Major Finding: Death or the need for a shunt was significantly less likely in the prenatal surgery group, compared with the postnatal surgery group (68% vs. 98%).
Data Source: In the Management of Myelomeningocele Study (MOMS), 183 volunteer women with singleton pregnancies were randomized to prenatal surgery before the 26th week of pregnancy or surgery for their infants after birth.
Disclosures: The study was sponsored by the National Institutes of Health.
Prenatal surgery to repair myelomeningoceles significantly reduced the need for shunts at 1 year of age and improved children's motor function at age 30 months, compared with children who had surgery after birth, based on data from a randomized trial of 183 pregnant women.
The results reflect data from 158 children who were evaluated at 12 months of age and 134 children evaluated at 30 months. Data collection is ongoing.
The surgery to repair the opening in the spine is usually performed after birth, but data from animal studies suggest that prenatal surgery could result in fewer complications, said Dr. N. Scott Adzick of the Children's Hospital of Philadelphia and his colleagues.
In the Management of Myelomeningocele Study (MOMS), 183 volunteer women with singleton pregnancies were randomized to prenatal surgery before the 26th week of pregnancy or surgery for their infants after birth (N. Engl. J. Med. 2011 [doi:10.1056/NEJMoa1014379]).
The children were examined for two primary outcomes. The first outcome, at age 12 months, was patient death or the need for a shunt. The second outcome, at age 30 months, was a composite score of motor function and brain development. The score was based on the Bayley Scales of Infant Development II (BSID-II) Mental Development Index and the difference between each child's actual ability and his or her expected motor function based on the severity of the spinal defects.
Death or the need for a shunt was significantly less likely in the prenatal surgery group, compared with the postnatal surgery group (68% vs. 98%). The rates of shunt placement were significantly lower in the prenatal surgery group, compared with the postnatal surgery group (40% vs. 82%).
All the fetuses in the study suffered from hindbrain herniation, in which the base of the brain is pulled into the spinal canal. But at 12 months, 36% of the children in the prenatal surgery group had no evidence of hindbrain herniation, compared with 4% in the postnatal surgery group. In addition, infants in the prenatal surgery group had lower rates of moderate or severe hindbrain herniation than did the postnatal surgery group (25% vs. 67%).
In addition, infants in the prenatal surgery group scored an average of 21% higher on measures of mental and motor function, compared with the postnatal surgery group, with primary outcome scores of 149 vs. 123, respectively.
Infants who underwent prenatal surgery were born at a mean 34.1 weeks of pregnancy, compared with a mean 37.3 weeks of pregnancy for the postnatal surgery group. Significantly more infants in the prenatal surgery group had respiratory distress syndrome, compared with the postnatal surgery group (21% vs. 6%).
In terms of secondary outcomes, children in the prenatal surgery group were more likely to be able to walk without crutches or other orthotic devices, compared with the postnatal surgery group (21% vs. 42%).
The mean age of the pregnant women was 29 years. Each fetus had a myelomeningocele located between the T1 and S1 vertebrae, evidence of hindbrain herniation, and a gestational age of 19.0-25.9 weeks. Exclusion criteria included body mass index of 35 kg/m
Approximately one-third of the women in the prenatal surgery group showed uterine thinning or an area of dehiscence at the time of delivery. Women undergoing prenatal surgery must understand that they will require a cesarean delivery for the current pregnancy and any future pregnancies, the researchers added.
Myelomeningocele, a severe form of spina bifida in which the backbone and spinal canal do not close completely before birth, occurs in approximately 4 of every 10,000 births in the United States, Dr. Diana L. Farmer, division chief of pediatric surgery at the University of California, San Francisco, said in a teleconference. Dr. Farmer was one of several researchers on the study who took part in a teleconference to present the study findings.
The study was not large enough to show an impact of gestational age on the results, but data collection is ongoing. “This is a priceless cohort of patients that we will follow for a longer period of time,” Dr. Farmer said. She noted that the National Institutes of Health has agreed to fund follow-up of the patients until age 6–9 years. Future studies will include whether the children in the prenatal surgery group remain free of shunts, maintain improved motor function, and require fewer procedures, compared with the postnatal group.