Association between upper and lower respiratory disease among patients with primary ciliary dyskinesia: an international study.

Introduction: Nearly all patients with primary ciliary dyskinesia (PCD) report ear-nose-throat (ENT) symptoms. However, scarce evidence exists about how ENT symptoms relate to pulmonary disease in PCD. We explored possible associations between upper and lower respiratory disease among patients with PCD in a multicentre study. Methods: We included patients from the ENT Prospective International Cohort (EPIC-PCD). We studied associations of several reported ENT symptoms and chronic rhinosinusitis (defined using patient-reported information and examination findings) with reported sputum production and shortness of breath, using ordinal logistic regression. In a subgroup with available lung function results, we used linear regression to study associations of chronic rhinosinusitis and forced expiratory volume in 1 s (FEV1) accounting for relevant factors. Results: We included 457 patients (median age 15 years, interquartile range 10-24 years; 54% males). Shortness of breath associated with reported nasal symptoms and ear pain of any frequency, often or daily hearing problems, headache when bending down (OR 2.1, 95% CI 1.29-3.54) and chronic rhinosinusitis (OR 2.3, 95% CI 1.57-3.38) regardless of polyp presence. Sputum production associated with daily reported nasal (OR 2.2, 95% CI 1.20-4.09) and hearing (OR 2.0, 95% CI 1.10-3.64) problems and chronic rhinosinusitis (OR 2.1, 95% CI 1.48-3.07). We did not find any association between chronic rhinosinusitis and FEV1. Conclusion: Reported upper airway symptoms and signs of chronic rhinosinusitis associated with reported pulmonary symptoms, but not with lung function. Our results emphasise the assessment and management of upper and lower respiratory disease as a common, interdependent entity among patients with PCD.

When age is not an obstacle: A case series of endoscopic transsphenoidal resection of pituitary macroadenomas in older patients.

Due to the increase in life expectancy, the number of elderly patients suffering from a pituitary macroadenoma is expected to increase in the future. The endoscopic endonasal transsphenoidal (EET) approach tends to be the first choice for the treatment of pituitary macroadenomas in the general population. Notwithstanding, in the geriatric population, the goals of management for this condition remain unclear. The present study retrospectively evaluated and describes the cases of 6 patients >70 years of age with a pituitary macroadenoma who were treated by a skull base team, composed of one ENT surgeon and one neurosurgeon. All the patients experienced a notable improvement in their neurological deficit, while their hormonal status also improved or at least did not deteriorate after the surgery. The EET approach appears to be a safe and effective approach for the treatment of pituitary macroadenomas in the geriatric population.

Characteristics of Otologic Disease Among Patients With Primary Ciliary Dyskinesia.

Importance: Otologic disease is common among people with primary ciliary dyskinesia (PCD), yet little is known about its spectrum and severity. Objective: To characterize otologic disease among participants with PCD using data from the Ear-Nose-Throat Prospective International Cohort. Design, Setting, and Participants: This cross-sectional analysis of baseline cohort data from February 2020 through July 2022 included participants from 12 specialized centers in 10 countries. Children and adults with PCD diagnoses; routine ear, nose, and throat examinations; and completed symptom questionnaires at the same visit or within 2 weeks were prospectively included. Exposures: Potential risk factors associated with increased risk of ear disease. Main Outcomes and Measures: The prevalence and characteristics of patient-reported otologic symptoms and findings from otologic examinations, including potential factors associated with increased risk of ear inflammation and hearing impairment. Results: A total of 397 individuals were eligible to participate in this study (median [range] age, 15.2 [0.2-72.4] years; 186 (47%) female). Of the included participants, 204 (51%) reported ear pain, 110 (28%) reported ear discharge, and 183 (46%) reported hearing problems. Adults reported ear pain and hearing problems more frequently when compared with children. Otitis media with effusion-usually bilateral-was the most common otoscopic finding among 121 of 384 (32%) participants. Retracted tympanic membrane and tympanic sclerosis were more commonly seen among adults. Tympanometry was performed for 216 participants and showed pathologic type B results for 114 (53%). Audiometry was performed for 273 participants and showed hearing impairment in at least 1 ear, most commonly mild. Season of visit was the strongest risk factor for problems associated with ear inflammation (autumn vs spring: odds ratio, 2.40; 95% CI, 1.51-3.81) and age 30 years and older for hearing impairment (41-50 years vs ≤10 years: odds ratio, 3.33; 95% CI, 1.12-9.91). Conclusion and Relevance: In this cross-sectional study, many people with PCD experienced ear problems, yet frequency varied, highlighting disease expression differences and possible clinical phenotypes. Understanding differences in otologic disease expression and progression during lifetime may inform clinical decisions about follow-up and medical care. Multidisciplinary PCD management should be recommended, including regular otologic assessments for all ages, even without specific complaints.

