Toward Automating Diagnosis of Middle- and Inner-ear Mechanical Pathologies With a Wideband Absorbance Regression Model.

OBJECTIVES: During an initial diagnostic assessment of an ear with normal otoscopic exam, it can be difficult to determine the specific pathology if there is a mechanical lesion. The audiogram can inform of a conductive hearing loss but not the underlying cause. For example, audiograms can be similar between the inner-ear condition superior canal dehiscence (SCD) and the middle-ear lesion stapes fixation (SF), despite differences in pathologies and sites of lesion. To gain mechanical information, wideband tympanometry (WBT) can be easily performed noninvasively. Absorbance , the most common WBT metric, is related to the absorbed sound energy and can provide information about specific mechanical pathologies. However, absorbance measurements are challenging to analyze and interpret. This study develops a prototype classification method to automate diagnostic estimates. Three predictive models are considered: one to identify ears with SCD versus SF, another to identify SCD versus normal, and finally, a three-way classification model to differentiate among SCD, SF, and normal ears. DESIGN: Absorbance was measured in ears with SCD and SF as well as normal ears at both tympanometric peak pressure (TPP) and 0 daPa. Characteristic impedance was estimated by two methods: the conventional method (based on a constant ear-canal area) and the surge method, which estimates ear-canal area acoustically.Classification models using multivariate logistic regression predicted the probability of each condition. To quantify expected performance, the condition with the highest probability was selected as the likely diagnosis. Model features included: absorbance-only, air-bone gap (ABG)-only, and absorbance+ABG. Absorbance was transformed into principal components of absorbance to reduce the dimensionality of the data and avoid collinearity. To minimize overfitting, regularization, controlled by a parameter lambda, was introduced into the regression. Average ABG across multiple frequencies was a single feature.Model performance was optimized by adjusting the number of principal components, the magnitude of lambda, and the frequencies included in the ABG average. Finally, model performances using absorbance at TPP versus 0 daPa, and using the surge method versus constant ear-canal area were compared. To estimate model performance on a population unknown by the model, the regression model was repeatedly trained on 70% of the data and validated on the remaining 30%. Cross-validation with randomized training/validation splits was repeated 1000 times. RESULTS: The model differentiating between SCD and SF based on absorbance-only feature resulted in sensitivities of 77% for SCD and 82% for SF. Combining absorbance+ABG improved sensitivities to 96% and 97%. Differentiating between SCD and normal using absorbance-only provided SCD sensitivity of 40%, which improved to 89% by absorbance+ABG. A three-way model using absorbance-only correctly classified 31% of SCD, 20% of SF and 81% of normal ears. Absorbance+ABG improved sensitivities to 82% for SCD, 97% for SF and 98% for normal. In general, classification performance was better using absorbance at TPP than at 0 daPa. CONCLUSION: The combination of wideband absorbance and ABG as features for a multivariate logistic regression model can provide good diagnostic estimates for mechanical ear pathologies at initial assessment. Such diagnostic automation can enable faster workup and increase efficiency of resources.

Reconstructive ossiculoplasty options in primary cholesteatoma surgeries with an intact stapes.

PURPOSE: In primary cholesteatoma patients, incus destruction with an intact and mobile stapes is a frequent finding. Different techniques have been described to restore the ossicular chain, including incus interposition, stapes augmentation and type III tympanoplasty. Controversy about postoperative hearing results in open versus closed surgical techniques exist. METHODS: We performed a retrospective analysis of clinical, surgical and audiometric data of patients with primary cholesteatoma surgery operated between 2010 and 2020, and a mobile stapes and one-stage ossicular reconstruction. Pre- and post-operative audiograms were compared for the different surgical groups, mainly focusing on postoperative air-bone gap. Mastoid pneumatization and ventilation was also considered. RESULTS: The mean postoperative air-bone gap (0.5-4 kHz) of the 126 included patients was 20 dB. Hearing after type III tympanoplasty (26 dB) was worse than incus interposition (19 dB) and stapes augmentation (20 dB). Hearing after an open (23 dB) versus closed (19 dB) surgical technique was significantly different. No improvement in air-bone gap was observed for the higher frequencies. CONCLUSION: A residual postoperative air-bone gap should be considered after primary cholesteatoma surgery with intact and mobile stapes. Incus interposition in closed cavity operation is the optimal situation, but open cavity surgery should not be avoided because of hearing. Extent of the disease is prioritized and poorer ventilation before and after surgery may affect postoperative hearing.

