Navigation systems based on optical tracking are an essential component in minimally-inva-sive surgery. However, these assisting systems require additional hardware in the operating room and can only poorly adapt to the surgical skills and the anatomical knowledge. In the BIOPASS project, a novel localization approach for a markerless navigation system is devel-oped that potentially reduces the navigation hardware while assisting the surgeon’s cogni-tion with self-learning and adaptive assistance functions. Critical aspects for the develop-ment of such an intelligent system are the surgeon’s ambiguous perception of adaptive system behavior and information presentation. As a consequence, the primary goals of the BIOPASS project are the definition of clearer human-machine-interaction (HMI) require-ments for adaptive systems in the OR and the development of a corresponding presentation model of surgery-related situational infor-mation needed by the surgeon. As a result, current work steps comprise studies for knowl-edge representation of situational information in a functional endoscopic sinus surgery (FESS) and intraoperative information presentation in a preliminary mock-up demonstrator.