Corrective procedure performed in utero reduces effects of spina bifida

by Craig Boerner

A seven-year trial funded by the National Institutes of Health has demonstrated clear benefit for babies who undergo fetal surgery to treat spina bifida, the most common birth defect of the central nervous system. The surgical procedure, in utero repair of myelomeningocele, was pioneered at Vanderbilt University Medical Center in 1997.

Researchers at the Management of Myelomeningocele Study’s (MOMS) three trial sites – Vanderbilt, the University of California-San Francisco and Children’s Hospital of Philadelphia – halted the study in December 2010 after finding the procedure demonstrates significant benefit over the current standard of care, surgical repair after birth. The findings, published in the Feb. 9 online issue of the New England Journal of Medicine, show babies who have corrective surgery for a serious form of spina bifida while still in the uterus experience a reduction in potentially life-threatening hydrocephalus and have an increased ability to walk.

“The results are very exciting and confirm what our surgeons and researchers found back in 1999,” said John Brock III, surgeon-in-chief for the Monroe Carell Jr. Children’s Hospital at Vanderbilt and principal investigator for the Vanderbilt site of MOMS. Teams of Vanderbilt experts, led by maternal/fetal surgeon Joseph Bruner, who is no longer at Vanderbilt, and Noel Tulipan, director of pediatric neurosurgery, pursued research in the early 1990s that led to the first such procedures in the country. The Vanderbilt team published evidence that the surgery was beneficial in the Journal of the American Medical Association in 1999.

In myelomeningocele, which occurs in 3.4 per 10,000 births, 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 often are left with severe disabilities including paralysis below the waist and lifelong bladder and bowel problems. Nearly 90 percent of children with this disorder develop hydrocephalus, a buildup of fluid within the brain that requires surgical placement of a shunt to drain. Shunts can impact intellectual development.

The MOMS trial spanned seven years and included 183 participants. Half of the patients were randomized to receive fetal surgery to close their babies’ spines between the 19th and 25th weeks of gestation. The study was designed to address the “two-hit” theory – that in addition to the damage sustained during development, the nervous system continues to experience damage from environmental exposure in utero. The MOMS trial found fetal surgery reduced the need for a shunt by almost 30 percent and significantly improved the child’s chances of being able to walk. There was no increased risk of death for the baby or the mother when the fetal surgery group was compared with a group that received surgery after birth.

In light of the trial’s findings, VUMC is immediately offering the procedure to patients. Brock said Vanderbilt’s experience makes it one of only a few centers prepared to begin this intervention immediately.

The new Fetal Surgery for Spina Bifida Program will be housed in the Junior League Fetal Center at Vanderbilt. For more information, visit www.childrenshospital.vanderbilt.org/fetalsurgery. 

Posted 03/01/11