Middle Ear Dissection

The middle ear is found within the center of the os temporale and bears a highly complex anatomy. The most contiguous structures are the facial (FN), the cochlea (CO), the ossiculary chain (OC), the vena jugularis bulb (JVB), and therefore the internal arteria carotis (ICA). The middle ear cleft is anatomically divided in five parts: the epitympanum is found superiorly, and is interconnected by the antrum to the mastoid air cell system MACS the retrotympanum posterior may be a system of bony bridges and more or less shallow sinuses; inferiorly lies the hypotympanum; anteriorly is that the protympanum with its connection to the Eustachian tube; and in the center, lies the mesotympanum. The physiological access through the external auditory meatus (EAC) is narrow. Therefore, the quality surgical approach to the center ear requires a retroauricular incision and therefore the drilling of the MACS. These kinds of interventions are performed using an operating microscope. Its introduction was a milestone in otologic surgery, since it allowed the treatment of the microscopic tympanic cavity structures. However, the microscope features a forced straight view and a few areas, especially the sinus tympani, are difficult to access. This bears the danger of residual disease especially during cholesteatoma surgery. Moreover, healthy tissues of the EAC, MACS, and tympanic cavity need to be removed simply for access purposes. This not only extends the operating time, but also accounts for more surgical morbidity and a prolonged healing time.