COMMENTARY

Spina Bifida: What Is Best for the Baby?

N. Scott Adzick, MD

Disclosures

February 13, 2012

Editorial Collaboration

Medscape &

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I'm Scott Adzick. I'm a surgeon and Chief, The Children's Hospital of Philadelphia, and Medical Director, Center for Fetal Diagnosis and Treatment.

Fetal surgery started 30 years ago. It began out of frustration from pediatric surgeons taking care of babies at the time they were born. We were too late: The baby had a birth defect, and the end-organ damage was already done -- whether the result of a lung tumor, diaphragmatic hernia, or urinary tract obstruction -- or problems had occurred with twins with a life-threatening condition before birth. It was out of that frustration and the advent of new prenatal diagnostic techniques, such as maternal fetal ultrasonography, that we had the idea that maybe, just maybe, we could fix birth defects before birth.

At that time, 3 decades ago, most people thought we were totally crazy. We developed animal models for birth defects and worked with experimental sheep and rhesus monkeys. We developed the techniques to do repairs of birth defects before birth. We initially treated life-threatening birth defects before birth. About 20 years ago, we turned our attention to the spina bifida problem. Spina bifida is the most common birth defect, outside of heart defects, in the United States and the world. About 1500 babies are born with spina bifida each year. This condition is straightforward to diagnose before birth.

Our idea 20 years ago was that not only did the neural tube fail to close properly, but there was also progressive damage to the exposed spinal cord before birth due to the amniotic fluid environment and the back of the fetus rubbing against the inside of the uterus. We proved that this was the case in experimental animal models and fetal sheep and published the results in Nature Medicine.[1] Our research showed that there was progressive damage before birth.

At The Children's Hospital of Philadelphia, we began 15 years ago to use fetal surgery techniques that we had developed for life-threatening fetal malformations to actually treat spina bifida before birth. We reported the first successful repair of spina bifida in a 22-week-gestation fetus in The Lancet in 1998.[2] We demonstrated that by doing in utero repair, there seemed to be some benefits in terms of improved leg function; less severe hydrocephalus; and a decreased need for a ventricular peritoneal shunt to decompress hydrocephalus and decrease in the likelihood of hindbrain herniation, which is characteristic of spina bifida.

Around that time, there were other medical centers worldwide with an interest in performing spina bifida surgery, and 2 of those centers -- Vanderbilt University and University of California, San Francisco -- joined with us around 2003 to begin a randomized prospective trial comparing fetal surgical repair of spina bifida with standard conventional care after birth with postnatal closure. This study was sponsored by the National Institute of Health. Mothers with fetuses with spina bifida were referred and, if they met criteria and were willing to be randomized, could enter this trial.

This trial, begun in 2003, closed about 1 year ago because the efficacy of fetal therapy -- the fetal therapeutic approach -- had been demonstrated. Babies who were treated before birth did better in virtually all aspects of their neurologic function. Fewer needed a ventricular peritoneal shunt for hydrocephalus. The ability to walk occurred twice as frequently in the fetal surgery group compared to the postnatal surgery group. Finally, the effects of hindbrain herniation were much less marked in the fetally repaired group.

The results of this multicenter trial were published in the New England Journal of Medicine about a year ago.[3] Since that time, we've been flooded with referrals. We do about 1 fetal surgery a week to repair spina bifida before birth, and we receive referrals from all around the United States and the world. We view fetal surgery for spina bifida to be, in appropriate, highly selected circumstances, a standard-of-care option for families who are dealing with a fetus with spina bifida.

What's on the horizon? We are doing experimental work to try to perform these repairs in a minimally invasive way, using tissue-engineered techniques to seal the lesion before birth and doing the formal repair after birth. By sealing the lesion before birth, we can protect the same neurologic function, hopefully, and not have to do as big of an operation prenatally.

The downsides to the operation are maternal and fetal risk. Babies who have the fetal surgery performed are born, on average, 3 weeks prematurely. Mothers who have the operation with current techniques have a scar high on the uterus that can break down during the fetal surgery pregnancy or subsequent pregnancies. Mothers who have fetal surgery for spina bifida need to have a cesarean section for the fetal surgery pregnancy, as well as for all other pregnancies.

If you would like to learn more about this, you can go to our Website to get online CME or vignettes from patients whom we have treated. You will also find more information about specific birth defects that we treat before birth with fetal surgery.

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