Sinonasal disease among patients with primary ciliary dyskinesia: an international study.

Background: Sinonasal symptoms are a common feature of primary ciliary dyskinesia (PCD); however, literature about their severity and frequency, particularly during the life course, is scarce. Using baseline data from the Ear, nose and throat (ENT) Prospective International Cohort of PCD patients, we describe sinonasal disease in PCD. Methods: We included participants who had a routine sinonasal examination during which they completed a symptoms questionnaire. We compared frequency of reported symptoms and examination findings among children and adults, and identified characteristics potentially associated with higher risk of sinonasal disease using ordinal regression. Results: 12 centres contributed 384 participants; median age was 16 years (IQR 9-22), and 54% were male. Chronic nasal problems were the most common feature, reported by 341 (89%). More adults (33; 24%) than children (10; 4%) described hyposmia. Quality of life was moderately affected by rhinosinusitis among 136 participants with completed SNOT-22 questionnaires (median score 31; IQR 23-45). Examinations revealed nasal polyps among 51 of 345 participants (15%) and hypertrophic inferior nasal turbinates among 127 of 341 participants (37%). Facial pain was detected in 50 of 342 participants (15%). Nasal polyps, hypertrophic turbinates, deviated septum and facial pain were found more commonly in adults than children. The only characteristic associated with higher risk of sinonasal disease was age 10 years and older. Conclusions: Based on our findings, regular sinonasal examinations are relevant for patients with PCD of all ages. There is a need for improved management of sinonasal disease supported by evidence-based guidelines.

Comparison of the endoscopic endonasal to microscopic sublabial transsphenoidal approach in a case series of pituitary macroadenomas.

For a number of years, the microscopic sublabial transsphenoidal (MST) approach was considered the gold standard approach for the treatment of pituitary macroadenomas. Nonetheless, the trend is currently shifting away from the MST to the endonasal transsphenoidal (EET) approach. The aim of the present study was to examine the post-operative outcomes of the first cases operated by a team of two young surgeons using the EET approach, compared to the cases operated by a team of senior neurosurgeons with extensive experience with the MST approach. For this purpose, data from 20 patients with pituitary adenoma were retrospectively collected from a single center who were operated by the current and previous pituitary-surgery teams. All the patients who presented with visual impairment in the EET group recovered completely (5/5), whereas 4/5 patients in the MST group recovered completely. Primary hospitalization duration was similar in the two groups. Gross tumor removal was achieved in 90% of patients in the EET group compared to 70% of the patients operated with the MST technique. Intraoperative complications were comparable between the two groups. The first cases operated at the center with EET proved to have better visual outcomes and a larger tumor removal when compared to the MST group. A greater experience in using this technique could exponentiate the differences in the post-operative outcomes, such as a lower hospitalization duration and fewer intraoperative complications. On the whole, colleagues who have yet to familiarize themselves with the EET approach could perhaps be encouraged to learn to utilize this technique, provided that their center is staffed with an experienced team of skull base surgeons to intervene in an intraoperative complication.

