AMEDD Advanced Medical Technology Initiative (AAMTI)

AAMTI Project Spotlight: T.R.O.N. Telesurgical Robotic Operative Network and Counter-measures to Excessive Signal Latency in Robotic Telesurgery

June 29, 2018  |  Download PDF

In early 2018, the U.S. Army Medical Department (AMEDD) defined its strategic vision on the role of medical robotics and man-machine interfaces for the future of Army medicine. In line with the Army’s Robotic and Autonomous Systems Strategy, AMEDD outlines mid and long-term goals for research and development of strategies to enable semi-autonomous tele-robotic surgery for combat casualty care in austere and combat environments. Currently, the development and implementation of tele-robotic surgical capabilities to support prolonged field care under the Army’s future Multi-Domain Battle (MDB) concept faces several challenges.

In the MDB environment, an operational environment involving greater dispersion and near isolation of maneuver units, is likely to cause severe restrictions on mobility for medical missions and shortfalls in both human and materiel resources due to area denial challenges. Combat units will need to be more self-sufficient as delayed medical evacuation becomes increasingly likely due to the freedom of movement challenges imposed by the MDB environment.  These scenarios will require patients to be held for longer durations near the point of injury with limited medical resources. The implementation of tele-robotic surgery has the potential to bring advanced procedures further forward in the battlefield by allowing surgeons to remotely perform the types of interventions necessary for preserving life, preventing morbidity, and improving outcomes. However, employment of tele-robotic surgery in the battlefield is currently not feasible due to the operational communications challenges of limited bandwidth, latency, and loss of signal in the deployed combat environment. These types of communication challenges are likely exacerbated by the MDB environment. Identification and evaluation of the methods to mitigate these communications challenges which hamper tele-robotic surgery are required to enable safe and effective tele-robotic technologies for future forward surgery applications on Multi-Domain Battlefields.

Schematic of Motion-Scaling to counter excessive signal latency in tele-robotic operations

Schematic of Motion-Scaling to counter excessive signal latency in tele-robotic operations

Latency is an especially unique challenge with tele-operated surgical systems because of the bi-directional nature of communications, the need for real-time communication of commands and immediate feedback. Signal disruption or latency carries significant ramifications because it leads to robotic overshoot, oscillations, and instabilities. Without appropriate compensation and safeguards for signal latency, the surgeon’s inability to view and control the robot in real-time prevents the safe implementation of telerobotic surgery. With the goal of enabling safe and effective telerobotic surgery for combat casualty care, our team set out to identify and evaluate the problems caused by signal latency in telesurgical robotics, and to develop solutions that effectively act as counter-measures to mitigate these problems. With support from the AMEDD Advanced Medical Technology Initiative (AAMTI) Rapid Innovation Fund, we studied one potential solution by modifying motion-scaling (MS) of the robot to identify optimal degrees of MS that produces the best performance outcome under different latency constraints.

In this study, we used a Da Vinci robotic manipulator to perform a simple task transferring a rubber ring between multiple pegs under different delay and MS combinations. We were able to demonstrate in our study that increasing signal delay causes a significant decrease in task performance and increase in task time. Additionally, our novel technique of decreased MS and velocity-based MS under increased signal latency conditions demonstrated statistically significant improvements in task performance.

As we move forward, we plan to utilize the information we have learned from this project and apply it as one of many solutions to enable safe and effective robotic telesurgery. As in prior research and development efforts in robotic telesurgery, the DoD will need to lead the research efforts. Our next step is to have TRON team members from multiple military medical centers closely collaborate with renowned DoD and civilian research institutions such as TATRC, ISR (Institute of Surgical Research), University of California San Diego (UCSD), Stanford, and SRI International to create telesurgery research hubs to explore other potential counter-measures such as development and incorporation of machine learning algorithms for greater robotic autonomy, improving robotic perception capabilities, and development of virtual man-machine interfaces to enable low-bandwidth tele-robotic surgery.

The participation of multiple DoD and civilian research hubs in the development of semi-autonomous protocols for robotic telesurgery is critical as this allows for true, real-time development and testing across vast geographic distances between multiple hubs. Additionally, development of machine learning algorithms for autonomous systems depends on large volumes of relevant data. Engaging multiple institutions allows for the scalability needed for this effort and having military surgeons and DoD research centers leading such efforts ensures that the data collected, and any future designs are tilted towards combat care applications.

The unique infrastructure of the global military treatment facilities including universal licensing, credentialing, and collaborative culture would serve as the perfect incubator for telesurgery. As the TRON project catalyzes the clinical application and ubiquitous adoption of robotic telesurgery within military medicine, there is an opportunity to establish military medicine as a paragon of robotic surgery excellence. The development of semi-autonomous telesurgery is the essential innovation to meet the present and future challenges unique to military medicine.

This project is a combined, collaborative initiative between Walter Reed and National Capital Consortium, Tripler, Madigan, Balboa Naval Medical Center, San Antonio Army Medical Centers, SRI International, UCSD, and Stanford University.

This article was published in the June 2018 issue of the TATRC Times.