Differential effects of mass-loading the eardrum and stiffening the middle ear on wideband absorbance.

The current work investigated the effects of mass-loading the eardrum on wideband absorbance in humans. A non-invasive approach to mass-loading the eardrum was utilized in which water was placed on the eardrum via ear canal access. The mass-loaded absorbance was compared to absorbance measured for two alternative middle ear states: normal and stiffened. To stiffen the ear, subjects pressurized the middle ear through either exsufflation or insufflation concurrent with Eustachian tube opening. Mass-loading the eardrum was hypothesized to reduce high-frequency absorbance, whereas pressurizing the middle ear was hypothesized to reduce low- to mid-frequency absorbance. Discriminant linear analysis classification was performed to evaluate the utility of absorbance in differentiating between conditions. Water on the eardrum reduced absorbance over the 0.7- to 6-kHz frequency range and increased absorbance at frequencies below approximately 0.5 kHz; these changes approximated the pattern of changes reported in both hearing thresholds and stapes motion upon mass-loading the eardrum. Pressurizing the middle ear reduced the absorbance over the 0.125- to 4-kHz frequency range. Several classification models based on the absorbance in two- or three-frequency bands had accuracy exceeding 88%.

Congenital Absence of Stapes Suprastructure and Footplate: A Case Report.

INTRODUCTION: Congenital ossicular chain anomalies are rare conductive hearing loss conditions that remain difficult to diagnose even with high-resolution computed tomography (CT). The preoperative diagnosis is helpful for surgical planning and counseling patients regarding treatment outcomes. CASE PRESENTATION: We report a case involving a 14-year-old boy presenting with left conductive hearing loss without history of trauma for 5 years, physical examination showed normal otoscopic examination bilaterally and high-resolution CT showed absent of stapes suprastructure and footplate. Subsequent diagnosis was done via endoscopic middle ear exploration which revealed an absent long process of the incus, stapes suprastructure and footplate, but with intact oval window membrane. The residual incus was removed, and a tragal perichondrium graft was used over the oval window. A total ossicular replacement prosthesis was placed between the malleus and oval window to repair the chain. Postoperatively, the patient had no complications. Preoperative pure tone average revealed an air/bone result of 52/8 dB. Follow-up after surgery at 6 months showed a pure tone average air/bone result of 15/3 dB. The air-bone gap was reduced from 44 to 12 dB. CONCLUSION: Congenital absence of the stapes suprastructure and footplate remains a rare condition compared to the myriad of middle ear anomalies in the literature.

Genetic variants and altered expression of SERPINF1 confer disease susceptibility in patients with otosclerosis.

Otosclerosis (OTSC) is a focal and diffuse bone disorder of the human middle ear characterized by abnormal bone growth and deposition at the stapes' footplate. This hinders the transmission of acoustic waves to the inner ear leading to subsequent conductive hearing loss. The plausible convections for the disease are genetic and environmental factors with yet an unraveled root cause. Recently, exome sequencing of European individuals with OTSC revealed rare pathogenic variants in the Serpin Peptidase Inhibitor, Clade F (SERPINF1) gene. Here, we sought to investigate the causal variants of SERPINF1 in the Indian population. The gene and protein expression was also evaluated in otosclerotic stapes to ameliorate our understanding of the potential effect of this gene in OTSC. A total of 230 OTSC patients and 230 healthy controls were genotyped by single-strand conformational polymorphism and Sanger sequencing methods. By comparing the case controls, we identified five rare variants (c.72 C > T, c.151 G > A, c.242 C > G, c.823 A > T, and c.826 T > A) only in patients. Four variants c.390 T > C (p = 0.048), c.440-39 C > T (p = 0.007), c.643 + 9 G > A (p = 0.035), and c.643 + 82 T > C (p = 0.005) were found to be significantly associated with the disease. Down-regulation of SERPINF1 transcript level in otosclerotic stapes was quantified by qRT-PCR, ddPCR and further validated by in situ hybridization. Similarly, reduced protein expression was observed by immunohistochemistry and immunofluorescence in otosclerotic stapes that corroborate with immunoblotting of patients' plasma samples. Our findings identified that SERPINF1 variants are associated with the disease. Furthermore, reduced expression of SERPINF1 in otosclerotic stapes might contribute to OTSC pathophysiology.

