By The Biomedical Observer
Let me paint you a picture that sounds like science fiction but is absolutely happening right now in operating rooms around the world: A pregnant woman lies on the surgical table, her abdomen exposed. Three tiny incisions - 5 millimeters each - are made through her uterus. A camera the size of a pencil goes in, along with surgical instruments that look like they belong in a watchmaker's toolkit. And then, while the baby floats in amniotic fluid, a surgeon repairs a defect in the baby's spine. The baby isn't born for months afterward. If that doesn't blow your mind, I'm not sure what will.
Clinical trial NCT03090633 at Johns Hopkins University is studying exactly this procedure - fetoscopic repair of myelomeningocele (MMC), the most severe form of spina bifida. It's part of a global effort to figure out whether we can give babies a better start in life by fixing their spines before they ever take their first breath.
What Exactly Is Myelomeningocele?
Spina bifida is a neural tube defect - essentially, the spine doesn't fully close during fetal development, leaving a gap through which spinal cord tissue and membranes can protrude. Myelomeningocele is the serious form, where a sac containing spinal cord tissue and fluid bulges out through the opening in the back.
The consequences are significant. Most children with MMC have some degree of leg weakness or paralysis, bladder and bowel dysfunction, and about 90% develop hydrocephalus - excess fluid in the brain that requires treatment. Many end up needing wheelchairs, catheters, and multiple surgeries throughout childhood. The condition is lifelong.
For decades, the standard treatment was postnatal repair - waiting until the baby was born, then surgically closing the defect. This fixed the immediate problem (an open wound on the back that could get infected) but didn't address the cumulative damage that occurred while the baby was still in the womb. Every day that the spinal cord remained exposed to amniotic fluid, more harm accumulated.
The MOMS Trial Changed Everything
In 2011, the Management of Myelomeningocele Study (MOMS) dropped a bombshell on the fetal surgery world. This landmark randomized controlled trial compared prenatal repair (done via open hysterotomy - basically, a big incision in the uterus similar to a C-section, but while the pregnancy continued) to postnatal repair. The results were stunning.
Babies who had prenatal repair were significantly less likely to need a shunt for hydrocephalus by 12 months of age (40% vs 82%). They were more likely to walk independently at 30 months (42% vs 21%). Prenatal surgery also reversed the Chiari malformation type 2 - a herniation of brain tissue that's common in MMC - much more frequently than postnatal repair.
The catch? Open prenatal surgery is rough on mothers. The hysterotomy carries real risks: uterine rupture, preterm labor, significant maternal morbidity. All future pregnancies require C-sections. Some women had concerning findings in their uterine scars - thinning or partial separations that could have been catastrophic if they'd labored.
So researchers asked the obvious question: what if we could get the benefits of prenatal repair without cutting a 6-centimeter hole in the uterus?
Enter Fetoscopy
Fetoscopic surgery uses tiny cameras and instruments inserted through small ports in the uterus. Instead of a major incision, you get three 5-mm punctures. The surgery is technically challenging - operating on a fetus through a tube while it floats in fluid is exactly as difficult as it sounds - but the potential benefits are significant.
The International Fetoscopic Neural Tube Defect Repair Consortium published data on their first 300 cases in the American Journal of Obstetrics & Gynecology (PMID: 34089698). The results were encouraging:
Gestational age at delivery: The fetoscopic group delivered at 35.3 weeks on average, compared to 34.1 weeks in the MOMS trial. Later delivery generally means bigger, healthier babies.
Preterm birth rate: Spontaneous preterm birth before 34 weeks occurred in only 15.8% of fetoscopic cases, compared to 46.2% in the MOMS trial. That's a massive difference.
Vaginal delivery: Here's the kicker - 44% of fetoscopic closures that survived to delivery had vaginal births. After open fetal surgery, 100% require C-sections. Being able to deliver vaginally isn't just about preference; it affects future pregnancies and long-term maternal health.
Uterine complications: Areas of dehiscence or thinning in the uterine scar were observed in 34% of MOMS cases and 49% in a post-MOMS cohort. In the fetoscopic registry? Zero percent.
The NCT03090633 Trial at Johns Hopkins
This specific trial is studying fetoscopic repair of isolated fetal spina bifida in a single-arm study of 10 participants. It's examining conditions including myelomeningocele, Chiari malformation type 2, neural tube defects, spinal dysraphism, and congenital abnormalities.
