Doctors believe they may have come up with a safer way of operating on babies while they are in the womb.
Operating on babies while they are in the womb is risky
Surgeons in Germany have used minimally invasive techniques to treat three unborn babies with suspected spina bifida.
The surgery involved making three tiny incisions into the womb and inserting three thin tubes and a camera to help them to repair the damaged spine.
Operating on unborn babies is notoriously difficult and only a few surgeons around the world have tried it.
Surgeons in the United States have led the way. Their technique involves opening the abdomen and womb of the pregnant woman by large incisions in much the same way as a caesarean section.
However, this type of surgery is risky not least because it can cause the woman to go into premature labour.
The German surgeons believe their technique reduces the risks of this happening.
They tested their technique extensively on pregnant sheep before trying it on humans.
But it has now been used successfully on three unborn babies.
All three were at risk of developing spina bifida. This occurs when the bones of the spine fail to come together. This leaves key nerves exposed.
If left untreated it can cause permanent damage, leading to paralysis.
In the UK, the established practice is to operate on the baby almost immediately after birth and place a protective layer of tissue around the spine.
This reduces the damage, although frequently it cannot prevent some permanent disability.
"All children operated on showed only slight symptoms of lower limb paralysis after delivery," said Dr Thomas Kohl, who carried out the surgery.
He said doctors were now monitoring their progress.
"We will need to wait until these children are at least two years of age to get an idea about the therapeutic value of the new operation," he said.
In the UK 18,000 people are known to suffer from spina bifida. Approximately 1,000 pregnancies a year are affected, and in nine out of 10 cases the pregnancy is terminated.