Hindbrain herniation develops in surgically created myelomeningocele but is absent after repair in fetal lambs

OBJECTIVE: The purpose of our study was to determine whether prenatal repai r of myelomeningocele prevents or reverses hindbrain herniation in the shee p model. STUDY DESIGN: A myelomeningocele was surgically created in fetal sheep. One group was repaired later in utero; the others were delivered without repai r. After delivery, lambs were assessed for the presence of hindbrain hernia tion. RESULTS: In all lambs that had not undergone repair of the myelomeningocele , severe hindbrain herniation developed, whereas the brains of all lambs th at had undergone fetal repair were normal. CONCLUSION: Prenatal repair of myelomeningocele prevents or reverses develo pment of hindbrain herniation in the fetal lamb model.