Overlay visualization in endoscopic ENT surgery

Purpose In endoscopic ENT surgery, the identification and localization of target structures is challenging—depth information is missing, relevant tissues could be hidden behind opaque material and image distortion affects the instrument handling. In this paper, a novel overlay visualization is presented that supports the surgeon by superimposing planning and navigation information on the endoscopic image. Method Target regions, which have been identified in preoperative CT data, are superimposed on the endoscopic image, allowing the use of guiding lines for distance visualization. To match the overlay information with the geometrically distorted endoscopic images, a new intraoperative calibration procedure has been developed. Results The accuracy of this new method has been verified by cadaver studies. Clinical evaluation in three paranasal sinus interventions was performed to show the intraoperative assistance and practicability with promising results. Conclusion The new techniques safely support the surgeon in locating target structures in the paranasal sinuses with little change in the actual workflow.