[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.

[From reconstruction to function : Hands-on training in tympanoplasty using real-time feedback]. / Von der Rekonstruktion zur Funktion : Tympanoplastik-Training mit Real-Time-Feedback.

BACKGROUND: Surgery of the middle ear requires a very high level of fine motor skills. Due to the increased potential for complications in middle ear operations, it is appropriate to acquire these skills beforehand by operating on a model. OBJECTIVE: How satisfactory is the training on suitable models? Are the skills acquired from working on a model transferable to intraoperative situations? Will the type of model and its use for training influence ear surgery in the future? MATERIAL AND METHODS: Available publications and own experiences with the Dresden tympanoplasty model (DTM) are analyzed and discussed. RESULTS: Although middle ear surgery makes very high demands on the surgeon and there is a significant risk for severe complications to the ear as a sense organ, there are currently very few options to train surgeons in advance. The DTM is a validated training model, which is capable of closing this gap. Due to the possibility of using a real-time feedback variation of the model, the understanding for reconstruction quality and intraoperative acoustic stress can be improved. The translation of the real-time feedback idea into actual middle ear surgery can improve reconstruction quality in the future. CONCLUSION: Training on suitable models is indispensable, especially when training as a surgeon to carry out middle ear operations. Adding another sense perception to the internal and external quality assessment of tympanoplasty by inclusion of the real-time feedback option, can optimize learning and operating processes.

[Development and validation of the Stapesplasty Outcome Test 25 (SPOT-25)]. / Entwicklung und Validierung des Stapesplasty Outcome Test 25 (SPOT-25).

BACKGROUND: Otosclerosis affects health-related quality of life (HRQOL). Until now, measurements have only been performed using audiometric data or non-validated quality of life questionnaires. OBJECTIVE: The objective of this study was to develop the first validated disease-specific HRQOL measuring instrument to determine HRQOL in otosclerosis. MATERIALS AND METHODS: After sequential analysis and item reduction of the initial Stapesplasty Outcome Test 47 (SPOT-47), the SPOT-25 was validated prospectively on 52 otosclerosis patients undergoing stapes surgery. In addition to the overall score, four subscores were defined (hearing function, tinnitus, social restrictions, mental condition). RESULTS: The SPOT-25 showed a high internal consistency (Cronbach's α > 0.7), allowed discrimination between otosclerosis patients and healthy subjects, and demonstrated acceptable test-retest reliability (r = 0.85). After stapes surgery, the HRQOL improved significantly. The responsiveness was high. CONCLUSION: The SPOT-25 is the first validated disease-specific instrument for HRQOL measurement in otosclerosis patients. It should be used routinely for quality control.

[The Vibrant Soundbridge as an active implant in middle ear surgery]. / Die Vibrant Soundbridge als aktives Implantat in der Mittelohrchirurgie.

Implantable hearing aids are not only gaining importance for the treatment of sensorineural hearing loss, but also for treatment of mixed hearing loss. The most frequently used active middle ear implant is the Vibrant Soundbridge (VSB) system (Fa. MED-EL, Innsbruck, Österrreich). Following widening of the spectrum of indications for the VBS, various new coupling systems have been established. Based on the literature, available petrosal bone investigations and finite element model (FEM) calculations, this article summarizes the current knowledge concerning mechanical excitation by the VSB. Important concomitant aspects related to coupling, transmission and measurement are also discussed.

[Development of a computed tomography data-based Vibrant Bonebridge viewer]. / Entwicklung eines CT-Daten-basierten Vibrant-Bonebridge-Viewers.

