Medical robotics: where we come from, where we are and where we could go

Medical robotics can be split in subfields depending on who has to be assisted by a robot; it can be:-The hospital: for instance for patient transportation and handling,-the patient: by providing him/her robotized prostheses or artificial organs, rehabilitation aids or assistance for every day tasks,-the clinician: by assisting his diagnostic or therapeutic tasks. This short note focuses on the third type of systems which purpose is to provide the clinician with robotic aids for moving and actuating medical sensors and tools in minimally invasive interventions. Such robots were introduced in the early eighties first in neurosurgery applications, then, a little later, for orthopaedics; the aim was to transfer accurate machining and positioning capabilities from the industrial world to the clinical one. However one major difference with industrial robotics is the need for interaction with a clinical user. Different types of systems have been proposed depending on the level of autonomy they leave to the robot. In the first generation of robots, two main types of interactions were implemented: active robots execute in an autonomous way subtasks under human supervision (" the automation dream ") whilst semi-active robots position a tool-guide which is used by the clinician to carry out his task, for instance introducing a needle into the body. Because the clinical environment is very complex and constrained, because the medical knowledge is very large and difficult to model exhaustively and finally because the clinician is an expert with high abilities to detect, analyze and react to unwanted critical situations, the automation dream has often turned into a collaborative framework where both the clinician and the robot have to work together in a synergistic way. Thus more recently, new interaction paradigms were proposed: co-manipulation consists in having a tool attached to the robot end-effector and held by the clinician; both of them contribute to its motion in a programmable way depending on the task execution status. Tele-operation approaches, involving master-slave architectures were also introduced for complex interventions on movable and deformable organs and for microsurgery applications. The automation paradigm has been recently re-explored in order to synchronize tool motions to organ ones in specific applications (radiotherapy in particular). Robot architectures also evolved this last decade from multipurpose large robotic arms to more dedicated and small robots. Medical robotics raises specific issues related to the application field. For instance, a robot that carries a surgical tool has to be at least …