[Clinical experience of image-guided neurosurgery with a frameless navigation system (StealthStation)]

We have applied the frameless navigation system (StealthStation) to various neurosurgical procedures to examine its usefulness. The system consists of a UNIX based workstation that creates triplanar and 3-dimensional images; an infrared optical digitizer with camera array; a reference-light-emitting diode (LED) array (e.g., reference array); and pointer probe modified by the addition of LEDs. This system was used to assist in placing a minimal skin incision and craniotomy in 4 cases, to determine the tumor/brain interface in 2 cases, to target the subcortical lesion in one case, and to correlate bony structure with a skull base tumor in 3 cases. The combined use with magnetic source imaging of the somatosensory cortex allowed a fast orientation of eloquent areas in 2 cases with peri-Rolandic tumor. This system, thus, was proved to be a useful adjunct to open-tumor biopsy or resection.