Diagnostic Value of the Air-Bone Threshold Gap in Stapes Fixation.

INTRODUCTION: The Carhart notch is a well-known sign of stapes fixation. However, previous studies have reported that the Carhart notch is not specific to stapes fixation and is also present in other middle ear diseases. Therefore, this study investigated the diagnostic value of threshold gap between air conduction and bone conduction (ABG) for stapes fixation, instead of the bone conduction dip representing the Carhart notch. METHODS: A total of 199 ears that underwent exploratory tympanotomy were enrolled in this retrospective study. They were categorized into three groups according to surgical findings: stapes fixation (SF), other ossicle fixation (OF), and chain disconnection (CD). Preoperative pure-tone audiograms and impedance audiograms were compared between the groups. RESULTS: The incidence of the Carhart notch did not differ between the groups. The ABG at 2,000 Hz showed a good diagnostic performance for distinguishing between the SF and CD groups (area under the curve, AUC = 0.816, p < 0.001), but poor performance for distinguishing between the SF and OF groups (AUC = 0.662, p = 0.003). Bone conduction at 2,000 Hz showed a moderate performance for distinguishing between the SF and CD groups (AUC = 0.707, p < 0.001) and did not show statistically significant results for distinguishing between the SF and OF groups (AUC = 0.594, p = 0.080). The tympanic membrane compliance was significantly higher in the CD group than in the SF group (p = 0.001). CONCLUSIONS: The Carhart notch was not a specific finding of SF. The sensitivity and specificity of ABG ≤15 dB at 2,000 Hz for distinguishing between SF and CD were 60.4% and 89.2%, respectively. To prepare for surgical interventions in patients with conductive hearing loss but a normal tympanic membrane, clinicians should comprehensively consider these results.

Use of a Flexible Ruler in Measuring the Length of Artificial Stapes During Stapedotomy Under Otoendoscopy.

BACKGROUND We explored a new method for measuring the length of artificial stapes during stapedotomy in otoendoscopic middle-ear surgery using a flexible ruler. MATERIAL AND METHODS A retrospective analysis was conducted on 56 cases of otosclerosis, comprising 56 ears with a follow-up of over 6 months and complete data. Patients were admitted to the Department of Otology, Huazhong University of Science and Technology Union Shenzhen Hospital from July 2020 to June 2022. SPSS statistical software was used for efficacy analysis. The results of different measurement methods on the implantation time of the prosthesis and postoperative hearing follow-up were compared. RESULTS The 56 patients were randomly divided into 2 groups. In 1 case measured by the metal measuring stick, the prosthesis was too short and was replaced during the operation; 2 patients experienced transient dizziness postoperatively, and the other patients had no surgical complications. All 56 patients had varying degrees of hearing improvement after surgery, and no dislocation of the ossicular chain was observed during the follow-up. There was a statistically significant difference in the implantation time of the prosthesis between the different measurement methods (P<0.05). The improvement in hearing in the flexible ruler group was statistically significant (P<0.05). CONCLUSIONS The selection of the length of the ossicular prosthesis is a crucial step in the operation and can directly affect hearing outcomes. The use of a flexible ruler to measure prosthesis length can significantly shorten operation time and improve hearing, and the ruler is easily obtainable. It is worth promoting its application in ear endoscopic stapedotomy.

Impact of Otosclerosis on Auditory Ossicle Remodeling: A Scanning Electron Microscopy Analysis of Stapes Head Overloads.

