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Prenatal Surgery

Prenatal surgery

Definition

Prenatal surgery is a surgical procedure performed on a fetus prior to birth.

Purpose

Prenatal surgery, also called fetal surgery, antenatal surgery, or maternal-fetal surgery, usually is performed under circumstances in which the fetus is not expected to survive delivery or to live long after birth without prenatal intervention. The most common prenatal surgeries are for conditions in which the child will not be able to breathe on its own after birth. There are only about 600 candidates for prenatal surgery in the United States each year and far fewer prenatal surgeries are performed. Most of these procedures are high-risk and may be considered experimental.

More common prenatal surgeries

Urinary tract obstructions in male fetuses are usually caused by a narrowing of the urinary tract. This can cause the urine, which normally flows out into the amniotic fluid surrounding the fetus, to back up and injure the kidneys. If only one kidney is affected and there is a normal amount of amniotic fluid, prenatal intervention is not required. However, in addition to kidney damage, urinary tract obstructions can lead to multiple abnormalities and depleted amniotic fluid, which endangers the fetus and prevents the lungs from growing. About 10 percent of fetuses with urinary tract obstructions may require prenatal surgery in which a device is placed in the fetus's bladder to drain the urine into the amniotic sac.

Congenital diaphragmatic hernia (CDH) occurs when the diaphragm does not form completely at about eight weeks of gestation, leaving a hole in this muscle that separates the chest and the abdomen. The stomach, intestines, liver, spleen, and kidneys can move into the chest cavity through this hole, which is most often on the left side. Most babies with CDH are treated after birth. However, about 50 percent of fetuses with CDH do not survive after birth because their lungs are too small (pulmonary hypoplasia). A fetus whose liver has moved into its chest, seriously restricting lung development, whose lung-to-head ratio is less than one in four, and whose chance of survival through delivery is less than 50 percent may be a candidate for surgery. CDH fetuses whose livers have not moved into the chest have a survival rate of about 90 percent without prenatal intervention.

Congenital cystic adenomatoid malformation (CCAM) occurs when one or more lobes of the lungs develop into fluid-filled sacs called cysts rather than into normal lung tissue. Most CCAMs disappear on their own or are small enough to not cause problems. Large CCAMs can limit lung development, causing pulmonary hypoplasia. About 10 percent of fetuses with CCAMs are at risk of heart failure because the cysts push into the heart. CCAMs also can push on the trachea and the esophagus where they prevent the fetus from ingesting amniotic fluid. Prenatal surgery to drain or remove the cyst is performed only on severely affected fetuses.

Sometimes prenatal surgery is performed to remove a tumor. Sacrococcygeal teratoma (SCT) is the most common tumor in newborns, occurring in one out of every 35,000 to 40,000 births. It is more common in girls than in boys. These tumors at the base of the tailbone can grow very large. With early diagnosis, most SCT babies are delivered normally and the tumor is removed after birth. However, a small percentage of these tumors are large, hard, and full of blood vessels and may stress the fetal heart. These may be treated with a surgical procedure that destroys the blood vessels leading to the tumor, thereby preventing its growth.

Up to 15 percent of twins who share a placenta (monochorionic twins) have twin-twin transfusion syndrome (TTTS). Because of abnormal blood vessel connections in the placenta, one twin pumps the circulating blood for both twins. As a result the pumping twin has reduced volumes of blood and amniotic fluid and the recipient twin as increased volumes, leading to a variety of problems, including the risk of heart failure in both fetuses. TTTS may be treated by removing fluid from the overfilled recipient amniotic sac and placing it into the depleted sac of the pumping twin. If this fails, prenatal surgery may be used to destroy the abnormal blood vessel connections in the placenta.

Twin-twin reverse arterial perfusion (TRAP) sequence occurs in about 1 percent of monochorionic twins. In a TRAP sequence one twin develops normally and the other lacks a heart. The normal twin pumps all the blood for both twins and is at risk for heart failure. If left untreated 50 to 75 percent of these normal twins die. In prenatal surgery for TRAP sequence, the connections between the twins are severed.

Other prenatal surgeries

Other conditions that may be treated by prenatal surgery include:

  • various congenital defects that block air passages and will prevent the newborn from breathing on its own
  • various lung malformations
  • omphalocele, a birth defect in which an opening in the fetus's abdominal wall enables portions of the stomach, liver, and intestines to protrude
  • fetal gastroschisis, a birth defect in which the abdominal wall muscles do not form correctly and the stomach and intestines protrude and float in the amniotic fluid, a condition that occurs primarily in fetuses of mothers in their late teens or early 20s
  • bowel obstructions, usually caused by a narrowing in the small intestine
  • experimental hematopoietic stem cell transplants for X-linked severe combined immunodeficiency syndrome

Hypoplastic left heart syndrome, in which the blood flow through the left side of the heart is obstructed, is the most common congenital heart defect that is a candidate for prenatal surgery. In this condition, which is often fatal, the left side of the heart is very small and stops working.

Spina bifida

Until the late 1990s, prenatal surgery was almost exclusively limited to life-threatening conditions. However in 1994 the first prenatal surgery to treat spina bifida (myelomeningocele) was performed. This is the second most common birth defect in the United States, affecting one out of every 2,000 newborns. It is not considered to be life-threatening.

Spina bifida occurs during the first month of fetal development when a small bit of bone and skin fails to fully enclose the nerves of the spinal cord, leaving a hole or lesion. Depending on the location of the lesion, spina bifida may not require treatment; the higher up the opening in the spinal cord, the more severe the condition, and myelomeningocele can cause severe deformities, paralysis, and mental retardation . The damage appears to be caused by leakage of fluid from the spinal cord and exposure of the cord to amniotic fluid. The risk of infant death is about 10 percent and after the age of one, about 1 percent of affected children die each year.

Surgery for spina bifida requires closing the opening in the cord. Since the damage from spina bifida occurs during fetal development, prenatal surgery may reduce the damage. However, prenatal surgery for spina bifida has become enmeshed in the politics of reproductive rights and fetal rights. As of 2004, prenatal surgery for spina bifida was available only as part of a prospective randomized clinical trial.

