Prenatal surgery is a relatively new field of medicine. Its purpose is to operate on the fetus inside the pregnant uterus. Such treatments save his life or give him a chance to avoid severe disability after birth. There are only a few types of medical conditions and birth defects that can be treated with prenatal surgery techniques. The choice of this method of treatment requires each time to consider the balance of potential benefits for the fetus and the risk of complications. How is intrauterine surgery performed? In which cases are they indicated? What are the complications?
Prenatal surgeryorfetal surgeryis a relatively young branch of medicine. The first prenatal surgery procedures were performed on animal fetuses. They allowed for the initial development of surgical techniques, which were then used in the treatment of human fetuses.
The first successfulintrauterine surgerywas performed by Dr. Michael Harrison in 1981 in California. The procedure consisted in the implantation of a special catheter (the so-called vesico-amniotic shunt) enabling the outflow of urine in a fetus with congenital hydronephrosis.
Since then, there has been an intensive development and improvement of surgical techniques, allowing for obtaining better and better results while reducing the risk of complications.
The list of diseases in which the use of prenatal surgery is associated with an improved prognosis in relation to starting treatment only after the birth of a child is also gradually expanding.
The development of fetal surgery goes hand in hand with the continuous improvement of the methods of prenatal diagnosis. The availability of better and better imaging techniques of the fetus enables early and precise diagnosis of fetal diseases.
The development of prenatal diagnostics allows for the gradual introduction of criteria for distinguishing those cases in which intrauterine intervention is beneficial.
Prenatal surgery: indications for treatments
Currently, most fetal diseases are diagnosed during prenatal examinations. However, you should be aware that only some of them can and should be treated with prenatal surgery techniques.
Interventionintrauterine treatment is undertaken only when it gives a chance to obtain better results than the implementation of postnatal therapy.
What diseases are therefore subject to the criteria for inclusion in this type of therapy?
- Małowodzie
Too little amniotic fluid is an indication of one of the simpler prenatal surgery procedures, the so-called amnio infusion. It consists in puncturing the amniotic cavity with a special needle and giving it an appropriate amount of replacement amniotic fluid.
This is a relatively easy way to prevent serious effects of oligohydramnios, such as lung hypoplasia (underdevelopment).
This procedure is only a symptomatic treatment, however, it allows you to extend the pregnancy and increase the chance of the proper development of the fetus.
- Neural tube defects
One of the most common defects in prenatal surgery is the meningeal hernia, a consequence of spina bifida. In this condition, the spine does not close, leaving the spinal cord exposed and exposed to the amniotic fluid.
The consequences of the defect are very serious - they include, among others hydrocephalus, paralysis, disorders of the nervous system.
The closure of the cleft is performed both on the open uterus and using endoscopic techniques (see section 3). The prognosis after surgery depends on the location of the hernia and the degree of damage to the spinal cord. You should be aware that although such an operation limits the effects of the development of the defect, it does not guarantee full recovery.
- Heart defects
The vast majority of congenital heart defects require surgery only after the baby is born. Exceptions for prenatal surgery include, but are not limited to, valvular disease such as severe narrowing of the pulmonary or aortic valve. The operation consists in widening them using stents - tiny tubes that allow blood to flow.
- Urinary system defects
Obstructive urinary tract disease is a condition in which the outflow of urine is blocked. It results in urinary retention in the kidney (hydronephrosis) and oligohydramnios (because the amniotic fluid is formed from the fetal urine). A surgical procedure involving the implantation of a vesico-amniotic catheter allows urine to drain away and prevents kidney damage.
- Congenital cystic adenomatosis of the lungs
This defect with a complicated name consists in the formation of large cysts in the lungs, compressing the normal parenchyma of the lungs and inhibiting their physiological development. Intrauterine treatment involves the implantation of a catheter (similar to the previous onesub-point), allowing the outflow of the contents of the cyst into the amniotic cavity. The lung then gains additional space, expands and can continue to develop.
- Diaphragmatic hernia
The development of a diaphragmatic hernia causes the abdominal organs to shift through the opening in the diaphragm to the chest. There is pressure on the heart, mediastinal structures and the space where the lungs should develop is occupied.
Prenatal treatment of this defect involves placing an inflated balloon in the trachea, which blocks the outflow of fluid in the lungs. By stopping it, the lungs increase in volume, have a chance to "push away" the abdominal organs and have a better chance of proper development.
- Tumors
Prenatal tumor removal operations are performed when they threaten the proper course of pregnancy or the life of the fetus. This is a relatively rare situation.
The most frequently operated tumors include sacral teratomas. Their characteristic feature is rich vascularization. The large amount of blood pumped into the tumor vessels puts additional strain on the fetal heart and may, in extreme cases, lead to circulatory failure. Such cases require surgical removal of the tumor.
- Amniotic band syndrome
The amniotic band syndrome poses a risk of severe deformation and even amputation of entire limbs or their distal fragments. This is where pieces of the amniotic membrane wrap around parts of the fetus. Prenatal surgery techniques allow the bands to be cut and removed while allowing the fetus to develop properly.
- Intrauterine blood transfusions
Giving blood into the fetal umbilical vein was one of the first prenatal treatments. The main indication for intrauterine transfusion was hemolytic disease of the newborn, caused by serological conflict.
