Research team creates a surgical navigation system for fetal surgery

The placenta of every expectant mother is located in a different place, its blood vessels are never the same, and its connection to the fetus and the umbilical cord also varies from one pregnancy to another. Moreover, the fetus is also always in a different position in each case and floating in amniotic fluid. The fetus is surrounded by highly delicate membranes that can only be perforated once so as not to risk losing the pregnancy. So, when a fetus has a life-threatening condition and requires an emergency intervention in the womb, the fetal surgeon faces a huge challenge because he/she has to decide very precisely where to enter the uterus and, once inside, has very few references to navigate safely.

To date, the surgeon could only resort to an ultrasound to guide the entrance to the uterus and the movement of surgical tools to the fetus. Now, a team of professionals from BCNatal, a consortium formed by Hospital Sant Joan de Déu and Hospital Clínic in collaboration with the team of M.A. González Ballester, ICREA research professor with the Department of Information and Communication Technologies (DTIC) at UPF, has developed for the first time, a system of three-dimensional surgical planning and navigation for fetal surgery that offers many advantages: greater precision for the surgeon, shorter operating time, and in the future, it is set to improve the results by making fetal surgery more accessible.

The system provides a virtual reconstruction of the placenta based on MRI and ultrasound. With this 3-D map of the placenta, before the procedure, the fetal surgeon has a much more accurate understanding of the status of the placenta and the umbilical cord, and can analyse which is the best entry point to the placenta to gain access to the fetus.

Once in the operating room, the surgeon uses a 3-mm endoscope especially designed for fetal surgery. "Fetoscopic" vision is very limited and therefore requires continuous guidance on its position within the uterus. Until now, this was done using ultrasound, but the new system allows additional 3-D navigation that gives information that was not available until now. This is because the endoscope incorporates a sensor at the tip that is detected by external antennae and, using complex algorithms and mathematical formulas, it allows synchronizing the virtual reconstruction of the placenta with the actual movements of the surgical instruments.