Computer-assisted neurosurgery by using a noninvasive vacuum-affixed dental cast that acts as a reference base: another step toward a unified approach in the treatment of brain tumors

Object. The purpose of the study was to evaluate the use of the Vogele-Bale -Hohner (VBH) mouthpiece, which is attached to the patient's upper jaw by n egative pressure, for patient-image registration and for tracking the patie nt's head during image-guided neurosurgery. Methods. A dynamic reference frame (DRF) is reproducibly mounted on the mou thpiece. Reference points, optimally distributed and attached to the mouthp iece, are used for registration in the patient's absence on the day before surgery. In the operating room, the mouthpiece and DRF are precisely reposi tioned using a vacuum, and the patient's anatomical structures are automati cally registered to corresponding ones on the image. Experimental studies a nd clinical experiences in 10 patients confirmed repeated (rigid body) loca lization accuracy in the range of 0 to 2 mm, throughout the entire surgery despite movements by the patient. Conclusions. Because of its noninvasive, rigid, reliable, and reproducible connection to the patient's head, the VBH vacuum-affixed mouthpiece grants the registration device an accuracy comparable to invasive fiducial markers .