A team at University of California San Diego invented a way to make steerable catheters that can more precisely navigate the tortuous architecture of the brain vasculature. The device was bioinspired by delicate structures found in nature, including flagella and insect legs, and uses principles from soft robotics to create a hydraulic steering system, which is encased within a tiny silicone rubber catheter. The UCSD researchers hope that the technology could allow clinicians to treat areas of vasculature that are currently out of reach.
Intracranial aneurysms can pose a tricky problem to treat. In approximately 25% of cases, they can be inoperable because of their inaccessible location within the tortuous vasculature of the brain. “As a neurosurgeon, one of the challenges that we have is directing catheters to the delicate, deep recesses of the brain,” said Dr. Alexander Khalessi, a researcher involved in the study. “Today’s results demonstrate proof of concept for a soft, easily steerable catheter that would significantly improve our ability to treat brain aneurysms and many other neurological conditions, and I look forward to advancing this innovation toward patient care.”
At present, clinicians use a curved tip guide wire to advance a catheter through the vasculature, all the way from the femoral artery to the cerebral artery where the aneurysm resides. However, this technology is not always optimal, even for aneurysms that are theoretically accessible. Unfortunately, when the guidewire is removed to allow treatment to begin, problems can arise. “Once the guidewire is retrieved the catheter will return to its native shape, often straight, resulting in loss of access to the pathology,” said Dr. Jessica Wen, another researcher involved in the study.
In a change of approach, this latest technology allows the surgeon to steer the tip through a handheld controller that is compressed to manipulate a hydraulic system within the device. The hydraulic fluid is simple saline, which is a safety measure that ensures any leakage is not harmful.
A fluoroscopic image of the steerable catheter navigating a brain artery in a pig and deploying coils.
The catheter design is inspired by structures found in nature. “We were inspired by flagella and insect legs, as well as beetles mating, where microscale hydraulics and large aspect deformation are involved,” said Gopesh Tilvawala, another researcher involved in the study. “This led us to developing [a] hydraulically actuated soft robotic microcatheter.”
So far, the researchers have tested the technology in pigs, and hope to advance to human studies soon.
See a video about the catheter technology below:
Study in Science Robotics: Soft robotic steerable microcatheter for the endovascular treatment of cerebral disorders