Minimally invasive surgery is at this moment one of the outstanding developments in surgery. In this type of surgery the actual operation is performed through a number of small incisions in the skin. In the operations special instruments are inserted via trocars, i. e. tubes which allow the surgeon to bring instruments or sensors into the body. The view at the operating field comes from a laparoscope, a camera presenting a two-dimensional image on a monitor. The minimally invasive surgical technique has many potentional benefits for the patients. However, compared to open surgery there are severe disadvantages for the surgeon, such as the loss of three-dimensional visual feed back and proprioception, the disturbed eye-hand coordination, and the poor ergonomic design of the surgical instrumentation, and of the working place. At this moment the differences beween open and minimally invasive surgery can mainly be ascribed to differences in the manual control task. In this paper, the man-machine aspects of the traditional open operation process will be compared with those of the minimally invasive surgery process. Especially the consequences of the restricted perception in minimally invasive surgery will be discussed. Some future developments will be discussed.@en