Description

The decision to have prenatal surgery is made on the basis of detailed ultrasound imaging of the fetus, including an echocardiogram that uses ultrasound to obtain images of the fetal heart, as well as other diagnostic tools. Consultations include a perinatologist, a neonatologist, a pediatric surgeon, a clinical nurse specialist, and a social worker. Usually only fetuses with a very poor prognosis are candidates for maternal-fetal surgery. Only about 10 percent of those referred for evaluation actually undergo the surgery. Since additional congenital defects preclude prenatal surgery, amniocentesis or chorionic villi sampling (CVS) are used to check for chromosomal abnormalities in the fetus. Prenatal surgeries usually are performed between 18 and 26 weeks of gestation.

Prenatal surgery usually requires a general anesthetic. The fetus receives the anesthetic via the mother's blood. During the operation the anesthesiologist controls the mother's breathing through a tube into her throat and airway. The anesthesiologist and a perinatologist monitor the heart rates of the mother and fetus. For some procedures an epidural anesthetic that numbs the abdominal region may be used instead of general anesthesia.

Open surgeries

Open prenatal surgery requires a procedure similar to a cesarean section (C-section) for delivering a baby through the mother's abdomen. Incisions are made through the mother's abdominal wall. In some procedures the fetus is partially removed from the uterus. In other procedures the entire uterus is removed from the mother's body cavity through her abdomen.

Using ultrasound as a guide, the surgeon feels for the affected fetal part. The fetus must be moved away from the placenta, the disk-shaped organ within the uterus that provides the blood supply to the fetus. The surgeon may knead and push on the uterus to move or flip the fetus. A narrow tube in placed through a tiny hole in the uterine wall, through which the amniotic fluid is drained and collected in syringes. Opening the uterus is the riskiest component of prenatal surgery. The first incision is made at a point away from the placenta to prevent damaging it. A special device simultaneously makes the incision and clamps the edges to prevent bleeding. Following the procedure the fetus is replaced in the uterus and the incision is stitched. Prior to the final stitch the amniotic fluid is re-injected into the uterus. The uterus is repositioned in the mother's body cavity and her abdominal wall is closed.

The first successful open fetal surgery was performed in 1981 for a urinary tract obstruction. A tiny hole was made in the bladder of the fetus and a catheter (a long, thin tube) was inserted to drain the urine directly into the amniotic fluid. The first successful open fetal surgery for CDH was performed in 1989.

Prenatal open surgery for CCAM requires opening the fetal chest. If a large cyst does not have a hard component, procedures called thoracoamniotic shunting or catheter decompression may be used to drain the cyst. Otherwise the surgeon must remove all or a portion of the mass. The first successful resection (removal) of a CCAM from a fetal lung was performed in 1990. The first resectioning of a fetal SCT was performed in 1992.

Between 1997 and 2004, more than 200 open surgeries were performed for myelomeningocele. An incision the size of a small fist is made in the uterus. The surgeon loosens and lifts the tissues of the spinal canal lesion and stitches them closed. The entire procedure takes about one hour.

Less invasive procedures

For urinary tract obstructions a needle may be used to insert a catheter through the mother's abdomen and uterus and into the fetal bladder where it drains the urine into the amniotic fluid. The catheter may have an expandable wire mesh that expands in the bladder to prevent the catheter from plugging up or dislodging.

The first successful fetoscopic temporary tracheal occlusion for CDH was performed in 1996. Small surgical openings are made in the uterus, and a tiny fiber optic fetoscope is inserted to guide the operation. A needle-like instrument enters the uterus through a small incision in the mother's abdomen. A balloon placed in the fetus's trachea prevents lung fluid from escaping through the mouth, enabling the lungs to expand, grow, and push the abdominal organs out of the chest and back into the abdomen. The balloon is removed at birth. In a successful procedure the lungs are developed enough that the baby will breathe on its own at birth.

Hypoplastic left heart syndrome is treated by passing a needle, guided by ultrasound, through the mother's abdominal wall, into the uterus and the fetal heart. A catheter is passed through the needle across the fetus's aortic valve. A balloon is inflated, opening the valve and allowing blood to flow through the left side of the heart.

Radiofrequency ablation

Radiofrequency ablation (RFA) sometimes can be used for SCT. Guided by ultrasound a needle is inserted through the mother's abdomen and uterus and into the tumor. Radiofrequency waves sent through the needle destroy the blood supply to the tumor with heat. This slows the tumor's growth and may enable the fetus to survive until delivery. The first RFA of a SCT was performed in 1998.

A TRAP sequence also may be treated by RFA. A 3-mm needle targets the exact point where the blood enters the twin without a heart. Using an echocardiogram device, RFA is applied until the blood vessels and surrounding tissue are destroyed and the blood flow is halted. This procedure has eliminated the need for open surgery or larger fetoscopes to treat a TRAP sequence.

Laser treatment

TTTS is a progressive disorder and early intervention may prevent later complications. The most common treatment for TTTS is amnioreduction in which a syringe through the mother's abdomen is used to remove amniotic fluid from the overfilled sac and place it in the sac of the other twin. This procedure may need to be repeated during the course of the pregnancy. If TTTS does not respond to amnioreduction, laser treatment may be attempted to stop the abnormal blood circulation. Following detailed ultrasound, a thin fetoscope is inserted through the mother's abdominal and uterine walls and into the amniotic cavity of the recipient twin to examine the surface placental vessels. The abnormal blood vessel connections are located and eliminated with a laser beam. The first successful fetoscopic laser treatment for TTTS was performed in 1999.

EXIT

Ex utero intrapartum treatment (EXIT) is a surgery performed for a congenital defect that blocks the fetus's airway. The fetus is removed from the womb by cesarean section but the umbilical cord is left intact so that the mother's placenta continues to sustain the fetus. After the air passage is cleared, the umbilical cord is cut and the newborn can breathe on its own. The EXIT procedure is used for various types of airway obstruction including CCAM.

