HISTORY

Robots were first developed by the National Aeronautics and Space Administration (NASA) for use in space exploration.^[2] These devices, or telemanipulators, were capable of doing manual tasks aboard a spacecraft or out in space. The slave devices were controlled electronically from a remote master control on Earth or aboard a spacecraft. Telemanipulators were used extensively aboard NASA's Space Shuttle missions between 1983 and 1997. Research in trajectory and missile guidance systems eventually led to highly precise targeting mechanisms. Precision pointing at targets, such as the Earth and stars, was crucial for Spacelab telescope experiments. Telemanipulators such as the Instrument Pointing System (IPS) were specifically designed for extreme accuracy (±1.2 arcsec).^[3] Scientists at NASA Ames Research Center were responsible for developing virtual reality. The idea took root with contributions of VPL, a visual programming language, and Dataglove.^[4] Their integration made it possible to interact with three-dimensional virtual scenes. However, it took

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From these applications, it became apparent to the U.S. Department of Defense that virtual reality and telepresence might serve a useful function in treating wartime casualties on the battlefield. Through virtual reality, the surgeon could be brought to the patient's side, an idea described by the term telepresence. Data from wounded casualties of the Vietnam War estimated that, of all wounded soldiers, one third died of head and massive injuries and another third died of exsanguinating hemorrhage but had the potential to survive if they were treated in time.^[2] The Department of Defense sought to improve medical presence on the battlefield given that one third of casualties can be saved. Telepresence allowed a surgeon located aboard an aircraft carrier to perform surgery (with the aid of telemanipulation) on wounded soldiers located in a remote location on the battlefield. With this idea in mind, the Department of Defense funded much of the research in telemanipulation for remote mobile surgical units that would allow for telepresence.

Engineers realized that the distance between patient and surgeon had an upper limit, beyond which accuracy and dexterity of instrument control would suffer degradation. Latency is the time it takes to send an electrical signal from a hand motion to actual visualization of the hand motion on a remote screen. The lag time to send an electrical signal to a geosynchronous satellite at 22,300 miles above the earth and return is 1.2 seconds. This transmission delay would prohibit practical surgery. Humans can compensate for delays of less than 200 msec. Longer delays compromise surgical accuracy. Tissue moves when force is applied to it, and with a visual delay greater than 200 msec, the movement would not be noticed fast enough to avoid cutting in an unintended place. The most optimistic attempt to provide telesurgical presence over long distances was undertaken using high-bandwidth fiberoptic ground cable. The latency time of 155 msec allowed Marescaux and Gagner^{[6] [7]} to perform a robotassisted laparoscopic cholecystectomy between New York City and Strousbourg, France.

Phillipe Mouret^[8] performed the first video-laparoscopic cholecystectomy in Lyons, France, in 1987, but it was not until Perissat^[9] presented the innovation to the Society of American Gastrointestinal Endoscopic Surgeons in 1988 that an exponential spread of laparoscopic surgical procedures began. Although laparoscopic surgery provided a great benefit for the patient, it brought tremendous surgical limitations, such as loss of three-dimensional vision, impaired touch sensation, and poor dexterity provided by the long instruments and the fulcrum effect. The fulcrum effect is a nonintuitive motion of the instrument tips in opposite direction about a fixed point, usually at the skin entrance site. New skills had to be learned. Initial attempts to surmount the burdens of endoscopic surgery have provided the impetus for robotic support systems that can enhance surgical skills and control of instruments. The first of such systems in the medical field was applied in surgical field camera guidance.

In 1994, the U.S. Food and Drug Administration (FDA) approved the first Automated Endoscopic System for Optimal Positioning (AESOP)^[10] arm to be used in laparoscopic surgery. The device is controlled through voice activation to provide a flexible view of the surgical field. Around the same time, the TISKA Endoarm became available, and it could act as a camera guided by electromagnetic friction and could work as a tissue retractor.^[11] While foot pedals were being replaced by voice-activated systems, other manufacturers were designing cameras that moved in synchrony with the movements of the surgeon's head.^[12] Other devices provided finger "joysticks" that could be used to control the camera field.^[13]

To combat dexterity problems, the master-slave telemanipulator concept was developed for medical use in the early 1990s. The first master-slave manipulator for medical use was developed at Stanford Research Institute. The goal was to have computer algorithms that translate a surgeon's master manual movements to end-effector slave instruments at a remote site. The robotic slave arms mimic the natural movements of the surgeon's hand. Early designs had only 4 degrees of freedom, but by 1992, a German prototype was developed with 6 degrees of freedom ( Fig. 66-1 ).^[14] It was used experimentally but never achieved clinical application.^[15] In 1994, Intuitive Surgical obtained technologic rights and eventually developed robotic instruments with 6 degrees of freedom.

Robots can be preprogrammed with limits set by the operator and run autonomously, or its kinematics can be completely defined online in real-time tracking when immediate human interventions and decisions are required. The design of surgical robots must include sterility barriers and enhanced patient safety features. It must meet operating room constraints and be compatible with imaging equipment, as well as require special ergonomic features.

To overcome endoscopic surgery handicaps, engineering technology has developed three-dimensional video imaging, robot camera holders, and robotic flexible effector instruments with the ability for tactile pressure sensation. Unfortunately, every instrument has different stress feedback characteristics, and the surgeon's ability to "feel" the elastic properties of tissue are not yet fully developed. The robotic fingers can be made smaller than those of the human hand to help reach confined spaces. The robot can filter the surgeon's hand tremor and scale the movements of the instruments to the level of high precision and stability that is required for microsurgery. Best of all these advantages, repetitive robot motions and tasks are not prone to fatigue.