Image-guided otologic surgery

Application of image-guided surgical systems to otologic surgery has been limited by the need for submillimeter accuracy via a fiducial system that is easily useable (i.e. noninvasive and nonobstructive). To overcome these limitations and demonstrate the feasibility of image-guided otologic surgery, a novel fiducial marker system was constructed which attaches to a dental biteblock and has fiducial markers surrounding the surgical field of interest (the ears/temporal bones). Accuracy was tested by fitting the device to a cadaveric skull and embedding targets near anatomically important locations. High-resolution CT scanning (thickness=0.5 mm) was then performed. Marker and target locations were measured in physical space using an infrared, image-acquisition system. These measurements were used in calculating target registration error-the error associated with identification of the surgical targets. This error was minimized when the maximum number of fiducial markers was used (nine fiducials surrounding each ear). Submillimeter target registration error was repeatedly achieved with five markers surrounding the ear of interest and one marker centrally located on the contralateral side. (C) 2003 Published by Elsevier Science B.V.