The increasing use of screening ultrasonography and amniocentesis has resulted in early detection of neural tube defects (NTDs), and the use of fetal MRI has improved accuracy of the diagnosis (Figure 1). Diagnosis is now common at 18 weeks of gestation, allowing time for a thorough discussion of the likely outcome with parents. In addition to the standard options of termination of the pregnancy and continuation of the pregnancy until term with cesarean or vaginal delivery, fetal closure of the defect as part of the Management of Myleomeningocle Study (MOMS) is an option for some families in the United States.

The uterus is exposed through a low transverse abdominal incision. The fetal and placental positions are determined by ultrasound and the uterus is mobilized for optimal exposure. The hysterotomy is performed with monopolar cautery between large hemostatic sutures, and enlarged with a uterine stapler, which simultaneously incises the uterine wall and lays down a layer of absorbable hemostatic clips to preserve the intrauterine membranes. The hysterotomy is in the upper segment of the uterine corpus and fetal surgery necessitates cesarean delivery for all subsequent pregnancies because of the risk of uterine rupture. Every attempt is made to maintain intrauterine volume to prevent placental separation, contractions, and expulsion of the fetus. This is accomplished by continuous high-volume perfusion of the amniotic cavity with warm Ringer's lactate solution and by exposing only the portion of the fetus that is necessary. The fetus is not removed from the uterus, and the surgery is performed through the hysterotomy opening (Figure 2). Care must also be taken throughout the procedure to avoid umbilical cord compression, which can occur at the margins of the hysterotomy. Fetal cardiac sonography is perfomed throughout the operation to warn of any threat to fetal circulation.50,51