In seventeen patients we used the Stereoplan Plus programme with a PC work station and Zamo- rano-Dujovny stereotactic device for virtual planning of peroperative demarcation of organic brain affections and tumours. The accuracy of this system was plus minus 1 mm for navigation of determination in the space during intervention. The intervention was completed by application of peroperative functional mapping using superficial electrocorticography. The results of this combi- ned operative techniques were relativelly accurate resections of pathological brain tissues while preserving important functions of the CNS.

        Key words: navigation - virtual reality - stereotaxy - minimal invasiveness