It’s not unusual for a baby who has spina bifida to require a permanent shunt to drain fluid from her brain. Because the neural tube defect affects nerves in the lower back and pelvis, many such children are incontinent and never learn to walk. Then there’s Anna Williamson, a basketball-playing, bike-riding, piano-playing 10-year-old.
Anna was operated on while still in the womb in an experimental fetal surgery that became the subject of an eight-year clinical trial designed to evaluate whether babies who receive corrective surgery prenatally have better outcomes than those who undergo the operation after birth.
The trial, led by researchers at the University of California, San Francisco (UCSF), was stopped early because of clear evidence that operating in utero resulted in healthier children. Specifically, it led to a decreased need for permanent shunts to direct fluid away from the brain, improved mental development and motor function and a greater likelihood that some children with spina bifida will learn to walk. Results were published online Wednesday in the New England Journal of Medicine. (More on Time.com: Prolonging Pregnancy: New Drug Helps Prevent Premature Birth)
“This is game-changing for spina bifida,” says Diana Farmer, the study’s senior author and surgeon-in-chief at UCSF Benioff Children’s Hospital. “It’s a pretty devastating disease.”
The conclusion of the trial means that fetal surgery for spina bifida — a type of neural tube defect that occurs early in pregnancy when the spinal cord fails to close completely — will be offered right away to expectant moms, first at UCSF and the Children’s Hospital of Philadelphia, then at a handful of other locations that support multidisciplinary fetal centers. Seeking treatment at centers that have experience with the surgery is important because the procedure is delicate for both mom and baby.
Although the upsides are significant, there are also accompanying risks, namely prematurity. Babies operated on after birth were born at 37 weeks — close to full-term — while babies operated on prenatally arrived at 34 weeks, and 13% were born before 30 weeks. (More on Time.com: Too Many Babies Are Delivered Too Early: Hospitals Should Just Say No)
Affecting 1 in every 1,000 live births, spina bifida can leave a child paralyzed beneath the spot of the lesion, which can translate to incontinence and inability to walk. Affected children also experience varying symptoms of Chiari malformation, in which the cerebellum dips too low into the neck, causing problems with speaking and swallowing. And most require a permanent shunt, a tube that drains a life-threatening accumulation of fluid from their brain into their abdomen. Shunts can get blocked or infected, which is why the study’s finding that 30% of babies operated on prenatally did not need one was particularly encouraging.
Fetal surgery was pioneered 30 years ago at UCSF, but it’s still considered complicated and risky. Prenatal surgery for twin-to-twin transfusion syndrome — in which abnormal blood vessel connections cause one twin to steal too much of the blood supply, leaving the other twin undersupplied — is the most common kind of fetal surgery.
Until doctors began correcting spina bifida in utero, fetal surgery had been reserved only for fatal defects out of concern for the safety of the mother. “I thought it was critically important to prove this really helped fetuses before we put the lives of mothers at risk,” says Farmer, who initiated the trial. “I know women will die from this procedure once it goes worldwide. It is a serious operation.” (More on Time.com: IVF Linked to Elevated Maternal Death Rate)
Before the trial began, about 150 prenatal surgeries for spina bifida had been performed in the U.S. The study assessed the best way to treat the most severe form of spina bifida — myelomeningocele, in which the bones of the spine don’t form completely. It was designed to track 200 women who were carrying a child with myelomeningocele, dividing them into two groups: one slated for surgery before their 26th week of pregnancy and the other scheduled for a postnatal operation. The study was halted in December after enrolling 183 participants since the results in favor of prenatal surgery were obvious.
Babies were assessed at 1 year and again at 30 months. About two-thirds — or 68% — of those operated on before birth needed a shunt, compared with 98% of babies operated on after delivery. Babies operated on in utero scored 21% higher on tests of mental development and motor ability. They were also twice as likely to walk unassisted as babies who underwent surgery after they were born — 42% versus 21% — although walking is largely dependent on the location of the spinal lesion.
Now, news of the study’s results have to percolate through the health-care system, and insurance companies must decide if they’ll pay for the operation. “We hope the trial data will be convincing enough that they cover it,” says Nalin Gupta, chief of pediatric neurosurgery at UCSF and a study co-author. “What we’re doing is prevention of disability, and that should be important.”
The incidence of spina bifida has been on the decline because of widespread folic acid supplementation. The condition is usually detected during the standard mid-pregnancy ultrasound around 18 weeks; in developed countries, many families choose to terminate the pregnancy. (More on Time.com: Do We Need Vitamin-Supplemented Birth Control Pills?)
That wasn’t an option for Susan Williamson, Anna’s mom. A devout Christian, Williamson never considered ending the pregnancy. She was operated on when she was 22 weeks pregnant at Vanderbilt University Medical Center, one of the three hospitals subsequently involved in the trial.
The operation took just an hour and a half, followed by strict bed rest that eventually eased up. For the two weeks following the surgery, Williamson experienced waves of contractions, but Anna stayed put until 35 weeks. Shortly before her second birthday, she took her first steps.
“I can still feel that moment,” says Williamson, from Holly Springs, N.C.
Anna lives a pretty normal life, although she’s paralyzed below her knees. She earns A’s and B’s in school. She never needed a shunt.
Williamson has since had three other children, none of whom have spina bifida. But she still speaks regularly about her experience with fetal surgery. “I’m very thankful that other families will feel there is an option that can help their child long-term,” she says. “But it’s still so scary. It’s the womb, and no one is supposed to be messing with that.”