Philadelphia, Pa. - Physicians at The Children's Hospital of Philadelphia have shown that performing neurosurgery on fetuses months before birth can dramatically reverse a potentially devastating nervous system condition that occurs in severe forms of the birth defect spina bifida, according to a study in the November 17 issue of the Journal of the American Medical Association. By closing the hole in the tissue covering the fetal spine, the surgeons relieve a condition farther up the spinal column called hindbrain herniation that can cause hydrocephalus, a dangerous buildup of fluid pressure in the brain.
The surgeons are at The Center for Fetal Diagnosis and Treatment of Children's Hospital, one of only two centers in the world offering comprehensive treatments in the emerging field of fetal surgery. Members of the surgical team have performed more than 250 fetal surgeries for a variety of conditions. In their study, the team reported on spina bifida surgeries performed between November 1997 and March 1999 on 10 fetuses at gestational ages of 22 to 25 weeks. "Our research suggests that performing this surgery earlier in pregnancy rather than later better prevents injury to the fetus," said Leslie N. Sutton, M.D., director of Neurosurgery at Children's Hospital, and lead author of the study.
Magnetic resonance imaging (MRI) scans taken every three weeks after the surgery showed the recession of hindbrain tissue that had formerly protruded into the spinal column. The MRI scans, using an ultrafast technology that does not require the mother to be sedated, also documented the opening of spinal fluid pathways that were previously blocked by the protruding hindbrain tissue. After their birth, seven infants avoided the need for a shunt, a surgically inserted tube that drains excess spinal fluid from the brain, and which is usually necessary for children with spina bifida.
In spina bifida, the most common birth defect of the central nervous system, a failure during fetal development early in pregnancy leaves an opening in part of the bone covering the spinal cord. Depending on the severity of the defect, the newborn may suffer potentially devastating conditions such as paralysis, bowel and bladder problems, and fluid pressure on the brain.
Occurring in approximately one out of every 2,000 births, spina bifida almost always involves a hindbrain herniation, also called the Chiari malformation, in which a portion of the brain is squeezed from the skull into the spinal column. Depending on its severity, the condition may cause infant death or lifelong disability. If the protruding tissue blocks the flow of cerebrospinal fluid from the brain, an accumulation of excess fluid called hydrocephalus may exert a hazardous pressure on the brain. The protruding hindbrain tissue may also compress the spinal cord and paralyze nerves, including those needed for breathing, swallowing or leg function.
In addition to damage to the spinal cord from direct pressure from the hindbrain, the defective covering at the spina bifida lesion leaves the spinal cord exposed to injury, both from the amniotic fluid and from the physical trauma of bumping into the wall of the uterus.
Protecting the spinal cord requires covering the lesion. Although this surgery is commonly performed shortly after birth, surgeons at The Children's Hospital of Philadelphia have explored the benefits of performing the surgery while the fetus is still in the mother's womb.
In their first surgery, performed on a 23-week-old fetus, the surgeons noted improvement in hindbrain herniation - an unexpected benefit, since the purpose of the surgery was to improve leg function after the child's birth.
In subsequent fetal operations, after the surgical team performed surgery on the mother and opened the uterus, Dr. Sutton covered the opening in the fetal skin with acellular human dermis, a product that is obtained from human skin tissue. Of the 10 surgeries, six babies were delivered at term. Four were delivered prematurely, of whom one died shortly after birth. Only two of the nine surviving babies required a shunt for hydrocephalus. The children's leg function appeared better than predicted, although research limitations prevented the authors from drawing firm conclusions about leg function. Overall, however, they concluded, "the data are sufficiently promising to warrant offering fetal closure to selected patients."
The Center for Fetal Diagnosis and Treatment at Children's Hospital, directed by N. Scott Adzick, M.D., a pioneer in fetal surgery, offers comprehensive, multidisciplinary care for mothers carrying a fetus with a known birth defect. Sophisticated diagnostic testing, genetic and prenatal counseling, and delivery and postnatal care at the neighboring Hospital of the University of Pennsylvania are provided through the Center. In addition to performing open fetal surgery for several life-threatening and debilitating conditions, the Center also offers minimally invasive fetal surgery and fetal cell transplants for genetic diseases.
[For a full press packet, including a copy of the original article, a diagram, photos and background information, please call Maria Stearns at 215-590-4091. For details on fetal surgery, including a video with footage of fetal spina bifida repair, see http://www.fetalsurgery.chop.edu/]
The Children's Hospital of Philadelphia, the nation's first children's hospital, is a leader in patient care, education and research. This 373-bed multispecialty hospital provides comprehensive pediatric services, including home care, to children from before birth through age 19. The Children's Hospital of Philadelphia admits more than 16,000 patients, and cares for more than 50,000 emergency patients and 500,000 outpatients annually. The Children's Hospital of Philadelphia operates a pediatric healthcare network that also includes The Joseph Stokes, Jr. Research Institute, eight outpatient specialty care centers, four primary care centers, inpatient units at three community hospitals, a poison control center and 28 Kids First physician practices in Pennsylvania, New Jersey and Delaware.