An optical 3D digitizer for frameless stereotactic surgery

This frameless system for defining the precise spatial coordinates of a site of surgical interest has many advantages over conventional frame based systems and provides accuracy comparable to commonly used units. The system uses computer hardware and software to reconstruct 2D digital images into a 3D volumetric image display. The 3D images, when combined with a spatially digitizing sensor to define a location in space, can be directly registered to anatomical structures or markers in the surgical field. The display can then be used to track the sensor position and, therefore, the surgical position, thus eliminating the guesswork of intuitively transferring radiographic information to the operative field. This system, the ISG Viewing Wand, has proved to be objective and accurate at integrating imaging data with the structures in the operative field, with a clinical accuracy of approximately 3 millimeters.