Nov. 11, 1999 (Washington) -- Before the advent of fetal surgery, the only two options for women whose fetuses were found to have spina bifida were to end the pregnancy or subject the infant to surgery almost immediately after birth. But fetal surgery, surgery performed while a fetus is still developing in the womb, may provide another option.
Spina bifida is a serious disorder caused when fusion of the developing spinal cord does not occur properly. Children with spina bifida have various physical disabilities and experience many developmental delays. Some suffer from brain defects. Many have an obstruction along the abnormal spinal cord that causes fluid to collect in the brain. This condition, called hydrocephalus, requires a shunt to be inserted in their spine to help drain this fluid out of the brain. This surgery must be performed immediately after birth and repeated throughout their lives to maintain it.
Now physicians at Vanderbilt University in Nashville and Children's Hospital in Philadelphia report that they have successfully repaired spina bifida lesions in several dozen affected fetuses. Using fetal surgery, they have significantly reduced the severity of the brain defect that accompanies the disorder and decreased the need for shunts after birth. The Vanderbilt and Philadelphia physicians have been at the forefront of pioneering fetal surgery for spina bifida and are the only medical groups performing the surgery today.
However, their surgical feats, described in the Nov. 17 issue of JAMA, also come with serious complications to the mother. And the surgeons still don't know much about how the infants -- about half of whom are born prematurely -- are faring developmentally.
"I can say this is a success in that we are reversing [brain] malformation," lead researcher Leslie Sutton, MD, a neurologist at Children's Hospital, tells WebMD. "Our preliminary data indicates we are putting in less shunts, and as far as the legs, we have 4-5 [infants] that had better leg motion than what was expected. We are very encouraged about it."
The Vanderbilt study compared 29 infants with spina bifida who had fetal surgery and 23 with the disorder who did not have fetal surgery. Overall, about 60% of those undergoing the surgery required a shunt to treat hydrocephalus, while almost 90% of those without fetal surgery required a shunt. Only 7% of the fetal surgery group had moderate or severe brain defects compared with 45% of the nonsurgery group.
But the researchers were troubled by some of their findings. Those undergoing fetal surgery were born premature, on average, at 33 weeks. Those without the fetal surgery were born at term, on average at 37 weeks. Fifty percent of the women who underwent surgery had to be hospitalized for preterm labor, compared with 9% who did not have surgery.
The Vanderbilt babies, on average, showed levels of paralysis equal to what was expected without surgery, based on the location of the spinal defect, a finding Noel Tulipan, MD, a pediatric neurologist at Vanderbilt University Medical Center, termed "disappointing." Tulipan, a co-researcher on one of the studies, adds, "The benefit [of surgery] is the reduction of shunt dependence and Chiari malformation [a type of brain defect]."
Whether the babies possess developmental problems is "completely unknown," Tulipan says. The oldest child, who is 2 1/2 years old, "is doing well and seems to have normal intelligence," he says. None of the babies were tested during a return visit to Vanderbilt last spring because they were considered too young. "There were none that were obviously terrible, but we are talking about babies who are on average about 6 months old. We are a long way off before we can present significant data" on their progress.
The Philadelphia group reported on 10 surgeries performed from March 1998 to February 1999. One fetus was born at 25 weeks and died. Of the nine survivors, three were delivered earlier than planned -- at 30 or 31 weeks -- while the remaining six were delivered by cesarean section at 36 or 37 weeks. Four have some paralysis in both legs or feet, two have problems with one leg only, and two appear to have no paralysis. Seven have remained without a shunt; two needed to have a shunt inserted.
"If you can eliminate the need for a shunt, that is a tremendous thing," Sutton says. "It is a lifelong thing. Some will have 30 to 40 surgeries," because shunts malfunction over time, and the shunt site can become infected.
The oldest child who had the surgery in Philadelphia is now 18 months old. "They all seem to be normal as far as we can tell from the cognitive point of view," Sutton says.
"I think this is a very important advance in the management of [spina bifida]," John Freeman, MD, tells WebMD. Freeman, a professor of neurology at Johns Hopkins University in Baltimore and former head of its genetics birth defects clinic, reviewed the Vanderbilt study for WebMD. "As with any advance in surgery, the more they do the better they get. What's important to me is the procedure can be done, and it can be done relatively safely and that we hope that that will decrease the motor deficits. We will eagerly look forward to their next report."