Fetal surgery
Encyclopedia
Fetal surgery is any of a broad range of surgical techniques that are used to treat birth defects in fetus
es who are still in the pregnant uterus
.
s are generally given to prevent labor. However, these should not be given if the risk is higher for the fetus inside the womb than if delivered, such as may be the case in intrauterine infection, unexplained vaginal bleeding and fetal distress.
Regarding anesthesia, an H2 antagonist is usually given the evening before and the morning of the operation, and an antacid
is usually given before induction to reduce the risk of acid aspiration. Rapid sequence induction
is usually used for sedation and intubation.
Open fetal surgery is similar in many respects to a normal cesarean section performed under general anesthesia, except that the fetus remains dependent on the placenta and is returned to the uterus. A hysterotomy
is performed on the pregnant woman. Once the uterus
is open and the fetus is exposed, the fetal surgery begins. Typically, this surgery consists of an interim procedure intended to allow the fetus to remain in utero until it has matured enough to survive delivery and neonatal surgical procedures.
Upon completion of the fetal surgery, the fetus is put back inside the uterus and the uterus and abdominal wall are closed up. Before the last stitch is made in the uterine wall, the amniotic fluid is replaced.
The mother remains in the hospital for 3–7 days for monitoring and is required to subsequently deliver the baby via a second cesarean section. Often babies who have been operated on in this manner are born pre-term
.
Open fetal surgery has proven to be reasonably safe for the mother. For the fetus, safety and effectiveness are variable, and depend on the specific procedure, the reasons for the procedure, and the gestational age and condition of the fetus. The overall perinatal mortality after open surgery has been estimated to be approximately 6%, according to a study in the United States 2003.
All future pregnancies for the mother require cesarean delivery because of the hysterotomy. However, there is no presented data suggesting decreased fertility for the mother.
, as the primate uterus is extraordinarily sensitive to external stimuli compared with that of other species such as the sheep.
Fetal closure of neural tube defects is an option for some families as part of the Management of Myleomeningocle Study (MOMS) in the United States.
Other conditions that potentially are treated by open fetal surgery include:
Less invasive than open fetal surgery, some fetal surgeries can be achieved with just a small guided wire sent through a needle-puncture of the skin (percutaneous), though in some cases it may require that a small opening be made in the mother's abdomen. The fact that it is less invasive reduces the mother's postoperative recovery and lessens the troubles with preterm labor.
Minimally-invasive fetoscopic surgery (or Fetendo
) has proven to be very useful for some, but not all, fetal conditions. Some examples include:
in 1980 by Dr. Michael R. Harrison
and his research colleagues.
On April 26, 1981, the first human open fetal surgery in the world was performed at University of California, San Francisco under the direction of Dr. Michael Harrison. The fetus in question had a congenital hydronephrosis
, a blockage in the urinary tract that caused the bladder to dangerously extend. To correct this a vesicostomy was performed placing a catheter
in the fetus allowing the urine to be released normally. The blockage itself was removed surgically after birth.
Further advances have been made in the years since this first operation. New techniques have allowed additional defects to be treated and for less invasive forms of fetal surgical intervention.
Fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
es who are still in the pregnant uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
.
- Open fetal surgery involves completely opening the uterus to operate on the fetus.
- Minimally invasive fetoscopic surgery (fetendoFetendoFetendo is a form of fetal intervention in the treatment of birth defects and other fetal problems. The procedure uses real-time video imagery from fetoscopy and ultrasonography to guide very small surgical instruments into the uterus in order to surgically help the fetus...
) uses small incisions and is guided by fetoscopyFetoscopyFetoscopy is an endoscopic procedure during pregnancy to allow access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity...
and sonographySonogramA sonogram may refer to the following:* A diagnostic medical image created using ultrasound echo equipment, see medical ultrasonography...
. - Some fetal surgery can sometimes be done without either an incision in the uterus or an endoscopic view inside the uterus: it is done entirely with a real-time cross-sectional view provided by the sonogramMedical ultrasonographyDiagnostic sonography is an ultrasound-based diagnostic imaging technique used for visualizing subcutaneous body structures including tendons, muscles, joints, vessels and internal organs for possible pathology or lesions...
.
Technique
TocolyticTocolytic
Tocolytics are medications used to suppress premature labor . They are given when delivery would result in premature birth...
s are generally given to prevent labor. However, these should not be given if the risk is higher for the fetus inside the womb than if delivered, such as may be the case in intrauterine infection, unexplained vaginal bleeding and fetal distress.
