Computer-Integrated Surgery: Technology and Clinical Applications

Abstract

COMPUTER ASSISTED SURGERY Computer assisted surgery is such a recent development on the orthopaedic scene that it is too early to identify a classic article. Rather, what is needed is a brief exposition of what the relationship between the computer and the surgeon promises for the future. The application of computer science to aid in the performance of surgical procedures holds real promise, especially for orthopaedic surgery. The following selection is from the introduction of a recent book devoted to the subject.1 The authors represent an international collaboration involving various disciplines. The authors are as follows: Russell H. Taylor, professor of computer science, Johns Hopkins University, Baltimore, MD, and former manager of Computer Assisted Surgery Research, IBM J. Watson Research Center; Stephane Lavallée, PhD, investigator for the Computer Assisted Surgery Group, Techniques de l'Imagerie, de la Modelisation et de la Cognition (TIMC) Laboratory, Genoble, France; Grigore C. Burdea. MD, assistant professor of computer engineering, Rutgers, The State University of New Jersey, and Ralph Mosges, head of Clinical Research, Department of Otolaryngology, Aachen Technical University, Aschen, Germany. Leonard F. Peltier, MD, PhD INTRODUCTION An emerging partnership For clinicians, this human-machine partnership is important because it offers the possibility both of significantly improving the efficacy, safety, and cost-effectiveness of existing clinical procedures and of developing new procedures that cannot be performed at all otherwise. For technologists, this partnership offers real, challenging applications with articulate end users. Furthermore, incremental progress is possible. Even relatively simple uses of new technology can make significant differences clinically, and the lessons learned can then be applied to harder problems. In exploring a partnership involving complementary capabilities, it is useful to consider the strengths and weaknesses of each party. Human surgeons have, of course, many capabilities. They are very dexterous, quite strong, and fast, and are highly trained to exploit a variety of tactile, visual, and other cues. They are adaptable and can exercise these skills over a surprisingly wide range of geometric scales. "Judgmentally" controlled, they understand what is going on in the surgical procedure and use their dexterity, senses, and experience to execute the procedure. They can analyze their own performance and apply the lessons learned-that is, they can improve with practice. However, surgeons do have limitations. They are not geometrically accurate. In other words, they cannot easily place an instrument at an exact, numerically defined location relative to the patient and then move it through a defined trajectory, nor are they very good at exerting exactly a predefined force in a particular direction. They do not tolerate ionizing radiation well and are understandably not eager to be exposed to it on a daily basis. They get clumsy if forced to work in very confined spaces or over long periods of time. They may have small hand tremors that limit their ability to operate on very delicate structures. They get tired and make mistakes. They get old and lose some of their skill. Unfortunately, many of these limitations affect the efficacy of certain surgical procedures, especially in cases where great geometric accuracy is required or in which the surgeon's direct use of his or her senses or manual dexterity are impaired. Fortunately, machines have complementary capabilities that can remedy some of these defects. Machines are very precise and untiring. They can be equipped with any number of sensory feedback devices and can measure and position instruments very accurately in six degrees of freedom. Numerically controlled machines can move a surgical instrument through an exactly defined trajectory with precisely controlled forces. Potentially, they can be miniaturized to function in very confined spaces and can be hardened to withstand significant doses of ionizing radiation. When properly maintained, they are reliable, and their every move can be recorded for subsequent analysis. Viewed in this light, even very sophisticated computer-controlled machines such as robots are simply better surgical tools. As such, they do not pose any significant threat to replace surgeons, but they can help surgeons to work better. Nonetheless, the computer control required to achieve many of these advantages of machines introduces important questions. Because surgeons are responsible for everything that goes on in the operating theater, they are naturally wary of any entity-be it a scrub nurse, intern, resident, or machine- that may not respond to their wishes in exactly the desired manner and at exactly the right time. Surgeons have learned (more or less) to trust human assistants, who can be trained to respond to verbal and nonverbal commands and to exercise some judgment in carrying out ass