Ultrasound exams performed at 20 weeks of gestation can tell parents the gender of the baby they’re expecting. In rare cases, these exams also identify the presence of congenital diaphragmatic hernia (CDH) — a life-threatening hole in the fetal diaphragm separating the chest from the abdomen. Pediatric surgeons at Johns Hopkins Children’s Center, working with maternal-fetal medicine experts at the Johns Hopkins Center for Fetal Therapy, are among few surgeons nationwide who are equipped to intervene in such cases via minimally invasive fetal surgery, increasing the odds of survival for the fetus.
CDH, which affects about one in 3,000 infants, can allow the intestines or stomach to move into the chest cavity, compressing the lungs and preventing them from growing normally, explains pediatric surgeon Shaun Kunisaki, director of the CDH program at the Children’s Center. “In severe cases, when a baby [with CDH] is ready to be born and breathe on their own, their lungs are too small to function,” he says. “Over half will die because their lungs just don’t work.”
With a fetoscopic endotracheal occlusion (FETO) procedure, Johns Hopkins surgeons insert a small optical instrument into the mother’s uterus and guide it into the mouth of the fetus. Then, they place a tiny inflated balloon into the trachea, which blocks the windpipe and causes the lungs to grow more rapidly. The balloon is removed about five weeks later through another minimally invasive procedure. The Johns Hopkins team has performed the procedure for about 20 patients to date, with an 80% survival rate for the babies, who often require close follow-up by pediatric experts, Kunisaki says.
The procedure allows physicians to plan for vaginal delivery and does not affect future child bearing, adds obstetrician and maternal-fetal medicine expert Ahmet Baschat, director of the Center for Fetal Therapy, where the FETO procedures are performed. The average gestational age at delivery at Johns Hopkins following the procedure is about 39 weeks — higher than the average 34.5 weeks achieved by other centers, he says, which allows for greater maturity of the lungs at birth.
FETO is one of several in utero procedures offered at Johns Hopkins. Another is laser surgery for twin-to-twin transfusion syndrome, a rare condition in which blood volumes or fluids among identical twins sharing a placenta are distributed unevenly. This occurs in about 5% to 15% of identical twin fetuses. Without treatment, both are likely to die.
To best increase the odds of both infants’ survival, Johns Hopkins surgeons insert a fetoscope into the uterus under ultrasound guidance, then use a laser to coagulate their connecting placental blood vessels to give each fetus independent placental supply. Johns Hopkins is one of the leading centers for this procedure, Baschat says, with experts performing it over 400 times for twins and triplets since the center launched in 2014. About 78% of cases have resulted in two surviving babies, and 18% had one surviving baby.
Johns Hopkins also is one of only a few centers nationwide to offer open and minimally invasive prenatal surgeries for spina bifida, a birth defect caused by incomplete closure of the spine. First, experts study the lesion using ultrasound and use a 3-D printer to create a model from the ultrasound imaging to plan the surgery. Then, they can minimally invasively repair the defect using the fetoscope. Doctors install ports through the uterine wall and insert a camera and surgical instruments, then close the defect by dissecting the spinal cord membrane away from the skin edge that falls into the spinal canal, then layering muscle and skin on top.
Johns Hopkins is a referral center for other fetal conditions, too, Baschat says, including fetal arrhythmia and fetal tumors. In all cases, maternal-fetal medicine and pediatric experts work together to ensure a continuum of comprehensive care from pregnancy through birth and beyond, which is exactly the setting found to increase survival rates among patients with CDH in a meta-analysis that Kunisaki, Baschat and colleagues published in the Journal of Pediatric Surgery last spring.
“Fetal therapy has evolved from just treating babies with blood transfusions,” says Baschat. “We can now provide minimally invasive, fetoscopic surgical treatments and coordinated care transition, where babies that are prenatally identified to require specific care afterward are delivered at a center with pediatric experts prepared to care for them.”
A recent paper Baschat published in Obstetrics & Gynecology outlines three care levels for fetal therapy centers, based on expertise and services offered. The care levels are suggested by a consensus statement from the American College of Obstetricians and Gynecologists, the Society for Maternal-Fetal Medicine and the American Academy of Pediatrics. Johns Hopkins qualifies at the highest level, meaning it can offer the full range of minimally invasive and open fetal interventions, and can manage all levels of maternal and neonatal risk or complications, along with meeting other qualifications.