Experimentelle Untersuchungen zur statischen Belastung der Fußplatte bei Rekonstruktion des Schalleitungsapparates

Fehlerm�glichkeiten bei der Ossikelkettenrekonstruktion

Today, the reconstruction of the ossicular chain is standard in middle ear surgery. It is performed as a one step procedure in cases of non-inflamed middle ears, as well as in cases of chronic ear diseases. In contrast to the past, a large tympanic cavity is today regularly reconstructed, which contributes to a normally ventilated middle ear. Reconstruction of the ossicular chain is necessary to keep the tympanic membrane in its normal position.However, many modern prostheses are available with different designs and material properties. This article aims to give an overview of the acusto-mechanical and surgical aspects of ossicular chain reconstruction. After a description of normal middle ear vibration, the biomechanical background of the reconstructed middle ear (incus reconstruction, stapes reconstruction) is discussed.

Inner ear damage in TORP-operated ears: experimental study on danger from environmental air pressure changes

In some cases of sudden inner ear hearing loss in ears with a total ossicular replacement prosthesis, the prosthesis has been found to be penetrating the footplate. Some authors have assumed an external pressure increase for this event. In this study I tried to estimate experimentally the pressure needed for perforating a normal footplate in a temporal bone model. From the data I concluded that "cracking" the footplate can hardly be due to 1 major event of increased pressure. On the other hand, different mechanisms making the footplate a "weak spot" must be discussed and further investigated. In those cases, secondary to thinned or even perforated footplates, environmental pressure changes may be dangerous.