A team of Minneapolis surgeons is helping to pioneer a bold advance in prenatal medicine — operating on fetuses with spinal deformities while they're still in the womb, then leaving them in place until they are ready to be born.

Doctors with the Midwest Fetal Care Center, a collaboration between Children's Minnesota and Allina Health, have performed six open fetal surgeries, each one to halt the physical and cognitive degeneration caused by open spina bifida, an incomplete closing of the skin and backbone over the spinal cord.

While surgery after birth is common for this condition, research suggests that operating before birth can give the infant a better chance at a healthy life while reducing the risk of disability or death.

"Open fetal surgery enables us to potentially save the life of the fetus or provide long-term health benefits that couldn't be achieved if we waited until after the baby was born," said Dr. Joseph Lillegard, a pediatric surgeon who was recruited from Philadelphia as part of the center's preparations to add the complex procedure.

Only a dozen U.S. hospitals provide the surgery, in which doctors cut through a mother's uterus, position her fetus to reveal the protruding spinal cord, and then stretch the baby's own skin over the top to cover it up.

The procedure remains controversial, because it exposes mothers to the risks of surgery and requires them to undergo C-section deliveries. Surgeons have long used prenatal surgery to save dying babies, but the risk calculation changes when using it on a disabling condition such as spina bifida. Three in four U.S. patients born with open spina bifida at least reach adulthood.

The American College of Obstetricians and Gynecologists has termed it a "heroic intervention" that should be left to experienced centers because "it is a highly technical procedure with potential for significant morbidity and possibly mortality, even in the best and most experienced hands."

There also are ethical and spiritual issues of personhood because the procedure takes place between the 23rd and 26th weeks of pregnancy, when a fetus is smaller than a rutabaga.

"This is a Pandora's box," acknowledged Dr. Brad Feltis, surgery director at the Midwest Fetal Care Center. But he added that the research strongly favors early correction of spina bifida. Unchecked, it allows spinal fluid to leak out of the body and amniotic fluid to seep in. The result is often impaired mobility, cognitive deficits and other permanent disabilities.

Toughest decision

It seemed that everyone had an opinion when Suaado Salah of Hopkins was advised to undergo the surgery during her fifth pregnancy. A Muslim immigrant and a worker in a medical device factory, Salah faced long-distance resistance from relatives in Somalia while her husband sought their imam's advice.

"[My father] asked a couple times, 'Are you sure the baby is still going to be left inside after surgery?' " Salah said.

An ultrasound in her second trimester identified the baby's spina bifida, and subsequent scans found signs, such as clubbed feet, that the disorder was already harming her daughter's development. Salah eventually agreed to the surgery because she didn't want to spend the rest of her life wondering if it would have given her child a better chance.

"This decision is the hardest one we've ever made," said her husband, Tahlil Wehlie.

The primary arguments in favor were results published in 2011 from the so-called MOMS trial, in which doctors in three U.S. medical centers compared the outcomes of prenatal vs. postnatal repair of open spina bifida — also called myelomeningocele. It is the most severe form of spina bifida, occurring in 3.5 of every 10,000 births.

Comparing the children at 30 months of age, researchers found that those who underwent prenatal surgery were less likely to need shunts, which drain excess fluid from the brain but also can cause swelling and life-threatening complications. Prenatal surgery also prevented or reversed hindbrain herniation — slippage of the brain into the neck, which increases pressure inside the skull and inhibits the brain's communication with the body.

"Once you're born, none of that reverses," Lillegard said. "What's done is done."

Infants who underwent prenatal surgery also were more likely to walk without orthotics.

In some countries, the social norm is to terminate pregnancies when spina bifida is discovered early in a pregnancy. Lillegard said broader awareness of fetal surgery could change that thinking. "There are a lot of providers out there who are still talking about only terminating the pregnancies," he said, "that it's the only [medical] option."

Once the prenatal surgery is performed, the mother is generally scheduled for a C-section delivery at 36 weeks because of the risk that the labor of a vaginal birth could tear her surgical scars.

Now surgeons are studying ways to make this prenatal surgery safer; a national group of experts has tested minimally invasive incisions on animals rather than open surgeries. Feltis said his center is eyeing that approach some day as well, but has spent years in preparation and practice to do the open procedure safely.

Salah, 26, underwent surgery Dec. 21, and is scheduled for a C-section in early March. Time and healing have left her confident in her decision.

Routine ultrasounds still show her daughter's clubbed feet, meaning she faces some disability after birth, but her baby has been kicking excitedly — especially after Salah eats. Doctors have told her that is the best sign that her baby is in good health.

"Every time she kicks," she said, "I feel like I did good. I feel like I made the right decision."