Surgical interventions in the petrous bone have to be performed in close relationship to vital and delicate anatomical structures. In cases of revision surgery or with massive pathological changes 3D computer-assisted navigation provides an essential tool for preoperative planning, definition of target structures and intraoperative orientation. This technology can help to diminish intraoperative risks for the patient and may help to optimize any microsurgery. In this report we present our first experiences in using the ISG Viewing Wand in the petrous bone through a specially designed model. By recording more than 4000 single measurements we found that the ISG Viewing Wand can be used with sufficient precision. We have now outlined the most important conditions necessary for possible application to a patient.