Abstract: A device and method for preparing for and supporting surgical operations includes a numerically controlled positioning appliance which is arranged in a predetermined or measurable geometric relationship with respect to an operating site. A surgical instrument, such as a machining tool or a holder for a graft, can be releasably connected to this positioning appliance for movement in relation to the operation site. A measurement appliance is used for measuring coordinates of the operation site in relation to a stationary reference system. The holder can be releasably secured to the positioning appliance or, alternatively, can be secured on a securing device which is stationary in relation to the reference system. The securing device is arranged in a predetermined or measurable geometric relationship with respect to the operation site. A data processing unit with memory controls the positioning appliance. The memory stores a data record of a three-dimensional structural image of the operation site.

Abstract: In a process for planning and monitoring a surgical operation, an operation site is established. At least one desired image of the operation site is generated from structural data which can be obtained by noninvasive means, and the planning is based on at least one section surface along which tissue is to be severed during the operation. An image of the planned section surface is then generated, which image is superposed during the operation on an actual image of the operation site or is projected onto the operation site itself. A three-dimensional desired image is used as the basis for planning the section surface. A three-dimensional image of the section surface is generated which is superposed on the desired image. It is created by computer-aided means from data taken from images generated in different ways. The images show the operation site in layers, each lying on& above the other.