Flexibility of Head Positioning and Head Fixation Provided by a Novel System for Non-invasive Maxillary Fixation and Frameless Stereotaxy: Technical Note - Ortler, M.; Unterhofer, C.; Bauer, R.; Dobesberger, J.; Trinka, E.; Bale, R. (min - Minimally Invasive Neurosurgery, 2009)