BACKGROUND: Because of the anatomy of the mastoid and the size of the actuator, positioning of the Vibrant Bonebridge B-FMT can be difficult without prior evaluation of the individual computed tomography (CT) scan of the temporal bone. Development of a user-friendly CT data viewer to enable positioning of the B-FMT in the temporal bone model, whilst identifying individual, potential anatomic conflicts and offering possible solutions could provide a useful tool for preoperative positioning. OBJECTIVES: Aim of the study was to define the requirements of a Vibrant Bonebridge viewer and construct a prototype. MATERIALS AND METHODS: Based on a ZIBAmira software version and inclusion of a B-FMT model upon creation of a model of the temporal bone-which allows the intuitive estimation of individual, anatomic conflicts-a Vibrant Bonebridge viewer was constructed. RESULTS: The segmentation time of the individual digital imaging and communications in medicine (DICOM) data set is about 5 min. Positioning within the individual three-dimensional temporal bone model allows quantitative and qualitative estimation of conflicts (sigmoid sinus, middle cranial fossa) and determination of a preferred position for the B-FMT. Lifting of the B-FMT can be simulated with the help of a virtual washer. CONCLUSION: The Vibrant Bonebridge viewer reliably allows simulation of B-FMT positioning. The clinical value of the viewer still has to be evaluated.

Clinical investigation of flat panel CT following middle ear reconstruction: a study of 107 patients.

OBJECTIVES: After middle ear reconstruction using partial or total ossicular replacement prostheses (PORP/TORP), an air-bone gap (ABG) may persist because of prosthesis displacement or malposition. So far, CT of the temporal bone has played the main role in the diagnosis of reasons for postoperative insufficient ABG improvement. Recent experimental and clinical studies have evaluated flat panel CT (fpCT) as an alternative imaging technique that provides images with high isovolumetric resolution, fewer metal-induced artefacts and lower irradiation doses. METHODS: One hundred and seven consecutive patients with chronic otitis media with or without cholesteatoma underwent reconstruction by PORP (n = 52) or TORP (n = 55). All subjects underwent preoperative and postoperative audiometric testing and postoperative fpCT. RESULTS: Statistical evaluation of all 107 patients as well as the sole sub-assembly groups (PORP or TORP) showed a highly significant correlation between hearing improvement and fpCT-determined prosthesis position. FpCT enables detailed postoperative information on patients with middle ear reconstruction. CONCLUSIONS: FpCT is a new imaging technique that provides immediate feedback on surgical results after reconstructive middle ear surgery. Specific parameters evaluated by fpCT may serve as a predictive tool for estimated postoperative hearing improvement. Therefore this imaging technique is suitable for postoperative quality control in reconstructive middle ear surgery. KEY POINTS: • Flat panel CT offers advantages with regard to artefacts and radiation dose. • FpCT provides higher isovolumetric resolution of temporal bone and middle ear implants. • FpCT allows prediction of the postoperative hearing outcome in patients. • FpCT is an important tool for immediate postoperative quality control. • FpCT improves postoperative management of patients with complications following ossicular replacement.

[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.

[Sinunasal hemangiopericytoma]. / Hämangioperizytom vom sinunasalen Typ.

A 65-year-old female was admitted to hospital for evaluation of recurrent, right-sided sometimes ensanguined, rhinorrhea and epistaxis. Clinical examination revealed a right-sidedunilateral polypoid nasal mass. After endoscopic sinus surgery a sinunasal hemangiopericytoma (SNHPC) was diagnosed. Revision surgery was performed without any residual tumor. To date the patient is free of recurrence. SNHPCs are uncommon neoplasms of vascular origin. The prognosis is mainly determined by initial tumor size and expansion as well as primary complete resection.

[Experimental investigations on middle ear prostheses with an integrated micro joint]. / Experimentelle Untersuchungen zu Mittelohrimplantaten mit integriertem mikromechanischem Gelenk.

