Prenatal surgery for spina bifida, one of the most common disabling birth defects, had significantly more benefit than surgery conducted after birth, and allowed some children to walk who otherwise likely couldn’t, according to a major study.
The study, published online Wednesday by the New England Journal of Medicine, means expectant parents who learn that their baby has spina bifida have an option beyond terminating the pregnancy or waiting until birth to correct the defect.
Researchers cautioned that the fetal procedure isn’t a cure and that for many babies it had limited impact on brain malformation and other complications of the defect. The procedure is also technically challenging and carries risks for baby and mother. But the findings were nevertheless significant validation for what once seemed improbable—that it is possible to enter the womb for surgical fixes that can better the lives of children with birth defects.
“This is really the first time there has been any hope for improving the outcomes for kids with spina bifida,” said Diana Farmer, senior author of the study and surgeon-in-chief at Benioff Children’s Hospital at the University of California, San Francisco. In addition to UCSF, the study was done at Children’s Hospital of Philadelphia and Vanderbilt University.
Spina bifida is one of a constellation of birth defects known as neural tube defects that affect development of the brain and spinal cord. Spina bifida, in which the skin around the lower spine fails to close during development, typically causes weakness or paralysis that leaves patients in wheelchairs or unable to walk without assistance. Most have bladder and bowel problems and a malformation of the brain that can require frequent surgeries to help drain fluid.
The incidence of neural tube defects had been on decline since the early 1990s thanks in part to a public health campaign to introduce more folic acid into the diets of women of childbearing age. But the decline has leveled off; about 1,500 children are born each year in the U.S. with spina bifida.
The first fetal surgery was performed 30 years ago, for a defect that would have been fatal. Spina bifida is the first usually nonfatal birth defect to be treated with fetal surgery.
The study involved 183 expectant mothers whose babies were diagnosed during the second trimester and who were randomly assigned to the repair either before or after the baby was born. Either way, the operation involves putting a patch over the defect in the lower back. The aim is to stop leakage of spinal fluid and prevent further injury to the spinal cord, but it doesn’t fix nerve and other damage already done.
In the study, the prenatal procedure was typically done at 24 weeks gestation. Surgeons make an incision in the abdomen and take out the uterus to get access to the fetus’s lower spine. They apply a patch and put the fetus and uterus back in the mother. The baby is delivered, ideally at close to full term, by Caesarean section.
At 12 months old, 40% of babies who had the surgery in the womb needed a shunt to drain fluid from the brain, compared with 83% in the post-natal group. That was the most significant benefit, researchers said. Revising or changing shunts can subject spina bifida patients to a childhood of surgeries. “If you can avoid a shunt, that in itself is a wonderful thing,” said Scott Adzick, surgeon-in-chief at Children’s Hospital of Philadelphia and lead author of the study.
At 30 months, 42% of babies in the prenatal group and 21% in the post-natal group were able to walk without crutches or other devices, researchers said.
But babies in the prenatal group were born on average after 34 weeks gestation, about three weeks earlier than those who had the post-natal operation. About 20% of those who had fetal surgery had breathing problems, reflecting their lungs’ failure to fully develop.
Two babies in the prenatal group died before they were born; two in the post-natal group died shortly after birth.
In an editorial accompanying the study, Joe Leigh Simpson of Florida International University and Michael F. Greene of Massachusetts General Hospital called it “a major step in the right direction” for spina bifida but said significant numbers of babies still had poor outcomes while mothers were at high risk.Less-invasive approaches are necessary before such surgery can be widely implemented, they said.
One child who was apparently helped by the prenatal repair is Thomas Giovanola. When his defect was discovered 21 weeks into his mother’s pregnancy, some damage was already done. His feet weren’t moving and there was evidence of the characteristic brain malformation that could mean he’d require a shunt.
Now age three and a half, Thomas is walking with the help of braces and a walker, said his mother, Heather Giovanola, a high-school English teacher. “He’s highly verbal and right on target with all his learning milestones,” she said. Especially encouraging, she adds, is that the brain malformation had reversed itself by his one-year checkup, and he doesn’t have a shunt.
“Our son has never had to have brain surgery,” she said, describing him as a regular kid. “He wants to jump off the steps and bounce on the couch.”
The procedure is “probably not for everyone,” she added. But “we’ve felt incredibly blessed that our son had the opportunity to have this done in utero.”
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