Implementation and Evaluation of a Uterine Manipulation System Incorporated with an Existing Tiltable-Tip Uterine Manipulator for Gynecological Laparoscopy

Abstract

In gynecologic surgery, a uterine manipulator is one of the instruments used to perform the laparoscopy. Throughout the past decade, a number of robotic technology applications used for uterine manipulation during surgery have been designed with the aim of increasing the efficiency, improving the precision, and reducing the workload of medical assistants. Although the RCM (Remote Center of Motion) mechanism is one of the key features in a Minimally Invasive Surgical (MIS) robot, the preliminary result in this study, in which the RCM mechanism was applied in a uterine manipulation robot, proved that this may cause unpleasant sensations such as irritation or harm to the nearby area during such manipulation. Therefore, a design of a non-RCM 2-DoF (Degree of Freedom) Robotic Uterine Manipulation System, in cooperation with an existing, reusable and tiltable-tip uterine manipulator, for laparoscopic gynecologic surgery has been proposed and evaluated via a mathematical model along with numerical analysis, a 3D uterus model, and a 1:1 uterus manikin model in order to demonstrate the use of the essential functions. According to the experimental results, the maximum load of 500 g has been handled well by the prototype, with the movement ranges of ±150° in the roll panel and ±90° in the pitch panel (0∼90° for anteversion and 0∼−90° for retroversion, if needed, which can be achieved by rotating the instrument to the other side). Furthermore, to verify this new design prior to its use on patients, and also in consideration of the ethics of human experimentation, through extensive testing on five donated soft-tissue cadavers, the proposed robot received positive feedback from all five surgeons performing the experiments and could offer effective uterine manipulation at the angular velocity of 4 °/s (0.67 RPM) with steady delineation of the vaginal fornices to create necessary motions in the pitch and roll panels of 30∼80° and ±15°, respectively, providing efficient visualization of the uterus. These features make this robot a valuable addition to the surgical instruments available to gynecologic surgeons.