Precautions

The decision to undergo prenatal surgery is a difficult one. Considerations must include the following:

  • serious risks for the mother and fetus
  • time commitment for the surgery
  • extended postoperative bed rest, perhaps until delivery
  • travel to a hospital that performs the procedure
  • possible need to stay near the hospital until delivery
  • significant commitment of financial resources; some surgeries may not be covered by insurance
  • arrangements for care of other children

Preparation

Prior to surgery the mother will need to do the following:

  • arrange for help and support following the surgery since she will be on bed rest to prevent preterm labor
  • prepare for the possibility of having to remain near the hospital until delivery
  • possibly make arrangements for a blood donor in the unlikely event that she needs a blood transfusion
  • take betamethasone, a steroid, in two intramuscular injections 1224 hours apart to accelerate lung maturity in the fetus; if delivery occurs earlier than 34 weeks, the mother may have to take it again closer to the delivery date
  • wear a fetal/uterine monitor after hospital admission
  • have urine and blood samples taken
  • have her blood typed and cross-matched in case of the need for a transfusion
  • have an intravenous (IV) infusion of fluid and electrolytes
  • take a sleeping medication
  • sign a surgical consent
  • wear thick elastic stockings
  • take a medication for decreasing stomach acids

The mother usually is given medications called tocolytics to prevent contractions and labor during and after surgery. Tocolytics include:

  • indocin suppositories before surgery and up to 48 hours after surgery
  • magnesium sulfate for one to two days after surgery with careful monitoring
  • nifedipine, a pill given every four to six hours as the indocin is being decreased; usually nifedipine is continued until 37 weeks of gestation or delivery
  • terbutalin in pill form

Aftercare

Following the surgery the mother lies in bed on her side to provide the best circulation to the fetus and to help prevent contractions. The mother will have:

  • an oxygen mask to provide post-anesthetic supplemental oxygen
  • an IV catheter to supply fluids and antibiotics for at least 48 hours after surgery
  • a urinary catheter to collect urine from the bladder for 4872 hours
  • an epidural catheter to supply constant pain medication, usually morphine, for several days after surgery, followed by oral pain medications
  • a sequential compression device to improve blood circulation in the legs during bed rest
  • a continuous electronic fetal/uterine monitor to check the fetal heart and the uterine response to the tocolytics and to check for signs of preterm labor
  • a transparent dressing over the abdominal incision so that the fetus can be monitored and the incision site observed without removing the dressing

Fluids and food are not taken by mouth until the mother's digestive function returns. She usually remains in the hospital for four to seven days following surgery.

To prevent or treat postoperative lung or circulatory problems, the mother should:

  • practice deep breathing to keep all airways clear
  • perform incentive spirometer exercises, using a small simple device to assist deep breathing and opening of the lungs, five times during each waking hour
  • be turned from side to side at least every two hours to increase circulation and relieve areas of pressure
  • practice foot flexion exercises to improve circulation and help prevent blood clots

After discharge from the hospital the mother will be on modified bed rest, lying on her side until 37 weeks of gestation. This increases blood flow to the fetus and reduces pressure on the cervix to help prevent uterine contractions. She will be given bed rest exercises and prescribed a special diet. She will see a perinatologist once a week and have at least one ultrasound per week.

Risks

A major risk of prenatal surgery is nicking the placenta, causing blood hemorrhaging, uterine contractions, and birth of a premature infant who may not survive. Preterm labor is the most common complication of prenatal surgery. Fetoscopic surgeries are less dangerous and traumatic than open fetal surgery and reduce the risk of premature labor. Subsequent children of a mother who has undergone fetal surgery usually are delivered by cesarean section because of scarring of the uterus.

Other risks to the mother include:

  • extensive blood loss
  • complications from general anesthesia
  • side effects, potentially fatal, from medications to control premature labor
  • rupturing of the uterine incision
  • infection of the wound or uterus
  • psychological stress
  • inability to have additional children
  • death

All fetuses that undergo surgery are born prematurely. Infants born even six weeks early are at risk for delays in walking and talking and for learning problems. Infants born at 30 weeks of gestation or less are at risk for blindness, cerebral palsy , and brain hemorrhages.

About 25 percent of women undergoing prenatal surgery lose some amniotic fluid, often because of leakage at the uterine incision. Amniotic fluid is essential for lung development and protects the fetus from injury and infection. If all of the amniotic fluid is lost, the fetal lungs may not develop properly. Without the cushion that enables the fetus to float, the fetus may compress the umbilical cord causing death.

Other risks to the fetus include:

  • birth during surgery
  • membrane separation between the tissues surrounding the amniotic fluid sac and the uterus, causing early delivery or interference with blood flow to some fetal body part such as an arm or leg
  • further damage to the spinal cord and nerves during prenatal surgery for spina bifida
  • intrauterine infection requiring immediate birth of the fetus
  • brain damage
  • physical deformities
  • death

Normal results

Although fetal surgeries heal without scarring, they are rare and risky, and it is difficult to predict the outcome. In general, the following usually occurs:

  • Fetal surgery for CDH lessens the severity of the condition so that the fetus usually survives delivery and lives long enough to undergo corrective surgery.
  • Thoracoamniotic shunting for CCAM usually results in survival.

KEY TERMS

Amniocentesis A procedure performed at 16-18 weeks of pregnancy in which a needle is inserted through a woman's abdomen into her uterus to draw out a small sample of the amniotic fluid from around the baby for analysis. Either the fluid itself or cells from the fluid can be used for a variety of tests to obtain information about genetic disorders and other medical conditions in the fetus.

Amniotic fluid The liquid in the amniotic sac that cushions the fetus and regulates temperature in the placental environment. Amniotic fluid also contains fetal cells.

Cesarean section Delivery of a baby through an incision in the mother's abdomen instead of through the vagina; also called a C-section, Cesarean birth, or Cesarean delivery.

Chorion The outer membrane of the amniotic sac. Chorionic villi develop from its outer surface early in pregnancy. The villi establish a physical connection with the wall of the uterus and eventually develop into the placenta.

Chorionic villus sampling A procedure used for prenatal diagnosis at 10-12 weeks gestation. Under ultrasound guidance a needle is inserted either through the mother's vagina or abdominal wall and a sample of the chorionic membrane. These cells are then tested for chromosome abnormalities or other genetic diseases.

Congenital cystic adenomatoid malformation (CCAM) A condition in which one or more lobes of the fetal lungs develop into fluid-filled sacs called cysts.

