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Fetal surgery | |
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Other names | Antenatal surgery |
ICD-9-CM | 75.36 |
Fetal surgery also known as antenatal surgery, prenatal surgery, [1] is a growing branch of maternal-fetal medicine that covers any of a broad range of surgical techniques that are used to treat congenital abnormalities in fetuses who are still in the pregnant uterus. There are three main types: [2] open fetal surgery, which involves completely opening the uterus to operate on the fetus; minimally invasive fetoscopic surgery, which uses small incisions and is guided by fetoscopy and sonography; and percutaneous fetal therapy, which involves placing a catheter under continuous ultrasound guidance.
Fetal intervention is relatively new. Advancing technologies allow earlier and more accurate diagnosis of diseases and congenital problems in a fetus.
Fetal surgery draws principally from the fields of surgery, obstetrics and gynecology, and pediatrics- especially the subspecialties of neonatology (care of newborns, especially high-risk ones), maternal-fetal medicine (care of high-risk pregnancies), and pediatric surgery. It often involves training in obstetrics, pediatrics, and mastery of both invasive and non-invasive surgery, which require several years of residency and at least one fellowship (usually lasting more than one year each), to become proficient. It is possible in the U.S. to become trained in this approach whether one started in obstetrics, pediatrics, or surgery. Because of the very high risk and high complexity of these cases, they are usually performed at Level I trauma centers in large cities, at academic medical centers which provide the full spectrum of maternal and newborn care. This includes a high level neonatal intensive care unit, suitable operating theaters and equipment, and access to many surgeons and physicians, nurse specialists, therapists, and a social work and counseling team. The cases can be referred from multiple levels of hospitals from many miles, sometimes across state and provincial lines. In continents other than North America and Europe, these centers are not as numerous, though the techniques are spreading.
Most congenital conditions either do not require, or are not treatable through, fetal intervention. Those which are involve anatomical problems, for which in utero treatment is both feasible and can significantly improve the fetus’s continuing development and survival. Addressing anticipated concerns prior to birth increases the probability of a healthy baby, with few long-term health problems related to the treated condition.
Fetal intervention involves risk to fetus and pregnant patient alike. In addition to the general risks associated with any surgery, there is also a risk that scarring of the uterus will lead to difficulties with future pregnancies.[ citation needed ] This risk is higher than for a typical Cesarean section, for several reasons:
Tocolytics are generally given to prevent labor; [3] 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. [3] An H2 antagonist is usually given for anaesthesia the evening before and the morning of the operation, and an antacid is usually given before induction to reduce the risk of acid aspiration. [3] Rapid sequence induction is often used for sedation and intubation. [3]
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, and 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. Often[ quantify ] babies who have been operated on in this manner are born pre-term.[ citation needed ]
The main priority is maternal safety, and, secondary, avoiding preterm labor and achieving the aims of the surgery. [3] In 2008, open fetal surgery was considered a possibility 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 preference for delivering the child and performing the surgery in ex utero/pediatric surgery, instead. [3] The risk of premature labor is increased by concomitant risk factors such as multiple gestation, a history of maternal smoking, and very young or old maternal age. [3]
Open fetal surgery has proven to be reasonably safe for the mother. [3] 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. [4]
All future pregnancies for the mother require cesarean delivery because of the hysterotomy. [3] However, there is no presented data suggesting decreased fertility for the mother. [3]
Neural tube defects (NTD), which begin to become observable at the 28th day of pregnancy, occur when the embryonic neural tube fails to close properly, the developing brain and spinal cord are openly exposed to amniotic fluid and with this, causes the nervous system tissue to break down. Prenatal repair of the most easily treated NTD, myelomeningocele (spina bifida cystica) is as of 2011, a growing option in the United States. Although the procedure is technically challenging, children treated with open fetal repair have significantly improved outcomes compared to children whose defects are repaired shortly after birth. [5] Specifically, fetal repair reduces the rate of ventriculoperitoneal shunt dependence and Chiari malformation, while improving motor skills at 30 months of age compared to post-natal repair. Children having fetal repair are twice as likely to walk independently at 30 months of age than children undergoing post-natal repair. As a result, open fetal repair of spina bifida is now considered standard of care at fetal specialty centers.
