Intraoperative navigation and orientation systems in skull base surgery

Computer-assisted surgery has reached an advanced stage of development, which presents new possibilities for routine surgical procedures. The navigation system MKM/Zeiss is an intraoperative guiding system with a touchless autofocus system coupled to an operating microscope. Landmarks and routes can be preoperatively established. They are later visualised through the surgeon's ocular. The orientation systems Stealth Station/Sofamor Danek and OTS/Radionics consist of an infrared light-emitting navigation system and several freehand pointer instruments. In a study involving more than 180 patients a positioning accuracy of less than 1.5 mm was achieved, suggesting that the non-invasive reference system and the locatable surgical tools may be effective, accurate and useful aids for the computer-assisted identification of vital structures..