Reconstructive methods in hearing disorders - surgical methods

Restoration of hearing is associated in many cases with resocialisation of those affected and therefore occupies an important place in a society where communication is becoming ever faster. Not all problems can be solved surgically. Even 50 years after the introduction of tympanoplasty, the hearing results are unsatisfactory and often do not reach the threshold for social hearing. The cause of this can in most cases be regarded as incomplete restoration of the mucosal function of the middle ear and tube, which leads to ventilation disorders of the ear and does not allow real vibration of the reconstructed middle ear. However, a few are also caused by the biomechanics of the reconstructed ossicular chain. There has been progress in reconstructive middle ear surgery, which applies particularly to the development of implants. Implants made of titanium, which are distinguished by outstanding biocompatibility, delicate design and by biomechanical possibilities in the reconstruction of chain function, can be regarded as a new generation. Metal implants for the first time allow a controlled close fit with the remainder of the chain and integration of micromechanical functions in the implant. Moreover, there has also been progress in microsurgery itself. This applies particularly to the operative procedures for auditory canal atresia, the restoration of the tympanic membrane and the coupling of implants. This paper gives a summary of the current state of reconstructive microsurgery paying attention to the acousto-mechanical rules

Die Nanowelt des Hörens

Engineers and physicians alike are impressed by the micromechanics of the human hearing organ with its broad dynamic range. Sound waves which pass the external ear are transformed into mechanical vibrations in the middle ear and than transferred to the inner ear fluid. The vibrations of the inner ear structures lead to an evoked nerve potential which stimulates the hearing areas in the brain. Nowadays, vibration patterns in the nanometre range are detectable in the smallest middle and inner ear structures by laser Doppler vibrometry measurements. This paper demonstrates how multidisciplinary research at the Technische Universität Dresden has furthered knowledge of the mechanical dynamic processes in the hearing organ. The results influence also clinical investigations concerning new middle and inner ear implants.Das menschliche Hörorgan ist für Mediziner und Ingenieure gleichermaßen ein mikromechanisches Wunderwerk mit großem Dynamikbereich. Schallwellen werden vom äußeren Ohr aufgenommen, im Mittelohr in mechanische Schwingungen umgewandelt und an das flüssigkeitsgefüllte Innenohr weitergeleitet. Erst dort erfolgt die Umwandlung der Schwingungsprozesse in ein elektrisches Signal, welches mehrfach verarbeitet an das Gehirn weitergeleitet wird. In den letzten Jahren ist es gelungen, Schwingformen des Mittel- und Innenohres im Nanometerbereich nach akustischer Anregung sichtbar zu machen. Als entscheidendes Messinstrument ist dabei das Laser-Doppler- Vibrometer zum Einsatz gekommen. Die vorliegende Arbeit zeigt beispielhaft, wie sich anhand dieser an der TU Dresden interdisziplinär durchgeführten Untersuchungen das bisherige Bild von den mechanischen Vorgängen des Ohres verändert hat und wie diese Erkenntnisse direkt in die klinische Medizin und Implantatentwicklung übernommen werden konnten

Imaging the tympanic membrane oscillation ex vivo with Doppler optical coherence tomography during simulated Eustachian catarrh

Recently, optical coherence tomography (OCT) was utilized in multiple studies for structural and functional imaging of the middle ear and the tympanic membrane. Since Doppler OCT allows both, the spatially resolved measurement of the tympanic membrane oscillation and high-resolution imaging, it is regarded as a promising tool for future in vivo applications. In this study, Doppler OCT is utilized for the visualization of the tympanic membrane oscillation in temporal bones with simulated Eustachian catarrh, which was realized by generating a depression in the tympanic cavity. The transfer function, meaning the oscillation amplitude normalized to the applied sound pressure, is measured frequency resolved in the range from 0.5 kHz to 6 kHz and with a lateral spatial resolution of 0.4 mm. Typical oscillation patterns could be observed in case of ambient pressure in the tympanic cavity. Under depression the characteristic oscillation patterns were observed with widely congruent appearance but at higher frequencies