Other conditions that potentially are treated by open fetal surgery include:
Minimally-invasive fetoscopic surgery has proven to be useful for some fetal conditions.
Fetal surgical techniques were first developed at the University of California, San Francisco, in 1980 using animal models. [8]
On April 26, 1981, the first successful human open fetal surgery in the world was performed at University of California, San Francisco, under the direction of Dr. Michael Harrison. [9] [10] The fetus in question had a congenital hydronephrosis, a blockage in the urinary tract that caused the kidney to dangerously extend. To correct this a vesicostomy was performed by placing a catheter in the fetus to allow the urine to be released normally. The blockage itself was removed surgically after birth. [10]
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.
The first two percutaneous ultrasound-guided fetal balloon valvuloplasties, a type of fetal surgery for severe aortic valve obstruction in the heart, were reported in 1991. [11] Among the first dozen reported attempts at this repair in the 1990s, only two children survived long-term. [11] [ quantify ] Dr. Oluyinka Olutoye, alongside Darrell Cass, from the Texas Children's Fetal Centre, removed a 23-week-old fetus from her mother's womb in order to perform surgery upon a spinal tumor she had. The girl was placed back in the womb after a five-hour surgery and was born without complications. [12]
Obstetrics is the field of study concentrated on pregnancy, childbirth and the postpartum period. As a medical specialty, obstetrics is combined with gynecology under the discipline known as obstetrics and gynecology (OB/GYN), which is a surgical field.
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptoms. The pain may be described as sharp, dull, or crampy. Pain may also spread to the shoulder if bleeding into the abdomen has occurred. Severe bleeding may result in a fast heart rate, fainting, or shock. With very rare exceptions, the fetus is unable to survive.
Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is necessary to conclusively diagnose the majority of genetic disorders, with amniocentesis being the gold-standard procedure after 15 weeks' gestation.
Spina bifida /ˌspaɪnə ˈbɪfɪdə/ is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, meningocele and myelomeningocele. Meningocele and myelomeningocele may be grouped as spina bifida cystica. The most common location is the lower back, but in rare cases it may be in the middle back or neck.
Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in the uterus (womb). The procedure is a standard part of prenatal care in many countries, as it can provide a variety of information about the health of the mother, the timing and progress of the pregnancy, and the health and development of the embryo or fetus.
Prenatal testing is a tool that can be used to detect some of these abnormalities at various stages prior to birth. Prenatal testing consists of prenatal screening and prenatal diagnosis, which are aspects of prenatal care that focus on detecting problems with the pregnancy as early as possible. These may be anatomic and physiologic problems with the health of the zygote, embryo, or fetus, either before gestation even starts or as early in gestation as practicable. Screening can detect problems such as neural tube defects, chromosome abnormalities, and gene mutations that would lead to genetic disorders and birth defects, such as spina bifida, cleft palate, Down syndrome, Tay–Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, muscular dystrophy, and fragile X syndrome. Some tests are designed to discover problems which primarily affect the health of the mother, such as PAPP-A to detect pre-eclampsia or glucose tolerance tests to diagnose gestational diabetes. Screening can also detect anatomical defects such as hydrocephalus, anencephaly, heart defects, and amniotic band syndrome.
Placenta praevia is when the placenta attaches inside the uterus but in a position near or over the cervical opening. Symptoms include vaginal bleeding in the second half of pregnancy. The bleeding is bright red and tends not to be associated with pain. Complications may include placenta accreta, dangerously low blood pressure, or bleeding after delivery. Complications for the baby may include fetal growth restriction.
A hysterotomy is an incision made in the uterus. This surgical incision is used in several medical procedures, including during termination of pregnancy in the second trimester and delivering the fetus during caesarean section. It is also used to gain access and perform surgery on a fetus during pregnancy to correct birth defects, and it is an option to achieve resuscitation if cardiac arrest occurs during pregnancy and it is necessary to remove the fetus from the uterus.
Fetoscopy is an endoscopic procedure during pregnancy to allow surgical access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small (3–4 mm) incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity. Fetoscopy allows for medical interventions such as a biopsy or a laser occlusion of abnormal blood vessels or the treatment of spina bifida.
