Fetal surgery allows doctors to treat certain abnormalities of the fetus that might otherwise be fatal or cause significant problems if permitted to progress.
Approximately 3% of babies born in the United States each year have a complex birth defect. Parents are often left with the options of choosing to abort the fetus or treat the condition after birth. Certain birth defects, however, are complicated by the labor and delivery process; others may progress quickly after birth to cause significant disability or death. Fetal surgical techniques offer early intervention in order to treat such defects before they become more serious. The first open fetal surgery took place at the University of California at San Francisco (UCSF) in 1981.
Some of the fetal abnormalities that may be treated by fetal surgery are:
What fetal surgical technique is used depends on the specific condition of the fetus and its severity. The fetoscopic temporary tracheal occlusion procedure is used to treat CDH. The trachea is temporarily blocked (occluded) by a small balloon to trap fluid in the lungs (that normally escapes into the amniotic fluid); buildup of the fluid enlarges the lungs and stimulates their growth, pushing any abdominal organs that have moved into the chest cavity back into the abdomen. The occlusion is removed immediately after birth of the baby. The procedure is performed endoscopically. Rather than make a large incision into the abdomen and uterus, the surgeon inserts telescopic instruments through a tiny 1 in (2.5 cm) incision and uses them to perform the surgery. Other conditions that are treated with fetoscopic surgery are TTTS (to remove abnormal connections between blood vessels with a laser) and urinary tract obstruction (to insert a wire mesh tube called a stent into the bladder to allow urine to exit the body).
Open fetal surgery is used for conditions that cannot be treated endoscopically. An incision is made through the abdomen and the uterus is partially removed from the body. Amniotic fluid is drained from the uterus and kept in a warmer for replacement after completion of the surgery. An incision is made in the uterus (called a hysterotomy). In order to minimize bleeding of the uterus, an instrument called a uterine stapler is used to make an incision while simultaneously placing staples around the perimeter of the incision to prevent bleeding. Surgery is then performed on the fetus through the opening in the uterus to locate the abnormality and remove or fix it. Open fetal surgery is used for CCAM (to remove the cystic mass), myelomeningocele (to close the exposed spine), and SCT (to remove the tumor). Because of the nature of open fetal surgery, delivery for this child and all subsequent children of this mother will have to be performed by cesarean section .
Detection of many birth defects is possible through the use of sophisticated imaging and diagnostic techniques such as:
Once a congenital abnormality has been diagnosed, the condition will be assessed to determine if the fetus is eligible for fetal surgery. Generally only the most severe conditions that are certain to cause fetal death or significant disability are treated with fetal surgery. If fetal surgery is indicated, the parents will meet with the team of health care providers that will be involved in the surgery.
To prepare for the surgery, the steroid betamethasone will be given in order to speed up the development of the fetus's lungs. A complete history and physical examination will be performed. A monitor will be used to track uterine contractions and fetal heart rate. The patient will be instructed to refrain from eating and drinking after midnight the day of surgery, and will sign a surgical consent. Blood samples may be taken for laboratory tests and to type match the patient's blood in case a blood transfusion is necessary. An intravenous (IV) catheter will be used to infuse fluids and/or medications to the patient.
Postoperative recovery generally takes from five to 10 days. The patient will be closely monitored to ensure that she does not go into premature labor. She may be put on bed rest to minimize this risk. Some signs of premature labor include contractions, cramping, lower back pain or abdominal pain or pressure, vaginal bleeding, and leaking of fluid from the vagina. Tocolytics are drugs given to delay or stop labor; some commonly administered tocolytics are terbutaline, indocin, and magnesium sulfate. Antibiotics will usually be administered to prevent postsurgical infection.
Some risks associated with fetal surgery include infection of the incision or lining of the uterus, premature labor and delivery, bleeding, gestational diabetes, leakage of amniotic fluid, and infertility as well as those complications associated with anesthesia.
The results of fetal surgery depend on the reason for the procedures. Successful results of fetal surgery generally include halting the progression of the congenital malformation and perhaps reversing some of the potential complications that would arise without intervention.
One study of open fetal surgery used to repair myelomeningocele indicated that the risk of going into premature labor was significantly increased among women who had had the procedure (50% compared to 9% of similar cases with no fetal surgery performed). There was also an increased risk of oligohydramnios or low amniotic fluid (48% compared to 4% of similar cases with no fetal surgery performed). Because of the high risk of premature labor associated with fetal surgery, some fetuses have died during premature birth.
There are some alternative procedures that are offered for treating specific birth defects, depending on their severity. Fetal surgery is generally recommended only for the most severe defects. For example, myelomeningocele may be treated by closing of the lesion soon after delivery. SCTs and CCAMs may also be removed soon after the baby is born. Parents are often given the option of aborting the fetus (termed therapeutic abortion); or they may decide to refrain from medical intervention.
Bruner, Joseph, Noel Tulipan, Ray Paschall, Frank Boehm, William Walsh, Sandra Silva, Marta Hernanz-Schulman, Lisa Lowe, and George Reed. "Fetal Surgery for Myelomeningocele and Incidence of Shunt-Dependent Hydrocephalus." Journal of the American Medical Association 282, no. 19 (November 17, 1999): 1819–25.
Center for Fetal Diagnosis and Treatment, Children's Hospital of Philadelphia. 34th Street and Civic Center Boulevard, Philadelphia, PA 19104-4399. (800) IN-UTERO. http://fetalsurgery.chop.edu .
Fetal Diagnosis & Therapy, Vanderbilt University Medical Center. B-1100 Medical Center North, Nashville, TN 37232. (615) 343-5227.
Fetal Treatment Center, University of California at San Francisco. 513 Parnassus Ave., HSW 1601, San Francisco, CA 94143-0570. (800) RX-FETUS. http://www.fetus.ucsf.edu .
Spina Bifida Association of America. 4590 MacArthur Blvd., SW, Washington, DC 20007. (800) 621-3141. http://www.sbaa.org .
Danielpour, Moise, and Diana L. Farmer. "Fetal Surgery for Congenital CNS Abnormalities." Cedars-Sinai Net Journal. 2002 [cited February 28, 2003]. http://www.cedarssinai.edu/mdnsi/images/fetalsurg.pdf .
"The Fetal Treatment Center: Our Treatments." University of California at San Francisco. 2001 [cited February 28, 2003]. http://www.fetus.ucsf.edu/ourtreatments.htm .
Iannelli, Vincent. "Surgery Before Birth?" Pediatrics. January 29, 2000 [cited February 28, 2003]. http://pediatrics.about.com/library/weekly/aa012900.htm .
Stephanie Dionne Sherk
Fetal surgery is a highly specialized procedure that is offered at only a handful of hospitals around the United States. Among those health care providers who will have a role in the surgery are: