The ability to perform surgery on a baby before birth can change the trajectory of a child’s disease. Pediatric neurosurgeon Jennifer Strahle, MD, operates on increasing numbers of her spina bifida patients before they leave the womb – and, as a result, is seeing increasingly better outcomes.
The implications of this innovative type of surgery (known as prenatal, in utero, or fetal surgery) are profound for the patient. While prenatal surgery is not always the right approach, a successful procedure can make a big difference in treating birth defects by preserving and maximizing functional outcomes.
Strahle, along with a team that includes fetal surgeon Jesse Vrecenak, MD, and pediatric anesthesiologist Preeta George, MD, frequently performs prenatal surgery to repair the birth defect known as myelomeningocele (MMC), a common and severe form of spina bifida in which the spinal cord does not form correctly.
This condition results in an incomplete spinal canal, causing the spinal cord and spinal membranes to protrude from the infant’s back. The sooner the spinal cord is put back in place and the opening closed, the better the result for the child.
Myelomeningocele is pronounced “mai·uh·low·muh·ning·guh·seel”
“With open myelomeningocele there is a direct connection between the spine and the amniotic fluid in the uterus. This results in on-going exposure of amniotic fluid to the developing nervous system. Through fetal surgery and in utero closure of the myelomeningocele we are able to interrupt ongoing damage to the spine and the rest of the central nervous system,” says Strahle.
“The number of total MMC repairs performed each year by Washington University pediatric neurosurgeons has quintupled since 2017, when the fetal program began at Washington University in St. Louis/St. Louis Children’s Hospital,” according to Strahle.
“Prior to offering fetal repair for myelomeningocele we were treating four to five patients per year. In the last 12 months we have treated over 25 patients for open myelomeningocele with prenatal and postnatal repair.”
Because prenatal surgery is not appropriate for every patient, and requires significant commitment from the mother, Washington University experts offer both approaches (as well as counseling to help mothers make this decision.)
A well-choreographed procedure
A prenatal procedure for MMC repair involves a large team including a maternal-fetal medicine specialist and fetal surgeon. During the surgery, the mother receives general anesthesia, which also relaxes the uterus and anesthetizes the fetus. The fetal surgeon then performs a laparotomy (an incision across the mother’s abdomen).
Sterile intraoperative ultrasound is used to map the position of the placenta and the fetus, as the baby’s back is rotated into view. The uterus is then opened with a special stapling device that pinches off all blood vessels and keeps membranes secured to the muscle.
As the pediatric neurosurgeon, Dr. Strahle then disconnects the abnormal end of the spinal cord from the surrounding skin, returns the spinal cord to the spinal canal, and closes the surrounding tissue and skin to protect the spinal cord from exposure to the amniotic fluid. The uterus and the abdominal incision are then closed.
After surgery, the mother completes her pregnancy and the baby is delivered by planned cesarean section.
Strahle, who treats children of all ages, is particularly passionate about her work with the prenatal, neonatal, and infant populations. She credits patients and their families for placing their trust in the innovation that WashU offers, giving surgeons valuable experience to grow the prenatal program.
The success of the prenatal program also has broader implications for fetal surgery in general. Because prenatal MMC repair is the most common procedure performed, it functions as the backbone of a successful open fetal surgery program.
Fetal intervention is always a complex ordeal, carefully choreographed with many specialists and moving parts. The high volume of MMC repair procedures provides frequent repetition of this choreography, which improves surgeons’ ability to react in other, more unpredictable, prenatal procedures such as cardiac interventions or catheter-based interventions for twin-to-twin transfusions.
The future of prenatal surgery at Washington University
The future of prenatal surgery is bright. Vrecenak looks forward to the day when surgeons will be able to offer cellular therapy or genetic therapy to patients. MMC repair is just one procedure, but part of the success of all prenatal procedures is the ability to salvage function at an early stage.
“It’s all based on us being able to access places [in utero] that we wouldn’t be able to access later on,” says Vrecenak.
Soon, Strahle and Vrecenak hope to offer minimally invasive fetoscopic MMC repair, a surgery in which the spinal defect is repaired through several small incisions in the uterus, using a small camera known as a fetoscope. The prenatal team is working together to evaluate this potential.