Cervical Diffuse Idiopathic Skeletal Hyperostosis: Rare Cause of Emergency Tracheostomy.

Diffuse idiopathic skeletal hyperostosis (DISH) is a rare and potentially life-threatening syndrome. We present the case of a patient complaining about severe dyspnoea and diagnosed with vocal cord paresis. An emergency tracheotomy was performed to restore his breathing. Diagnostic imaging revealed large mass-occupying cervical osteophytes compressing the larynx. The osteophytes were removed via an anterior cervical approach, and vital signs were normalized. However, postoperatively, a fistula was discovered between the upper part of the oesophagus and the trachea. As a result, a gastrostomy tube had to be placed indefinitely. Literature review confirms the rare frequency of emergency tracheostomy due to DISH syndrome. The aim of the present study is to expand on our knowledge of a rare pathological entity that can frequently be misdiagnosed.

Study protocol: the ear-nose-throat (ENT) prospective international cohort of patients with primary ciliary dyskinesia (EPIC-PCD).

INTRODUCTION: Primary ciliary dyskinesia (PCD) is a rare, genetic, multiorgan disease with an estimated prevalence of 1 in 10 000. It affects mainly the upper and lower airways due to impaired mucociliary clearance. Almost all patients have sinonasal or otologic (ear-nose-throat, ENT) problems, although the ENT clinical phenotype may present great variability. Despite that, data on PCD ENT manifestations are scarce and based on small single-centre studies. To date, we know little about the spectrum and severity of PCD ENT disease, its association with lung disease, its course over life and its determinants of prognosis.This study protocol describes the aims and methods of the first prospective, observational, multinational cohort study focusing on ENT disease in patients with PCD. METHODS AND ANALYSIS: The ENT prospective international cohort of patients with PCD (EPIC-PCD) is a prospective standardised observational clinical cohort set up as a multinational multicentre study, embedded into routine patient care. It aims to longitudinally characterise ENT disease in patients with PCD and its association with lung disease, and to identify determinants of its prognosis. Patients of all ages, diagnosed with PCD who undergo an ENT clinical assessment at least once a year at one of the participating centres will be invited to participate. Collected data include diagnostic test results, results of ENT examinations, lung function measurements, information on management of ENT disease and patient-reported data on clinical symptoms and health-related quality of life (QoL). Data are collected using the standardised PCD-specific FOLLOW-PCD form and the validated QoL-PCD questionnaire. ETHICS AND DISSEMINATION: The study has been reviewed and approved by the Human Research Ethics Committees at all participating centres, based on local legislation. The results of the study will be published in scientific journals, presented at scientific conferences and disseminated to participants and national patient organisations. TRIAL REGISTRATION: NCT04611516.

The diagnostic value of computed tomography in delayed complications after cochlear implantation.

BACKGROUND: Delayed complications after cochlear implant (CI) surgery can result in the need for revision surgery. Temporal bone computed tomography (tCT) is frequently used in the diagnostic work-up for these patients. AIMS/OBJECTIVES: We aimed to test for the value of tCT in delayed complications after CI surgery. MATERIAL AND METHODS: Retrospective chart review including all patients with CI who were consecutively enrolled in our academic tertiary care centre and received a tCT due to delayed complications between January 2008 and December 2017. RESULTS: A total of 85 patients with a mean age of 28 years at CI surgery were identified. Mean time between CI and tCT was 4.3 years. Reasons for performance of tCT were device malfunction (20%), cephalgia (20%), scalp hematoma/seroma (15.3%), device failure (11.8%), vertigo (10.6%), local infection (7.1%), trauma (5.9%), meningism (3.5%), tinnitus (3.5%) and facial palsy (2.4%). No abnormalities in tCT were detected in 82.4%. However, an abnormal tCT was a predictor for surgical therapy (p < .001). CONCLUSIONS AND SIGNIFICANCE: We recommend the performance of tCT in CI patients with delayed complications to identify or rule out pathology in order to choose the most ideal and relevant individual treatment.

