Nov. 23, 1998 Daniel Meyer, the first child to ever receive open fetal surgery for spina bifida, is now one and a half years old. Daniel, who was born June 12, 1997 to Cory and Scott Meyer of Nashville, still suffers from some weakness in his lower body, but is able to flex his hips and appears to have good bladder and bowel function.
The cutting-edge fetal surgery procedure involves opening the mother's abdomen and uterus, partially removing the fetus and sewing shut the opening over the fetus's spinal cord.
VUMC is one of only three medical centers in the United States doing open fetal surgery, and has so far performed 26 of the procedures, far more than any other center.
Spina bifida is the most common neurologic birth defect in the United States, occurring in 1.5 to 2 out of every 1,000 live births. Babies born with the defect have an opening in their spine, and although it is not considered to be a lethal disorder, in most cases it is severely handicapping. Babies typically have lower extremity weakness or paralysis, sensory loss, dysfunction of urinary or bowel functions, and are prone to develop hydrocephalus, or the increase of spinal fluid in the brain.
About 95 percent of babies born with spina bifida require a drainage shunt placed in the brain to help remove excess fluid.
Dr. Joseph P. Bruner, assistant professor of Obstetrics and Gynecology, is optimistic that the operation will improve the outcomes of these children.
Bruner is part of a team of VUMC researchers ? which includes Dr. Noel B. Tulipan, associate professor of Neurosurgery, and Dr. William F. Walsh, associate professor of Pediatrics.
"From studies that looked at the physiological causes of spina bifida, researchers came up with the 'two hit' hypothesis for neurological deficits with spina bifida," Bruner said.
The first damage, or hit, to the spinal cord comes from the fact that the fetus has spina bifida and the spinal cord is developing in an abnormal fashion. The second hit results from the prolonged exposure of the spinal cord to amniotic fluid.
"These studies have been repeated in sheep and pigs and show the same thing. If you protect the spinal cord from the intrauterine environment, the baby will develop more normally. If you expose the spinal cord to the fluid, the baby develops neurologic lesions," said Bruner.
This led Vanderbilt researchers first to the animal labs, then to a human study three years ago for the first attempt at fetal surgery to protect the spinal cord from the possible damaging effects of sustained exposure to amniotic fluid. That early technique, performed endoscopically, has now been replaced by the new open fetus technique.
Basic laboratory research at VUMC has also shown that the major damage from amniotic fluid occurs late in pregnancy.
"Armed with this information, we decided that rather than trying to cover this lesion very early in pregnancy, we could wait until later," Bruner said.
The new procedure is performed sometime between the 24th and 28th weeks, or the third trimester.
"This means that at this point we can actually do the same procedure to repair the spine that is done after delivery in spina bifida patients. We couldn't do that at 22 weeks because the skin isn't developed enough. A little later and the skin is strong enough," Bruner said.
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