Feasibility Study of a Mechanical Real-Time Feedback System for Optimizing the Sound Transfer in the Reconstructed Middle Ear

Abstract

Objective: To evaluate electromechanical excitation as an alternative excitation mode for middle ear transfer function (METF) measurements as well as real-time feedback in prosthetic ossicular reconstruction. Method: In eight human cadaveric temporal bones, the ossicular chain was excited using acoustic and mechanical (floating mass transducer, FMT) stimulation to determine the METF. After disconnecting the ossicular chain and reconstruction with partial or total prosthesis the METFs were measured again. Continuous FMT stimulation was then applied to improve the prosthesis’ position using real-time feedback of the METF. Results: Mechanical stimulation of ossicular vibration showed characteristic differences to acoustic excitation resulting from the force characteristics of the FMT. Furthermore, the interspecimen METF variability was greater with electromechanical than acoustic stimulation because of interspecimen variability in the FMT coupling conditions. When the METF with FMT excitation was used as a real-time feedback tool, a measurable improvement in the quality of ossicular reconstruction could be achieved. Conclusions: Mechanical excitation is an effective and suitable alternative stimulation method in experimental METF measurements. The system provides real-time feedback for ossicular reconstruction in the experimental setting. Some influencing factors still need to be distinguished for reliable measurements. However, the method does not yet meet the requirements for clinical application as an intraoperative, real-time monitoring tool. However, the system could be an excellent model for high-end cadaveric temporal bone training in ossiculoplasty.

Evaluation of Vibrant® Soundbridge™ positioning and results with laser doppler vibrometry and the finite element model

“…A micromanipulator was used to focus the helium-neon laser on the target (squares of foil of 0.5 mm 2 with reflective polystyrene microbeads). The sound generator (insert earphone, eartone 3A) was inserted into the ear canal and the probe microphone (ER7c; Ethymotic Research Inc.) positioned through an extra opening in the external ear canal next to the eardrum for reference measurements (16).…”

Prevalence of GJB2 gene mutations correlated to presence of clinical and environmental risk factors in the etiology of congenital sensorineural hearing loss of the Romanian population

“…The etiology of congenital SNHL entails environmental, clinical and genetic factors. Hearing disorders also were significantly associated with the presence of maternal pathologies but not with other prenatal or environmental factors such as radiation, or use of illegal drugs (34,35).…”

Materials for ossicular chain reconstruction: History and evolution (Review)

“…another parameter to consider in evaluating the functional results of oCr is the appearance of uncontrollable situations, since even optimally positioned prothesis can migrate post-operatively and dislocate from the adjacent structures (malleus handle, tM or stapes). thus, the human factor becomes paramount, as the surgeon should achieve optimal functional results by placing the prosthesis properly, which is also dependent on experience, anatomy and a number of other uncontrollable factors (14,15). From a practical and experimental point of view, the most useful parameter to measure in order to obtain the quality control of a prosthesis is the middle ear transfer function which, ideally, is determined by directly measuring stapes velocity in response to a constant sound pressure at the tM using a trans-mastoid or trans-tegmen approach (14).…”