Congenital diaphragmatic hernia (CDH) A condition in which the fetal diaphragm (the muscle dividing the chest and abdominal cavity) does not close completely.

Echocardiography A non-invasive technique, using ultrasound waves, used to look at the various structures and functions of the heart.

Ex utero intrapartum treatment (EXIT) A cesarean section in which the infant is removed from the uterus but the umbilical cord is not cut until after surgery for a congenital defect that blocks the air passage.

Fetoscope A fiber optic instrument for viewing the fetus inside the uterus.

Monochorionic twins Twins that share a single placenta.

Omphalocele A birth defect where the bowel and sometimes the liver, protrudes through an opening in the baby's abdomen near the umbilical cord. Placenta The organ that provides oxygen and nutrition from the mother to the unborn baby during pregnancy. The placenta is attached to the wall of the uterus and leads to the unborn baby via the umbilical cord.

Pulmonary hypoplasia Incomplete or defective development of the lungs.

Radiofrequency ablation (RFA) A procedure in which radiofrequency waves are used to destroy blood vessels and tissues.

Sacrococcygeal teratoma (SCT) A tumor occurring at the base of the tailbone in a fetus.

Spina bifida A birth defect (a congenital malformation) in which part of the vertebrae fail to develop completely so that a portion of the spinal cord, which is normally protected within the vertebral column, is exposed. People with spina bifida can suffer from bladder and bowel incontinence, cognitive (learning) problems, and limited mobility.

Tocolytic drug A compound given to women to stop the progression of labor.

Twin-twin transfusion syndrome (TTTS) A condition in identical monochorionic twins in which there is a connection between the two circulatory systems so that the donor twin pumps the blood to the recipient twin without a return of blood to the donor.

Twin:twin reverse arterial perfusion (TRAP) sequence A condition in which one fetus lacks a heart and the other fetus pumps the blood for both.

Ultrasonography A medical test in which sound waves are directed against internal structures in the body. As sound waves bounce off the internal structure, they create an image on a video screen. Ultrasonography is often used to diagnose fetal abnormalities, gallstones, heart defects, and tumors. Also called ultrasound imaging.

  • Removal of solid CCAM cysts has a survival rate of about 50 percent.
  • RFA to slow the growth of a tumor usually enables the fetus to survive delivery, after which the tumor can be removed.
  • Survival rates for prenatal treatment of TTTS are about 70 percent.

Prenatal surgery for spina bifida does not cure the condition. However, babies who survive the surgery appear to be 33 to 50 percent less likely to have hydrocephalus , a condition that requires surgically implanted tubes or shunts to remove fluid from the ventricles (cavities of the brain). The surgery also appears to reverse hindbrain herniation, in which the back of the brain slips down into the spinal canal. This condition can cause difficulties in breathing and swallowing and leads to death in 15 percent of children with spina bifida. In addition, children who have prenatal surgery for spina bifida appear to have better brain function than children who do not have surgery. However prenatal surgery does not prevent two of the most serious conditions associated with spina bifida: leg movement and bladder and bowel control. As of 2004, the long-term prognosis for these children was not known.

When to call the doctor

The doctor should be called if any of the following occurs:

  • The abdominal incision become red, warm, tender to the touch, or is draining fluid.
  • The mother's body temperature rises above 101°F (38.5°C).
  • Fluid is leaking from the vagina.
  • Vaginal bleeding occurs.
  • The baby does not move daily.
  • Persistent back pain, cramping, abdominal tightening, or pelvic pressure occurs.
  • Chest pain or difficulty breathing develops.

Signs of preterm labor include:

  • gas pain
  • abdominal tightening
  • cramping
  • backache
  • pelvic pressure
  • change in vaginal discharge
  • leakage of vaginal fluid
  • bleeding

Resources

BOOKS

Bianchi, Diana W., et al. Fetology: Diagnosis and Management of the Fetal Patient. New York: McGraw-Hill, 2005.

PERIODICALS

Hedrick, Holly L., et al. "History of Fetal Diagnosis and Therapy: Children's Hospital of Philadelphia Experience." Fetal Diagnosis and Therapy 18, no. 2 (March-April 2003): 6582.

Jones, Maggie. "A Miracle, and Yet." New York Times Magazine (July 15, 2001): 3843.

Kalb, Claudia. "Treating the Tiniest Patients." Newsweek, June 9, 2003.

Paek, Bettina W., et al. "Advances in Fetal Surgery." Female Patient 25, no. 6 (June 2000): 1518.

ORGANIZATIONS

Fetal Treatment Center. University of California at San Francisco (UCSF) Children's Hospital. 505 Parnassus Ave., San Francisco, CA 94143. Web site: <www.ucsfhealth.org/childrens/medical_services/surgical/fetal>.

Management of Myelomeningocele Study (MOMS). The George Washington University Biostatistics Center, 6110 Executive Blvd., Suite 750, Rockville, MD 20852. Web site: <www.spinabifidamoms.com>.

WEB SITES

Bunch, Kathy. "Giving Baby a Chance, Before Birth." WebMDHealth, 2001. Available online at <http://my.webmd.com/content/article/14/3606_466.htm?lastselectedguid={5FE84E90-BC77-4056-A91C-9531713CA348> (accessed January 17, 2005).

"Fetal Treatment." UCSF Children's Hospital, April 2002. Available online at <www.ucsfhealth.org/childrens/medical_services/surgical/fetal> (accessed January 17, 2005).

"Fetal Treatment: Patient Education." UCSF Children's Hospital, March 2003. Available online at <www.ucsfhealth.org/childrens/medical_services/surgical/fetal/moreinfo/patient_education.html> (accessed January 17, 2005).

Mayo Clinic Staff. "Spina Bifida: Treatment." Mayo Foundation for Medical Education and Research, December 8, 2003. Available online at <www.mayoclinic.com/invoke.cfm?objectid=CB5F085A-6152-42FC-8CFC55380EF705A2&dsection=8> (accessed January 17, 2005).

Margaret Alic, Ph.D.

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Prenatal Surgery

Prenatal Surgery

Definition

Prenatal surgery is a surgical procedure performed on a fetus prior to birth.

