A long-awaited study of surgery on fetuses with spina bifida has found that the drastic treatment can help in the first few years after birth—but at a price. The trial, the largest ever of fetal surgery, randomly assigned those afflicted with this debilitating disease to get surgery either in utero or after birth and tracked them until they were 2½ years old. It also examined risks to the mothers—one of the great controversies of fetal surgery, because they are usually healthy to begin with. Although this type of surgery is associated with a risk of premature birth, it nonetheless offers clear health benefits, the trial found.
Fetal surgery has been around for nearly 30 years, but it's proven difficult to test how well it really works. Most fetal surgeries have focused on rare, fatal malformations, in which the fetus is likely to die without intervention. Spina bifida is different: It can leave children unable to walk and control bowel and bladder function, and in need of shunts to drain fluid from the brain, but it's less often life-threatening. Still, because surgery for spina bifida is straightforward—sealing an opening in the spinal column, which fails to close around the spinal cord as it should—surgeons began offering it prenatally more than 10 years ago. Families flocked to get it. But no one knew if operating before birth was preferable to operating after. What they did know was that fetal surgery had a number of complications, including causing premature birth, which in some cases killed babies who would otherwise have survived.
So in the early 2000s, three hospitals banded together with millions of dollars of support from the National Institute of Child Health and Human Development in Bethesda, Maryland. They studied whether fetal surgery could reduce the neurologic effects of a severe form of spina bifida by protecting the spinal cord from amniotic fluid by sealing the opening before birth. The results, published online today in The New England Journal of Medicine, report on 158 mothers and their babies. The surgeries took place at Children's Hospital of Philadelphia (CHOP), Vanderbilt University, and the University of California, San Francisco (where the first successful fetal surgery was performed). The results were solid: Among 78 babies who underwent surgery while in the womb, during the second trimester, 40% needed a shunt by 1 year of age compared with 82% in the control group. The control group included 80 babies who had surgery very soon after birth. Forty-two percent of the fetal surgery group could walk without help from devices, compared with 21% in the control group. Cognitive scores were basically the same. The trial was stopped early after a data safety board concluded the surgery was making a substantial difference.
The "new therapy, we believe, is a standard of care in terms of the benefits," said N. Scott Adzick of CHOP, a pediatric surgeon who heads the fetal surgery program there and leader of the trial, at a press conference. All three hospitals in the trial plan to start offering the surgery to families.
That said, other numbers tell a more sobering story. Thirty-six babies, or almost half, who underwent fetal surgery were born at or before 34 weeks gestation, compared with four in the control group. One-fifth of babies who received prenatal surgery had respiratory distress syndrome, which the doctors attributed to premature birth. Five mothers experienced a placental abruption, which can kill the baby. (No mothers in the control group did.) Women who undergo fetal surgery must also have C-sections to deliver any future children. Two babies in each group died. In the fetal surgery group, one fetus died in utero at 26 weeks after the surgery, and another died from extreme prematurity. In the control group, two babies died from severe effects of spina bifida.
"I think that we will be offering this" fetal surgery, says Timothy Crombleholme, director of the Fetal Care Center at Cincinnati Children's Hospital Medical Center in Ohio, "however, with great trepidation and appropriate counseling." Crombleholme was at CHOP until 2004, when the trial was just beginning, but hasn't had any connection to it since. He worries that families will be overly enthusiastic and the risks need to be well communicated. Another challenge, he says, is that so far, the children in the trial haven't been followed all that long: Some children with spina bifida don't learn to walk until puberty, so in theory both groups—or just one—could experience improved motor skills. Developmental delays from prematurity often don't show up for years. And on the flip side, the neurologic downside of shunts, including on IQ, may not become apparent for some time. "I don't think we can say that we have an answer" yet about how helpful this surgery is, in many respects, says Crombleholme.
The researchers hope to continue following the children until they're between 6½ and 10 years old.