Johns Hopkins maternal-fetal medicine specialists have begun in utero spina bifida surgeries that are minimally invasive to the mother’s uterus. The technique uses a small laparoscopic instrument, known as a fetoscope, to perform the repair and avoids the risks associated with cutting open the uterus.
In this surgery, performed at just three hospitals nationwide, doctors move the uterus outside the body, install ports through the uterine wall to replace some amniotic fluid with carbon dioxide, and insert a camera and surgical instruments. The surgeons then close the defect in a manner similar to the open surgery 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 maternal-fetal medicine specialists Ahmet Baschat, Jena Miller and Edward Ahn began offering this procedure to eligible patients in February 2017. To qualify, the surgeons say, the upper border of the spina bifida defect must be a myelomeningocele and fall between the T1 and S1 vertebra. There must also be a Chiari II malformation, in which the cerebellum is pulled into the spinal canal, and the fetus must have no other known genetic defects or physical abnormalities. The mother must have no known risks of early labor and must have a body mass index of less than 35 kg/m2 before pregnancy.
By the end of September, Baschat and Miller had performed this procedure on five patients. So far, none of the babies born required additional surgery. They will be followed over the next 30 months to assess their neurological outcomes to determine how they compare to those who received fetal surgery with the open technique. The trial is approved and monitored by the Food and Drug Administration.
Until recently, the gold standard for spina bifida treatment was surgery within two days after birth to close the defect over the spinal cord and correct spinal deformities.
However, research within the past decade has shown that surgically repairing the defect before birth, between about 20 and 26 weeks gestation, leads to better outcomes for the babies.
Despite the proven benefits of this open fetal surgery, only a fraction of parents whose children are eligible choose it, say Baschat and Miller. That’s because this therapy confers risks: about 10 percent of women require blood transfusions during surgery or delivery and the resulting scar leaves the uterus vulnerable to potentially rupture in the present or future pregnancies, requiring women to deliver by scheduled cesarean sections. She also must deliver before 37 weeks, increasing the odds of neurological and other complications for the baby.
The new technique is minimally invasive to the uterus, essentially abolishing these risks, they say.
“We feel strongly about being able to offer procedures that provide proven benefits to mothers and children without fear for their health or future pregnancy outcomes,” Miller says. “This surgery is the latest to meet that goal.”