Part of the spinal cord and spinal nerves, usually encased in a sac, protrude through an opening in the back and is exposed to the amniotic fluid. The brainstem (hindbrain) descends, or herniates, into the spinal canal in the neck and blocks the flow of cerebrospinal fluid. This can cause a damaging buildup of fluid in the brain called hydrocephalus.
Babies who undergo an operation to repair the birth defect spina bifida while still in the womb develop better and experience fewer neurologic complications than babies who have corrective surgery after birth, according to findings from a major multicenter trial led by UCSF researchers. The study is the first to systematically evaluate the best treatment for myelomeningocele, the most serious form of spina bifida, in which the bones of the spine do not fully form.
The eight-year trial, which was stopped early because results were so positive, shows that prenatal surgery greatly reduces the need to divert fluid away from the brain; improves mental development and motor function; and increases the likelihood that a child will one day walk unassisted. This is the first time a randomized clinical trial has clearly demonstrated that surgery before birth can improve the outcome for patients.