Otolaryngology in the COVID-19 pandemic era: the impact on our clinical practice.

PURPOSE: To give an overview of the current knowledge about COVID-19 pandemic and its impact on otolaryngology clinical practice. METHODS: Recent findings about SARS-CoV-2 virus and the COVID-19 infection it causes are reviewed. In addition to international databases and in the absence of hard scientific data, literature search included reports published online from scientific societies and other institutions. RESULTS: The role of anosmia as a COVID-19-related symptom is presented. Further, considerations about steroid administration in ENT-related conditions are also discussed. Due to the close work with mucosa surfaces of the upper aerodigestive tract, otolaryngologists and surrounding staff are considered high risk for coronavirus transmission. Hence, staff protection measures for ENT examinations, surgeries and other procedures during COVID-19 pandemic are recommended. CONCLUSION: Knowledge and evidence about the impact of COVID-19 infection on otolaryngology clinical practice are accumulating rapidly. Additionally to patient's management, safety of health care professionals should be a main goal right now by following strict safety guidelines.

Preservation of Vestibular Function and Residual Hearing After Round Window Cochlear Implantation.

OBJECTIVE: To examine the possible correlation between the loss of short-term residual hearing and vestibular function after cochlear implantation (CI). STUDY DESIGN: Retrospective patient review. SETTING: Academic tertiary referral center. PATIENTS: One hundred twenty patients with normal vestibular function (VF) in the caloric testing and residual hearing (RH) at the frequencies 250, 500, and 1000 Hz on the surgery side between 2008 and 2016 were included in the study. INTERVENTION: Primary CI on the first side via round window with a conventional full-length electrode. MAIN OUTCOME MEASURES: Changes of RH and VF 7 weeks after surgery were analyzed. Preservation of RH was defined as measurable postoperative thresholds at the frequencies 250, 500, and 1000 Hz in the pure-tone audiogram. Preservation of the VF after CI was assessed both by an absolute and relative threshold in the caloric testing. RESULTS: Seven weeks after implantation, the preservation of RH was achieved in 52 (43.3 %) patients and the preservation of VF in 95 (79.2 %) patients on the operated side. There was no significant statistical correlation between these two parameters. CONCLUSION: The loss of RH was more than twice as frequent as the loss of VF. However, no statistical correlation between the failure of the two inner ear functions was found. The exact causes are still unknown, but our data could give an indication that there may be different underlying pathomechanisms.

Aberrant internal carotid artery in the middle ear: the duplication variant.

Vascular variants concerning the internal carotid artery (ICA) at the skull base level are rare. Correct workup and diagnosis in case of suspicion of such a variant are important as it mimics glomus tumours and could complicate myringotomy or middle ear surgery. We report a case of a 39-year-old woman presented with a 6-month history of right pulsatile tinnitus and aural fullness. Ear microscopy examination revealed a pale red pulsatile mass anterior to the umbo. Radiological assessment using CT and MRI/magnetic resonance angiography confirmed the diagnosis of an aberrant ICA. Interestingly, a duplication of the ICA was demonstrated, in which the enlarged inferior tympanic artery presented as the aberrant ICA, whereas a narrower collateral hypoplastic native ICA was also present. A conservative approach with regular follow-up appointments was recommended.

Cochlear implantation after canal wall down mastoidectomy - Outcomes after partial mastoid obliteration.