Johns Hopkins is one of several centers worldwide developing expertise in this procedure. The technique continues to evolve, with surgeons refining approaches and sharing lessons learned through international collaboration. A 2017 alternative technique combined maternal laparotomy (a small abdominal incision for access) with fetoscopic closure through just two ports, promising lower risk of premature rupture of membranes.
Recent research published in 2025 describes ongoing implementation efforts, including new programs in Taiwan that have achieved their first successful cases (doi:10.1016/j.tjog.2024.10.001). The learning curve is real, but centers are accumulating experience rapidly.
What Happens During the Surgery?
The procedure typically happens between 19-26 weeks of pregnancy - early enough that there's plenty of time for the baby to benefit from the repair, but late enough that the baby is big enough to operate on.
After appropriate anesthesia for both mother and baby (yes, fetal anesthesia is a thing - you can't have an unborn baby squirming around while you're trying to suture their spine), the surgeon makes those three small uterine punctures. Carbon dioxide or amniotic fluid infusion provides working space. Using the fetoscope and specialized instruments, the surgeon carefully closes the defect layer by layer.
The closure techniques vary by center but generally involve covering the exposed spinal cord with available tissue - sometimes a patch, sometimes the baby's own skin carefully mobilized to cover the defect. The goal is the same as open surgery: protect the spinal cord from further damage and allow healing to occur in utero.
After surgery, the mother stays in the hospital for monitoring, then goes home on modified activity restrictions until delivery. The hope is an uneventful remaining pregnancy with delivery as close to term as possible.
The Debate Continues
Not everyone is convinced that fetoscopy has proven itself. Open fetal surgery for MMC is now well-established, with predictable outcomes backed by a rigorous randomized trial. Fetoscopy is still considered experimental by some - the International Fetoscopic Consortium data, while impressive, comes from a registry rather than a randomized controlled trial.
A 2021 analysis noted that "the use of fetoscopy for spina bifida repair is adopted by an increasing number of centers worldwide. On the other hand, its efficacy has not been established within a randomized controlled trial and thus it is still considered experimental by others."
There are also technical considerations. Some data suggests fetoscopy may take longer, has a steeper learning curve, and might have different failure modes than open surgery. And despite improvements, about 40% of babies still require shunting for hydrocephalus - prenatal surgery doesn't eliminate this problem, just reduces it.
The Human Stakes
Behind all these statistics are real families facing impossible decisions. Finding out your baby has spina bifida is devastating. Being told there's a surgery that might help - but it's done before birth, there are significant risks, and the nearest center might be across the country - doesn't make that decision easier.
For parents, the question becomes deeply personal: Do we accept the risks of fetal surgery for the potential benefits? Open or fetoscopic? Travel to a specialized center or choose a local option for postnatal repair? These are conversations happening in genetic counseling offices and high-risk OB clinics every day.
What the research community is trying to provide is better evidence to guide those conversations. Trials like NCT03090633 are building the case for fetoscopic repair, documenting outcomes, identifying best practices, and helping define which patients are most likely to benefit.
The Future
The trajectory seems clear: fetoscopic techniques will continue to improve, outcomes will be refined, and eventually a randomized trial comparing fetoscopic to open prenatal repair may settle some of the remaining questions. Meanwhile, both approaches will likely continue to coexist, with center expertise and individual patient factors guiding recommendations.
For now, if you or someone you know receives a spina bifida diagnosis during pregnancy, know that options exist. Prenatal repair is real, it works, and the technology is advancing rapidly. It's not perfect - no surgery is - but it represents a remarkable human achievement: healing babies before they're born.
That's not science fiction anymore. That's just Tuesday in a fetal surgery center.
Disclaimer: This blog post is for informational purposes only and does not constitute medical advice. Decisions about fetal surgery for spina bifida should be made in consultation with maternal-fetal medicine specialists and fetal surgery centers experienced in these procedures. The trial discussed (NCT03090633) is registered at ClinicalTrials.gov and is conducted at Johns Hopkins University. Images and graphics are for illustrative purposes only and do not depict actual medical devices, procedures, mechanisms, or research findings from the referenced studies.
No comments:
Post a Comment