Brain surgery on a fetus
Her parents signed up for a clinical trial of an in-utero surgical treatment to see if doctors could intervene before any of these outcomes materialized. It seems to have worked. The team behind the operation now plans to treat more fetuses in the same way. Other, similar brain conditions might benefit from the same approach. For conditions like these, fetal brain surgery could be the future.
The baby’s condition, known as vein of Galen malformation, was first noticed during a routine ultrasound scan at 30 weeks of pregnancy. The condition occurs when a vein connects with an artery in the brain. These two types of vessels have different functions and should be kept separate—arteries ferry high-pressure flows of oxygenated blood from the heart, while thin-walled veins carry low-pressure blood back the other way.
When the two combine, the high-pressure blood flow from an artery can stretch the thin walls of the vein. “Over time the vein essentially blows up like a balloon,” says Darren Orbach, a radiologist at Boston Children’s Hospital in Massachusetts, who treats babies born with the condition.
The resulting balloon of blood can cause serious problems for a baby. “It’s stealing blood from the rest of the circulation,” says Mario Ganau, a consultant neurosurgeon at Oxford University Hospitals in the UK, who was not involved in this particular case. Other parts of the brain can end up being starved of oxygenated blood, causing brain damage, and there’s a risk of bleeding in the brain. The extra pressure put on the heart to pump blood can lead to heart failure. And other organs can suffer too—especially the lungs and kidneys, says Ganau.
Fetuses with the condition are thought to be protected by the placenta to some degree. But that changes from the moment the umbilical cord is clamped at birth. “All of a sudden there’s this enormous burden placed right on the newborn heart,” says Orbach. “Most babies with this condition will become very sick, very quickly.”
Several teams are attempting to treat the condition before this can happen—while the fetus is still inside the womb. Orbach is a member of one such team. He and his colleagues at Boston Children’s Hospital and Brigham and Women’s Hospital, also in Boston, registered a clinical trial in 2020 to test whether fetal brain surgery might help.
The girl’s mother was referred to Orbach’s clinical trial. On March 15, at 34 weeks, she underwent the experimental operation—a two-hour procedure that involved a range of medical professionals.