OBJECTIVE: To describe and evaluate the partial mastoid obliteration of the so-called radical mastoid cavity after canal-wall down mastoidectomy (CWD) for cochlear implantation (CI) compared to overclosure of the external ear canal as two stage procedures. METHODS: Out of 1020 patients undergoing cochlear implantation between January 1st, 2003 and June 15th, 2016 at the Department of Otolaryngology, Head & Neck Surgery, University Hospital Cologne, eight patients underwent obliteration of the radical cavity prior to cochlear implantation. In four additional patients, the external ear canal was overclosed prior to cochlear implantation. RESULTS: Patients undergoing partial mastoid obliteration (five ♀, 4 left ears) and overclosure of the external ear canal (one ♀, 3 left ears) averaged 56years and 61years, respectively. The radical cavities had been present for 21.8years on average before partial obliteration and for 19.5years before overclosure. Cochlear implantation following mastoid obliteration was performed after a mean period of 5.1months and 3.8months after overclosure. After partial mastoid obliteration, complete insertion of all electrodes was achieved and the clinical courses were uneventful for all patients. Likewise, no patient revealed any complications after overclosure of the external ear canal. CONCLUSION: Partial mastoid obliteration with bone paté and cartilage after canal wall down mastoidectomy can be advocated as a feasible alternative technique that allows for a safe subsequent cochlear implantation.

Cochlear implantation using the underwater technique: long-term results.

INTRODUCTION: The opening of the round window and the insertion of the electrode array into the scala tympani during cochlear implant surgery can lead to a pressure shock of the delicate inner ear structures. By filling the tympanic cavity with Ringer Solution during these surgical steps (underwater technique), the hydrostatic pressure of the fluid acts as a smooth pressure stabilizer, avoiding a pressure shock of the inner ear structures. The aim of this retrospective study was to present long-term results of this new method of cochlear implantation in underwater technique. METHODS: Altogether, 47 implantations in 43 patients with residual hearing at the frequencies 250, 500 and 1000 Hz in the unaided preoperative pure tone audiometry were included. A cochlear implantation via round window with a conventional full-length electrode was performed in underwater technique. Changes of residual hearing 7 weeks and 24 months after surgery were analyzed. RESULTS: Overall postimplant hearing preservation 7 weeks after implantation was achieved in 22 ears (47%). Subsequent follow-up was performed on average 24 months after surgery (range 12 months-4.2 years) in all patients. At this late postoperative evaluation, preservation of hearing was recorded in 18 ears (38%). Neither the follow-up time nor the type of electrode had a significant impact on the postoperative hearing loss. CONCLUSION: The underwater technique is an atraumatic cochlear implantation technique with hearing preservation rates comparable to results in literature and a very small hearing preservation decline rate over time even when using full-length CI electrodes.

Analysis of the dura involvement in cholesteatoma surgery.

OBJECTIVE: The involvement of the dura is a rare yet potentially life-threatening complication during cholesteatoma surgery. Thus, the knowledge about treatment and consequences of this issue is of great importance to every ear surgeon. METHODS: This retrospective study analyzed the dura involvement with regard to the type of defect, reconstruction method used, and the post-operative complications of 1291 pediatric and adult cholesteatoma surgeries performed at an academic tertiary care center over a twelve-year period. RESULTS: From a total of 1291 cholesteatoma surgeries, we identified 84 patients (6.5%) with dura involvement intraoperatively, most of them adult patients. The majority of the reported cases were bony defects and exposed dura without CSF leakage (79.73%, 67 out of 84). In 14.28% of the cases (12 out of 84) a meningo(encephalo)cele or dura defect with liquorrhea were detected. In 30 surgeries (35.7%, 30 out of 84) no reconstruction of the lateral skull base was considered necessary. The most common material used for reconstruction was conchal cartilage (25.0%, 21 out of 84), followed by polydioxanone (PDS)-foil (11.9%, 10 out of 84), bone pâté (9.5%, 8 out of 84) and a combination of materials (17.9%, 15 out of 84). Revision surgery of the reconstruction was necessary in 16.7% (14 out of 84) of the cases. Long-term evaluation (mean of 19.3 months) showed no complication related to the skull base defect. CONCLUSION: During cholesteatoma surgery, bony and dura defects can be managed effectively, with good long-term reliability. No intracranial or mastoidal complications are expected.