Purpose

In most cases prenatal surgery is performed only when the fetus is not expected to survive delivery or live long after birth without prenatal intervention. The most common prenatal surgeries are for conditions in which the newborn will not be able to breathe on its own.

Most prenatal surgeries are performed for:

  • urinary tract obstructions in males, usually caused by a narrowing of the urinary tract, in which urine backs up and injures the kidneys. About 10% of fetal urinary tract obstructions require prenatal surgery to prevent multiple abnormalities and depleted amniotic fluid.
  • congenital diaphragmatic hernia (CDH), a condition in which the diaphragmthe muscle that separates the chest and the abdomendoes form completely. Without surgery about 50% of fetuses with CDH do not survive after birth because of underdeveloped lungs.
  • congenital cystic adenomatoid malformation (CCAM), a condition in which one or more lobes of the lungs become fluid-filled sacs called cysts. Large CCAMs may prevent lung development, cause heart failure, or prevent the fetus from ingesting amniotic fluid.
  • sacrococcygeal teratoma (SCT), tumors at the base of the tailbone. The most common tumor in newborns, occurring in one out of every 35,000-40,000 births, some prenatal SCTs are very large, hard, and full of blood vessels, and can stress the heart.
  • twin-twin transfusion syndrome (TTTS), a condition in which, because of abnormal blood-vessel connections in the placenta, one twin pumps the circulating blood for both twins. Affecting up to 15% of twins sharing a placenta (monochorionic), TTTS can lead to a variety of problems including heart failure.
  • twin:twin reverse arterial perfusion (TRAP) sequence, a condition in which one twin lacks a heart. Occurring in about 1% of monochorionic twins, the healthy twin pumps all of the blood and, if untreated, 50-75% of these normal twins die.

Other conditions that may be treated by prenatal surgery include:

  • various congenital defects that block air passages and will prevent the newborn from breathing on its own
  • various lung malformations
  • omphalocele, a birth defect in which portions of the stomach, liver, and intestines protrude through an opening in the abdominal wall
  • fetal gastroschisisa birth defect in which the stomach and intestines protrude through improperly formed abdominal wall muscles and float in the amniotic fluid
  • bowel obstructions, usually caused by a narrowing in the small intestine
  • hypoplastic left heart syndrome, in which the blood flow through the left side of the heart is obstructed
  • X-linked severe combined immunodeficiency syndrome
  • spina bifida (myelomeningocele)the second most common birth defect in the United States, affecting one out of every 2,000 newborns. It is a lesion or hole where the nerves of the spinal cord are not completely enclosed and is not considered to be life-threatening.

Precautions

Prenatal surgery involves:

  • serious risks for the mother and fetus
  • travel to a hospital that performs the procedure
  • possibly having to stay near the hospital until delivery
  • extended postoperative bed rest, sometimes until delivery
  • a significant financial commitment.

Description

Prenatal surgery may be referred to as fetal surgery, antenatal surgery, or maternal-fetal surgery. There are only about 600 candidates for prenatal surgery in the United States each year. Of these, only about 10% actually undergo the procedure. Most prenatal surgeries are performed between 18 and 26 weeks of gestation. Some surgeries may not be covered by insurance.

Prenatal surgery usually requires a general anesthetic, although sometimes an epidural anesthetic to numb the abdominal region may be used. The fetus receives the anesthetic via the mother's blood. An anesthesiologist and a perinatologist monitor the heart rates of the mother and fetus during the procedure.

Prenatal surgeries include:

  • inserting a device into the fetal bladder to drain urine into the amniotic sac for treating urinary tract obstruction
  • draining or removing CCAMs
  • destroying blood vessels leading to a large SCT
  • amnioreduction for TTTS, in which a syringe through the mother's abdomen is used to remove fluid from the overfilled amniotic sac and replace it in the depleted sac of the twin pumping the blood. The procedure that may be repeated during the course of the pregnancy.
  • destroying abnormal blood vessel connections in the placenta of TTTS twins
  • severing the connections between TRAP sequence twins
  • experimental hematopoietic-stem-cell transplants for X-linked severe combined immunodeficiency syndrome
  • closing the lesion in spina bifida

Open surgeries

In open prenatal surgeries incisions are made through the mother's abdominal wall and the fetus is partially removed from the uterus or the entire uterus is removed through the mother's abdomen. Using ultrasound as a guide, the surgeon feels for the affected fetal part. The surgeon may knead and push on the uterus to move or flip the fetus away from the placenta, the disk-shaped organ within the uterus that supplies the fetal blood. A narrow tube is placed through a tiny hole in the uterine wall to drain and collect the amniotic fluid. Opening the uterus is the riskiest part of prenatal surgery. The first incision is made at a point away from the placenta to prevent damaging it. Following the procedure the fetus is replaced in the uterus and the incision is stitched. Prior to the final stitch the amniotic fluid is re-injected into the uterus. The uterus is repositioned in the mother's body cavity and her abdominal wall is closed.

The first successful open fetal surgery was performed in 1981 for a urinary tract obstruction. The first successful open fetal surgery for CDH was performed in 1989.

Prenatal open surgery for CCAM requires opening the fetus's chest. If a large cyst does not have a hard component, procedures called thoracoamniotic shunting or catheter decompression may be used to drain it. Otherwise the surgeon must remove part or all of the cyst. The first successful resection (removal) of a CCAM from a fetal lung was performed in 1990. The first resectioning of a fetal SCT was performed in 1992.

In prenatal surgery for spina bifida, An incision the size of a small fist is made in the uterus. The surgeon loosens and lifts the tissues of the spinalcanal lesion and stitches them closed. Between 1997 and 2004, more than 200 open surgeries were performed for spina bifida. As of 2005 the surgery was available only as part of a prospective randomized clinical trial.

Less invasive procedures

For urinary tract obstructions a needle may be used to insert a catheter through the mother's abdomen and uterus and into the fetal bladder where it drains the urine into the amniotic fluid. The catheter may have a wire mesh that expands in the bladder to prevent it from plugging up or dislodging.

The first successful fetoscopic temporary tracheal occlusion for CDH was performed in 1996. Small openings are made in the uterus and a tiny fiberoptic fetoscope is inserted to guide the operation. A needle-like instrument is used to place a balloon in the fetus's trachea to prevent lung fluid from escaping through the mouth, enabling the lungs to expand, grow, and push the abdominal organs out of the chest. The balloon is removed at birth.

