Authors: Liebmann, Florentin; Roner, Simon; von Atzigen, Marco; Scaramuzza, Davide; Sutter, Reto; Snedeker, Jess; Farshad, Mazda; Fürnstahl, Philipp
Methods: A novel navigation method, tailored to run on the Microsoft HoloLens, was developed. It comprises capturing of the intra operatively reachable surface of vertebrae to achieve registration and tool tracking with real-time visualizations without the need of intraoperative imaging. For both, surface sampling and navigation, 3D printable parts, equipped with fiducial markers, were employed. Accuracy was evaluated within a self-built setup based on two phantoms of the lumbar spine. Computed Tomography (CT) scans of the phantoms were acquired to carry out preoperative planning of screw trajectories in 3D. A surgeon placed the guiding wire for the pedicle screw bilaterally on ten vertebrae guided by the navigation method. Postoperative CT scans were acquired to compare trajectory orientation (3D angle)and screw insertion points (3D distance) with respect to the planning.
Results: The mean errors between planned and executed screw insertion were 3.38±1.73◦ for the screw trajectory orientation and 2.77±1.46 mm for the insertion points. The meantime required for surface digitization was 125±27s.