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. We present an in-depth statistical analysis of 478 data sets of middle ear transfer functions (METFs) from different laboratories. The data sets are preprocessed and various contributions to the variance of the data are evaluated. We then derive a statistical range as a reference against which individual METF measurements may be validated. The range is calculated as the two-sided 95% tolerance interval at audiological frequencies. In addition, the mean and 95% confidence interval of the mean are given as references for assessing the validity of a sample group. Finally, we provide a suggested procedure for measuring METFs using the methods described herein

Site of cochlear stimulation and its effect on electrically evoked compound action potentials using the MED-EL standard electrode array

<p>Abstract</p> <p>Background</p> <p>The standard electrode array for the MED-EL MAESTRO cochlear implant system is 31 mm in length which allows an insertion angle of approximately 720°. When fully inserted, this long electrode array is capable of stimulating the most apical region of the cochlea. No investigation has explored Electrically Evoked Compound Action Potential (ECAP) recordings in this region with a large number of subjects using a commercially available cochlear implant system. The aim of this study is to determine if certain properties of ECAP recordings vary, depending on the stimulation site in the cochlea.</p> <p>Methods</p> <p>Recordings of auditory nerve responses were conducted in 67 subjects to demonstrate the feasibility of ECAP recordings using the Auditory Nerve Response Telemetry (ART™) feature of the MED-EL MAESTRO system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation.</p> <p>Results</p> <p>Findings show significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function have been observed. The refractory time shows an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions.</p> <p>Conclusions</p> <p>Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex.</p> <p>Trial registration</p> <p>The Clinical Investigation has the Competent Authority registration number DE/CA126/AP4/3332/18/05.</p

The German cochlear implant registry : one year experience and first results on demographic data

Purpose: Clinical registries have great potential for quality control of medical procedures regarding the indications, therapeutic processes and results, including their possible complications. This is particularly true when providing patients with severe hearing loss or deafness with a cochlear implant (CI). This treatment represents a lifelong care process that requires continuous quality control over time. On the initiative of the Executive Committee of the German Society of Otorhinolaryngology (Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e.V., DGHNO-KHC), a national German CI registry (Deutsches Cochlear Implant Register, DCIR) was established in January 2022. This article focuses on the first demographic and baseline data of the DCIR. Methods: The DCIR covers the complete therapeutic process from indication, surgery, fitting and lifelong aftercare in CI therapy. By the end of 2022, 75 hospitals in Germany had agreed to contribute to the DCIR. Results: During the year 2022, 63 hospitals actively contributed data to the DCIR. Pseudonymized data from 2,292 CI implantations (2,176 primary implantations, 99 explantations with immediate re-implantations and 17 re-implantations following an earlier explantation) in 2,108 patients were documented. Cochlear implantation was accomplished in 1,807 adults (≥ 18 years) and 301 children ( 85 years. From the total of 2,292 implantations, 226 (9.9%) were performed as simultaneous bilateral implantations (CI implantation in both ears of 113 patients on the same day of surgery) and 412 implantations (19.1% of 2,162 implantations with data provided on the contralateral ear’s hearing status) were in patients with single sided deafness (normal hearing in the contralateral ear). In addition, the reported complications in 2022 were also evaluated. Seven reports (0.4%) of mild to moderate severe facial nerve dysfunctions were documented. No reports of severe or total facial nerve dysfunction (House-Brackmann grade V/VI), meningitis or death related to CI therapy were documented. Conclusion: Although still in the start-up phase, these initial DCIR data already provide an interesting first insight into the demographic structure and baseline data of CI therapy in Germany. The successful implementation of the DCIR represents an important step towards continuous quality control of CI care

Struktur und Einrichtung des Deutschen Cochlea-Implantat-Registers (DCIR)

