Noise exposure of the inner ear during robotic drilling.

Introduction: Preserving the cochlear structures and thus hearing preservation, has become a prominent topic of discussion in cochlear implant (CI) surgery. Various approaches and soft surgical techniques have been described when approaching the inner ear. Robot-assisted cochlear implant surgery (RACIS) reaches the round window in a minimally invasive manner by following a trajectory of minimal trauma.

Influence of inner ear impedance on middle ear sound transfer functions.

Introduction: For experimental studies on sound transfer in the middle ear, it may be advantageous to perform the measurements without the inner ear. In this case, it is important to know the influence of inner ear impedance on the middle ear transfer function (METF). Previous studies provide contradictory results in this regard.

Auditory thresholds compatible with optimal speech reception likely evolved before the human-chimpanzee split.

The anatomy of the auditory region of fossil hominins may shed light on the emergence of human spoken language. Humans differ from other great apes in several features of the external, middle and inner ear (e.g.

Multimodal additive manufacturing of biomimetic tympanic membrane replacements with near tissue-like acousto-mechanical and biological properties.

The three additive manufacturing techniques fused deposition modeling, gel plotting and melt electrowriting were combined to develop a mimicry of the tympanic membrane (TM) to tackle large TM perforations caused by chronic otitis media. The mimicry of the collagen fiber orientation of the TM was accompanied by a study of multiple funnel-shaped mimics of the TM morphology, resulting in mechanical and acoustic properties similar to those of the eardrum. For the different 3D printing techniques used, the process parameters were optimized to allow reasonable microfiber arrangements within the melt electrowriting setup.

Real-time monitoring of middle ear prosthesis coupling.

Introduction: In reconstructive middle ear surgery, acoustic quality has received a high level of attention in recent years. Careful intraoperative selection and positioning of passive middle ear prostheses during tympanoplasty with ossiculoplasty is essential to ensure satisfactory sound transmission and postoperative hearing outcome. The reconstruction quality of the ossicular chain (OC) can be evaluated intraoperatively using a surgical assistance system which is based on a real-time monitoring system (RTM system) that acquires the transmission (middle ear transfer function (METF)) with electromagnetic excitation of the OC.

microstructural investigation of the human tympanic membrane by endoscopic polarization-sensitive optical coherence tomography.

Significance: Endoscopic optical coherence tomography (OCT) is of growing interest for diagnostics of the tympanic membrane (TM) and the middle ear but generally lacks a tissue-specific contrast.

Aim: To assess the collagen fiber layer within the TM, an endoscopic imaging method utilizing the polarization changes induced by the birefringent connective tissue was developed.

Approach: An endoscopic swept-source OCT setup was redesigned and extended by a polarization-diverse balanced detection unit.

Methods and reference data for middle ear transfer functions.

Human temporal bone specimens are used in experiments measuring the sound transfer of the middle ear, which is the standard method used in the development of active and passive middle ear implants. Statistical analyses of these experiments usually require that the TB samples are representative of the population of non-pathological middle ears. Specifically, this means that the specimens must be mechanically well-characterized.

Influence of the Coupling on the Hearing Outcome After Implantation of an Active Middle Ear Implant: Comparison of the Transmission Behavior in Temporal Bone Experiments With Clinical Data.

Objectives: The active middle ear implant, Vibrant Soundbridge (VSB), can be implanted with a variety of couplers. Hearing outcome after implantation has been investigated in both temporal bone (TB) experiments and patient studies, but the relationship between experimental and clinical data is still weak in the literature. Therefore, experimental data from TB experiments should be compared with patient data in a retrospective study, in which the floating mass transducer is used with couplers of the third generation.

Development of electrospun, biomimetic tympanic membrane implants with tunable mechanical and oscillatory properties for myringoplasty.

Most commonly, autologous grafts are used in tympanic membrane (TM) reconstruction. However, apart from the limited availability and the increased surgical risk, they cannot replicate the full functionality of the human TM properly. Hence, biomimetic synthetic TM implants have been developed in our project to overcome these drawbacks.

Measurement of middle ear transfer function in temporal bones using electromagnetic excitation: Comparison to sound excitation and evaluation of influencing factors.

Hearing a sound produces vibrations of the ossicles in the middle ear, which can be measured in the micrometer to nanometer range. Destruction of middle ear structures results most commonly from chronic inflammatory diseases. In these cases, passive and active middle ear implants are used for reconstruction of the ossicular chain.

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

The etiology of hearing loss originates from genetic factors and includes several other events including infections, working or living environment, as well as several endocrine and metabolic disorders. The Vibrant Soundbridge (VSB) is an implantable hearing aid whose floating mass transducer (FMT) is attached to the long process of the incus. The device is used for pure sensorineural hearing loss with an intact middle ear.

[Coupling of active middle ear implants-biomechanical aspects].

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.

Biomimetic Tympanic Membrane Replacement Made by Melt Electrowriting.

