NEW HAVEN — A patient at Yale New Haven Hospital recently underwent spinal surgery, before the patient, a fetus with spina bifida, had even been born.
It was the first prenatal surgery performed in Connecticut. The operation repaired the spinal cord, which was protruding from the fetus’ lower back. It is the rarest form of spina bifida, known as myelomeningocele, in which the backbone and spinal sheath fail to close, exposing the spinal cord and its connecting nerves.
The surgery to repair the spine is most often done after birth, but a study at Children’s Hospital of Philadelphia showed that when it is performed before birth there is a greater chance the child will be able to walk and perform other bodily functions. Also, the baby will have a reduced risk of excess fluid on the brain, a common symptom of spina bifida, which must be drained with a shunt throughout the patient’s life.
The “open, in-utero spinal-repair surgery has the potential to significantly improve the quality of a baby’s life,” said Dr. Ozan Bahtiyar, director of the Yale Medicine Fetal Care Center. He called it a “high-risk, high-rewards surgery.”
While the exact results won’t be known until the baby is born, which could be more than three months, the clinical team is confident that, after two years of planning, they have given the baby a better chance at a life with fewer complications and disabilities.
Surgery on an exposed spinal cord is best done in utero because “amniotic fluid is potentially toxic to neural tissue,” said Dr. Michael DiLuna, the pediatric neurosurgeon on the team. That compounds the issues caused by the birth defect.
In the recent case, the defect in the fetus’ spine was at the fourth lumbar vertebra, just above the buttocks. If there are no active nerves from that point down, “that makes walking very difficult without ankle braces and crutches … and 100 percent they won’t be able to go to the bathroom” on their own, DiLuna said.
Such patients often use wheelchairs because they are unable to flex their feet. But repairing the defect improves function by up to “three levels,” bringing function back as far down as the first or second sacral vertebra, which are just above the coccyx or tailbone.
That means the patient will be able to walk and not have to use a catheter or wear diapers to school, DiLuna said. “What we think is happening is that some of the nerves are still working, and they’re being damaged by the environment in the uterus,” he said. Once the spinal cord is repaired, the nerves are believed to begin sending out signals again.
Also, “repairing the defect in utero while the mother’s still pregnant has been shown to slash the rate of hydrocephalus,” DiLuna said. That offers a greater chance that the baby will not suffer from cognitive defects and avoid having a shunt, “a permanent device that has a massive complication and failure rate,” he said.
“If they do get a shunt, they will need half a dozen surgeries” to replace it as they grow, DiLuna said. “If you close it in utero, the risk of needing a shunt goes down dramatically.”
“The quality-of-life improvement is remarkable,” he said. “They’re not perfect but they’re markedly better.”
Dr. David Stitelman, a pediatric surgeon, noted that “surgery is not a cure, but the neurological outcomes are better,” said. “There’s risks to the mother and risks to the fetus.”
However, the Yale New Haven team prepared by consulting with others who have experience in fetal surgery, especially the Fetal Center at Vanderbilt Children’s Hospital in Nashville. “We didn’t just decide overnight to do this case. The people on the team have experienced this on other teams,” Stitelman said.
There were at least 22 people in the operating room for the 21/2-hour surgery, including anesthesiologists for both the mother and fetus, two pediatric surgeons, doctors, cardiologists, nurses, an ultrasonographer and others.
“It’s truly a multidisciplinary case, with doctors and nurses with a variety of expertise coming together to do this safely,” Stitelman said. Bahtiyar emphasized the point. “Everyone on the team is necessary. Without any one we could not do the surgery,” he said.
Bahtiyar said that while surgery in utero has a better potential outcome than waiting until the baby is born, it can only be done up to the 26th week of pregnancy. DiLuna added that the 25th and 26th weeks are the “sweet spot” when the fetus is large enough to be operated on, but not old enough for too much damage to have been done to the spinal cord.
“They found this optimal time period where the greatest benefit with the least amount of risk is,” he said.
Normally, the spinal cord is protected by a sheath called the dura, one of three layers of meninges that surround the spinal cord and brain. But in spina bifida, the meninges haven’t closed and the vertebrae are misshapen.
“The vertebrae are going to be abnormal. They’re open,” DiLuna said. “The shape of them is going to be extremely abnormal. The bone stays open.”
“The spinal cord is outside the spinal canal and it’s attached to the skin,” DiLuna said. “It looks like a little balloon. It’s kind of bowed out … and the nerves are kind of tethering it back to the body.”
Stitelman said the mother is given “very deep anesthesia to keep the uterus relaxed,” then “the uterus is opened in a manner where the fluid around the fetus can be maintained,” exposing as little of the back to the air as possible.
DiLuna said the next task is to separate the cord from the skin and then the cord is able to be placed in position. The dura also must be separated from the skin and closed, and then the layers of skin are closed. DiLuna said he was able to repair the skin on this patient.
DiLuna said while the surgery was successful, ultimate success won’t be known until after the baby is born. First, it’s essential that “the mother remains safe and pregnant at the end of the case. The second is that the mother is able to maintain pregnancy for several weeks.” Finally, everyone must wait “to see the neurological benefit … in the long term.”
DiLuna said Yale New Haven has the only fetal surgery center in New England, although Women and Infants Hospital, affiliated with Brown University in Providence, has performed fetal surgeries on occasion.