The objective of Computer-Assisted Surgery (CAS) is to provide the surgeon with benefits deriving from the integration of advanced image processing techniques and computer graphics with new robotic and mechatronic surgical instruments, in order to achieve more effective planning and more accurate execution of surgical interventions.

A variety of new surgical tools are currently under development as part of CAS systems and as stand-alone devices. According to our vision of this field, all new surgical tools can be classified conceptually into one of three main classes, based on their technical characteristics and on the aspect of surgeon performance they aim to enhance: a) robotic tools; b) teleoperated dexterous tools; and c) manually operated mechatronic tools.

Robotic tools are integral parts of CAS systems. They execute very accurately and autonomously (though under the supervision of the surgeon) the tasks pre-planned by the surgeon using preoperative data on the patient. The main advantage of the robotic tool as compared to direct human operation is much higher accuracy due to the intrinsic stiffness of the robot manipulator and the resulting precise execution of desired trajectory and force patterns.

The distinctive feature of teleoperated dexterous tools is dexterity. This class of surgical tools comprises teleoperated instruments supporting different levels of direct surgeon control. These instruments allow the surgeon to access sites in the human body which are difficult to reach, and to use a variety of miniaturized tools for different types of intervention and therapy.

The third class of surgical instruments, the mechatronic tools, are perhaps the least well known and investigated in the field of CAS. Mechatronic surgical tools include integrated and miniaturized precision mechanisms, sensors, actuators, preprocessing electronics, embedded microcontrollers and a human/machine interface. Simple and intuitive operation, little or no need for complex training of the surgeon and of the operating room personnel, real time compensation for perturbations, easy integration with CAS systems, and low cost are the main advantages of smart mechatronic tools as compared to both traditional surgical tools and to robotic tools, which may result in their use widespread in clinical practice.

In this presentation, the authors will discuss the working principles and objectives of each class of robotic systems for CAS, and will present examples of their present applications in clinical practice, along with some considerations on future principles.