• Biotherapeutics

    Science Saturday: Fetal surgery to expand lungs

Zane Fouts with parents Trevor Fouts,
Alyse Ahern-Mittelsted

Baby Zane Fouts’ boundless curiosity starts at his feet, which he grabs and plays with happily. The energetic boy who’s full of smiles is a trailblazer for regenerative surgery performed in a clinical trial at Mayo Clinic even before birth.

“He’s our miracle baby,” says his mother, Alyse Ahern-Mittelsted.  “He’s a rock star.”

Ahern-Mittelsted was 20 weeks pregnant when an ultrasound showed Zane had severe congenital diaphragmatic hernia (CDH). This life-threatening condition blocks lungs from growing enough for babies to breathe on their own. Without intervention, 70% of infants born with severe CDH die. The bombshell news came less than a year after Ahern-Mittelsted unexpectedly lost a daughter at 31 weeks of gestation to a different condition — a failed placenta.

“We thought we were going to lose another baby. We were really scared.”

CDH is a hole in the muscle separating the chest and abdomen. That causes the spleen, stomach and bowels to push up into the chest cavity and stunt lung growth. The result is small, underdeveloped lungs, known as pulmonary hypoplasia.  It’s a rare condition that affects 1 in 10,000 babies.

To try to save Zane’s life, Rodrigo Ruano, M.D., Ph.D., head of Maternal Fetal Medicine at Mayo Clinic, recommended fetal endoscopic trachea occlusion surgery while Zane was still in the womb.

Rodrigo Ruano, M.D., Ph.D.

“It’s a delicate procedure. We insert a 3-to-4 millimeter telescope through the mother and into the fetus. We advance a balloon into the baby’s mouth and detach it from a catheter placed inside the trachea, which is the airway of the fetus. The goal of this surgery is to regenerate and expand the lungs,” says Dr. Ruano.  “I feel so passionately about this surgery that I have dedicated my life to moving it toward standard of care treatment.”

When the balloon inside the fetus’ trachea inflates, it fills the lungs with fluid, potentially causing the lungs to expand and grow. Because a fetus breathes through the placenta, the balloon does not choke the baby.

Dr. Ruano is pioneering this procedure at Mayo Clinic through U.S. Food and Drug Administration (FDA) -approved clinical trials with support from the Mayo Clinic Center for Regenerative Medicine and a grant from Regenerative Medicine Minnesota.

While the surgery shows promise, it also comes with risk of preterm labor and delivery. That meant the young couple from Cresco, Iowa, had a decision to make about the health of their unborn child.

“We were told that without the surgery, our baby would only have a 25% chance of ever coming home. With the surgery, the chances jumped to 75%,” says Ahern-Mittelsted. “We knew there was a chance this surgery might not work. But, if this was going to give our son the best chance of survival, I wasn’t going to second guess it.”

“After the doctor told us our options, I was looking for more information (to help make a decision.) I looked online, but this procedure is so new, there wasn’t a lot about it. I had to put my faith and trust in our surgeon,” says Trevor Fouts, Zane’s father.

Surgery to place the balloon inside Baby Zane’s trachea was performed at 27 weeks under local anesthesia and took only about 15 minutes.  

“When they were going to place the balloon, they had to move the baby and place him in the right position. That was painful for me, but it went fast,” she adds.

The balloon was removed at 34 weeks of pregnancy, and Zane was born full-term at 39 weeks. How well a baby with Zane’s condition does at birth depends on development of the lungs. Some babies whose lungs successfully grow and develop may recover with few lingering medical issues. Others whose lungs do not respond as well may have mild to long-term handicaps.

Immediately after birth, a breathing tube was placed in Zane’s airway and he was connected to a ventilator. But, he was only on machine-assisted breathing for a couple of weeks.

The balloon surgery expanded his lung capacity by about 60%. After 52 days in the Neonatal Intensive Care Unit, he had improved enough to go home.

Zane Fouts

“Without this procedure he likely would not have been as healthy as he is now.  He still has a raspy voice and has a tough time with coughs. Eventually, we expect him to live a normal life with normal activities.  We think he’ll be able to participate in sports, although he may need an inhaler,” says Ahern-Mittelsted.  “I believe this surgery pretty much saved his life.”

Dr. Ruano has performed a total of five fetal endoscopic trachea occlusion surgeries so far at Mayo Clinic. His research team is compiling the data to establish whether this surgery improves chances for survival and reduces recovery time. The long-term goal is to secure FDA approval of the balloon used in the procedure so this surgery can be offered in daily clinical care.

Read about Dr. Ruano’s research on fetal endoscopic trachea occlusion surgery.