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Fetal Surgery: The New Normal

Surgeons perform fetal surgery for spina bifida

Surgeons perform fetal surgery for spina bifida

It’s 1981, and a woman, seven months pregnant with twins, knows that one of her unborn babies will probably die. He has a blocked urinary tract, a life-threatening condition.

But he doesn’t die. Instead, something unprecedented happens.  A doctor in San Francisco opens the woman’s abdomen and performs the first successful fetal surgery. The baby is born, leads a normal childhood and grows up.

The baby’s name was Michael Skinner, and he was the first of many whose lives have been saved or dramatically improved through fetal surgery.

“The first fetal surgeries were mostly done to address situations in which the fetus would not survive if nothing was done,” says Michael Bebbington, MD. “But today, we have a changed paradigm that focuses on decreasing morbidity and improving quality of life for babies.” Bebbington, a maternal-fetal medicine specialist, is director of the Fetal Care Center, which is part of the Women & Infants Center, a collaboration between Barnes-Jewish Hospital, St. Louis Children’s Hospital, and Washington University School of Medicine. 

Perhaps the best example of this paradigm shift is fetal surgery for myelomeningocele, the most severe form of spina bifida. Though fetuses with this birth defect usually survive if not treated in utero, they may have paralysis of the arms and legs, and dysfunction of the bladder and bowel, as well as scoliosis and fluid buildup in the brain. 

Children born with myelomeningocele used to undergo surgery after birth. But by then, the damage to the developing nervous system had already been done. Most of them would never learn to walk, and they faced lifelong challenges. In the 1990s, some surgeons began performing the operation in utero, though at first it wasn’t clear whether it was more effective than surgery after birth. 

Then came the MOMS trail, a landmark study published in 2011 in which researchers randomized 183 pregnant women to either prenatal repair of myelomeningocele or standard postnatal repair. The results were so striking that the research team terminated the study early. Their findings indicated that surgery in utero meant there was a significantly less likely need that an infant would require a shunt to drain fluid from the brain after birth, and would also have better motor function at 30 months post-delivery. Forty-two percent of those in the prenatal surgery group were later able to walk, compared with just 21 percent in the postnatal surgery group.

For now, fetal spina bifida repair is still performed as an open procedure, meaning surgeons open the mother’s abdomen and uterus to operate on the fetus as they would on a newborn. Research of minimally invasive procedures for myelomeningocele is in a preliminary phase. “As we make advances in minimally invasive procedures, we subject them to research to learn whether they are actually better for babies and moms,” Bebbington says.

And for many conditions, minimally invasive surgery has become the norm. For example, to treat congenital diaphragmatic hernia, or a hole in the diaphragm, surgeons insert a scope down the throat of a fetus through a small incision in the mother’s abdomen, then place a balloon inside the trachea to help lung development. Bebbington says this procedure is much less risky to the mother and the fetus than an older form of treatment in which the mother’s abdomen is opened more fully to allow the surgeon to place a clip on the fetus’s trachea through an incision in the neck.

Many of the advances in fetal surgery over the years are due in part to changes in imaging technology. For example, advances in ultrasound have made it possible for doctors to diagnose congenital conditions earlier and more accurately. And improved ultrasound is used to guide surgeons as they perform fetal surgery.

One of the first conditions for which minimally invasive fetal surgery became the norm was twin-to-twin transfusion syndrome, in which one twin receives too much blood and the other too little. When advanced cases of this syndrome are untreated, perinatal mortality is estimated at 70 to 100 percent. Bebbington says that the intervention through fetal surgery achieves an overall survival rate of 85 percent. 

“This is the kind of medicine I always wanted to practice,” Bebbington says. “It never ceases to amaze me what a mother will do to try to improve life for her child.”

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