The tympanic membrane (TM) transfers sound waves from the air into mechanical motion for the ossicular chain. This requires a high sensitivity to small dynamic pressure changes and resistance to large quasi-static pressure differences. The TM achieves this by providing a layered structure of about 100µm in thickness, a low flexural stiffness, and a high tensile strength.

Fully Implantable Active Middle Ear Implants After Subtotal Petrosectomy With Fat Obliteration: Preliminary Clinical Results.

Objectives: In patients with chronic middle ear disease, especially after revision surgery for ventilation problems and mixed hearing loss, active middle ear implants may provide an alternative treatment option. The fully implantable active middle-ear implant (FI-AMEI) is designed for implantation in a ventilated mastoid with an intact posterior canal wall. Until now, there have been no reports on audiometric results after implantation of a FI-AMEI in a fat-obliterated cavity after subtotal petrosectomy (SPE).

Endoscopic Optical Coherence Tomography for Evaluation of Success of Tympanoplasty.

Objective: After tympanoplasty, it is often challenging to differentiate between different causes of a remaining air bone gap (ABG). Optical coherence tomography (OCT) offers a new approach for combined morphologic and functional measurements of the tympanic membrane and adjacent parts of the middle ear. Thus, it provides valuable diagnostic information in patients with a reduced sound transfer after middle ear surgery.

Sensor-actuator component for a Floating Mass Transducer-based fully implantable hearing aid.

We propose a novel system based on the Floating Mass Transducer (FMT) to be used as the active component of a fully implantable, Vibrant Soundbridge-like middle ear implant. The new system replaces the external microphone used in the currently available design with an implantable piezoelectric sensor that is inserted into the incudostapedial joint and picks up the vibrations transmitted to the long process of the incus. The FMT is coupled to the round window of the cochlea.

Vibroplasty combined with tympanic membrane reconstruction in middle ear ventilation disorders.

Although the Vibrant Soundbridge is one of the most frequently used active middle ear implants, data regarding how middle ear ventilation disorders may affect the transmission behavior of its floating mass transducer are still insufficient. Studies involving coupling the floating mass transducer to the stapes head are particularly lacking. This temporal bone study evaluated the influence of simulated middle ear ventilation disorders on the middle ear transfer function in the reconstructed middle ear.

Static and dynamic forces in the incudostapedial joint gap.

Dynamic pressure at the tympanic membrane is transformed and subsequently transferred through the ossicular chain in the form of forces and moments. The forces are primarily transferred to the inner ear. They are transferred partly to the stapedial annular ligament which exhibits non-linear behavior and stiffens for larger static forces.

Endoscopic optical coherence tomography with wide field-of-view for the morphological and functional assessment of the human tympanic membrane.

An endoscopic optical coherence tomography (OCT) system with a wide field-of-view of 8 mm is presented, which combines the image capability of endoscopic imaging at the middle ear with the advantages of functional OCT imaging, allowing a morphological and functional assessment of the human tympanic membrane. The endoscopic tube has a diameter of 3.5 mm and contains gradient-index optics for simultaneous forward-viewing OCT and video endoscopy.

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

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.

Function, Applicability, and Properties of a Novel Flexible Total Ossicular Replacement Prosthesis With a Silicone Coated Ball and Socket Joint.

Hypothesis: A total ossicular replacement prosthesis (TORP) with a silicone coated ball and socket joint (BSJ) is able to compensate pressure changes and therefore provide better sound transmission compared with rigid prostheses.

Background: Dislocation and extrusion are known complications after TORP reconstruction, leading to revisions and recurrent hearing loss. Poor aeration of the middle ear, scar tension, and static pressure variations in conjunction with rigid prosthesis design causes high tension at the implant coupling points.

A New Intraoperative Real-time Monitoring System for Reconstructive Middle Ear Surgery: An Experimental and Clinical Feasibility Study.

Hypothesis: Electromagnetical excitation of ossicular vibration is suitable for middle ear transmission measurements in the experimental and clinical setting. Thereby, it can be used as a real-time monitoring system for quality control in ossiculoplasty.

Background: Positioning and coupling of middle ear prosthesis are a precondition for good postoperative hearing results, but at the same time completely dependent upon the surgeon's subjective judgment during surgery.

Adaptive Mechanical Stabilization of a Free-Floating Fully Implantable Hearing Aid.

Hypothesis: An implantable acousto-mechanical transducer will yield a higher output if its mass can be virtually increased through the use of a secondary actuator.

Background: Current hearing aids and implants rely on feedback compensation to prevent instability (e.g.

Impact of Prosthesis Length on Tympanic Membrane's and Annular Ligament's Stiffness and the Resulting Middle Ear Sound Transmission.

Hypothesis: Prosthesis' length creates tension in ossicular reconstructions, which directly effects the middle ear sound transmission.

Background: Relatively long prostheses are often used to stabilize the middle ear reconstruction to prevent dislocation. Thereby, tension on the flexible components such as the tympanic membrane (TM) and the annular ligament (AL) is increased.