fifth percentile and in 25% the cerebellar diameter was ≤fifth percentile. US findings included banana sign in 17%, and lemon sign in 33%. On MRI, posterior fossa anomalies were seen in 33% of cases, with hindbrain herniation below the foramen magnum in two cases. Mean clivus‐supraocciput angle (CSA) was 74°. Additional anomalies outside the CNS were observed in 50%. Abnormal foot position was demonstrated prenatally in 17%. Neurogenic bladder was present in 90% of patients after birth. Conclusion: Arnold Chiari II malformation and impaired motor function can be present on prenatal imaging of fetuses with CD and may be associated with a specific type of CD. Prenatal distinction of CD can be challenging. Associated extra CNS anomalies are frequent and the rate of neurogenic urinary tract dysfunction is high. Key points: What is already known about this topic? Closed dysraphism poses a challenge in prenatal diagnosis.There is limited data on the prenatal findings and postnatal outcome. What does this study add? Cranial findings associated with Arnold Chiari II (AC II) malformation and impairment of motor function can be present on prenatal imaging of fetuses with closed spinal dysraphism and may depend on the specific type of closed dysraphism. MRI adds important information.Ventriculoperitoneal Shunt rate is very low and abnormal corpus callosum seems not to be a typical finding. Anomalies of the urogenital and skeletal systems are frequently associated. Neurogenic bladder is a common finding. [ABSTRACT FROM AUTHOR]