Three Degrees of Freedom-Based Master–Slave Uterine Manipulation Robot System for Laparoscopic Hysterectomy

Abstract

A laparoscopic hysterectomy has been highlighted to early diagnose uterine and cervical cancers. Reflecting these needs, commercial uterine manipulators employing a kinematic linkage system without mechanical actuators have been developed. None of them have achieved versatile movements, enabling anteversion and retroversion articulation of the uterus together with translational motion. More recently, motorized uterine manipulators capable of versatile and multifunctional movements are proposed. They have shown a strong potential to alleviate the burdens that gynecological surgeons can experience. Building on these concepts, we propose a master–slave system-based uterine manipulation robot (UMaRo). The device features a simple mechanism with a larger workspace, achieved by combining translational motion together with roll and pitch motions. The UMaRo also has an ergonomically designed uterus-shaped handle which enhances ease of use and convenience during procedures. More importantly, the master–slave system enables surgeons to operate the manipulator with less force, thereby reducing operator fatigue. A linkage mechanism allows the UMaRo to accommodate a higher load capacity, a larger workspace, and makes the device simpler. Numerical analyses are performed to determine the specifications of the UMaRo. Based on the results, the UMaRo is designed and fabricated. Then, experiments are performed in a phantom uterus model to validate the UMaRo performance. Results demonstrated a lifting force of 13 N in the pitch motion and 45 N in the roll motion, and the movement of the master–slave system was found to be well-synchronized out–inside of the phantom.