Fetal surgery, also known as antenatal surgery or prenatal surgery, 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 A birth defect is an abnormal condition that is present at birth, regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth de ...

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

es who are still in the pregnant

uterus The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the hollow organ, organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic development, embryonic and prenatal development, f ...

. There are three main types: open fetal surgery, which involves completely opening the uterus to operate on the fetus;

minimally invasive Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definitio ...

fetoscopic surgery, which uses small incisions and is guided by

fetoscopy 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 i ...

and

sonography Medical ultrasound includes diagnostic techniques (mainly imaging) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints ...

; and percutaneous fetal therapy, which involves placing a

catheter In medicine, a catheter ( ) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. ...

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 Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

obstetrics 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 su ...

and

gynecology Gynaecology or gynecology (see American and British English spelling differences) is the area of medicine concerned with conditions affecting the Female reproductive system, female reproductive system. It is often paired with the field of obste ...

, and

pediatrics Pediatrics (American English) also spelled paediatrics (British English), is the branch of medicine that involves the medical care of infants, children, Adolescence, adolescents, and young adults. In the United Kingdom, pediatrics covers many o ...

- especially the sub-specialties of

neonatology Neonatology is a subspecialty of pediatrics that consists of the medical care of newborn infants, especially the ill or premature newborn. It is a hospital-based specialty and is usually practised in neonatal intensive care units (NICUs). Th ...

(care of newborns), 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 surgical techniques. Because of the very high risk and technical complexity of fetal surgery, the procedure is usually performed at specialist centers. 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

will lead to difficulties with future pregnancies. This risk is higher than for a typical

Cesarean section Caesarean section, also known as C-section, cesarean, or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen. It is often performed because vaginal delivery would ...

, for several reasons: * the incision is usually a classical vertical one, with a greater risk of complications in subsequent pregnancies; * the longer duration of the surgery, while the fetal intervention is performed; * a second surgery is required days or weeks later – a Caesarean section to deliver the baby, which brings its own set of risks.

Types

Open fetal surgery

Technique

Tocolytic Tocolytics (also called anti-contraction medications or labor suppressants) are medications used to suppress premature labor (from Greek τόκος ''tókos'', "childbirth", and λύσις ''lúsis'', "loosening"). Preterm birth accounts for 70% ...

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. An H₂ antagonist is usually given for anaesthesia the evening before and the morning of the operation, and an

antacid An antacid is a substance which neutralization (chemistry), neutralizes gastric acid, stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhe ...

is usually given before induction to reduce the risk of acid aspiration. Rapid sequence induction is often used for sedation and intubation. Open fetal surgery is similar in many respects to a normal

cesarean section Caesarean section, also known as C-section, cesarean, or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen. It is often performed because vaginal delivery would ...

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

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 The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products betwee ...

is replaced. The mother remains in the hospital for 3–7 days for monitoring. Often babies who have been operated on in this manner are born pre-term.

Safety and complications

The main priority is maternal safety, avoiding preterm labor and achieving the aims of the surgery. 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. Risks of fetal surgery, specifically prenatal spina bifida repair, include

premature rupture of membranes Prelabor rupture of membranes (PROM), previously known as premature rupture of membranes, is breakage of the amniotic sac before the onset of labour. Women usually experience a painless gush or a steady leakage of fluid from the vagina. Compl ...

uterine rupture Uterine rupture is when the muscular wall of the uterus tears during pregnancy or childbirth. Symptoms, while classically including increased pain, vaginal bleeding, or a change in contractions, are not always present. Disability or death of the ...

in future pregnancies,

premature birth Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is betwee ...

and intraspinal inclusion cysts or a

tethered cord Tethered cord syndrome (TCS) refers to a group of neurological disorders that relate to malformations of the spinal cord. 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. Fetal surgery is not thought to decrease maternal fertility.

Indications

Neural tube defect Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal side of the embryo ...

s (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. After birth, exposure of the spinal cord to the outside environment (

myelomeningocele Spina bifida (SB; ; Latin for 'split spine') 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, ...

or spina bifida) is associated with several morbidities including weakness or sensory deficits in the lower extremities, bladder dysfunction, fluid buildup in the brain and Type 2 Chiari malformations (herniation of the

cerebellar vermis The cerebellar vermis (from Latin ''vermis,'' "worm") is located in the medial, cortico-nuclear zone of the cerebellum, which is in the posterior cranial fossa, posterior fossa of the cranium. The primary fissure in the vermis curves ventrolatera ...

and medulla from the brain into the

spinal canal In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the dorsal bony arches of the vertebral column, which contains the spinal cord, spinal roots and dorsal root ganglia. It is a pro ...

. Prenatal repair of spina bifida is available in specialty centers. Fetuses treated with prenatal fetal repair have significantly improved outcomes compared to children whose defects are repaired shortly after birth. Specifically, fetal repair reduces the rate of hydrocephalus, ventriculoperitoneal shunt dependence, and Chiari malformation. Prenatal repair also shows improved motor skills at 30 months and improved mobility, neuropsychological function, and independent functioning between the ages of 5 and 10. Other conditions that potentially are treated by open fetal surgery include: *

Congenital diaphragmatic hernia Congenital diaphragmatic hernia (CDH) is a birth defect of the diaphragm. The most common type of CDH is a Bochdalek hernia; other types include Morgagni hernia, diaphragm eventration and central tendon defects of the diaphragm. Malformation ...

(if indicated at all, it is now more likely to be treated by endoscopic fetal surgery) *

Congenital cystic adenomatoid malformation 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 replac ...

Congenital heart disease A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital he ...

Pulmonary sequestration A pulmonary sequestration is a medical condition wherein a piece of tissue that ultimately develops into lung tissue is not attached to the pulmonary arterial blood supply, as is the case in normally developing lung. This sequestered tissue is the ...

Sacrococcygeal teratoma Sacrococcygeal teratoma (SCT) is a type of tumor known as a teratoma that develops at the base of the coccyx (tailbone) and is thought to be primarily derived from remnants of the primitive streak. Sacrococcygeal teratomas are Benign tumor, benign ...

Minimally invasive fetal surgery

Minimally-invasive fetoscopic surgery has proven to be useful for some fetal conditions. * Twin-twin transfusion syndrome – Laser Ablation of Vessels *

Spina bifida Spina bifida (SB; ; Latin for 'split spine') is a birth defect in which there is incomplete closing of the vertebral column, spine and the meninges, membranes around the spinal cord during embryonic development, early development in pregnancy. T ...

– Fetoscopic closure of the malformation. Prenatal repair of the spina bifida lesion through this approach has been purported to result in less complications to the mother, whilst affording benefit to the baby.

History

Fetal surgical techniques were first developed at the

University of California, San Francisco The University of California, San Francisco (UCSF) is a Public university, public Land-grant university, land-grant research university in San Francisco, California, United States. It is part of the University of California system and is dedic ...

, in 1980 using animal models. 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. The fetus in question had a congenital

hydronephrosis Hydronephrosis is the hydrostatic dilation of the renal pelvis and Renal calyx, calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dila ...

, a blockage in the urinary tract that caused the kidney to dangerously extend. To correct this a vesicostomy was performed by placing a

in the fetus to allow 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. The first two percutaneous ultrasound-guided fetal balloon valvuloplasties, a type of fetal surgery for severe

aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. ...

obstruction in the heart, were reported in 1991. Among the first dozen reported attempts at this repair in the 1990s, only two children survived long-term. 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.