A landmark study shows that an operation to fix a hole in the spine while the foetus is still in the womb leads to better outcomes for children with spina bifida.
The operation showed such a clear benefit over waiting until the infant is born that the study was stopped early.
"This is the first hope for spina bifida foetuses," said lead researcher Dr Scott Adzick of Children's Hospital of Philadelphia, one of three places that participated in the study.
Doctors started experimenting with foetal surgery for spina bifida in the mid-1990s, cutting into the mother's abdomen and uterus to close the gap in the spine. It even became part of the abortion debate when a photo of a tiny hand poking out of a womb during surgery was published.
The government-funded study showed that babies who have the operation in the womb were more likely to walk without help and less likely to need a tube to drain fluid build-up in the brain.
Many risks involved
Foetal surgery did come with some risks, however, including a higher chance of being born premature and complications for the mother.
Spina bifida –which means split spine, happens when the spine doesn't develop properly. In the most severe cases, the spinal cord sticks out through an opening in the spine. Children often are paralysed or have weakness below the waist and many need crutches or a wheelchair.
They also suffer from incontinence and fluid build-up in the brain.
Cases in the US have dropped to 1,500 a year since 1998, when the government ordered that foods like cereals, breads and pasta be fortified with folic acid, which reduces the risk of the spinal defect.
Though spina bifida is usually diagnosed before birth, the operation is typically done days after delivery. Quick surgery can prevent further harm, but cannot reverse the nerve damage that has already occurred.
When foetal surgery for spina bifida was first tried, it was controversial because operations in the womb were typically done for life-threatening problems.
There was also no long-term research on the safety of the surgery. The operation even got caught up in the abortion debate when abortion opponents seized on a photo taken during surgery on a 21-week-old foetus at Vanderbilt University.
By the end of 2002, more than 230 spina bifida operations had been done, but some doctors remained skeptical.
So the National Institutes of Health launched a big study that year at Vanderbilt, the Philadelphia hospital and the University of California, San Francisco. Other hospitals agreed not to do the surgery while the research was under way.
The researchers, whose findings were published online in the New England Journal of Medicine, studied 158 babies who had the surgery either in the womb or after delivery. The foetal surgery was done between 19 and 25 weeks of gestation.
By the time they turned a year old, 40% in the foetal surgery group needed a drainage tube, or shunt, in the brain, compared with 82% in the standard surgery group. The foetal surgery group scored higher on combined tests of mental development and motor skills at 2½ years, though there was no difference in cognitive function alone.
Of the toddlers in the foetal surgery group, 42% could walk without crutches or other support versus 21% in the other group.
Two children died within days of the foetal surgery; two children who had the fix after birth and had shunts died later.
Not all patients helped
"Not all the patients were helped here, and there are significant risks," said paediatric surgeon Dr. Diana Farmer of UC San Francisco. "So this procedure is not for everyone."
For safety reasons, the study did not include obese women, even though they have higher rates of foetuses with spina bifida.
Since foetal surgery is highly specialised, some experts said that the results may not be as good in hospitals with little experience and that more work is needed to better determine who will benefit most.
"Caution is necessary here," Dr Joe Simpson of Florida International University and Dr Michael Greene of Massachusetts General Hospital wrote in an editorial.
(Sapa, February 2011)