Surgical Treatment for Early Stage Glottic Carcinoma with Involvement of the Anterior Commissure.

Objective Assessment of the value of transoral laser microsurgery (TLM) compared with open surgery (OS) for early stage squamous cell carcinoma of the glottic larynx with special regard to involvement of the anterior commissure (AC). Study Design Case series with chart review. Setting Tertiary care otolaryngology clinic. Subjects and Methods Review of clinicopathological data of all patients with previously untreated T1a, T1b, and T2 glottic squamous cell carcinoma of the larynx who were consecutively enrolled over a 10-year period (January 1, 1992, to December 31, 2002). Results Local recurrence rate was 20.4% (10 of 49) for TLM and 10.7% (3 of 28) for OS. Comparison of the TLM and OS groups regarding local recurrence rates revealed a significant difference only for tumors invading the AC ( P = .046). Within the TLM group, tumors with involvement of the AC showed a significantly higher recurrence rate (38.1%; 8 of 21) compared with tumors without involvement of the AC (7.1%; 2 of 28; P = .008). In the OS group, involvement of the AC revealed no significant difference ( P = .45). The overall survival in both groups was comparable in both groups (TLM, 93.9%; OS, 89.3%; P = .47). Conclusion TLM and OS are equally effective surgical treatments for early stage glottic cancer without involvement of the AC, with selection of treatment based on pretreatment endoscopy. However, TLM is associated with less morbidity. In case of invasion of the AC, OS yields lower recurrence rates.

The Impact of a Cochlear Implant Electrode Array on the Middle Ear Transfer Function.

OBJECTIVES: As a treatment for partial deafness with residual hearing in the lower frequency range, the combined acoustic and electric stimulation of the cochlea has become widespread. Acoustic stimulation is provided by a hearing aid's airborne sound and the electric stimulation by a cochlear implant electrode array, which may be inserted through the round window or a cochleostomy. To take advantage of that concept, it is essential to preserve residual hearing after surgery. Therefore, the intracochlear electrode array should not compromise the middle ear vibration transmission. This study investigates the influence of different electrode types and insertion paths on the middle ear transfer function and the inner ear fluid dynamics. DESIGN: Sound-induced oval and round window net volume velocities were calculated from vibration measurements with laser vibrometers on six nonfixated human temporal bones. After baseline measurements in the "natural" condition, a cochleostomy was drilled and closed with connective tissue. Then, four different electrode arrays were inserted through the cochleostomy. Afterwards, they were inserted through the round window while the cochleostomy was patched again with connective tissue. RESULTS: After having drilled a cochleostomy and electrode insertion, no systematic trends in the changes of oval and round window volume velocities were observed. Nearly all changes of middle ear transfer functions, as well as oval and round window volume velocity ratios, were statistically insignificant. CONCLUSIONS: Intracochlear electrode arrays do not significantly increase cochlear input impedance immediately after insertion. Any changes that may occur seem to be independent of electrode array type and insertion path.

Acoustic effects of the reconstructed lateral epitympanic wall in a temporal bone and clinical study.

