The open surgical repair of myelomeningoceles before 26 weeks gestational age provides a correction of the anomaly of Chiarri, reduces the incidence of ventriculomegaly (defined as a measure of the ventricles at the crossroads ≥ 10 mm), and get a lower of injury than one corresponding to the anatomical defect (as defined by the last upper normal vertebra before the defect).

The purpose of this study is to introduce in France an innovative technique for prenatal repair of myelomeningocele until now developed only on the American continent.

Spina bifida (SB) represents one of the most severe congenital malformation of the central nervous system and amenable to prenatal diagnosis. In the past 20 years, prenatal repair of SB has become an established technique.

The PRIUM study will include 10 cases of fetuses with prenatal diagnosis of SB and for whom the maternal willing will be to continue the pregnancy. A surgical prenatal repair of the defect will be planed at 19-25+6 weeks gestation following maternal laparotomy and hysterotomy under maternal general anesthesia. The delivery will be planed at 36 weeks'. Postnatal evaluation of the neonates will be scheduled at birth, 1 month, 12 months and 36 months of age. Those data will be matched to controls who have underwent a conventional postnatal repair of the SB

Inclusion Criteria:

• patient of majority age, with an assumption by health insurance, understanding and speaking French
• A term between 19 and 25 +6 weeks gestational age (not for control)
• Single-Pregnancy
• Normal fetal karyotype
• Myelomeningocele with higher-level defect between S1 and T1
• Placenta not low-inserted or not covering
• Fault-isolated ultrasound reference

Exclusion Criteria:

• Age under 18 years
• Patient foreigner who understands not French
• Multiple Pregnancy
• Low Placenta inserted or covering
• Severe kyphosis
• Placental abruption
• Fetal malformation unrelated to the existence of myelomeningocele (the existence of a malposition of one or both feet do not represent an exclusion criterion)
• Increased risk of preterm birth: a history of preterm delivery before 37 weeks gestational age, cervical length <26 mm before 26 weeks gestational age (not for control)
• Bleeding active between 20 and 26 weeks gestational age (not for control)
• Maternal obesity with BMI> 35 (not for control)
• History of uterine surgery involving the anterior surface of the uterus (not for control)
• Maternal contradiction in surgery or general anesthesia (not for control)