Abstract: A computer assisted surgery apparatus includes a surgical instrument having an intervention member to cut tissue of a body part of a patient; a control unit arranged to control position and orientation of the intervention member in relation to the body part with regard to a predefined osteotomic line on the body part; and a tracking device arranged to track a position and orientation of the body part. The surgical instrument includes an optical monitoring system mounted in relation to the intervention member, wherein the optical monitoring system is arranged to continuously detect positions of marks applied to the body part, and the control unit is arranged to adjust position and/or orientation of the intervention member when a predefined deviation of the positions of the marks is detected. The surgery apparatus allows for application of cuts in the body part at comparably complex cutting geometries and at comparably high precision.

Abstract: Method for planning a process of cutting human or animal bone tissue. The method includes: obtaining initial data of an initial situation of the bone tissue; defining target data of a target situation of the bone tissue; and computing a cut geometry using the initial data and the target data for cutting the bone tissue apart. The cut geometry includes a structure such that the bone tissue is reassemblable at least in one degree of freedom in the target situation after being cut apart along the cut geometry. By shaping the structure of the cut geometry according to the target situation the planned cut can be provided with a particular function. Such a functional cut can geometrically define and restrict possible movements of cut apart bone portions. The functional cut can allow for comparably precisely repositioning the bone into the target position and any movement therefrom can be prevented.

Abstract: A computer assisted surgery apparatus (1) comprises a surgical instrument (12) having an intervention member (31) for cutting tissue of a body part (2) of a patient; a control unit (16) arranged to control a position and orientation of the intervention member of the surgical instrument (12) in relation to the body part (2) of the patient with regard to a pre-defined osteotomic line (21) on the body part (2) of the patient; and a tracking device (14) arranged to track a position and orientation of the body part (2) of the patient.

Abstract: Method for planning a process of cutting human or animal bone tissue. The method includes: obtaining initial data of an initial situation of the bone tissue; defining target data of a target situation of the bone tissue; and computing a cut geometry using the initial data and the target data for cutting the bone tissue apart. The cut geometry includes a structure such that the bone tissue is reassemblable in an at least in one degree of freedom in the target situation after being cut apart along the cut geometry. By shaping the structure of the cut geometry according to the target situation the planned cut can be provided with a particular function. Such a functional cut can geometrically define and restrict possible movements of cut apart bone portions. The functional cut can allow for comparably precisely repositioning the bone into the target position and any movement therefrom can be prevented.