[Recognition function for the Freiburg monosyllabic test in noise with a signal to noise ratio (SNR) of 5 dB]. / Die Verständlichkeitskurve für den Freiburger Einsilbertest im Störschall mit einem Signal-Rausch-Abstand (SNR) von 5 dB.

OBJECTIVE: The Freiburg monosyllabic test (FBE) has been an important German speech audiometry test for years. It is nowadays also used to assess the benefit of hearing aids in noise (FBE-S). This study investigates hearing in noise using the FBE at different sound pressure levels and a signal to noise ratio of 5 dB to generate a recognition curve. METHODS: In autumn 2018, 60 normal-hearing German native speakers (age 18-31 years) participated in the study at the military hospital in Hamburg. Using one FBE test list, speech intelligibility was measured from sound pressure levels of 15 to 90 dB in 5­dB steps with a noise level 5 dB lower in each case. Subsequently, the average of all intelligibility rates and 95% confidence intervals (CI) were determined. RESULTS: Participants comprised 29 female and 31 male subjects. Average age was 24.32 years (±3.29 years). The fixed effects analysis of variance with recognition as the dependent variable demonstrated a highly significant correlation between the levels of sounds/noise and the intelligibility of speech (p < 0.0001). The average intelligibility rates with 95% CI and the frequency distributions were presented tabularly and graphically. CONCLUSION: In comparison to the normative curve, the FBE­S recognition curve is shifted to the right. The average values of the FBE­S reach the saturation area at a volume of 70/65 dB with an intelligibility rate of 90% (for comparison: the point of saturation for 100% intelligibility of the FBE without noise is reached at 55 dB). Using these averaged values of the FBE­S enables better interpretation of individual results without and with hearing aids. In the future, the benefit of hearing aids should be measured at lower noise levels than it is today.

Matrix change of bone grafting substitute after implantation into guinea pig bulla.

BACKGROUND: Many different surgical techniques have been developed to remove open mastoid cavities. In addition to autologous materials, alloplastic substances have been used. A very slow absorption of these materials and extrusion reactions have been reported. We investigated a newly developed, highly porous bone grafting material to eliminate open mastoid cavities, in an animal model. To characterise the transformation process, the early tissue reactions were studied in relation to the matrix transformation of the bone material. MATERIAL AND METHODS: NanoBone (NB), a highly porous bone grafting material based on calcium phosphate and silica, was filled into the open bullae from 20 guinea pigs. The bullae were examined histologically. Energy dispersive X-ray spectroscopy (EDX) was used to investigate the change in the elemental composition at different sampling times. The surface topography of the sections was examined by electron microscopy. RESULTS: After 1 week, periodic acid-Schiffs (PAS) staining demonstrated accumulation of glycogen and proteins, particularly in the border area of the NB particles. After 2 weeks, the particles were evenly coloured after PAS staining. EDX analysis showed a rapid absorption of the silica in the bone grafting material. CONCLUSIONS: NanoBone showed a rapid matrix change after implantation in the bullae of guinea pigs. The absorption of the silica matrix and replacement by PAS-positive substances like glycoproteins and mucopolysaccharides seems to play a decisive role in the degradation processes of NB. This is associated with the good osteoinductive properties of the material.

[Optotensometry for measuring the tube function - a feasibility study on a middle ear model]. / Optotensometrie Langzeitmessung der Tubenfunktion - erste Versuche am Mittelohrmodell.

BACKGROUND: The amount of pressure in the middle ear depends mainly on the function of the Eustachian tube. Currently there are no continuous recording techniques measuring Eustachian tube function in clinical context and under physiological conditions over extended periods of time. In this paper we investigate the suitability of an active optic triangulation method on the basis of a projected laser-point-pattern in measuring tympanic membrane movement during pressure variations in a middle ear model. MATERIAL AND METHODS: For projection we used a green semiconductor laser with an output of 1 mW and a diffractive optical element (DOE). As our measured object we used purple latex-foil (Kimberley-Clark (®)), fixed airtight on the cut-off end of a 2 ml syringe-tube. The movement of the foils was measured by an active optic triangulation method. To simulate pathological variations of the tympanic membrane we prepared the latex-foils in specific ways. One foil was perforated and then covered again (simulating tympanic membrane perforation), another one was partly strengthened by sticking a piece of thick, hard paper to it from the inside (simulating calcification). RESULTS: The test-setup, as well as the appliance of pressure-changes worked fine and measurement of foil movement in all the modified foil surfaces was possible. This shows that it is possible to record foil-movement with this system even in tympanic membranes with pathological variations. CONCLUSIONS: In the course of this study we were able to show that it is possible to assess and record foil movement using a system of optic triangulation and to simulate different tympanic membrane pathologies. This could be used both in ENT medicine, as well as in aviation and diving medicine.

[Acoustic-mechanical trauma during cochleostomy: animal experimental studies]. / Akustisch-mechanisches Trauma während einer Cochleostomie: Tierexperimentelle Untersuchungen.

