Virtual fixture assistance for needle passing and knot tying

Suturing is a challenging and highly dexterous task in minimally invasive surgery, even with the assistance of robotic surgical systems. In this work, we propose a simple yet versatile impedance virtual fixture framework, which can be applied on the master manipulator in a tele-operated robotic surgical system. With this framework, we further develop two types of virtual fixtures that assist with the needle passing and knot tying sub-tasks in suturing. The paper also presents the results of a 14-participant user study for both needle passing and knot tying sub-tasks, showing that virtual fixture assistance for novice users increases the needle passing exit point accuracy, reduces the number of errors (suture slip) in knot tying, and simultaneously decreases the task completion time and overall operator workload.