Hydrops fetalis or hydrops foetalis is a condition in the fetus characterized by an accumulation of fluid, or edema, in at least two fetal compartments. By comparison, hydrops allantois or hydrops amnion is an accumulation of excessive fluid in the allantoic or amniotic space, respectively.
Large for gestational age (LGA) is a term used to describe infants that are born with an abnormally high weight, specifically in the 90th percentile or above, compared to other babies of the same developmental age. Macrosomia is a similar term that describes excessive birth weight, but refers to an absolute measurement, regardless of gestational age. Typically the threshold for diagnosing macrosomia is a body weight between 4,000 and 4,500 grams, or more, measured at birth, but there are difficulties reaching a universal agreement of this definition.
An abdominal pregnancy is a rare type of ectopic pregnancy where the embryo or fetus is growing and developing outside the womb in the abdomen, but not in the Fallopian tube, ovary or broad ligament.
Ventriculomegaly is a brain condition that mainly occurs in the fetus when the lateral ventricles become dilated. The most common definition uses a width of the atrium of the lateral ventricle of greater than 10 mm. This occurs in around 1% of pregnancies. When this measurement is between 10 and 15 mm, the ventriculomegaly may be described as mild to moderate. When the measurement is greater than 15mm, the ventriculomegaly may be classified as more severe.
Kyprianos "Kypros" Nicolaides is a Greek Cypriot physician of British citizenship, Professor of Fetal Medicine at King's College Hospital, London. He is one of the pioneers of fetal medicine and his discoveries have revolutionised the field. He was elected to the US National Academy of Medicine in 2020 for 'improving the care of pregnant women worldwide with pioneering rigorous and creative approaches, and making seminal contributions to prenatal diagnosis and every major obstetrical disorder'. This is considered to be one of the highest honours in the fields of health and medicine and recognises individuals who have demonstrated outstanding professional achievement and commitment to service.
Maternal–fetal medicine (MFM), also known as perinatology, is a branch of medicine that focuses on managing health concerns of the mother and fetus prior to, during, and shortly after pregnancy.
The Fetal Treatment Center at the University of California, San Francisco is a multidisciplinary care center dedicated to the diagnosis, treatment, and long-term follow-up of fetal birth defects. It combines the talents of specialists in pediatric surgery, genetics, obstetrics/perinatology, radiology, nursing, and neonatal medicine.
Percutaneous umbilical cord blood sampling (PUBS), also called cordocentesis, fetal blood sampling, or umbilical vein sampling is a diagnostic genetic test that examines blood from the fetal umbilical cord to detect fetal abnormalities. Fetal and maternal blood supply are typically connected in utero with one vein and two arteries to the fetus. The umbilical vein is responsible for delivering oxygen rich blood to the fetus from the mother; the umbilical arteries are responsible for removing oxygen poor blood from the fetus. This allows for the fetus’ tissues to properly perfuse. PUBS provides a means of rapid chromosome analysis and is useful when information cannot be obtained through amniocentesis, chorionic villus sampling, or ultrasound ; this test carries a significant risk of complication and is typically reserved for pregnancies determined to be at high risk for genetic defect. It has been used with mothers with immune thrombocytopenic purpura.
The MOMS Trial was a clinical trial that studied treatment of a birth defect called myelomeningocele, which is the most severe form of spina bifida. The study looked at prenatal and postnatal surgery to repair this defect. The first major phase concluded that prenatal surgery had strong, long-term benefits and some risks.
Congenital pulmonary airway malformation (CPAM), formerly known as congenital cystic adenomatoid malformation (CCAM), is a congenital disorder of the lung similar to bronchopulmonary sequestration. In CPAM, 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. The underlying cause for CPAM is unknown. It occurs in approximately 1 in every 30,000 pregnancies.
The anomaly scan, also sometimes called the anatomy scan, 20-week ultrasound, or level 2 ultrasound, evaluates anatomic structures of the fetus, placenta, and maternal pelvic organs. This scan is an important and common component of routine prenatal care. The function of the ultrasound is to measure the fetus so that growth abnormalities can be recognized quickly later in pregnancy, to assess for congenital malformations and multiple pregnancies, and to plan method of delivery.