Regarding anesthesia, an H2 antagonist is usually given the evening before and the morning of the operation, and an antacid
Antacid
An antacid is a substance which neutralizes stomach acidity.-Mechanism of action:Antacids perform a neutralization reaction, increasing the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous...
is usually given before induction to reduce the risk of acid aspiration. Rapid sequence induction
Rapid sequence induction
Rapid Sequence Induction is a medical procedure involving the expeditious induction of general anesthesia and subsequent intubation of the trachea. RSI is generally used in an emergency setting or for patients who have an increased risk of aspirating stomach contents into the lungs...
is usually used for sedation and intubation.
Open fetal surgery is similar in many respects to a normal cesarean section performed under general anesthesia, except that the fetus remains dependent on the placenta and is returned to the uterus. A hysterotomy
Hysterotomy
A hysterotomy is an incision in the uterus, commonly combined with a laparotomy during a caesarean section. Hysterotomies are also performed during fetal surgery....
is performed on the pregnant woman. Once the uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
is open and the fetus is exposed, the fetal surgery begins. Typically, this surgery consists of an interim procedure intended to allow the fetus to remain in utero until it has matured enough to survive delivery and neonatal surgical procedures.
Upon completion of the fetal surgery, the fetus is put back inside the uterus and the uterus and abdominal wall are closed up. Before the last stitch is made in the uterine wall, the amniotic fluid is replaced.
The mother remains in the hospital for 3–7 days for monitoring and is required to subsequently deliver the baby via a second cesarean section. Often babies who have been operated on in this manner are born pre-term
Premature birth
In humans preterm birth refers to the birth of a baby of less than 37 weeks gestational age. The cause for preterm birth is in many situations elusive and unknown; many factors appear to be associated with the development of preterm birth, making the reduction of preterm birth a challenging...
.
Safety and complications
The main priority is maternal safety, and, secondary, avoiding preterm labor and achieving the aims of the surgery. Open fetal surgery is possible first after approximately 18 weeks of gestation due to fetal size and fragility before that, and up to approximately 30 weeks of gestation due to increased risk of premature labor and, practically, the preferability of delivering the child and performing the surgery ex utero instead. The risk of premature labor is increased by comcomitant risk factors such as multiple gestation, a history of maternal smoking, and very young or old maternal age.Open fetal surgery has proven to be reasonably safe for the mother. For the fetus, safety and effectiveness are variable, and depend on the specific procedure, the reasons for the procedure, and the gestational age and condition of the fetus. The overall perinatal mortality after open surgery has been estimated to be approximately 6%, according to a study in the United States 2003.
All future pregnancies for the mother require cesarean delivery because of the hysterotomy. However, there is no presented data suggesting decreased fertility for the mother.
Indications
Open prenatal surgery is very rare and of unproven benefit. There are estimated to be 600 candidates annually in the US, with only a fraction of these resulting in successful surgeries. Most prenatal procedures may be considered high-risk and experimental. A major complication is fetal expulsion resulting in miscarriageMiscarriage
Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...
, as the primate uterus is extraordinarily sensitive to external stimuli compared with that of other species such as the sheep.
Fetal closure of neural tube defects is an option for some families as part of the Management of Myleomeningocle Study (MOMS) in the United States.
Other conditions that potentially are treated by open fetal surgery include:
- Congenital diaphragmatic herniaCongenital diaphragmatic herniaCongenital diaphragmatic hernia is a congenital malformation of the diaphragm. The most common type of CDH is a Bochdalek hernia; other types include Morgagni's hernia, diaphragm eventration and central tendon defects of the diaphragm...
(if indicated at all, it is now more likely to be treated by endoscopic fetal surgeryFetoscopyFetoscopy is an endoscopic procedure during pregnancy to allow access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity...
) - Congenital cystic adenomatoid malformationCongenital cystic adenomatoid malformationCongenital cystic adenomatoid malformation is a congenital disorder similar to bronchopulmonary sequestration. In CCAM, usually an entire lobe of lung is replaced by a non-working cystic piece of abnormal lung tissue. This abnormal tissue will never function as normal lung tissue.In most cases the...
- Congenital heart disease
- Pulmonary sequestrationPulmonary sequestrationA pulmonary sequestration, also known as a bronchopulmonary sequestration or a cystic lung lesion, is a medical condition where a piece of tissue that develops into lung tissue is not attached to the pulmonary arterial blood supply and does not communicate with the other...
- Sacrococcygeal teratomaSacrococcygeal teratomaSacrococcygeal teratoma is a teratoma located at the base of the coccyx . It is thought to be a derivative of the primitive streak.-Natural history:...
