[3D endoscopy].

With the aid of a 6 mm 0 degree stereo-endoscope supplied with a 100 Hz monitor and high-speed liquid crystal shutter, three-dimensional endoscopy of the upper airway was realized for the first time. The equipment used is based on alternating sequential projections of left and right eye images on a single tv screen. Two high-speed liquid crystal stereo switches (LCSS) are integrated in glasses and a rapid switching time of 100 microseconds is used. In a comparative study this innovative endoscopic technique was tested for its practicability in sinus surgery and endoscopy of the upper airway. With this equipment an excellent view was obtained of the pharynx, larynx and trachea. For sinus surgery, however, a stereoendoscope with smaller dimensions has to be developed.