P. S. Mauz

Acoustomechanical properties of open TTP® titanium middle ear prostheses

OBJECTIVE The purpose of the study was to identify acoustcomechanical properties of various biostable and biocompatible materials to create a middle ear prosthesis with the following properties: (i) improved handling including a good view of the head of the stapes or footplate and adjustable length, (ii) improved acoustical characteristics that are adequate for ossiculoplastic. The identified material should serve to build CE and FDA approved prostheses for clinical use in patients. METHODS Test models made of Teflon, polyetheretherketone, polyethylenterephtalate, polysulfone, gold, Al2O3 ceramics, carbon and titanium were investigated for their potential to fulfill the requirements. Acoustical properties were investigated by laser Doppler velocimetry (LDV) in mechanical middle ear models (MMM). Measured data were fed in to a recently created computer model of the middle ear (multibody systems approach, MBS). Using computer-aided design (CAD) measured and computed data allowed creation and fine precision of titanium prostheses (Tübingen Titanium Protheses, TTP). Their handling was tested in temporal bones. Acoustomechanical properties were investigated using the MBS and mechanical middle ear models. MAIN OUTCOME MEASURES Input impedance, mass, stiffness, and geometry of test models and prostheses were determined. Furthermore, their influence on the intraprosthetic transfer functions and on coupling to either tympanic membrane or stapes was investigated. RESULTS Final results were FDA- and CE-approved filigreed titanium prostheses with an open head that fulfilled the four requirements detailed above. The prostheses (TTP) were developed in defined lengths of between 1.75 and 3.5 mm (partial) and 3.0 and 6.5 mm (total) as well as in adjustable lengths (TTP-Vario). CONCLUSIONS The results suggest acoustomechanical advantages of TTPs because they combine a significantly low mass with high stiffness. In contrast to closed prostheses, the open head and filigreed design allow an excellent view of the prosthesis foot during coupling to the head or footplate of stapes, contributing to an improved intraoperative reliability of prosthesis coupling.

Phase III results with a totally implantable piezoelectric middle ear implant: Speech audiometry, spatial hearing and psychosocial adjustment

Objective To evaluate the treatment efficacy of an electromechanical middle ear amplifier implant (AI) in patients with chronic moderate-to-severe sensorineural hearing loss (SNHL). The AI is a piezoelectric system with a sound processor and a rechargeable battery within a hermetically sealed titanium canister. Its titanium-sealed microphone is placed in the bony region of the ear canal. The incus-coupled transducer (actuator), which is also inside a titanium casing, is fastened to the adjacent bone. Material and Methods This was a phase III study comprising 20 intention-to-treat patients. Telemetrical adjustments followed electromechanical amplifier implantations. We used a word recognition test as our primary efficacy measure (Freiburg Speech Recognition Test; DIN 45621). Secondary efficacy measures were the sentence comprehension test (Goettinger Satztest, 1996) for auditory orientation within noisy and quiet environments and a psychosocial adjustment test (Gothenburg Profile Test, 1998). The 6-month follow-up comprised a complete medical examination. Nineteen patients completed the study (per-protocol patients; 100% reference). Results Seventeen patients (89%) demonstrated improved binaural recognition of phonetically balanced monosyllables. Fourteen postoperative patients (74%) attained a perfect score (100%) on this test, compared to only 3 preoperative patients (16%). Thirteen patients (68%) reached the sentence recognition threshold at a 2:1 dB signal-to-noise ratio during noisy trials. Correct identification of the noise source direction in the horizontal plane occurred in 89% of the trials. The Gothenburg Profile Test scores showed that the subjective evaluation of hearing, orientation, social behavior and self-confidence increased from 48% to 88%. Three patients did not benefit from the implant. Conclusion Treatment of SNHL with a totally implantable hearing system can be an efficient method for those patients unable to wear hearing aids. However, in order to avoid implantation in non-responders, there is a need for more specific audiological indication criteria.

Safe and Reliable Sound Threshold Measures with Direct Vibration of the Ossicular Chain

Objectives: The aim of the study was to evaluate the safety and feasibility of piezoelectric malleus vibration audiometer (MVA), which presents micromechanical vibrations to the umbo membranae tympani.

Comparison of the Implantability of Electronic Hearing Devices in a Virtual Reality Planning Environment and in Human Temporal Bones

Objective —To develop a procedure using a virtual reality (VR) environment that permitted us to simulate the preoperative fitting of an electronic implantable hearing device (IHD) and assess its implantability. Material and Methods —This was an experimental, prospective study based on VR simulations involving the pre- and postoperative comparison of the implantability of an IHD. The preoperative possibility of implanting an IHD in a VR environment was compared with the postoperative implantability of the device in the temporal bones of human cadavers and patients. Study groups were analyzed according to the criteria “VR implantation” and “real surgery” using contingency tables. Results —A computer simulation method based on CT images was developed for the preoperative planning of the implantation. The VR simulation proved feasible in all cases (15 temporal bones and 24 patients). There was no significant difference between the process of implanting the IHD in patients or in the VR environment. These results indicate that VR-based test fittings of an IHD allow prediction of the implantability of an IHD prior to actual surgery. Conclusion —We have described the development of a novel VR procedure for predicting the implantability of hearing devices in otoneurosurgical applications. The VR procedure can be applied universally and may also be used for other parts of the body.