Minimally invasive fetal surgery
Minimally-invasive fetoscopic surgery (aka Fetendo) uses real-time video imagery from fetoscopy and ultrasonography to guide very small surgical instruments into the uterus in order to surgically help the fetus. The name Fetendo was adopted for the procedure because of how the video-based manipulation recalls a child's video game.Less invasive than open fetal surgery, some fetal surgeries can be achieved with just a small guided wire sent through a needle-puncture of the skin (percutaneous), though in some cases it may require that a small opening be made in the mother's abdomen. The fact that it is less invasive reduces the mother's postoperative recovery and lessens the troubles with preterm labor.
Minimally-invasive fetoscopic surgery (or Fetendo
Fetendo
Fetendo is a form of fetal intervention in the treatment of birth defects and other fetal problems. The procedure uses real-time video imagery from fetoscopy and ultrasonography to guide very small surgical instruments into the uterus in order to surgically help the fetus...
) has proven to be very useful for some, but not all, fetal conditions. Some examples include:
- Twin-twin transfusion syndrome - Laser Ablation of Vessels
- Fetal bladder obstructions
- Aortic or Pulmonary Valvuloplasty - opening the Aortic or Pulmonary fetal heart valves to allow blood flow
- Atrial Septostomy - opening the inter-atrial septum of the fetal heart to allow unrestricted blood flow between the atriums
- Congenital diaphragmatic herniaCongenital diaphragmatic herniaCongenital diaphragmatic hernia is a congenital malformation of the diaphragm. The most common type of CDH is a Bochdalek hernia; other types include Morgagni's hernia, diaphragm eventration and central tendon defects of the diaphragm...
- Balloon tracheal occlusion - Spina bifidaSpina bifidaSpina bifida is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through...
- Fetoscopic closure of the malformation
History
Fetal surgical techniques using animal models were first developed at the University of California, San FranciscoUniversity of California, San Francisco
The University of California, San Francisco is one of the world's leading centers of health sciences research, patient care, and education. UCSF's medical, pharmacy, dentistry, nursing, and graduate schools are among the top health science professional schools in the world...
in 1980 by Dr. Michael R. Harrison
Michael R. Harrison
Michael R. Harrison, M.D. served as division chief in Pediatric Surgery at the Children’s Hospital at the University of California, San Francisco for over 20 years, where he established the first Fetal Treatment Center in the U.S...
and his research colleagues.
On April 26, 1981, the first human open fetal surgery in the world was performed at University of California, San Francisco under the direction of Dr. Michael Harrison. The fetus in question had a congenital hydronephrosis
Hydronephrosis
Hydronephrosis is distension and dilation of the renal pelvis calyces, usually caused by obstruction of the free flow of urine from the kidney, leading to progressive atrophy of the kidney...
, a blockage in the urinary tract that caused the bladder to dangerously extend. To correct this a vesicostomy was performed placing a catheter
Catheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
in the fetus allowing the urine to be released normally. The blockage itself was removed surgically after birth.
Further advances have been made in the years since this first operation. New techniques have allowed additional defects to be treated and for less invasive forms of fetal surgical intervention.
See also
- fetoscopyFetoscopyFetoscopy is an endoscopic procedure during pregnancy to allow access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity...
- EXIT procedureEXIT procedureThe EXIT procedure, or ex utero intrapartum treatment procedure, is a specialized surgical delivery procedure used to deliver babies who have airway compression...
- Pediatric surgeryPediatric surgeryPediatric surgery or paediatric surgery is a subspecialty of surgery involving the surgery of fetuses, infants, children, adolescents, and young adults...
- MOMS TrialMOMS TrialThe MOMS Trial is a Eunice Kennedy Shriver National Institute of Child Health andHuman Development sponsored study of prenatal and postnatal closure of myelomeningocele; a collaboration of The Children's Hospital of Philadelphia, the University of California at San Francisco, Vanderbilt University...
- Spina BifidaSpina bifidaSpina bifida is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through...
- NAFTNetNAFTNetThe North American Fetal Therapy Network is a voluntary association of medical centers in the United States and Canada with established expertise in fetal surgery and other forms of multidisciplinary care for complex disorders of the fetus....
- Samuel ArmasSamuel ArmasSamuel Alexander Armas is the child shown in a famous photograph by Michael Clancy of his surgeon holding his hand from out of a hole in his mother's uterus during open fetal surgery for spina bifida.-Story behind the photo:...