Fetal surgery for myelomeningocele: patient selection, perioperative management and outcomes.

Myelomeningocele (MMC), one of the most common congenital malformations, can result in severe lifelong disabilities,including paraplegia, hydrocephalus, Chiari II malformation(CM-II), incontinence, sexual dysfunction, skeletal deformations and mental impairment. MMC was the first nonlethal anomaly to be treated by fetal surgery. Experimental and clinical evidence suggests that the primary cause of the neurologic deficit associated with MMC is not simply incomplete neurulation but rather chronic mechanical injury and amniotic fluid-induced chemical trauma that progressively damages the exposed neural tissue during gestation. Case series and a prospective, randomized study show that fetal surgery for MMC before 26 weeks' gestation may preserve neurologic function, reverse the hindbrain herniation of the CM-II and obviate the need for postnatal placement of a ventriculoperitoneal shunt. However, these studies also demonstrate that fetal surgery is associated with significant maternal and fetal risks. Consequently, further research is warranted to further expand our understanding of the pathophysiology of MMC, to evaluate the long-term impact of in utero intervention and to refine the timing and technique of fetal MMC surgery.