[Influence of exogenic factors on age-related hearing impairment].

BACKGROUND Age-related hearing impairment is a complex disorder, the causes for which have been insufficiently studied. Genetic and environmental factors all play a role. METHODS A total of 406 persons aged between 53 and 67 years old were interviewed about various causes and audiometric data were collected. The audiometric pure tone data were adjusted for sex and age and tested for association with exposure to risk factors. RESULTS Significant negative effects of noise exposure, painkillers, overweight, and cardiovascular diseases on hearing loss were found. A positive effect of moderate alcohol consumption could also be shown in the elderly. These results suggest that a healthy lifestyle can positively affect age-related hearing impairment.ZusammenfassungHintergrundAltersschwerhörigkeit ist eine komplexe Erkrankung, deren Ursachen nur unzureichend erforscht sind. Sowohl genetische als auch Umweltfaktoren spielen eine Rolle.MethodenEs wurden 406 Personen im Alter von 53–67 Jahren zu verschiedenen Ursachen befragt und audiometrisch untersucht. Die audiometrischen Daten wurden nach Geschlecht und Alter bereinigt und auf Assoziationen mit einer Risikofaktorexposition untersucht.ErgebnisseEs konnten signifikante negative Effekte von Lärmexposition, Schmerzmitteln, Übergewicht und Herz-Kreislauf-Erkrankungen auf das Gehör gezeigt werden. Moderater Alkoholgenuss ist mit einem besseren Hörvermögen im Alter assoziiert. Diese Ergebnisse deuten an, dass ein gesunder Lebensstil sich positiv auf Altersschwerhörigkeit auswirken kann.AbstractBackgroundAge-related hearing impairment is a complex disorder, the causes for which have been insufficiently studied. Genetic and environmental factors all play a role.MethodsA total of 406 persons aged between 53 and 67 years old were interviewed about various causes and audiometric data were collected. The audiometric pure tone data were adjusted for sex and age and tested for association with exposure to risk factors.ResultsSignificant negative effects of noise exposure, painkillers, overweight, and cardiovascular diseases on hearing loss were found. A positive effect of moderate alcohol consumption could also be shown in the elderly. These results suggest that a healthy lifestyle can positively affect age-related hearing impairment.

SDF-1/CXCR4 expression is an independent negative prognostic biomarker in patients with head and neck cancer after primary radiochemotherapy

INTRODUCTION Preclinical and clinical data suggest that the chemokine pathway governed by SDF-1 and CXCR4 contributes to a resistant phenotype. This retrospective biomarker study aims to explore the specific prognostic value of SDF-1 and CXCR4 expression in locally advanced head and neck squamous cell carcinomas (HNSCC) treated with primary radiochemotherapy (RT-CT). MATERIAL AND METHODS Biopsies from 141 HNSCC tumours of the oral cavity, oropharynx and hypopharynx were evaluated for SDF-1 and CXCR4 expression by immunofluorescence. SDF-1 and CXCR4 expression was correlated with clinico-pathological characteristics and outcome after RT-CT. RESULTS Patients with tumours exhibiting overexpression of intracellular SDF-1 and CXCR4 have a higher risk for loco-regional relapse and a worse overall survival after RT-CT (multivariate analysis, hazard ratio 2.33, CI [1.18-4.62], p = 0.02 and hazard ratio 2.02, CI [1.13-3.59], p = 0.02, respectively). Similar results were observed when only the subgroup of HPV DNA negative patients were analysed (hazard ratio 2.23 and 2.16, p = 0.02 and p = 0.01, respectively). CONCLUSIONS Our data support the importance of SDF-1 and CXCR4 expression for loco-regional control and overall survival in HNSCC after primary radiochemotherapy. Prospective multivariate validation and further studies into CXCR4 inhibition to overcome radiation resistance are warranted.

Qualitätskontrolle audiologischer Befunde einer universitären phoniatrisch/pädaudiologischen Einrichtung

AIM An investigation was made to reveal whether suspicion of occupational hearing loss can be satisfactorily determined by an otolaryngologist or workplace audiological measurement. These were compared with a formal audiometrical assessment at a university clinic. METHODS AND RESULTS A retrospective study was made of 95 cases of noise induced hearing loss. A total of 78 individuals were investigated by an otolaryngologist and 70 by workplace audiometry. Using workplace audiometry, 27% of the tests showed a reduction in working capacity of at least 20%. In only five of these was a specialist opinion sought within a year. In 50%, this took longer than 5 years. A comparison of audiometric data from expert opinion revealed that there was conformity in only 47% with workplace audiometry and 48% with otolaryngologist testing. In some cases (27% workplace and 33% ENT practice), the measured hearing loss and calculation of disability exceeded that determined by the experts. CONCLUSIONS The results of workplace audiometry demonstrated that hearing loss was frequently reported only after the workers had received a disability of at least 20%. Possible reasons for discrepancies in audiological testing might be the exaggeration of hearing loss by the worker, insufficient recovery time after noise exposure, or inexperienced audiologists. Our data show that audiometric testing in workplace audiometry, as well as in ENT practice, often reveal a higher disability rating compared to formal audiological (university) assessment, even if these discrepancies do not reach statistical significance.