Fetal surgery is necessary or desirable in a number of different circumstances. Performing surgery on a fetus is complicated because not only do you have the risks associated with any surgery, but fetal surgery also greatly increases the chance of a premature birth even if the surgery is successful. However, there are many situations where the risks associated with fetal surgery are far lower than the risks associated with allowing a deformity or medical condition to continue to develop in the fetus. Fetal abnormalities are usually discovered by using routine tests during pregnancy. Some ways to determine if the fetus is having complications are through ultrasounds, blood and urine samples of the mother, and through amniocentesis, where the fluid that surrounds and protects the baby is tested directly.
Fetal surgery is performed in two different ways. The first is through endoscopy and is called fetoscopic surgery. In fetoscopic surgery, a small tube is inserted directly into the mother's womb. Tools are then used from within the tube to perform the surgery on the fetus. The uterus remains relatively intact and no large incision has to be made. This procedure is done whenever possible because it produces much lower chances of having a premature delivery because of damage to the uterus. Because of the small size of the tube, the procedures that can be done are very limited.
Open fetal surgery is exactly what the name implies. A surgical incision is made in the mother, which extends through the abdominal muscle and an incision is also made in the uterus. In open fetal surgery, the amniotic fluid must be removed also, which creates great distress on the fetus. The fetus is then operated on directly through the incision. Once the surgery on the fetus is completed, the uterus is closed back up along with the other incisions. The incision, and subsequent scarring of the uterus greatly increases the chances of a premature delivery.
Fetal surgery is most often used in only a few situations. Those situations are such that the fetus is very unlikely to survive until birth, or the baby is unlikely to survive the first few moments after birth.
Spina Bifida does not fall into those categories however. Spina Bifida is a condition where the spinal column does not close completely, and the baby is born with the spinal chord exposed. There is great risk of infection and paralysis in babies born with Spina Bifida, therefore, most doctors elect to close the spinal chord before birth.
Another fairly common disorder that necessitates fetal surgery is a diaphragmatic hernia. In this condition, the muscle that separates the chest from the abdomen isn't intact, and some of the digestive organs enter the chest cavity and prevent proper lung development. In this case, if the problem is not corrected before birth, the child will likely not be able to take it's first breath.
Problems with the proper development of the urinary tract will also cause a doctor to recommend fetal surgery. This is because the amniotic fluid surrounding the fetus becomes contaminated with urine and other debris from the fetus which cause problems with the development of many organs including the kidneys and lungs.
Tumors are also a frequent cause of fetal surgery. There is a fairly common tumor that sometimes develops at the base of the spine of the fetus. This tumor, while benign, can grow very large, sometimes as large as the fetus itself. This extra mass of tissues causes extreme stress on the heart to supply oxygenated blood to it.