Currently available diagnostics and prevention of serological conflict resulted in a reduction in the frequency of intrauterine blood transfusions. However, they still remain an effective treatment for neonatal anemia.
- Ste alth Team
When listing indications for prenatal surgery, mention should also be made of the pathology of twin pregnancies, called the Twin-to-Twin Transfusion Syndrome (TTTS).
This condition develops in unicellular pregnancies and consists of disturbances in placental circulation. They result in excessive blood leakage to one of the fetuses.
The "recipient" fetus receives a large amountblood volume, which puts you at risk of developing polyhydramnios and heart failure. The fetus "donating" blood has too little of it.
The use of laser coagulation (closure) of vascular connections gives a chance of healing in about 60% of cases both fetuses, and in over 80% of at least one of them.
Prenatal surgery - the course and techniques of procedures
There are several techniques in the field of prenatal surgery. Each of them is characterized by a different spectrum of applications and a different risk of postoperative complications.
Currently, there is a trend of abandoning extensive surgical procedures and increasing emphasis on the techniques of fetoscopic and minimally invasive surgery. The basic fetal surgery procedures include:
- Open uterine surgery
The first prenatal surgery procedures were performed after the laparo- and hysterotomy (cutting of the abdominal wall and uterus) of the pregnant woman.
After access to the fetus, the procedure was performed, then the missing amniotic fluid was replenished, the uterus was sutured and the abdominal wall was closed. It was an extensive operation with the risk of several significant complications. Currently, this type of procedure is performed less and less frequently - it is gradually being replaced by less invasive techniques.
The basic problems associated with this type of surgery include a significant increase in the risk of preterm labor and the need to perform a caesarean section (both during the postpartum and all subsequent births). Operations requiring hysterotomy are most often performed between the 20th and 30th week of pregnancy.
- Fetoscopic surgery
In view of the scope and the risk of complications of open uterine procedures, new, less invasive surgical techniques were sought.
Technological development made it possible to develop methods of fetoscopic surgery, i.e. endoscopic surgery of the fetus. They make it possible to perform procedures with the use of special specula inserted into the mother's abdomen.
The fetus is visualized by a combination of images from cameras mounted at the end of the specula and additional views from the ultrasound machine.
Fetoscopic surgery is associated with a lower risk of preterm labor and perioperative infection.
It also allows the pregnant woman to recover faster.
This technique requires the presence of suitably qualified staff.
You should also be aware that not all defects can be corrected endoscopically. One of the most common uses todayfetoscopic surgery are placental blood circulation disorders (e.g. theft syndrome - see point 2).
- Needle techniques
The least invasive procedures are interventions performed with a needle, under constant control of imaging tests (usually ultrasound). This technique is used, among others. for the collection or administration of amniotic fluid (amniocentesis / amniocentesis) and for intrauterine blood transfusions.
Prenatal surgery - and what next?
Prenatal surgery is the only intervention that allows for full recovery of the fetus only in a few cases. Intrauterine surgery is much more often the first of many stages of treatment.
The main goal of prenatal procedures is to enable termination of pregnancy and to prepare the fetus for further stages of therapy.
A good example is defects of the urinary system, in which prenatal implantation of a vesico-amniotic catheter is a temporary solution, enabling the proper development of the kidneys and preventing irreversible complications.
The final correction of the anatomical defect, which is the cause of the urinary outflow disorders, is made after birth.
Prenatal surgery - benefits vs. risks
The indications for prenatal surgery listed in point 2 suggest a wide range of its application in various types of congenital diseases. However, you should be aware that only some of the above-mentioned defects can be operated intrauterine.
The decision to qualify for such a procedure is made by a team of specialists (gynecologist-obstetrician, neonatologist, geneticist, anesthesiologist) in close consultation with the child's mother.
The priority is always the safety and he alth protection of the pregnant woman. An in-depth risk analysis of possible complications in both ongoing and future pregnancies is necessary.
A special problem is also the implementation of prenatal surgery techniques in juvenile malformations, where determining the limit of acceptable risk may be a very difficult decision.
The future of prenatal surgery
The progressive development of prenatal surgery generates questions about the future and the direction of its development. Will fetal surgeries be performed in any Polish hospital? What are the chances that more and more conditions and birth defects will qualify for such procedures?
Progress in terms of equipment and technology is taking place very quickly. In order to be able to fully use this potential, it is necessary, however, to appropriate financial outlays and to constantly improve the qualifications of medical staff. There is also a need for high-quality clinical research that determinesstandards for the use of prenatal surgery in specific groups of diseases.
Despite technological progress, making decisions about surgical prenatal treatment requires great caution and prudence. We are still looking for ways to avoid the most common complication of these procedures, which is preterm labor.
Until fully effective methods of its prevention are developed, the use of prenatal surgery will remain (with few exceptions) limited to the treatment of lethal defects.
The greatest development prospects are seen in minimally invasive techniques that reduce the risk of both maternal and fetal complications.
About the author
Krzysztof BialaziteA medical student at Collegium Medicum in Krakow, slowly entering the world of constant challenges of the doctor's work. She is particularly interested in gynecology and obstetrics, paediatrics and lifestyle medicine. A lover of foreign languages, travel and mountain hiking.
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