The touch and feel in minimally invasive surgery

Minimally invasive surgery (MIS) characterizes a sophisticated operation technique in which long instruments are inserted into the patient through small incisions. Though providing crucial benefits compared to open surgery (i.e. reduced tissue traumatization) it is also faced with a number of disadvantages. One of the major problems is that the operating tissue cannot be palpated any more and that appearing contact forces can hardly be sensed. To overcome some of the drawbacks minimally invasive robotic surgery (MIRS) constitutes a promising approach. Due to the remote control the operating instruments can be equipped with miniaturized force/torque sensors and thus the appearing contact forces can be displayed to the surgeon. As the development of sensorized surgical devices is challenging there are no commercially available robotic systems which provide kinesthetic feedback currently. In this work, a prototypical force reflecting MIRS system is presented and the importance of kinesthetic feedback is evaluated empirically. Based on the results of a psychophysical pre-experiment, a representative dissection task was realized which was accomplished by 25 surgeons. The study revealed that robot assisted surgery is actually suited to reduce unintentional injuries when appropriate force feedback is available, although it has to be mentioned that the operating time increased compared to a manual intervention. Further interesting insights were gained by a qualitative video analysis which revealed that robotic surgery affords acquisition instead of manual surgical skill transfer. Especially experienced surgeons have to get accustomed to a more continuous working style.