Raul Garay-Romero1, Akshay Pratap, MD2, Crystal Krause, PhD2, Dmitry Oleynikov, MD2, Carl Nelson, PhD1. 1University of Nebraska Lincoln, 2University of Nebraska Medical Center
OBJECTIVE: We have designed and tested a laparoscopic tool-exchanger and modular tool base for our robotic laparoendoscopic surgical robot.
DESCRIPTION: Minimally invasive surgery (MIS) allows access to the surgical site through small incisions, resulting in fewer traumas, reduced scarring, and faster recovery. Advances in surgical robotics may help overcome the limitations of MIS techniques. A robot can decrease the crowding of instruments at the surgical site, provide better visualization, lower the learning curve, and facilitate motion scaling. Our surgical robot has two arms which are inserted into the abdomen to perform laparoscopic surgery. It can be controlled on-site or remotely. The robot arms use exchangeable modular tools, which simplifies the design and reduces robot size because additional arms are not needed for different tools. The objective of a laparoscopic tool exchanger for the robot is aimed to decrease the need for removal and reinsertion of the robotic arm with each tool change, which decreases surgery time and risk for injury with each reinsertion. We have designed and tested a laparoscopic tool-exchanger and modular tool base for our robotic laparoendoscopic robot. The robot uses push-to-connect mechanisms to mount and unmount tools to the two arms. With a modular base, local operators can easily [un]mount and deliver a wide range of surgical tools through a trocar, without the need to extract the robot for each tool exchange. The end-effector of the tool-exchanger is similar to a collet and is connected to a 1-DOF elbow. It is composed of three jaw segments and an overtube. Cables connected to the overtube are used to retract the overtube and expose the jaws; closure of the jaws is accomplished using the stored energy in a spring. The jaws accommodate a 3/8" diameter modular tool. Pressure against the tool sleeve [un]mounts the tool.
PRELIMINARY RESULTS: Calculations were performed to determine the forces needed to [un]mount the modular tool base and provide the correct amount of jaw deflection. Finite element analysis supplemented the calculations. Our testing verified the device performance using mock modular surgical tools and mock robotic arms inside the peritoneal cavity of a mannequin. Seven participants with no training unmounted and mounted the tools once using the laparoscopic tool exchanger. Visualization for testing used a webcam placed between the mock robot arms. The average unmounting time was 54 seconds (min 36, max 83) and the average mounting time was 72 seconds (min 25, max 141). With the rotation allowed by the trocar and the 1-DOF of the tool-exchanger, the end-effector had ample flexibility within the cavity.
CONCLUSION/FUTURE DIRECTIONS: The end-effector performed exceptionally well, pulling and pushing as designed, and with practice the user can reduce the tool-exchange times. Future work includes reduction of instrument size and testing by a surgeon.
Figure 1. (a) Laparoscopic tool exchanger (b) Tool exchanger inserted through trocar with open jaws. (c) Jaws placed around recess (d) Tool unmounted and far into end-effector (e) Tool in narrow recess ready to be mounted.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 84362
Program Number: ETP725
Presentation Session: Emerging Technology Poster
Presentation Type: Poster