A novel multipurpose modular mini-endoscope for otology.

Transtympanic access to the round window membrane (RWM) for drug delivery is in the focus of otology and has stimulated development of various endoscopes. These endoscopes are tasked to enable best visualization at a low diameter and to offer a working channel for various instruments. The specific aspect of sterilization is a major issue especially in regard to the diameter of the endoscope with its integrated working channel. We evaluated a new multi-purpose modular semi-rigid optical fiber endoscope (10,000 pixel resolution) for minimal invasive middle ear endoscopy focusing on access to the RWM and micro instruments in 12 cadaver specimens. Microscopic visualization was compared to endoscopy. With the modular mini ear endoscope (MMEE) we were able to visualize the RWM in 3 specimens directly and in 8 specimens after removal of a mucous membrane using micro instruments. A bony overhang prevented visualization of the RWM in one case. The endoscope enabled minimal invasive RWM access initially in a higher number of cases compared to microscope investigation. The designed MMEE is suited to access transtympanic the round window membrane even in situations of an obstructed round window niche. The modular concept of the endoscope is attractive for different types of indications, various instruments and with regard to the aspects of sterilization. Experiences in humans are the next necessary step to define the possible role of this endoscope in otology.