UCSF Offers Minimally Invasive Fetal Surgery for Myelomeningocele

UCSF Benioff Children’s Hospitals performed the world’s first fetal surgery in 1981 and have continued to excel in fetal surgery ever since. UCSF is a high-volume tertiary/quaternary referral hub for complex fetal cases.

Now, this experienced team is among only a few in the nation to offer minimally invasive fetoscopic surgery for myelomeningocele (MMC), a severe form of spina bifida. In babies with MMC, the vertebral arches in the spine and overlying tissue don’t fully close. This leaves an opening through which the spinal cord and its meninges (coverings) protrude into a sac on the baby’s back, exposing these structures to injury and the chemical burn of the amniotic fluid.

Prenatal closure can reverse this process. Building on robust evidence, minimally invasive surgery provides improved outcomes for the baby. This approach also offers important advantages for the pregnant patient (reducing maternal morbidity and uterine scar burden), filling a critical need in the Northern California region and across the West Coast.

Building on fetal surgery excellence

UCSF has led advances in fetal surgery for decades, including the landmark Management of Myelomeningocele Study (MOMS trial), published in the New England Journal of Medicine in 2011. This trial showed that prenatal MMC repair is superior to postnatal correction, leading to better neurological outcomes for the baby and reducing the need for a postnatal shunt. The trial ended earlier than anticipated because the intervention proved so effective, a compelling indicator of clinical benefit.

“Before fetal surgery, many of these babies faced severe cognitive and motor function impairments,” explains Akos Herzeg, MD, PhD, perinatologist and fetal surgeon at UCSF. “Long-term exposure to amniotic fluid caused significant damage to the spinal structures. Closing the spine early in pregnancy improved neurological outcomes and reduced dependency on shunts, which require lifelong maintenance and carry risks of infection and malfunction.”

The path to minimally invasive options

Experimental fetoscopic MMC repair began as early as 20 years ago. But these first attempts faced technical challenges. Limited camera resolution, inadequate understanding of fetal physiology during the procedure and complications led many centers to pause their minimally invasive programs.

“The technology and insights we needed for minimally invasive approaches hadn’t been developed a few decades ago,” says Gabriella Grisotti, MD, PhD, pediatric and fetal surgeon at UCSF. “We knew that prenatal intervention improved neurologic outcomes for the baby, and we were safely performing the open fetal procedure at UCSF. The main drawback was that the pregnant patient required a major abdominal surgery and a cesarean section for all future deliveries, carrying a higher risk of complications and a longer recovery.”

Advances in high-definition fetoscopic cameras, precision tools, refined surgical techniques, and precise temperature and humidity control during surgery eventually made the minimally invasive procedure viable. Dr. Herzeg was mentored in these techniques by Denise Lapa, MD, PhD, a pioneer in percutaneous minimally invasive fetal approaches. The UCSF team also benefited from the experience of the teams at Colorado Children’s, Baylor College of Medicine and Cincinnati Children’s.

“Studies and accumulated experience have shown that the fetoscopic procedure can close the defect, stop cerebrospinal fluid leakage and protect neural structures from amniotic fluid,” Dr. Herzeg says. “Importantly, these goals can be achieved even though the fetoscopic closure is not the traditional, anatomic layer-by-layer reconstruction. For most cases, this represents a definitive approach, with no need for another surgery after birth, although individual outcomes vary.”

The UCSF approach

UCSF’s fetoscopic technique balances the benefits of a minimally invasive approach with surgical precision. Using a hybrid fetoscopic method, the team first exposes the uterus through a maternal abdominal incision. Then, they place small uterine ports under ultrasound guidance and direct visualization to access the amniotic cavity.

Compared with a fully percutaneous approach, this strategy can improve instrument control and allow secure closure of the port sites at the end of the procedure. This surgery is available to patients at the UCSF Fetal Treatment Center.

Patients who undergo fetoscopic repair may deliver vaginally, avoiding the risks and recovery associated with an open fetal procedure and a cesarean section. Their future pregnancies are also safer, without the placental complications and uterine rupture risks associated with large uterine scars from a traditional open fetal procedure requiring a bigger uterine incision.

“Closing the uterine port sites after surgery significantly reduces the risk of premature rupture of membranes – a major complication seen with fully percutaneous approaches,” Dr. Herzeg says.

Multidisciplinary expertise

UCSF’s fetoscopic MMC program leverages the institution’s deep bench of fetal surgery expertise. Each case involves many experts beyond the three surgical specialties of fetal surgery, maternal-fetal medicine and pediatric neurosurgery. These experts comprise an extensive team of neonatologists, radiologists, urologists, rehab specialists, orthopedic surgeons, anesthesiologists and nurses. UCSF provides seamless continuity from diagnosis through fetal intervention and delivery to long-term spina bifida care, building on its MOMS trial legacy with ongoing, carefully evaluated innovation.

“Our 360-degree approach harnesses everyone’s expertise, providing the most benefit for our patients,” explains Dr. Grisotti. “Our entire team in the operating room, including anesthesiologists, neonatologists and surgical nurses, also has extensive experience with fetal surgery.”

Importantly, UCSF maintains expertise in both open and fetoscopic approaches. “Having experience in both techniques provides important advantages,” says Dr. Herzeg. “If technical factors, complications or fetal positioning prevent completion of the minimally invasive procedure, our team can always convert to open surgery.”

Addressing a regional need

Currently, only a handful of West Coast fetal centers perform fetoscopic MMC repair. For families in Northern California and neighboring states such as Nevada, Oregon, Hawaii, Alaska and surrounding regions, this often meant traveling hundreds or thousands of miles for care.

“Fetal surgery centers are spread out across the United States,” Dr. Grisotti says. “By offering it at UCSF, we’re helping families who might not otherwise have access to this care.”

Referrals and consultations

UCSF is evaluating patients for fetoscopic MMC repair and is fully equipped to provide the surgery. Research has shown the ideal window for the procedure is between 19 and 26 weeks of gestation, with many centers aiming to proceed at approximately 24-25 weeks when feasible.

Initial evaluation can begin as early as 16 weeks, allowing time for comprehensive imaging and counseling. This timeline balances early intervention to protect the spinal cord with fetal maturity to improve surgical outcomes and reduce prematurity risks.

For patients who may not be candidates for fetoscopic repair due to defect size, maternal factors or personal preferences, UCSF continues to offer open fetal surgery and expert postnatal neurosurgical care with excellent outcomes. This ability allows all eligible families to have access to the approach that best fits their clinical situation and goals. For those who are not candidates for any fetal intervention, the UCSF Fetal Treatment Center provides comprehensive pregnancy management, coordinated delivery planning and seamless transition to our pediatric neurosurgery team for timely postnatal treatment as needed.

For referrals, UCSF offers rapid record review and coordinated evaluation through the Fetal Treatment Center, including fetal MRI, multidisciplinary consultation (maternal-fetal medicine, fetal/pediatric surgery, neurosurgery and neonatology) and delivery planning.

UCSF’s Fetal Treatment Center and the UCSF Fetal Neurology Center of Excellence provide full evaluation and counseling for patients with an MMC diagnosis. The combination of pioneering experience, multidisciplinary expertise and approach, and minimally invasive options positions UCSF as a comprehensive center for this complex condition.

For referrals or consultations, contact the UCSF Benioff Children’s Hospitals Fetal Treatment Center.