On the use of discrete steps in robot-aided flexible needle insertion

Needle steering devices present great potential for improving the safety and accuracy of medical interventions with percutaneous access. Despite significant advances in the field, needle steerability remains an issue to be solved by the scientific community. In this paper, we propose the use of discrete steps in flexible needle insertion, inspired by the manual procedure performed by physicians. Conceptually, the method relies in alternating between two motions: grasp-push and release-retreat. For experimental evaluation, a modified gripper is used along with a 6DOF robotic manipulator to control needle insertion velocity, rotation and grasping. Preliminary results indicate that the use of discrete steps minimizes some negative effects, such as slippage and needle buckling, observed on alternative methods, while preserving their functional advantages.