INTRODUCTION: When performing cochlear implant (CI) surgery in ears with residual hearing, cochlear function should be preserved as far as possible. Besides non-traumatic electrode insertion the acoustic-mechanical trauma of the cochleostomy should be minimized. According to experiences from temporal bone preparations the hypothesis that thorough exposition of the endosteal membrane with the drill prior to opening the cochlea might constitute a bigger acoustic mechanical trauma than direct drilling of the inner ear was examined. These experiments were performed in an animal model. MATERIAL AND METHOD: In 12 guinea pigs the cochlear capsule was exposed by opening the bulla under general anesthesia. In 6 animals the fluid-filled cochlea was exposed by careful unilateral abrasion of the bone, whereas on the other ear cochleostomy was performed by direct penetration drilling into the perilymphatic spaces. Hearing tests were performed before and after drilling by measuring evoked brainstem potentials (brainstem electric response audiometry, BERA). In 8 other guinea pig ears abrasive exposition of the cochlea was performed again by only softly touching the otic capsule with the running burr for 10 s. After a hearing test the drilling maneuver was repeated 4 times collectively. Thereby the inner ear was gradually opened from the surface but not deeper into the cochlear lumen. A total of 4 guinea pig ears treated with a single abrasion of 10 s were used as controls. Brain stem measurements were performed accordingly. RESULTS: Hearing loss was lower after a quick direct and deep penetration of the cochlea in comparison to a longer, less invasive opening of the inner ear. Hearing thresholds ascended depending on the duration of the drilling procedure. CONCLUSION: The results support the hypothesis that prolonged drilling of exposed inner ear structures causes more acoustical damage than a direct cochleostomy with the drill.

Detection of tympanic membrane movement using film patch with integrated strain gauge, assessed by optical coherence tomography: experimental study.

OBJECTIVE: We report an ex vivo and in vivo experimental study of a device designed to measure tympanic membrane movement under normal and pathological conditions, assessed using optical coherence tomography. MATERIALS AND METHODS: We designed two types of flexible, round film patch with integrated strain gauge, to be attached to the tympanic membrane in order to measure tympanic membrane movement. Tympanic membrane attachment was assessed using optical coherence tomography. The devices were tested experimentally using an ex vivo model with varying middle-ear pressure. RESULTS: Optical coherence tomography reliably assessed attachment of the film patch to the tympanic membrane, before and after middle-ear pressure changes. Strain gauge voltage changes were directly proportional to middle-ear pressure recordings, for low pressure changes. Tympanic membrane perforations smaller than 2 mm could be sealed off with the film patch. CONCLUSION: Attachment of the film patch with integrated strain gauge to the tympanic membrane was not ideal. Nevertheless, the strain gauge was able to precisely detect small pressure changes within the middle ear, in this experimental model.

[Tensometry - development of a measurement technique of the tube function in a temporal bone model]. / Tensometrie - Entwicklung eines Langzeitmessverfahrens der Tubenfunktion am Felsenbeinpräparat.

OBJECTIVE: Middle ear pressure depends widely on the function of the eustachian tube. Tube dysfunction is often a trigger for middle ear diseases like chronic otitis media but also for barotrauma. Patients with impaired tubal function should not be exposed to situations with extreme pressure changes. Until today, there is no valid examining method for long-time measuring of the development of middle ear pressure. MATERIAL AND METHODS: The basic idea was to develop a thin flexible film with integrated strain gauges made of platinum and gold, which can be applied directly on the surface of the tympanic membrane. Using these, shifts or distensions of the tympanic membrane in a temporal bone model can be measured and documented. RESULTS: We were able to show that the measuring system was sensitive enough to register pressure variations in the middle ear volume of a temporal bone model. While using a full bridge design of the strain gauge resistors it could be shown that the measuring voltage of the strain gauges were in phase of the pressure measurement curve or according to the positioning in opposite phase. In single resistor mode the measurement were not so positioning depended. Measuring tympanic membrane movement in case of perforation was feasible. CONCLUSIONS: To improve the longtime stability of the strain gauge film the next development step will be to make a new design with Konstantan resistors (CU-Ni-Mn). After a testing period, longtime measurements in clinical studies will follow.

Vibroplasty involving direct coupling of the floating mass transducer to the oval window niche.

OBJECTIVE: To demonstrate the technique and clinical application of vibroplasty in which the floating mass transducer component of the Vibrant Soundbridge implant is coupled directly to the oval window niche, in patients with a mobile stapes footplate but a malformed or destroyed stapes suprastructure. METHODS: The underlying concept was to create a soft tissue casing for the floating mass transducer, while also firmly connecting the transducer to a small, solid cartilage 'plunger' attached to the stapes footplate. This was realised by removing almost all the cartilage from a larger piece of cartilage-perichondrium, leaving only a tiny cartilage island about half a millimetre in diameter, attached to a much wider 'blanket' of perichondrium. RESULTS: By coupling the floating mass transducer directly to the oval window niche, patients' speech understanding was improved. Post-operative aided thresholds of 30-40 dB HL were achieved by all patients. CONCLUSIONS: In patients with mixed hearing loss combined with a destroyed stapes suprastructure but a mobile stapes footplate, we describe the coupling of the floating mass transducer component of a Vibrant Soundbridge to the stapes footplate, as an alternative to coupling to the round window.

