In a study published online Wednesday in the New England Journal of Medicine, researchers reported that fetuses with spina bifida, a defect that affects the spinal cord, were less likely to suffer some of the most serious complications of the disease when they were operated on in the womb compared with babies who underwent the same surgery after birth. They were twice as likely to be able to walk unaided by the time they were toddlers.
During the trial, participants were divided randomly into a prenatal or a postnatal surgery group. The study was supposed to last at least nine years, but the results were so positive after eight years that researchers stopped it so that all families could have access to the fetal surgery if they wanted it.
Surgeons involved with the trial hailed the results as the first major vindication for fetal surgery, which has long been controversial, in part because it puts the lives of healthy mothers at risk. The study did not address other types of fetal surgery.
Study a 'game-changer'
"This is a huge game-changer for fetal surgery," said Dr. Diana Farmer, lead author of the study and surgeon-in-chief at UCSF's Benioff Children's Hospital. "This study shows it can be done pretty safely, and it will open the door for other patients and other diseases. It really does validate the original hypothesis, 30 years ago, that you could improve the outcomes for these children if you operated on them before birth."
The spina bifida trial involved 183 mothers at three facilities around the country. In a show of cooperation, all medical facilities not involved in the study agreed to stop providing the surgery. That meant that any mother who wanted the surgery had to participate in the study, and take the chance that she might be not be selected for the fetal surgery group.
Spina bifida is one of the most common survivable birth defects, affecting about 1,500 newborns every year. In spina bifida, the neural tube - a structure that forms in the first few weeks of pregnancy and eventually becomes the brain and spinal cord - fails to develop or close properly. The UCSF trial focused on only the most severe cases, in which part of the spinal cord juts out of the child's back, protected only by a thin sac.
Children with the most serious type often suffer severe complications, including partial paralysis, bowel and bladder control problems, difficulty walking, and hydrocephalus, or water on the brain. Almost all children with spina bifida need a permanent shunt to drain fluid from their brain.
The theory with fetal surgery is that much of the damage done by the exposed spinal cord happens toward the end of pregnancy or just after birth, and if surgery is performed while the fetus is still in the womb, some of the worst complications can be prevented.
Spared complications
In the study, 68 percent of the babies who had fetal surgery needed a shunt by the time they were 1 year old, compared with 98 percent of babies who had postnatal surgery. By age 2 1/2, 42 percent of children who had the prenatal surgery were able to walk without orthotics or other devices, compared with 21 percent of the postnatal surgery children.
"It's clear here that by doing prenatal surgery, a number of kids were spared future complications," said Dr. Paul Fisher, chief of pediatric neurology at Lucile Packard Children's Hospital at Stanford. "In some kids, you can treat the disease before it gets out of control."
The first fetal surgery to treat spina bifida was performed in 1997, and over the next six years more than 200 fetuses underwent the procedure, although it hadn't yet been formally tested and no one knew for sure just how much babies benefited from it.
During the surgery, which is performed when the fetus is 19 weeks to 26 weeks, doctors make a small incision in the mother's belly, and then cut into the uterus, careful to avoid the placenta.
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