Abstract Hearing rehabilitation of patients with severe hearing loss or deafness using cochlear implants (CI) is a very successful but also complex and lifelong process that requires high quality standards for structure, process, and results. Medical registries represent an ideal tool for conducting quality control relevant to care while at the same time collecting scientific data. Therefore, at the initiative of the Executive Committee of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery (DGHNO-KHC), a Germany-wide CI registry (the German Cochlear Implant Register, DCIR) was to be established. The following goals were to be achieved: 1) legal and contractual basis for the register; 2) definition of the register contents; 3) development of evaluation standards (hospital-specific and national annual reports); 4) development of a logo; 5) practical operation of the registry. After defining a catalog of services that defines the content, structure, and operation of the DCIR, a registry operator with audiological expertise was sought. After considering various offers, the registry was technically implemented in cooperation with the provider INNOFORCE (Ruggell, Liechtenstein) as registry operator. This also included the realization of an interface for data transfer from previously existing databases and development of a data protection concept for productive operation of the DCIR under the scientific leadership of the DGHNO-KHC Executive Committee. Since January 2022, it has been possible for participating hospitals to enter pseudonymized data into the DCIR. To date, 75 hospitals in Germany have contractually agreed to participate in the registry. During the first 15 months, data from over 2500 implants in over 2000 patients were registered in the DCIR. The work presented here describes the structuring, development, and successful establishment of the DCIR. Introduction of the DCIR represents an important milestone of future scientifically based quality control in CI care. The registry presented here can therefore be considered as an example for other areas of medical care and thus also sets an international standard

Konzeption und Implementierung eines Zertifizierungssystems zur Qualitätssicherung der Cochlea-Implantat-Versorgung in Deutschland

A standardized and structured process is indispensable for optimal hearing rehabilitation with cochlear implants (CI). The Executive Committee of the German Society of Otorhinolaryngology, Head and Neck Surgery (DGHNO-KHC), initiated the conception of a certification program and a Whitepaper based on the Association of the Scientific Medical Societies in Germany (AWMF) clinical practice guideline (CPG) describing the current medical standards of CI care in Germany. The goal was to independently confirm implementation of this CPG and make this information publicly available. With the support of an independent certification organization, successful implementation of the CI-CPG by a hospital would then be verified and confirmed by awarding the “Cochlear implant-provision institution” ( Cochlea-Implantat-versorgende Einrichtung , CIVE) quality certificate. A structure for implementation of a certification system was developed based on the CI-CPG. The following steps were required: 1) conception of a quality control system for certification of hospitals working in accordance with the CI-CPG; 2) development of required structures for an independent review of quality-relevant structure, process, and result parameters; 3) development of a standard procedure for independent certification of hospitals; 4) development of a certificate and a logo to demonstrate successful certification; 5) practical implementation of the certification. Following design of the certification program and the required organizational structure, the certification system was successfully launched in 2021. Applications for the quality certificate could be formally submitted from September 2021. A total of 51 off-site evaluations were performed by December 2022. In the first 16 months from introduction, 47 hospitals were successfully certified as CIVE. In this period, 20 experts were trained as auditors, who have since then carried out 18 on-site audits in hospitals. In summary, the conceptual design, structure, and practical implementation of a certification program for quality control in CI care was successfully implemented in Germany

Conception and implementation of a certification system for quality control of cochlear implant treatment in Germany. German version

