[Expanded reality in head surgery].

The preoperative planning of complex craniofacial surgical interventions is increasingly realized with the aid of appropriate planning systems in order to achieve high precision, minimal invasion and protection of risk areas. But the most important step from the planning to the actual intervention consists of providing the planning data intraoperatively in a reasonable and easy to handle way. In this regard, augmented reality is one of the most challenging and promising techniques to solve this problem. In this paper we present two different systems based on see-through glasses resp. a common video projector to directly visualize the planning data in the surgeon's field of view. The work is funded by the 'Deutsche Forschungsgemeinschaft (DFG)' and Stryker Leibinger Freiburg/Germany.