Hypoplastic left heart syndrome is treated by passing a needle, guided by ultrasound, through the mother's abdominal wall, into the uterus, and the fetal heart. A catheter is passed through the needle across the fetus's aortic valve. A balloon is inflated, opening the valve and allowing blood to flow through the left side of the heart.

RADIOFREQUENCY ABLATION. Radiofrequency ablation (RFA) sometimes is used for SCT. Guided by ultrasound a needle is inserted through the mother's abdomen and uterus and into the tumor. Radiofrequency waves sent through the needle destroy the blood supply to the tumor with heat. This slows the tumor's growth and may enable the fetus to survive until delivery. The first RFA of a SCT was performed in 1998.

TRAP sequence also may be treated by RFA. A 3-mm needle targets the exact point where the blood enters the twin without a heart. Using an echocardiographic device, RFA is applied until the blood vessels and surrounding tissue are destroyed and the blood flow is halted. This procedure has eliminated the need for open surgery to treat TRAP sequence.

LASER TREATMENT. If TTTS does not respond to amnioreduction, laser treatment to halt the abnormal blood circulation may be attempted. A thin fetoscope is inserted through the mother's abdominal and uterine walls and into the amniotic cavity of the recipient twin to examine the surface placental blood vessels. The abnormal blood vessel connections are located and eliminated with a laser beam. The first successful fetoscopic laser treatment for TTTS was performed in 1999.

EXIT. Ex utero intrapartum treatment (EXIT) is a surgery performed for a congenital defect that blocks a fetal airway. The fetus is removed from the womb by cesarean section but the umbilical cord is left intact so that the mother's placenta continues to sustain the fetus. After the air passage is cleared, the umbilical cord is cut and the newborn can breathe on its own. The EXIT procedure is used for various types of airway obstruction including CCAM.

Preparation

The decision to perform prenatal surgery is made on the basis of detailed ultrasound imaging of the fetusincluding echocardiograms that use ultrasound to obtain images of the heartas well as other diagnostic tools. Consultations include a perinatologist, a neonatologist, a pediatric surgeon, a clinical nurse specialist, and a social worker. Since additional congenital defects preclude prenatal surgery, amniocentesis or chorionic villi sampling (CVS) are used to check for chromosomal abnormalities in the fetus.

Prior to surgery the mother must:

  • arrange for postoperative bed rest to prevent preterm labor
  • prepare for the possibility of remaining near the hospital until delivery
  • receive betamethasone, a steroid, in two intramuscular injections 12-24 hours apart to accelerate fetal lung maturation
  • wear a fetal/uterine monitor

The mother usually receives medications called tocolytics to prevent contractions and labor during and after surgery:

  • terbutalin
  • indocin suppositories before surgery and up to 48 hours after surgery
  • magnesium sulfate for one to two days after surgery with careful monitoring
  • nifedipine every four to six hours as the indocin is decreased, continuing until 37 weeks of gestation or delivery

Aftercare

In addition to usual post-surgical care, the mother:

  • usually remains in the hospital for four to seven days
  • lies on her side to help prevent contractions and ensure the best possible fetal circulation
  • has a transparent dressing over the abdominal incision for fetal monitoring
  • has continuous electronic fetal/uterine monitoring to check the fetal heart, the uterine response to tocolytics, and to watch for signs of preterm labor.

After discharge from the hospital the mother is on modified bed rest, lying on her side, until 37 weeks of gestation. This increases blood flow to the fetus and reduces pressure on the cervix to help prevent uterine contractions. She sees a perinatologist once a week and has at least one ultrasound per week.

Risks

Most prenatal surgeries are high risk and may be considered experimental. The greatest risk is that the placenta will be nicked during surgery, causing blood hemorrhaging, uterine contractions, and birth of a premature infant who may not survive. Preterm labor is the most common complication of prenatal surgery. Fetoscopic surgeries are less dangerous and traumatic than open fetal surgery and reduce the risk of premature labor. Subsequent children of a mother who has undergone prenatal surgery usually are delivered by cesarean section because of uterine scarring.

Maternal risks

Risks to the mother include:

  • extensive blood loss
  • complications from general anesthesia
  • side effectspotentially fatalfrom medications to control premature labor
  • rupture of the uterine incision
  • infection of the wound or uterus
  • psychological stress
  • inability to have additional children
  • death.

Fetal risks

All fetuses that undergo surgery are born prematurely. Those born even six weeks early are at risk for walking and talking delays and learning disabilities. Infants born at 30 weeks of gestation or less are at risk for blindness, cerebral palsy, and brain hemorrhages.

About 25% of women undergoing prenatal surgery lose some amniotic fluid, often because of leakage at the uterine incision. Amniotic fluid is essential for lung development and protects the fetus from injury and infection. If all of the amniotic fluid is lost, the fetal lungs may not develop properly. Without the fluid cushion in which the fetus floats, the umbilical cord may be compressed, causing death.

Other risks to the fetus include:

  • birth during surgery
  • separation of the tissues surrounding the amniotic fluid sac and the uterus, causing early delivery or interference with blood flow to some fetal body part such as an arm or leg
  • intrauterine infection requiring immediate birth of the fetus
  • further damage to the spinal cord and nerves during surgery to treat spina bifida
  • brain damage
  • physical deformities
  • death.

Normal results

Although fetal surgeries heal without scarring, it is difficult to predict their outcome because relatively few have been performed:

  • Fetal surgery for CDH lessens the severity of the condition so that the fetus usually survives delivery and lives long enough to undergo corrective surgery.
  • Thoracoamniotic shunting for CCAM usually results in infant survival.
  • The infant survival rate following prenatal removal of solid CCAMs is about 50%.
  • RFA to slow the growth of a tumor usually enables the fetus to survive delivery, after which the tumor can be removed.
  • The infant survival rate following prenatal treatment for TTTS is about 70%. Since TTTS is a progressive disorder, early intervention may prevent later complications.

KEY TERMS

Amniocentesis Withdrawal of amniotic fluid through the mother's abdominal wall, using a needle and syringe, to test for fetal disorders.

