Medical robotics – Constraints, specificities and challenges

The medical robots discussed in this article are systems used to assist doctors and surgeons in performing medical procedures on patients. They generally consist of a motorized mechanical structure located in the operating room, next to the patient at the time of surgery, which in some cases is similar in appearance to an industrial robotic arm. Added to this is a human/machine interface enabling a medical user to control the positioning or movements of the robotic arm. This interface can take a wide variety of forms, from a simple set of conventional computer peripherals (screen, keyboard, mouse) to advanced mechatronic systems known as haptic interfaces. The human/machine interface also enables the user to access medical decision-making tools, in particular medical images. The whole system is controlled by a software and electronic system linking the human/machine interface to the motorized structure, and ensuring that the user's commands are carried out.

The first medical robots were introduced in the mid-1980s for neurosurgical applications. An industrial robot of the PUMA-260 type was used on 22 patients at Long Beach Hospital in California. In France, the Speedy robot developed at the TIMC laboratory in Grenoble was also introduced in 1989 for neurosurgery. The first commercial robot was the Robodoc system for orthopedic hip surgery, available from 1992. The development of medical robots accelerated sharply in the late 1990s and early 2000s in the field of minimally invasive laparoscopic surgery, in particular with the Da Vinci system.

Robots have now taken over a large part of the medical field due to the following main advantages:

• precision and predictability: these characteristics are of particular interest in orthopaedics and neurosurgery;

• dexterity: in minimally invasive surgery, robots make it possible to control movements inside the patient's body intuitively, thanks to the principles of telemanipulation;

• simultaneous control of multiple degrees of freedom (DDL) and multiple instruments: telemanipulation also makes it possible for a single person to control more than two instruments. This makes it possible to perform minimally invasive surgery alone, without an assistant during the medical phases;

• stabilization and filtering of tremors: in microsurgery (eye surgery, neurosurgery), the robot's mechanical structure or control modes can be used to eliminate involuntary user movements;

• work in difficult-to-access environments: robots enable access to the center of medical imagers. They also protect the practitioner in the case of ionizing imagers by remote control. These features are particularly...