Prenatal evaluation for fetal surgery.

The selection of fetuses that may benefit with in utero surgery is being developed. Noninvasive and invasive prenatal diagnosis techniques are utilized to try and gain as much knowledge about the fetus so that the appropriate counseling of parents can be undertaken. The most common invasive techniques are amniocentesis and chorionic villus sampling for fetal karyotyping and genetic diagnosis. Noninvasive techniques include ultrasound (2D and 3D), fetal echocardiography and magnetic resonance imaging. Additional techniques such as specific Doppler evaluation of vascular components, new techniques to look at fetal electrocardiograms and the use of computer tomography are also considered. The most common conditions for which in utero fetal surgery is also being considered are twin to twin transfusion syndrome, myelomeningocele, sacrococcygeal teratoma, cystic adenomatoid malformation of the lung with fetal hydrops and other monochorionic twin abnormalities (severe discordant birth defects or twin reversal arterial perfusion sequences). Ongoing evaluation of the sensitivity, specificity, positive and negative predicted values of these evaluation tools is required so that appropriate selection of fetuses for the surgery can be made.