BACKGROUND: Quasi static pressure changes as they occur in altitude changes or Valsalva's manoeuvre are causing great tympanic membrane displacements. These can produce a prosthesis dislocation from the stapes footplate, in case of using a TORP for reconstruction. Additionally, prostheses extrusions can occur in the chronically poor ventilated middle ear. Anatomical studies on the ostrich demonstrate that the flexible columella in the avian middle ear provides a good sound transmission and features an effective inner ear protection in pressure changes. MATERIAL AND METHODS: Focusing on this bionic attempt, we designed a new micro joint TORP by interposing a silicone ball joint in the prosthesis shaft. This prototype was used for frequency response measurements with the laser Doppler vibrometer in the ventilated middle ear and under conditions of increased pressure in the external auditory canal. RESULTS: Frequency response measurements showed comparable results to those using a conventional TORP. Investigations on pressure changes in the external auditory canal demonstrated a significant decrease in footplate excursion after reconstruction with the new micro-joint prosthesis then compared to a common TORP. CONCLUSIONS: The insertion of the new silicone bordered micro joint into a TORP shaft provides an effective method to decrease the potentially damaging stapes footplate excursions after complete ossicular reconstruction. Limited deflections of the prosthesis shaft reduce the occurring forces on the stapes footplate as they partly bore the quasi static pressure changes. Thus, the micro joint can reduce the risk of prostheses dislocation and annular ligament damage and is additionally providing a proper sound transmission through the reconstructed middle ear. Moreover, the bionic modification of a TORP reflects the remaining possibilities for further improvements in prosthetic reconstruction.

[Conventional tomographic investigations of the reconstructed middle ear in temporal bone specimen]. / Röntgentomografische Untersuchungen des rekonstruierten Mittelohres am Felsenbeinpräparat.

BACKGROUND: In modern reconstructive middle ear surgery imaging plays an essential role as a diagnostic tool, especially in pre-operative planning. Nowadays imaging of surgical results as a matter of quality control in post-operative follow-up becomes more important. MATERIAL AND METHODS: Conventional tomography was performed in 10 temporal bone specimen using the CommCat IS 2000-system in order to evaluate anatomical structures and inserted middle ear prostheses (PORP/TORP). This imaging technique has not been used in middle ear surgery beforehand. RESULTS: Using conventional tomography characterization of anatomical structures of the temporal bone as e. g. the semicircular canals appeared to be of superior quality to comparable conventional radiographic imaging. Concerning imaging quality (contrast; resolution) conventional tomography allowed similar findings like computed tomography (CT)-scans in some of the investigated specimen while showing inferior sharpness quality due to technical reasons. Further advantages of conventional tomography in contrast to CT were the requirement of just 2.5 % of the CT's irradiation exposure, lack of metallic artefacts caused by implanted prostheses and the feasibility of distance- and angle-measurement of inserted prostheses towards the tympanic membrane which coincided extensively with the temporal bone preparation. CONCLUSIONS: Conventional tomography enables detailed anatomical imaging of the temporal bone region which outperforms conventional radiographic imaging, requires less irradiation dose than CT and helps avoid problems like metallic artefacts. This technique enhances immediate quality-control and seems to be therefore a promising tool for postoperative evaluation after reconstructive middle ear surgery.

[Objective measurement of normal nasality in the Saxony dialect]. / Objektive Messung der normalen Nasalanz im sächsischen Sprachraum.

In the United States of America, the nasometer was developed by Fletcher as an objective method for measuring nasality. There are no accepted normal values for comparable test materials regarding the German language. The aim of this study was the examination of the auditively normal nasality of Saxon-speaking people with the nasometer. The nasalance of 51 healthy Saxon-speaking test persons with auditively normal nasality was measured with a model 6200 nasometer (Kay-Elemetrics, U.S.A.). The text materials used were the vowels "a", "e", "i", "o", and "u", the sentences "Die Schokolade ist sehr lecker" ("The chocolate is very tasty") and "Nenne meine Mama Mimi" ("Name my mama Mimi"), and the texts of "North wind and sun", "A children's birthday", and an arbitrary selection from Strittmatter. The mean nasalance for the vowels was 17.7%, for the sentence containing no nasal sounds 13.0%, and for the sentence containing many nasal sounds 67.2%. The mean value of the texts was 33-41%. The results for the texts agreed well with the results of Reuter (1997), who examined people from the state of Brandenburg. A range from 20% to 55% is suggested as the normal value for nasalance in the German-speaking area.