Robotic Platform Advances Fetoscopic Treatment of Twin-to-Twin Transfusion Syndrome

Twin-to-twin transfusion syndrome is a life-threatening complication in monochorionic twin pregnancies caused by unbalanced placental blood flow. Definitive treatment requires endoscopic laser coagulation of shared placental vessels, a technically demanding procedure performed by few specialists. Rigid instruments and limited visualization can hinder complete vessel access and closure. To help address this challenge, researchers have developed a robotic, magnetically guided fetoscopic platform that adds real-time panoramic placental mapping.

The robotic platform was developed by researchers at ETH Zurich in collaboration with doctors at the University of Zurich. It centers on a 3.2‑millimeter flexible fetoscope whose tip contains small permanent magnets. Three external electromagnets generate a controllable magnetic field that bends the tip, allowing precise orientation toward targeted placental vessels.

The magnetic steering behaves like a compass needle aligning to a field, translating surgeon commands into smooth, stable movements at the tip. This increased maneuverability is designed to improve access to hard‑to‑reach anastomoses during laser coagulation. The magnetic field is described as harmless to the patient.

A second core component is real‑time panoramic guidance. The system stitches sequential endoscopic images into a two‑dimensional map of the placental surface. Surgeons can designate a target on this map for automated navigation, while maintaining manual override with a PlayStation game controller. Software converts the joystick input and camera view into corresponding magnetic‑field adjustments.

In simulator testing, participants struck targets more accurately with the robotic system, achieving a typical positional deviation of 140 micrometers, which the team reports is more than four times better than comparable conventional tools. The platform also completed key steps of the twin‑to‑twin transfusion syndrome procedure in an in vivo experiment on a pregnant ewe, conducted outside the laboratory under realistic conditions such as fetal motion and turbid amniotic fluid.

The work, published in Science Robotics on September 16, 2026, involved ETH Zurich, the University Hospital Zurich, and the University Children’s Hospital Zurich. The team plans additional safety assessments, algorithm refinements, and new assistance functions, and notes potential applications in gastrointestinal and urologic endoscopy where navigation and mapping are needed.

"Even the very steady hand of an experienced surgeon causes the fetoscope to wobble slightly. Our robotic platform, on the other hand, stabilizes the tip and holds it much more steadily at the desired location to coagulate the vessels precisely," the researcher says," said Michelle Mattille, postdoctoral researcher and lead author.

"With the robotic system, the deviation was typically 140 micrometers, meaning the system is more than four times more precise than comparable conventional instruments," Mattille added.

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