Myelomeningocele: prenatal diagnosis, pathophysiology and management.

Myelomeningocele (MMC) is a common birth defect that is associated with significant lifelong morbidity. Little progress has been made in the postnatal surgical management of the child with spina bifida. Postnatal surgery is aimed at covering the exposed spinal cord, preventing infection, and treating hydrocephalus with a ventricular shunt. In utero repair of open spina bifida is now performed in selected patients and presents an additional therapeutic alternative for expectant mothers carrying a fetus with MMC. Early fetal intervention may improve neurologic outcome and reduce the hindbrain herniation associated with the Arnold-Chiari II malformation. These changes may improve long-term neurologic function and limit requirements for shunt placements and other surgical interventions. Further research is needed to better understand the pathophysiology of MMC, the ideal timing and technique of repair, and the long-term impact of in utero intervention. A prospective, randomized clinical trial is planned comparing prenatal MMC repair with postnatal repair.