This limitation is improving. The challenge, he said, is the incision and closure of the uterus. Dr. Tulipan and his colleagues have recently given increased attention to suturing the amniotic membranes to prevent them from separating from the uterine wall "With this change, our results have gotten substantially better. We’re getting to a rate that could make it mainstream. If the [extreme] prematurity rate was less than 5%, it would be hard to argue against this surgery."
Dr. N. Scott Adzick
Fetal MMC repair "will continue to grow, but not by an order of magnitude until there is a new technique that could be offered earlier in gestation and in a minimally-invasive way," said Dr. N. Scott Adzick, surgeon in chief and director of the Center for Fetal Diagnosis and Treatment at CHOP. Currently, MMC repairs are done at 20 weeks’-25 weeks’ 6 days gestation. His group at CHOP, as well as others, is also trying to perfect less-invasive approaches. "We are working on a tissue-engineering approach to seal the MMC defect before birth, and thus prevent exposure of the spinal cord to damaging amniotic fluid, and also prevent leakage of the cerebrospinal fluid from the spina bifida. CSF leakage is the underlying cause of hindbrain herniation and hydrocephalus seen with spina bifida. The goal is for this tissue-engineered component to be introduced through a single fetoscopic port or through an amniocentesis needle under sonographic guidance," Dr. Adzick said.
The risk of prematurity, as well as potential complications for the mother, means that centers offering fetal MMC repair provide extensive counseling for potential parents. "We are proud of the fact that over half of our families decide not to have prenatal surgery after the counseling," said Dr. Hanmin Lee, professor and chief of pediatric surgery at UCSF, and one of the leaders of that center’s MMC fetal repair program.
At CHOP, during the first year after the MOMS publication 238 pregnancies underwent evaluation, with 137 making it to a more extensive stage of assessment. Of these, 40 mothers (29%) underwent fetal MMC repair, Dr. Adzick said.
At Cincinnati Children’s Hospital, which began offering fetal MMC repairs following publication of the MOMS results, the winnowing was about as sharp as at CHOP. Since the program began, the Cincinnati team evaluated 53 pregnancies and performed 10 repairs, said Dr. Foong-Yen Lim, surgical director of the Fetal Care Center there. A handful of these patients who were first seen at Cincinnati decided to travel to Vanderbilt or CHOP instead for the surgery and thereby take advantage of the greater experience those centers offered.
That sentiment underscores a challenge faced by the programs that are trying to establish themselves as new options for fetal MMC repair, as the procedure rolls out post-MOMS.