Zusammenfassung Ein standardisierter und strukturierter Versorgungsprozess ist unabdingbare Voraussetzung für eine optimale Hörrehabilitation mit einem Cochlea-Implantat (CI). Auf Initiative des Präsidiums der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V. (DGHNO-KHC) sollte auf Basis der aktuellen AWMF-Leitlinie (Arbeitsgemeinschaft Medizinisch-Wissenschaftlicher Fachgesellschaften), die den einheitlich in Deutschland geltenden medizinischen Standard in der CI-Versorgung beschreibt, ein Weißbuch erstellt und ein Zertifizierungssystem eingeführt werden, um die Umsetzung dieser Leitlinie standardisiert einrichtungsbezogen zu überprüfen und öffentlich zugänglich zu machen. Unter Einbindung einer unabhängigen Zertifizierungsorganisation sollte den beantragenden Kliniken durch die Erteilung des Qualitätszertifikats „Cochlea-Implantat-versorgende Einrichtung“ (CIVE) die erfolgreiche Umsetzung der Leitlinien- und Weißbuchinhalte bescheinigt werden können. Auf Grundlage der CI-Leitlinie wurde eine Struktur zur Umsetzung eines Zertifizierungsprogramms erarbeitet. Folgende Schritte waren hierzu notwendig: 1. Konzeption eines Qualitätssicherungssystems zur Zertifizierung leitlinienkonform arbeitender Kliniken; 2. Entwicklung der notwendigen Strukturen zur unabhängigen Überprüfung qualitätsrelevanter Struktur‑, Prozess- und Ergebnisparameter; 3. Erarbeitung eines Standardablaufs zur unabhängigen Zertifizierung von Kliniken; 4. Entwicklung eines Zertifikats und eines Logos zum Nachweis einer erfolgreichen Zertifizierung, 5. praktische Implementierung des Zertifizierungssystems. Nach Konzeption des Zertifizierungsprogramms, dessen Systematik und der dazugehörigen Organisationsstruktur wurde das Zertifizierungssystem 2021 erfolgreich eröffnet. Anträge zur Erteilung des Qualitätszertifikats CIVE konnten ab September 2021 formal gestellt werden. Bis Dezember 2022 wurden insgesamt 51 Offsite-Prüfungen durchgeführt. In den ersten 16 Monaten seit der Einführung wurden 47 Kliniken erfolgreich als CIVE zertifiziert. Im genannten Zeitraum konnten 20 Fachexperten als Gutachter geschult werden, die bis Dezember 2022 bereits 18 Vor-Ort-Prüfungen (Onsite-Audits) in Kliniken durchführten. Zusammenfassend konnte die Konzeptionierung, Strukturierung und praktische Umsetzung eines Zertifizierungssystems zur Qualitätssicherung in der CI-Versorgung für Deutschland erfolgreich umgesetzt werden.Abstract A standardized and structured process is indispensable for optimal hearing rehabilitation with cochlear implants (CI). The Executive Committee of the German Society of Otorhinolaryngology, Head and Neck Surgery (DGHNO-KHC), initiated the conception of a certification system and a Whitepaper based on the Association of the Scientific Medical Societies in Germany (AWMF) clinical practice guideline (CPG) describing the current medical standards of CI care in Germany. The goal was to independently confirm implementation of this CPG and make this information publicly available. With the support of an independent certification organization, successful implementation of the CI-CPG by a hospital would then be verified and confirmed by awarding the “Cochlear implant-provision institution” ( Cochlea-Implantat-versorgende Einrichtung , CIVE) quality certificate. A structure for implementation of a certification system was developed based on the CI-CPG. The following steps were required: 1) conception of a quality control system for certification of hospitals working in accordance with the CI-CPG; 2) development of required structures for an independent review of quality-relevant structure, process, and result parameters; 3) development of a standard procedure for independent certification of hospitals; 4) development of a certificate and a logo to demonstrate successful certification; 5) practical implementation of the certification. Following design of the certification system and the required organizational structure, the certification system was successfully launched in 2021. Applications for the quality certificate could be formally submitted from September 2021. A total of 51 off-site evaluations were performed by December 2022. In the first 16 months from introduction, 47 hospitals were successfully certified as CIVE. In this period, 20 experts were trained as auditors, who have since then carried out 18 on-site audits in hospitals. In summary, the conceptual design, structure, and practical implementation of a certification system for quality control in CI care was successfully implemented in Germany