[Coupling of active middle ear implants-biomechanical aspects]. / Ankopplung aktiver Mittelohrimplantate ­ biomechanische Aspekte.

Active middle ear implants or implantable hearing aids are used to treat sensorineural or combined hearing loss. Their coupling to the middle ear structures has a large impact on the success of rehabilitation. Practical issues such as the coupling site, influence of middle ear status, and forward and backward excitation of the inner ear are discussed in the context of biomechanics. For this purpose, experimental studies, model simulations, and current literature data are evaluated. The explanations are intended to contribute to a better understanding of certain procedures in hearing rehabilitation with active implants.

[Active hearing implants in chronic otitis media]. / Aktive Hörimplantate bei chronischer Otitis media.

In patients with inadequate hearing improvement after tympanoplasty and failure of conventional hearing aid fitting, active hearing implants provide an alternative treatment option. Active middle ear implants function as a vibromechanical bypass of the stiffness and damping effect of a poorly oscillating tympanic membrane and the (reconstructed) ossicular chain. The selection of the hearing system depends on the maximum output levels of the hearing system and the anatomical conditions in mostly multiply operated ears. The development of variable coupling elements for active middle ear implants led to an extension of the indications to include not only purely sensorineural hearing loss but also mixed and conductive hearing loss in patients, as the transducer can now be coupled to the (mobile) stapes or the round window membrane. The article provides an overview of current clinical study results and recommendations on the indications for active hearing implants in patients with chronic otitis media.

[Evaluation of the Dresden Tympanoplasty Model (DTM)]. / Evaluation des Dresdner Tympanoplastik Modells (DTM).

The training of microsurgical motor skills is essentiell for surgical education if the interests of the patient are to be safeguarded. In otosurgery the complex anatomy of the temporal bone and variations necessitate a special training before performing surgery on a patient. We therefore developed and evaluated a simplified middle ear model for acquiring first microsurgical skills in tympanoplasty.The simplified tympanoplasty model consists of the outer ear canal and a tympanic cavity. A stapes model is placed in projection of the upper posterior tympanic membrane quadrant at the medial wall of the simulated tympanic cavity. To imitate the annular ligament flexibility the stapes is fixed on a soft plastic pad. 41 subjects evaluated the model´s anatomical analogy, the comparability to the real surgical situation and the general model properties the using a special questionnaire.The tympanoplasty model was very well evaluated by all participants. It is a reasonably priced model and a useful tool in microsurgical skills training. Thereby, it closes the gap between theoretical training and real operation conditions.

[A new model for training in tympanoplasty]. / Entwicklung eines Tympanoplastik-Trainingsmodells.

BACKGROUND: Functional simulation of middle ear reconstruction is a valuable tools for training in otosurgery. We introduce a new experimental model which provides a direct acoustic feedback of the functional quality of ossicular chain reconstruction. METHOD: In this model the tympanic membrane and the ossicular chain have to be reconstructed for proper sound transmission to an artificial inner ear receptor. The received signal is converted into acoustic information and consecutively provided via headphone. RESULTS: Any changes in the reconstruction (e. g. tilting the prosthesis) can be experienced online and immediately optimized by the surgeon or a trainee. CONCLUSION: The experimental model can be used for demonstration and training in otosurgery. This model is also suitable for comparing measurements of transfer functions in a calibrated version and can be applied to development and critical evaluation of middle ear prostheses.