Surgical anatomy of the round windowImplications for cochlear implantation

BackgroundThe round window is an important portal for the application of active hearing aids and cochlear implants. The anatomical and topographical knowledge about the round window region is a prerequisite for successful insertion for a cochlear implant electrode. Objective of reviewTo sum up current knowledge about the round window anatomy and to give advice to the cochlear implant surgeon for optimal placement of an electrode. Type of reviewSystematic Medline search. Search strategySearch term round window[Title] with no date restriction. Only publications in the English Language were included. All abstracts were screened for relevance, that is a focus on surgical anatomy of the round window. The search results were supplemented with hand searching of selected reviews and reference lists from included studies. Evaluation methodSubjective assessment. ResultsThere is substantial variability in size and shape of the round window. The round window is regarded as the most reliable surgical landmark to safely locate the scala tympani. Factors affecting the optimal trajectory line for atraumatic electrode insertion are anatomy of the round window, the anatomy of the intracochlear hook region and the variable orientation and size of the cochlea's basal turn. ConclusionsThe very close relation to the sensitive inner ear structures necessitates a thorough anatomic knowledge and careful insertion technique, especially when implanting patients with residual hearing. In order to avoid electrode migration between the scalae and to achieve protect the modiolus and the basilar membrane, it is recommended to aim for an electrode insertion vector from postero-superior to antero-inferior

Implantable hearing aids

Strictly speaking, implantable hearing aids are technical systems that process audiological signals and convey these by direct mechanical stimulation of the ossicular chain or cochlea. They have certain benefits over conventional hearing aids in terms of wearing comfort and general acceptance. As current studies lack convincing audiological results, the indications for implantable hearing aids are primarily of medical or cosmetic nature. To date, three systems are available in Germany: Vibrant Soundbridge (R), Carina (R), and Esteem (R). Because the performance of the different implantable and nonimplantable hearing systems together with various surgical procedures are currently undergoing major changes, audiological indications may also develop in the future

Intraductal pressure during sialendoscopy

Background: Sialendoscopy can be followed by swelling and infection of the salivary gland. A possible pathomechanism is damage of the deeper salivary duct system by intraductal pressure generated by the irrigation fluid. Method: After measuring the physiological intraductal pressures which arise during sialendoscopy, these pressures were simulated in freshly excised salivary glands and the tissue was analysed histologically. Results: Normal intraductal filling pressure during sialendoscopy is 100-250 daPa, and pressure peaks can be up to 2000 daPa during flushing. A filling pressure of more than 400 daPa results in dilatation of the salivary ducts and acinar area. No direct damage to any duct structures could be observed histologically. Conclusion: Irrigation fluid should be administered intermittently rather than continuously during sialendoscopy. The intraductal filling pressure should not exceed 400 daPa to minimise the trauma to the salivary duct system and reduce the risk of developing oedema and inflammation

Prognosis of Surgically Treated Primary Parotid Gland Cancer - an Evaluation of 231 Cases

Objective: We present our results on the prognosis of parotid gland cancer with the help of a group of patients who were treated in a standardised manner and received a long term follow-up. Material and Methods: We retrospectively analysed the clinicopathological data of 231 patients with a surgically treated primary parotid gland cancer and calculated survival parameters. The mean follow-up time was 52 months. Results: The 5- and 10-year overall survival rate was 74.2 % and 66.9 %. 70 patients got a locoregional recurrence, 18.6% of those even after more than 5 years. Initial facial nerve palsy was a significant negative prognostic indicator for the disease-free survival. The most frequent histological subtypes could be divided into 3 prognostic groups with significant differences in the survival. The pathological tumour stage was a prognostic indicator for a worse overall and disease-free survival. The pT-stage, the pN-stage and the existence of distant metastases were independent prognostic factors. Conclusions: The group of patients is mainly characterised by the large size, the standardised therapy and the long follow-up time. We could show that the facial nerve palsy is a severe negative prognostic factor. For practical purpose, the classification into 3 histological subgroups seemed to be of great help. This should be considered in patient follow-up. Due to the amount of late recurrences, we propose a follow-up time longer than 5 years. We propose standardized surgery including total parotidectomy in combination with neck dissection

The pressure-equalizing function of the Eustachian tube. Evaluation in a hypo-/hyperbaric pressure chamber

