Fetal Surgery Procedure Yields Landmark Results

A new study demonstrates a clear benefit for babies who undergo in-utero repair of myelomeningocele to treat spina bifida, the most common birth defect in the central nervous system (CNS).

Researchers at Vanderbilt University Medical Center (Nashville, TN, USA), the University of California, San Francisco (UCSF; USA), and Children's Hospital of Philadelphia (CHOP; PA, USA) randomly assigned 183 eligible women participating in the management of myelomeningocele study (MOMS) to undergo either prenatal surgery before 26 weeks of gestation, or standard postnatal repair. The main study outcomes were a composite of fetal or neonatal death or the need for placement of a cerebrospinal fluid (CSF) shunt by the age of 12 months, and a composite of mental development and motor function at 30 months. The study was stopped for efficacy of prenatal surgery after the recruitment of 183 of a planned 200 patients

The researchers based on the study results on 158 patients whose children were evaluated at 12 months. The actual rates of shunt placement were 40% in the prenatal-surgery group and 82% in the postnatal-surgery group. Prenatal surgery also resulted in improvement in the composite score for mental development and motor function at 30 months, and in improvement in several secondary outcomes, including hindbrain herniation (Chiari Malformation) by 12 months and ambulation by 30 months. However, prenatal surgery was also associated with an increased risk of preterm delivery and uterine dehiscence at delivery. The study was published early online on February 9, 2011, in the New England Journal of Medicine (NEJM).

"Because mothers are willing to go to extraordinary lengths to help their babies, and bear significant risks, even to their own health, we needed compelling evidence that the procedure is beneficial and safe,” said study coauthor surgeon Kelly Bennett, MD, who performed the maternal portion of the surgery at Vanderbilt. "It is very satisfying to me that, with this new evidence, we can change our dialogue with families and offer the information they need to be able to make an informed decision.”

Spina bifida is a developmental birth defect caused by the incomplete closing of the embryonic neural tube due to lack of folic acid (folate). The layers of tissue and bone that normally cover and protect the spinal cord fail to close during development, leaving delicate nerves exposed to the intrauterine environment. Children are often left with severe disabilities, including paralysis below the waist and lifelong bladder and bowel problems. Nearly 90% of children with this disorder develop hydrocephalus, a fluid build-up within the brain, which requires surgical placement of a shunt to drain excess CSF, which, while necessary to save a child's life, can impact intellectual development.

Related Links:
Vanderbilt University Medical Center
University of California, San Francisco
Children's Hospital of Philadelphia