ABSTRACT
The introduction of frameless stereotaxy, or in other words intra-operative navigation systems, gave decisive impetus to computer-assisted surgery. Diagnosis precedes the computer-assisted reconstruction of the facial skeleton and is based on clinical findings and 3D imaging since the usefulness of conventional 2D radiographs is considerably limited as a result of superimposition. Virtual computer-assisted planning and simulation of a facial reconstruction is performed on the basis of preoperative 3D data sets to increase the predictability of the desired outcome and the safety of the surgical procedure. After reconstructions of the midface, 3D imaging should be performed even before surgery is completed. Furthermore, the patient's position must be permanently registered since patient movements during surgery cannot be prevented or may even be necessary during the procedure. Further methods of registration include the use of anatomical bone landmarks, skin surface matching and skin fiducials, which are registration points that are glued to the patient's skin.