Background. The Eustachian tube connects the tympanic cavity (cavum tympani) and the nasopharynx, and enables pressure equalization between the middle ear and ambient pressure. Functional pressure compensation is very important for flying and diving in particular, due to non-physiologically large pressure differences. Objective. Evaluation of the pressure-equalizing function of the Eustachian tube is still a clinical challenge. This review article evaluates the existing data. Methods. Based on a selective literature search, different methods for evaluation of tube function are presented and evaluated, with special reference to evaluation of the pressure-equalizing function in a hypo-/hyperbaric pressure chamber. Results. The pressure chamber enables the dynamics of active and passive pressure compensation to be provoked and also permits accurate measurement of pressures in the millibar range. Conclusion. A pressure chamber seems to be suitable to evaluate Eustachian tube function and therapeutic approaches to tube dysfunction. Further studies are needed to assess the value of the pressure chamber in combination with other functional tests

Generation Y in ENT. Leading a young generation of doctors

Background. The shortage of qualified doctors and nurses has led to a competition between hospitals. Analyzing the circumstances of the competition, nurses and doctors of so-called generation Y are important. These employees are mainly female and have different requirements compared to previous generations. Therefore, knowledge of these requirements will become a critical success factor for hospitals in the future. Method. We interviewed medical students in Kiel and Hannover from 2005 to 2011 about the clinical department chosen, the criteria for choosing a specific clinic, and the importance of MD and PhD programs. In addition, we conducted an internet and Medline search for scientific studies on labor shortage, generation Y, and demographics. The data were sorted by main categories and relevance for hospitals. Statistical analyses were performed using descriptive measures. Results. We received 1,097 answers which represents approx. 75% of all students. Sixty-seven percent of the students were female, 33% male. Preferences for departments revealed internal medicine, pediatrics, and anesthesiology as the top three. ENT followed at rank 10. The main criteria for choosing a clinic were working climate, structure and broadness of education, family friendliness, and respect. MD programs were rated 2.6, while PhD programs were rated 3.6. Staff members of Generation Y live while working and disagree with hierarchies. Internet and computers are part of their daily routine. Conclusion. Employees of Generation Y challenge leadership in hospitals by increasing demands. However, Generation Y can increase professionalization and competitiveness for hospitals significantly

Reliability of Eustachian tube function measurements in a hypobaric and hyperbaric pressure chamber

ObjectivesMeasurement of the Eustachian tube (ET) function is a challenge. The demand for a precise and meaningful diagnostic tool increasesespecially because more and more operative therapies are being offered without objective evidence. The measurement of the ET function by continuous impedance recording in a pressure chamber is an established method, although the reliability of the measurements is still unclear. MethodsTwenty-five participants (50 ears) were exposed to phases of compression and decompression in a hypo- and hyperbaric pressure chamber. The ET function reflecting parametersET opening pressure (ETOP), ET opening duration (ETOD) and ET opening frequency (ETOF)were determined under exactly the same preconditions three times in a row. The intraclass correlation coefficient (ICC) and Bland and Altman plot were used to assess test-retest reliability. ResultsICCs revealed a high correlation for ETOP and ETOF in phases of decompression (passive equalisation) as well as ETOD and ETOP in phases of compression (active induced equalisation). Very high correlation could be shown for ETOD in decompression and ETOF in compression phases. The Bland and Altman graphs could show that measurements provide results within a 95% confidence interval in compression and decompression phases. ConclusionsWe conclude that measurements in a pressure chamber are a very valuable tool in terms of estimating the ET opening and closing function. Measurements show some variance comparing participants, but provide reliable results within a 95% confidence interval in retest. This study is the basis for enabling efficacy measurements of ET treatment modalities

Acoustic effects of a superior semicircular canal dehiscence: a temporal bone study

A dehiscence of the superior semicircular canal is said to be responsible for a number of specific and unspecific ear symptoms and possible a conductive hearing loss of up to 40 dB. As in vivo a dehiscence would not be opened against air, but is naturally patched with dura and the brain, it was our aim to investigate the effects of an superior semicircular canal dehiscence on the air conduction hearing in fresh human temporal bones with different boundary conditions. At ten fresh human temporal bones, we investigated the transmission of sound energy through the middle and inner ear using a round window microphone and laser Doppler vibrometer for perilymph motions inside the dehiscence. After baseline measurements, the superior semicircular canal was opened. We investigated the change of the transfer function when the canal is opened against air (pressure equivalent water column), against a water column and when it is patched with a layer of dura. Opening the superior semicircular canal resulted in a loss of sound transmission of maximal 10-15 dB only in frequencies below 1 kHz. When covering the dehiscence with a water column, the conductive hearing component was reduced to 6-8 dB. Placing a dura patch on top of the dehiscence resulted in a normalization of the transfer function. If our experiments are consistent with the conditions in vivo, then superior semicircular canal dehiscence does not lead to an extensive and clinically considerable conductive air conduction component