Due to very complex structure of nasal area that is covered by facial bones, a tracking of surgical instruments
on the preoperative CT image is very important for obtaining an improved image guidance as well as preventing
surgical accidents in the paranasal sinus surgery. In this contribution, we present our recently developed an efficient
and compact navigation system for paranasal sinus surgery and its first clinical trial.
In our system, we use an optical-based 3D range imaging device intra-operatively, in order to achieve
registration and a tracking of instruments. Before the intervention, the range image of patient's face is acquired by a
3D range scanner and registered to corresponding surface extracted from the preoperative CT images. The surgical
instrument fitted with spherical markers that also can be measured by range scanning device, is tracked during the
procedure. The main advantages of our system are (a) markerless on the patient's body, (b) an easy semiautomatic
registration, (c) frameless during surgery, thus, it is feasible to update a registration and to restart the tracking when
a patient moves. In this paper, we describe a summary of used techniques in our approach including the benefits and
limitations of the system, experimental results using a precise model based on a human paranasal structure and a
first clinical trial in the surgical room.