ABSTRACT
Over the past decade computer-based neuronavigation systems have found a
greater role in the neurosurgery operating room (OR). Particularly in neuro-
oncologic surgery, frameless systems have become increasingly used to guide
and provide volumetric tumor resections (1-9). These systems provide the
surgeon with the intraoperative ability to correlate the operative anatomy to
the preoperative imaging. To utilize these systems, the patient undergoes
specialized preoperative imaging. This imaging is then registered into a computer
platform to generate a three-dimensional image that can be used in the operating
room. These frameless neuronavigation systems have been shown to be particu-
larly useful in defining normal anatomy and in tailoring resections, and have
accuracy comparable to frame based systems (10). Additionally, systems have
been modified to guide the placement of biopsy needles into target lesions
(11-14). Studies on frameless image guided needle biopsies have demonstrated
that such systems can be accurate to the millimeter scale (15). Because of the suc-
cessful experience with needle-guided biopsies, these systems were thought to be
potentially applicable to the placement of deep brain stimulator leads.