OBJECTIVE: Acoustic evaluation of reconstruction of the lateral epitympanic wall with bone or cartilage in a temporal bone study, and evaluation of audiometric data of patients who underwent cholesteatoma surgery with reconstruction of the lateral epitympanic wall with horseshoe-shaped cartilage. STUDY DESIGN: Temporal bone study and retrospective chart review. METHODS: Preparation of temporal bones included reconstruction of the epitympanic wall with fixated and loose cartilage and bone. The volume velocities of the stapes footplate were measured from the inner-ear side of the footplate by laser scanning doppler vibrometry following sound stimulation in the outer ear canal. Additionally, the audiometric data of 13 consecutive patients who underwent epitympanic cholesteatoma surgery, with an intact ossicular chain and reconstruction of the scutum with a horseshoe-shaped cartilage in contact with the malleus' neck, were evaluated retrospectively. RESULTS: The experimental results showed similar volume velocities at the stapes footplate for the fixated and unfixated cartilage as well as for the unfixated bone. However, the fixated bone yielded significantly reduced volume velocities. Clinical data confirmed that the cartilaginous horseshoe- technique allowed for a stable reconstruction of the scutum with satisfying audiometric outcome. CONCLUSION: In case of cholesteatoma surgery and the need for the reconstruction of the scutum, no adverse effects on hearing outcome are to be expected by using the malleus' neck as an anchoring point for cartilaginous scutum reconstruction. LEVEL OF EVIDENCE: NA. Laryngoscope, 127:1427-1434, 2017.

Long-term Follow-up Study of the Sandwich Cartilage Shoe Technique in Cases of Insecure Stapes Footplate.

OBJECTIVE: Analysis of the audiometric results after repair of a defective footplate with the sandwich cartilage shoe technique in a follow-up study. STUDY DESIGN: Retrospective analysis of audiometric data. SETTING: Hospital. PATIENTS: The cohort consisted of 12 patients, who underwent ossicular reconstruction after sandwich cartilage shoe technique in a case of insecure stapes footplate. The mean age was 42.7 years with an equal sex distribution. In every patient, cholesteatoma was the reason for surgery with 75% being revision cases. INTERVENTION: Sandwich cartilage shoe technique in case of insecure stapes footplate at the department of otorhinolaryngology, head and neck surgery at the University of Cologne over an 8-year period (2007-2015). MAIN OUTCOME MEASURE: The use of the "sandwich cartilage shoe technique" in case of a broken or unstable footplate allows a safe occlusion of the open vestibule. RESULTS: The statistical analysis revealed a significant improvement of the pure-tone average (p = 0.011) and air-bone gap (ABG) (p = 0.016) after total ossicular replacement prosthesis (TORP) implantation. The hearing was stable at 9 months of follow up. CONCLUSION: The sandwich cartilage shoe technique offers a safe and effective option as a two-stage procedure in treating patients with fractures of the stapes footplate in case of chronic otitis media. In view of the possible risk of deafness going along with a destruction of an inner ear window, our results can be considered substantial as all our patients will at least be able to regain "social hearing" as they all either achieved a hearing threshold is less than 30 dB or can be sufficiently supplied with a conventional hearing aid.

Loads and Coupling Modalities Influence the Performance of the Floating Mass Transducer as a Round Window Driver.

HYPOTHESIS: High loads forcing the floating mass transducer (FMT) of a single active middle ear implant toward the round window membrane (RWM) affect the backward stimulation of the cochlea. BACKGROUND: Various factors influence the backward stimulation of the cochlea. We investigated the effects of various loads applied to the FMT together with different coupling techniques at the fully exposed RWM on the vibration transmission. METHODS: Experimental study on temporal bones with the FMT linked to a load cell mounted on a translation stage moving it against the fully exposed RWM with increasing loads up to 200 mN by itself, with interposed perichondrium, cartilage or connected to the round window coupler. Cochlear stimulation is measured by the volume velocities of the stapes footplate using LASER-Doppler-vibrometry. RESULTS: Loads ranging from 5 to 20 mN induce the highest volume velocities of the stapes footplate. Increasing loads decrease the transmission of vibration in the low-frequency range but enhance the transmission of high frequencies. The interposition of perichondrium and cartilage proved to be advantageous. CONCLUSION: The load applied to the FMT distinctly affects the backward stimulation of the cochlea. Although increasing loads have inverse effects on the transmission of low and high frequencies, high loads lead to an overall decrease of cochlear stimulation. Out of the applied coupling techniques interposed perichondrium and cartilage allow for the most efficient stimulation.