Surgical Principles of Fetal Interventions

Surgical Principles of Fetal Interventions

Ahmed A. Nassr

Michael A. Belfort

Alireza A. Shamshirsaz


  • In the United States, structural congenital anomalies are detected in up to 3% of all children (1). Some of the major anomalies and fetal conditions can cause mortality or significant postnatal morbidity.

  • Recent advances in diagnostic prenatal imaging as well as open and endoscopic surgical techniques have allowed us to offer a variety of procedures in pregnancies associated with a high risk of fetal demise or lifelong morbidity if not timely corrected.


  • Curvilinear ultrasound transducers are commonly used for needle guidance in fetal interventions. These transducers allow some degree of flexibility in guiding the needle toward the target.

  • Simulation models and simple invasive procedures (e.g., amniocentesis) are of great value in initial training and improving the operator’s needle orientation skills.

  • Two operators are generally needed for complex fetal interventions, with one person holding the ultrasound transducer and the second operator performing the needle procedure. This allows for fine adjustment as the operator directs and advances the needle. A reasonable degree of coordination between the two operators is required for the successful completion of the procedure, and this comes from practice and experience working as a team. Many interventionists, based on their training and experience, prefer to direct the needle and hold the ultrasound probe themselves, and this is a perfectly acceptable alternate approach.

  • Careful planning regarding the ideal site of surgical access is the first step for safe and successful fetal intervention or surgery. The target should be clearly seen, and a clear path to that target should be identified. The placental location is often a determining factor in the location of the access site, and under most circumstances, avoidance of the placenta and the immediate placental edge is wise because of the risk of hemorrhage. Care should be taken to exclude the presence of uterine vessels, other pelvic structures, and bowel loops along
    the intended path of the needle, particularly so with lateral abdominal access.

  • We prefer to perform invasive fetal procedures in an operating room using standard sterile procedures. A transparent sterile plastic sheet is usually used to cover the ultrasound panel, and a probe cover is used to keep the probe sterile. This setup allows the ultrasound operator to control the image settings during the procedure.