A Robotic System with a Bendable Catheter for Laparoendoscopic Single Site Surgery

Robotic Laparoendoscopic Single Site Surgery (LESS) is emerging as a hot research topic with the advancement of robotics. However, the movement of the rigid catheter inserted through a fixed incision into the patient's body cavity is constrained to a conical workspace, and the surgical instruments introduced through channels in the catheter can hardly perform necessary operations when the target tissue is close to the boundary of this workspace. In this paper, we present a novel robotic system for LESS with a bendable catheter that allows the catheter centerline to be oriented towards the target tissue over a larger area, thus providing a better initial position for the surgical instruments and enlarging the workspace of the instruments. The diameter of the bendable catheter is 30 mm and the length is 22 mm. The bendable portion of the catheter provides 2 degrees of freedom (DOF) within the body cavity and can be bent up to 45°. The system consists of two continuum instruments with 6 DOF and a 3D endoscope with 5 DOF. System design, kinematic analysis and teleoperation algorithm are introduced in detail. Preliminary experiments are performed to verify the feasibility and effectiveness of the proposed system. The results prove the applicability of the system in LESS.