Fetal Treatment of Galenic Malformations

Inclusion Criteria: * Pregnant woman carrying a fetus harboring a vein of Galen malformation in whom the straight sinus or falcine sinus draining the prosencephalic varix measures 7 mm or more on fetal MRI (medio-lateral diameter measured at the narrowest point of the sinus along the rostral-caudal axis, assessed on a T2-weighted coronal slice). * Fetal gestational age between 23 weeks and term as determined by clinical information and evaluation of first ultrasound. * Anatomic diagnosis of fetal vein of Galen malformation. * Well preserved brain parenchyma. * Maternal age of 18 years and older. * Eligible for continuous lumbar epidural anesthesia. * Able to travel to study site for study evaluation, procedures and visits. Exclusion Criteria: * Extensive fetal brain parenchymal injury/gliosis, \>10% of supratentorial brain volume (i.e., SFP presentation). This is a degree of fetal brain injury beyond which the risk of significant neurological morbidity is high, based on studies of prenatal ischemic stroke. * Irreversible fetal non-brain organ injury (e.g. hydrops fetalis as a manifestation of heart failure, a finding which portends fatal outcome in fetuses with vein of Galen malformation), i.e., SFP presentation. * Fetus with VOGM in whom the straight sinus or falcine sinus draining the prosencephalic varix measures less than 7 mm on fetal MRI (T2-weighted coronal slice, medio-lateral diameter measured at the narrowest point of the sinus along the anterior-posterior axis),…