Amniotic fluid The watery fluid within the amniotic sac that surrounds the fetus.

Cesarean section C-section; incision through the abdominal and uterine walls to deliver a baby.

Chorion The outermost membrane of the sac enclosing the fetus.

Chorionic villus sampling (CVS) The removal of fetal cells from the chorion for the diagnosis of genetic disorders.

Congenital cystic adenomatoid malformation (CCAM) A condition in which one or more lobes of the fetal lungs develop into fluid-filled sacs called cysts.

Congenital diaphragmatic hernia (CDH) A condition in which the fetal diaphragmthe muscle dividing the chest and abdominal cavitydoes not close completely.

Echocardiography Ultrasonic examination of the heart.

Ex utero intrapartum treatment (EXIT) A cesarean section in which the infant is removed from the uterus but the umbilical cord is not cut until after surgery for a congenital defect that blocks an air passage.

Fetoscope A fiber-optic instrument for viewing the fetus inside the uterus.

Monochorionic twins Twins that share a single placenta.

Omphalocele A congenital hernia in which a small portion of the fetal abdominal contents, covered by a membrane sac, protrudes into the base of the umbilical cord.

Placenta The organ within the uterus that provides nourishment to the fetus.

Radiofrequency ablation (RFA) A procedure in which radiofrequency waves are used to destroy blood vessels and tissues.

Sacrococcygeal teratoma (SCT) A tumor occurring at the base of the fetus's tailbone.

Spina bifida Myelomeningocele; a congenital defect in which the fetal backbone and spinal canal do not close completely, allowing the spinal cord and its surrounding membranes to protrude.

Tocolytic A medication that inhibits uterine contractions.

Twin:twin reverse arterial perfusion (TRAP) sequence A condition in which one fetus lacks a heart and the other fetus pumps the blood for both.

Twin-twin transfusion syndrome (TTTS) A condition in monochorionic twins in which there is a connection between the two circulatory systems so that the donor twin pumps the blood to the recipient twin without a return of blood to the donor.

Ultrasound A procedure that uses high-frequency sound waves to image a fetus.

Spina bifida arises during the first month of fetal development. Fluid leaking from the spinal cord and exposure of the cord to amniotic fluid causes damage throughout gestation. Lesions higher up in the spinal cord can cause severe deformities, paralysis, and mental retardation. Prenatal surgery may reduce the abnormalities, although it does not cure the condition. Babies who survive prenatal surgery appear to be 33-50% less likely to have hydrocephalus, a condition that requires surgically implanted tubes or shunts to remove fluid from the ventricles (cavities) of the brain. The surgery also appears to reverse hindbrain herniation, in which the back of the brain slips down into the spinal canal, causing breathing and swallowing problems and death in 15% of affected children. Children who had prenatal surgery to treat spina bifida appear to have better brain function than those who did not. However prenatal surgery does not prevent two of the most serious conditions associated with spina bifida: leg movement and bladder and bowel control. As of 2005 the long-term prognosis for these children was not known.

Resources

BOOKS

Bianchi, Diana W., et al. Fetology: Diagnosis and Management of the Fetal Patient. New York: McGraw-Hill, 2000.

Casper, Monica J. The Making of an Unborn Patient: A Social Anatomy of Fetal Surgery. New Brunswick, NJ: Rutgers University Press, 1998.

PERIODICALS

Hedrick, Holly L., et al. "History of Fetal Diagnosis and Therapy: Children's Hospital of Philadelphia Experience." Fetal Diagnosis and Therapy 18, no. 2 (March/April 2003): 65-82.

Jones, Maggie. "A Miracle, and Yet." New York Times Magazine July 15, 2001: 38-43.

Kalb, Claudia. "Treating the Tiniest Patients." Newsweek June 9, 2003.

Paek, Bettina W., et al. "Advances in Fetal Surgery." Female Patient 25, no. 6 (June 2000): 15-18.

ORGANIZATIONS

Fetal Treatment Center, University of California at San Francisco Children's Hospital. 505 Parnassus Ave., San Francisco, CA 94143. 800-RX-FETUS. http://www.ucsfhealth.org/childrens/medical_services/surgical/fetal.

Management of Myelomeningocele Study (MOMS). Catherine Shaer, M.D., The George Washington University Biostatistics Center, 6110 Executive Blvd., Suite 750, Rockville, MD 20852. 866-ASK-MOMS. http://www.spinabifidamoms.com.

OTHER

Bunch, Kathy. Giving Baby a Chance, Before Birth. WebMDHealth. 2001 [cited March 11, 2005]. http://my.webmd.com/content/article/14/3606_466.htm?lastselectedguid={5FE84E90-BC77-4056-A91C-9531713CA348}.

Fetal Treatment. UCSF Children's Hospital. April 2002 [cited March 11, 2005]. http://www.ucsfhealth.org/childrens/medical_services/surgical/fetal.

Fetal Treatment: Patient Education. UCSF Children's Hospital. March 2003 [cited March 11, 2005]. http://www.ucsfhealth.org/childrens/medical_services/surgical/fetal/moreinfo/patient_education.html.

Mayo Clinic Staff. Spina Bifida: Treatment. Mayo Foundation for Medical Education and Research. December 8, 2003 [cited March 11, 2005]. http://www.mayoclinic.com/invoke.cfm?objectid=CB5F085A-6152-42FC-8CFC55380EF705A2&dsection=8.

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Fetal Surgery

Fetal surgery

Definition

Fetal surgery allows doctors to treat certain abnormalities of the fetus that might otherwise be fatal or cause significant problems if permitted to progress.


