PURPOSE: Endoscopic ear surgery has become a popular operative approach to treat middle ear diseases. Surgeons use either 0° or 30° endoscopes worldwide. The main aim of the work was to compare the properties of these two types of endoscopes. MATERIAL AND METHODS: Since this type of evaluation is hard to perform in vivo during the actual surgery, we designed 3D printed temporal bone models with different levels of complexity. The evaluation of endoscopes was based on image analysis or visibility of anatomical structures. RESULTS: The results show that a 30° endoscope offers a view of lateral walls from 4 mm distance, contrary to a 0° endoscope which cannot see lateral walls from this distance at all. On the other hand, visible area of the anterior wall is up to 40 % larger using 0° endoscope, compared to 30° endoscope. Angled endoscope distorts the picture and leads to the deterioration of the image. At commonly used distances above 5 mm from middle ear structures, resolution and image distortion is comparable between both endoscopes. CONCLUSIONS: Our results do not offer a definitive opinion on which endoscope is better for ear surgery. Both types of endoscopes have advantages and disadvantages, and the choice depends on the surgeon's personal preference and on the type of planned procedure.

Department of Computer Science Faculty of Science Palacky University Olomouc 17 listopadu 12 Olomouc 779 00 Czech Republic

Department of Medical Biophysics Faculty of Medicine and Dentistry Palacky University Olomouc Hnevotinska 3 Olomouc 775 15 Czech Republic

Department of Otorhinolaryngology and Head and Neck Surgery Faculty of Medicine and Dentistry Palacky University Olomouc and University Hospital Olomouc Zdravotniku 7 Olomouc 779 00 Czech Republic

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