Fetal Surgery: Better Odds for Spina Bifida Kids Feb. 10, 2011 -- Children's odds of a good outcome from spina bifida surgery are better if the operation is done before birth, a major clinical trial shows.

But fetal surgery carries risks for the mother, and not all outcomes are good.

The findings come from an eight-year study led by Diana Farmer, MD, of the University of California, San Francisco. The study was halted early when it became clear that kids tended to do better with fetal surgery than with surgery after birth.

"Based on our findings, it appears that fetal surgery can provide a better option for these patients than waiting to treat them after birth," Farmer says in a news release.

Spina bifida is a birth defect in which the spine does not form properly. In the most common form, myelomeningocele, the partially exposed spinal cord pushes out into a sac filled with spinal fluid. The spinal cord is underdeveloped and damaged.

About 10% of these babies die. Those who survive may have lifelong disabilities that include leg weakness or paralysis and loss of bowel and bladder control.

Many of these kids also have a kind of hernia of the brain stem, in which part of the brain is pulled down into the upper spinal canal. This may lead to hydrocephalus -- a buildup of spinal fluid in the brain that must constantly be drained via a hollow tube called a shunt. The shunt is typically needed for the rest of the patient's life, and usually means periodic operations for repair or to treat infection.

In traditional surgery performed after birth, surgeons cover the baby's defect with skin. The fetal surgery is similar -- but may have the added benefit of allowing further development of the spinal cord before birth.

Fetal surgery obviously involves additional risks to both the mother and the unborn child. It's an open operation requiring a large incision. Women who undergo the procedure must deliver any future children via C-section.

"This is serious surgery, and a woman risks her life just as if she donated a piece of her liver in a living [donor] transplant operation," Farmer says.