Magnetically Steerable Catheter to Speed up Stroke Treatment

Strokes are the world’s second most common cause of both death and long-​term disability. One in four adults over the age of 25 will suffer a stroke in their lifetime. If a blood clot in the brain cannot be removed using drugs, those affected require emergency surgery, which sees the surgeon maneuver a catheter through an artery past the heart into the brain to clear away the disturbance of the blood supply. The sooner and faster the procedure is carried out, the lower the patient’s risk of sustaining long-​term damage. Up until now, surgeons have commonly used a pull wire to manually navigate the catheter tip through the convoluted network of blood vessels. The drawback of this method is that, since the tip can only be moved in two directions, the complex procedure takes a long time and requires a great deal of skill and experience. Now, a new type of catheter steered by remote control and computer via a magnetic field is set to change all that.

Researchers from ETH Zurich (Zurich, Switzerland) who developed the magnetic catheter along with its spin-​off Nanoflex believe that its precision steering will speed up and simplify procedures compared to conventional catheters in the future. Since hospitals are currently short of catheter specialists, the team is hopeful that their system will give more patients access to prompt stroke treatment. Having a soft and more maneuverable catheter should also reduce the risk of accidental vessel damage. Another advantage is that the surgeon steers the magnetic catheter by remote control, which means they don’t have to be at the patient’s side during the procedure. This shields doctors from the radiation of the X-​ray machine that allows them to get their bearings inside the patient’s body. The researchers are hoping that, in future, stroke patients will be operated on as quickly as possible at the nearest local hospital by a specialist who doesn’t even have to be on the premises, thus saving precious time.

For surgeons to be able to work with the magnetic catheter, patients must lie next to a magnetic navigation system that creates a directed magnetic field. In contrast to commercially available equipment that is permanently installed in the operating theatre, Nanoflex’s magnetic field generator is significantly lighter and thus, has a wider range of applications. It can be wheeled into the operating theatre as needed and requires only power and water. The smaller and more flexible magnetic navigation system will be significantly cheaper than competing products. The researchers’ vision is for every big hospital to have one of their magnetic navigation systems in future. Until then, however, they still have a lot of work to do. The aim is to obtain approval for the U.S. market in two years. To this end, they must not only assess every conceivable risk and establish ways to minimize them, but also present a solid plan for how to manufacture the system in a standardized way and how to operate it with maximum reliability. The researchers are confident that the system will enter the market, and that the technology will lend itself to other fields as well, such as heart and eye surgery, gastroscopy and fetal surgery.

“Not only can the catheter tip be bent in any direction thanks to a magnetic head; it’s also smaller, more maneuverable and safer due to the soft­ness of the material,” explained ETH alumnus Christophe Chautems, one of the three founders of Nanoflex. “Even surgeons with less experience should be able to treat strokes with our system,”

“With our system, it will be possible to carry out procedures from a distance by remote control and on a screen,” added Silvia Vivi­ani, who studied robotics at ETH Zurich and has worked at Nanoflex since 2021.

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