[Investigation of a new highly porous hydroxyapatite matrix for obliterating open mastoid cavities - application in guinea pigs bulla]. / Untersuchung von hochporösem Knochenaufbaumaterial zur Mastoidhöhlenobliteration- Intrabulläre Applikation beim Meerschweinchen.

BACKGROUND: Many different techniques for obliterating open mastoid cavity have been described. The results after the application of alloplastic materials like Hydroxyapatite and Tricalciumphosphate were poor due to long-lasting resorption. Extrusion of those materials has been described. We investigated the applicability of a new high-porosity ceramic for obliterating large open mastoid cavities and tested it in an animal model (bulla of guinea pig). METHODS: A highly porous matrix (NanoBone) bone-inductor fabricated in a sol-gel-technique was administered unilaterally into the opened bullae of 30 guinea pigs. In each animal the opposite bulla was filled with Bio-Oss, a bone substitute consisting of a portion of mineral bovine bone. Histological evaluations were performed 1, 2, 3, 4, 5 and 12 weeks after the implantation. RESULTS: After the initial phase with an inflammatory reaction creating a loose granulation tissue, we observed the formation of trabeculare bone within the fourth week in both groups. From the fifth week on we found osteoclasts on the surface of NanoBone and Bio-Oss with consecutive degradation of both materials. CONCLUSION: In our animal model study we found beneficial properties of the used bone-inductors NanoBone and Bio-Oss for obliterating open mastoid cavities.

[Myxoma of the middle ear-a rare cause of facial palsy]. / Das Myxom des Mittelohrs als mögliche Ursache einer temporären Fazialisparese.

In case of the co-occurrence of facial palsy and inflammation-like symptoms of the same ear, the differential diagnosis is focused on viral (herpes zoster) or bacterial diseases. We report a patient for whom the surgical exploration of the middle ear revealed a benign tumor: a myxoma. These neoplasias are rare tumors in the head and neck region. The typical tumor site is the atrium of heart. In the ear, the tumor grows slowly and remains asymptomatic unless it irritates structures such as the facial nerve or the vestibular organ. Histologically, the tumor presents a "myxoid" matrix that is rich in acid mucopolysaccarides. The treatment of choice is complete surgical resection. Using the case presented, we discuss the causality between the tumor and the facial palsy, although during the operation the bony canal of the nerve was found to be intact. In any cases with clinically and radiologically unclear findings of the ear in connection with facial palsy, surgical exposure should be considered.

[Arrosion bleeding of the brachiocephalic trunc - a late complication after percutaneous dilatative tracheostomy in a patient with a cervical rib abnormality]. / Letale Blutung aus dem Truncus brachiocephalicus - Spätkomplikation nach Fehleinschätzung eines Dilatationstracheostomas bei rudimentärer Halsrippe.

BACKGROUND: In the last years percutaneous dilatative tracheostomy was increasingly established in many intensive care units, mostly performed by the anesthesiologists. This method becomes problematic, when it is used in patients requiring long time intubation. It must always be kept in mind that in the course of further rehabilitation the patients may be treated by persons, who are not familiar with the altered anatomy of the upper airways. This bears the risk for severy complications, like bleeding from major vessels. CASE REPORT: Letal arrosion bleeding of the brachiocephalic trunc was observed in a patient, 3 weeks after percutaneous dilatative tracheostomy (technique by Griggs). As an abnormality the patient had a cervical rib. The wrong position of the tracheostomy tube was not noticed because the patient had no dyspnoea, spontaneously breathing through the nose and mouth instead of through the tracheostomy tube. CONCLUSIONS: Particularly in patients requiring long-time intubation it is essential that the tube can be changed safely. We advocate an "epithelialized" tracheostoma with tracheocutaneous anastomosis for these patients. If the position of the tracheostomy tube is not clear, endoscopic control has to be performed.

[The "ancient schwannoma". A rare tumor of the mouth floor]. / Das "ancient schwannoma". Die seltene Form eines Mundbodentumors.

"Ancient schwannomas" of the mouth floor are rare, benign neoplasms derived from the nerve sheath of peripheral nerves. They show many degenerative changes such as necrosis and vascular thrombosis. Ancient schwannomas show histopathological features, such as degenerative changes and atypical nuclei, and may easily be confused with malignant neoplasms. B-scan sonography for the mouth floor and MRT imaging may be helpful in differential diagnosis. Here, we report on a patient with ancient schwannoma of the floor of the mouth.

[Extramedullary plasmocytoma of the left tonsil. A rare cause of tonsillar asymmetry]. / Extramedulläres Plasmozytom der linken Tonsille. Eine seltene Ursache der Tonsillenasymmetrie.

The plasmocytoma is a tumor, which can only rarely be found in the oropharynx. In this respective case an asymmetria of the tonsils was caused by an extramedullary plasmocytoma. Even if the asymmetria of the tonsils has a harmless nature, a tumor growth always has to be considered when thinking of the differential diagnosis. First of all, squamous-cell carcinoma has to be taken into account, more rarely with malignant lymphoma. Tonsillektomie added by immunhistological examination of the preparation brings diagnostic certainty.