This paper discusses the technology and developments behind transformations made to a commercial robotic surgical system, Computer Motion, Inc.'s Zeus/spl trade/, in order to make it possible to fully and safely support minimally-invasive human telesurgery performed over very large distances. Because human life is at stake, issues relating to safety, detection of errors, and fail-safe operation are principal in importance. Therefore, it was paramount that all of the safety features of the commercial product Zeus/spl trade/ remained intact during this transformation. This paper discusses the commercial robot and its safety features as well as the real-time communications system added to it as part of Operation Lindbergh, the first transatlantic human telesurgery. Particular attention is paid to the limiting effects of latency. Key techniques developed during this project are discussed, including the need to send the full robot state in each transmitted packet rather than incremental or modal data, thereby treating all telecom problems uniformly as dropped packets. The use of hierarchical design (incorporating Zeus as a drop-in component rather than modifying its internals) allowed the project to focus on the new issues arising due to teleoperation while gaining the robust, error checking, and fail-safe aspects of the design from the use of the unmodified commercial robot. The concept of local mode was created and used during initialization and during communications abnormalities and outages in order to keep the local and remote subsystems active and safely quiescent.

This paper presents an historic achievement. A commercial robotic surgical system was altered to enable remote surgery. This presented huge challenges because the Zeus/sup TM/ system is a tightly-coupled electromechanical system with tight sample and communication loops. We were, however, able to separate Zeus/sup TM/ into a remote surgeon-side system (located in New York City) and a patient-side system (located in Strasbourg, France). Never before have surgeons performed complete surgical tasks in the fashion presented in this paper. The remote surgical task was Laparoscopic Cholecystectomy (removal of the gall bladder) performed on animals. In this unique setup the patient (pig) was readied in the operating room in Strasbourg, France, while the operating surgeon was in Manhattan, NY. The Zeus/sup TM/ robotic system is a very safe surgical system for use in the operating room. For the remote transatlantic case, numerous safety features were built on top of those already available in Zeus/sup TM/. The ultimate goal of this development is to perform a transatlantic Lap Chole case on a human subject. As such, the animal cases were performed with the same setup, personnel, and equipment as will be used for the human case. The choices of the robotic system, networking equipment, and telecommunications lines were critical to the success of the project.

Describes a real-time system supporting a tele-surgery application based on the Zeus/sup TM/ system. The application involves performing minimally invasive surgical procedures remotely - i.e. without the surgeon being present in the same room with the patient. Because there is human life at stake, the underlying real-time system must be robust, fail-safe and resilient to communications problems. This paper focuses primarily on the approach taken in communicating between the surgeon-side and patient-side subsystems. In particular, techniques for dealing with the challenges of real-time communications are discussed, e.g. bit errors, packet errors and synchronization. In addition to the control actions and feedback data, several serial data streams are multiplexed, transmitted between one side and the other, demultiplexed, and delivered by the real-time system. These streams have a fundamentally different character from the control actions and feedback values used with the robots. Both types of real-time streams are sent over the same communications link.