Development of a soft robotic catheter for vascular intervention surgery

Soft robotics-based teleoperated robotic catheter systems hold great promise for improving the safety and effi-cacy of vascular interventional surgery (VIS). Despite advances, current robotic catheter systems actuated via cables have low stability, high force loss, lack of force sensing, and low stability when working against the dynamic cardiothoracic environment, all of which significantly reduce their effectiveness in clinical settings. Therefore, it is essential to equip the robotic catheters with a stabilizing mechanism (SM), a real-time force sensor, and the ability to expand the workspace without moving its body. This work introduces a new concept of a miniaturized soft robotic catheter (MSRC) for the VIS. The system consists of a soft manipulator for navigation and bending motion, a variable stiffness stabilizing mechanism (VSSM), and a soft force sensor for monitoring tool-tissue contact. By employing soft hydraulic filament artificial muscles (HFAMs), the flexible manipulator has an omnidirectional and extendable workspace and can generate a force of 0.375 N, which is monitored by a new HFAM-based sensor with a high sensitivity of about 10.7 KPa/N. The new VSSM can be deployed as a lantern form with a wide diameter range from 6 mm to 25 mm, potentially enhancing the catheter tip's stability at various blood vessels (e.g., the inferior vena cava IVC) to perform VIS. The VSSM has a controllable deploying force and is capable of withstanding highly compressed forces with little deflection. The system feasibility to perform cardiac ablation is demonstrated with a simulated heart's right atrium (RA), potentially offering a reliable tool for the treatment of atrial fibrillation (AF). The design, modelling, and fabrication of the device are also presented and followed by experimental characterizations, and ex-vivo tests.