Purpose

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:

  • Myelomeningocele. Also called spina bifida, myelomeningocele is a condition in which the spine fails to close properly during early fetal development. The spinal cord may protrude or be exposed through an opening in the lower back. Paralysis, neurological problems, bowel and bladder problems, and hydrocephalus (fluid buildup in the brain) may result. Myelomeningocele affects one out of every 1,000 babies born in the United States.
  • Congenital diaphragmatic hernia (CDH). In babies with CDH, the diaphragm (the thin muscle that separates the chest from the abdomen) doesn't develop properly. The abdominal organs may enter the chest cavity through a hole (hernia) and cause pulmonary hyperplasia (underdeveloped lungs). CDH occurs in about one out of every 2,000 births.
  • Urinary tract obstruction. The urethra (the tube that carries urine from the bladder to the outside of the body) may become obstructed in utero or fail to develop normally. When this happens, urine can back up into the kidneys and destroy tissue or cause the bladder to become enlarged. The amount of amniotic fluid also decreases because fetal urine is its major component. Pulmonary hypoplasia usually results because the lungs rely on amniotic fluid in their development.
  • Congenital cystic adenomatoid malformation of the lung (CCAM). CCAM is a large mass of malformed lung tissue that does not function properly. As a result of its large size, it may put pressure on the heart and lead to heart failure. Lung development is also affected, and pulmonary hyperplasia may result.
  • Twin/twin transfusion syndrome (TTTS). In some twin pregnancies, the two fetuses will share a placenta. TTTS occurs in approximately 15% of these twins when blood volume between the fetuses is unequal, causing abnormally low blood volume in the donor twin and abnormally high blood volume in the "recipient" twin. There is often a large difference in size between the twins. Approximately 7080% of fetuses suffering from TTTS will die without intervention.
  • Sacrococcygeal teratoma (SCT). This usually benign fetal tumor develops at the base of the spine (coccyx) and affects approximately one in 35,000 to 40,000 newborns in the United States. The tumor may become very large (sometimes as large as the fetus) and filled with blood vessels, causing stress on the heart.

Description

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 .


Diagnosis/Preparation

Detection of many birth defects is possible through the use of sophisticated imaging and diagnostic techniques such as:

  • Ultrasound. This imaging technique uses a machine that transmits high frequency sound waves to visualize structures in the human body, including the uterus and fetus. Ultrasound is used to determine the size, position, and age of the fetus; to measure the amount of amniotic fluid; and to assess the fetus for any congenital abnormalities.
  • Chorionic villus sampling (CVS). Cells are collected from the placenta with a thin plastic tube inserted through the cervix (opening to the uterus) or a needle inserted through the abdomen. The cells may then be analyzed for possible genetic disorders.
  • Alpha-fetoprotein (AFP) testing. AFP is a protein made by the developing fetus. Large amounts of AFP in the mother's bloodstream may indicate certain fetal abnormalities.
  • Amniocentesis. A needle is inserted through the woman's abdomen and into the uterus to procure a sample of amniotic fluid. Fetal cells in the fluid are then analyzed for possible genetic disorders.

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.


Aftercare

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.


Risks

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.


Normal results

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.


Morbidity and mortality rates

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.


Alternatives

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.


Resources

periodicals

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): 181925.

organizations

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>.

other

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

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?


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:

  • a perinatologist (a medical doctor specializing in the care and treatment of the fetus/infant during the time shortly before and after birth)
  • a pediatric surgeon (a surgeon specializing in the treatment of children)
  • a fetal treatment coordinator (a nurse who will coordinate the patient's care, including communication with the medical team and arranging various tests)
  • a sonographer (a person who is trained to perform ultrasounds and interpret their results)
  • an anesthesiologist (a medical doctor specializing in the science and application of techniques to decrease or eliminate pain)
  • operating room nurses
  • clinical nurses

QUESTIONS TO ASK THE DOCTOR


  • Why is fetal surgery recommended in my case?
  • What alternatives to fetal surgery are available to me?
  • What are the costs associated with fetal surgery? Will my insurance cover the procedure?
  • What will happen if there is no medical intervention?
  • Will my own obstetrician be able to care for me for the rest of my pregnancy or will I have to remain near the surgical center?

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Sherk, Stephanie Dionne. "Fetal Surgery." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Encyclopedia.com. 28 May. 2016 <http://www.encyclopedia.com>.

Sherk, Stephanie Dionne. "Fetal Surgery." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Encyclopedia.com. (May 28, 2016). http://www.encyclopedia.com/doc/1G2-3406200167.html

Sherk, Stephanie Dionne. "Fetal Surgery." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Retrieved May 28, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3406200167.html

Prenatal Surgery

Prenatal surgery

Prenatal surgery is an invasive procedure performed on a fetus (name given to unborn young from the end of the eighth week of development through birth). An invasive procedure is one in which the fetus is penetrated by an instrument. The first successful fetal operations were carried out in the 1920s on various animal subjects. Surgical experiments continued for the next four decades.

The first human fetal surgery was performed in the 1950s. It involved a blood transfusion to a fetus with a condition called "Rh incompatibility." In this condition, the fetus's Rh-positive red blood cells are destroyed by its Rh-negative immune system.

Ultrasound Makes Amniocentesis Possible

Ultrasound imaging was developed in 1977. Ultrasound devices bounce soundwaves off an object and draw a picture based on how deep the sound waves go. The ultrasound provides a photographic image of the developing fetus, making practical the procedure known as amniocentesis.

In amniocentesis, a hollow needle is inserted through a pregnant woman's abdomen into the amniotic sac that surrounds the fetus. A sample of amniotic fluid is removed and examined for evidence of genetic abnormalities like Down's syndrome.

Successful open-womb surgery was pioneered by pediatric surgeon Michael Harrison of the University of California at San Francisco. In 1982 Harrison performed his first open-womb operation. The operation was to correct a urinary tract obstruction that affects 1 in 2,000 male fetuses. In 1989 Harrison operated to repair a hole in the diaphragm of a 24-week-old fetus. This is a very serious malformation which is frequently fatal. The fetus's arm was pulled out through an incision in the mother's abdomen and uterus. The fetus's misplaced internal organs were repositioned, and the mother's incisions were patched with GoreTex. The baby was born seven weeks later, premature but healthy.

Prenatal surgery remains in its earliest stages of development. The success rate is not yet high. Some of the procedures with higher success rates include amniocentesis and the bladder shunt performed by Harrison. The risk remains high for both fetus and mother. One surgical technique that has exciting possibilities is fetal stem-cell transplantation. This involves injecting stem cells, the earliest precursor of all blood cells, from a dead fetus into a live one. This provides the living fetus with healthy genetic material to overcome defective genes of its own.

[See also Blood transfusion ; Gene ; Ultrasound devices ]

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