Fetal surgeon Tim Crombleholme pushes a tube thinner than a drinking straw — the tube of a fetoscope — into the belly of a frightened Phoenix woman. She’s 17 weeks pregnant with identical twins, and they’re in danger.
A routine prenatal visit the day prior revealed that one twin had a barely perceptible heartbeat, and the woman’s doctor diagnosed twin-to-twin transfusion syndrome (TTTS), a disorder in which one fetus draws more blood from the placenta than the other. Severe TTTS can be lethal to both twins, but if it’s treated — using a pinpoint laser to cauterize blood vessels and balance the blood supply — survival rates for both babies can be over 95 percent. The woman and her husband traveled through the night to reach Children’s Hospital Colorado and Dr. Crombleholme, the region’s only surgeon who treats TTTS.
But in this case, it isn’t TTTS that Crombleholme discovers. Further tests reveal an even more complex problem: twin anemia polycythemia sequence, in which one twin’s blood has a deadly deficiency of red blood cells, while the other’s has a dangerous overabundance.
Saving both twins will be difficult — unlikely, in fact — but losing both is a virtual certainty without surgery. And so Crombleholme presses on through the wall of the uterus with the fetoscope, which incorporates a tiny camera and a fiber-optic laser.
“We’re in,” Crombleholme says, and the race begins.
As if the life-and-death stakes and microsurgical complexity weren’t pressure enough, there’s also the tyranny of time: Survival rates drop if the laser procedure takes more than five minutes, so one of the nurses calls out the time at 60-second intervals. Zeroing in on blood vessels shared by both twins, Crombleholme fires the laser to cauterize the oversupplied twin’s branch of the vessel.
“Sixty seconds,” calls the nurse.
Crombleholme fires more laser bursts and soon completes the vascular separation of the twins’ circulations. Remarkably, fewer than three minutes have passed.
The lasering done, Crombleholme zeroes in on the umbilical cord of the weaker twin, inserts a needle and draws a blood sample. While a tech analyzes the blood, Crombleholme examines the placenta. What he sees is not encouraging: The sick twin’s umbilical cord is receiving just 10 percent of the blood supply.
The bloodwork brings more bad news: The distressed twin is acutely anemic, with a red-blood count barely half of what it should be. Crombleholme calls for 7 milliliters of high-hematocrit blood, centrifuged to pack in more red-blood cells.
The final step is the transfusion. Normally the transfusion could be injected into the umbilical cord without shifting the needle that drew the blood sample. But the sick twin’s heart is too weak to take a sudden load. Crombleholme decides to inject the blood into the baby’s abdominal cavity, so it can be absorbed over 24 hours. Seconds ticking, he shifts the needle and gently injects the transfusion.
At last he withdraws the fetoscope. But “at last” comes just 4 minutes and 15 seconds after the initial “we’re in.”
In the coming months, Crombleholme’s team will continue to do all they can to help the weaker twin, who still faces an uphill battle. But the stronger one now has a 92 percent chance of survival, thanks to a small miracle performed one Wednesday afternoon at Children’s Colorado.