BACKGROUND Otosclerosis is a pathology that interferes with the conduction of vibrations to the inner ear, triggering changes in the auditory ossicles and their associated joints due to mechanical overload. This study primarily aims to evaluate these overload-induced modifications in the stapes head resulting from the immobilization of the base of the third auditory ossicle in otosclerosis patients. MATERIAL AND METHODS We conducted a comparative analysis of patients undergoing their first surgery for otosclerosis. The test group consisted of 31 patients who underwent stapedotomy between 2020-2021. For comparison, we utilized a control group comprising stapes samples extracted during vestibular schwannoma surgeries via a transcochlear approach. A prospective analysis of bone tissue surface topography and chemical composition was executed using scanning electron microscopy (SEM). RESULTS SEM analysis of the stapes head in otosclerosis patients relative to the control group displayed no significant differences in chemical composition or the presence of otosclerotic foci. Nonetheless, various forms of bone tissue surface damage were noted on the stapes head in all otosclerosis patients. Mild changes were evident in 90% of the samples, while small linear bone tissue fractures were observed in 58% of the samples. Furthermore, minor osteophytic changes were detected in 16% of the samples. CONCLUSIONS The immobilization of the stapes base by otosclerotic foci instigates overloads in the incus-stapes joint, leading to the eventual remodeling of the stapes head articular surface.

Audiologic results of total ossicular replacement prosthesis bypassing the stapes suprastructure in canal wall down mastoidectomy.

OBJECTIVES: Sometimes performing PORP adequately is challenging when the stapes is tilted or the suprastructure is partially damaged owing to inflammation or infection. In such cases, the implementation of a TORP bypassing the stapes can be a useful alternative. This study aimed to investigate whether bypassing the stapes suprastructure during total ossicular replacement prosthesis (TORP) affects postoperative complications or audiological outcomes. MATERIAL AND METHODS: Among 104 patients who underwent open cavity mastoidectomy and ossiculoplasty using a titanium prosthesis at Korea University Ansan Hospital between January 2012 and December 2019, we compared the preoperative and postoperative audiological results and surgical complications of 52, 21, and 31 patients who underwent partial ossicular replacement prosthesis (PORP), TORP bypassing the remaining stapes suprastructure, and TORP on the stapes footplate or oval window, respectively. RESULTS: The air-bone gap before surgery was significantly different in the TORP on the stapes footplate group (34.2 ± 12.0 dB) than that in the PORP (22.9 ± 13.8 dB) and TORP bypassing the stapes groups (20.7 ± 11.5 dB, p < 0.001). After surgery, there were no significant differences among the groups (p = 0.818). The air-bone gap difference before surgery was associated with the presence of stapes before surgery (p < 0.001). There was no difference in the proportion of postoperative tympanic perforation, whether it was a revision surgery, malleus status, or the size of perforation of the tympanic membrane among the three groups. CONCLUSION: When performing ossiculoplasty using TORP, bypassing the stapes did not affect surgical and audiologic outcomes.

Radiological and audiological predictors of stapes destruction in adherent pars tensa.

PURPOSE: Progressive adherent pars tensa occasionally induces ossicular erosion. Specifically, stapes discontinuity adversely affects postoperative hearing. However, this irretrievable sequela is challenging to prove preoperatively, partly because perimatrix inflammation on the pars tensa can obscure the visibility of the ossicles or the partial volume effect of computed tomography (CT) imaging can hamper detailed ossicular visualization. Therefore, there is no consensus regarding the ideal timing for switching from a wait-and-see approach to a surgical one. Herein, we aimed to explore the potential predictors of stapes superstructure destruction in adherent pars tensa. METHODS: This retrospective cohort study enrolled consecutive patients who underwent primary tympanoplasty for adherent pars tensa categorized as grade IV on Sadé's grading scale between April 2016 and September 2021. The impact of features on otoscopy and CT and air-bone gap (ABG) on stapes superstructure destruction was assessed using uni- and multivariable logistic regression analyses. RESULTS: Sixty-four ears were included. Multivariate analysis revealed the presence of debris on the adherent pars tensa (odds ratio [OR] [95% confidence interval {CI}]): 4.799 [1.063-21.668], p = 0.0415), presence of soft-tissue density occupying the oval window (OR [95% CI]: 13.876 [3.084-62.437], p = 0.0006), and a ≥ 20-dB preoperative ABG at 3 kHz (OR [95% CI]: 7.595 [1.596-36.132], p = 0.0108) as independent predictors for stapes superstructure destruction. CONCLUSION: High preoperative awareness of the possibility of destruction of the stapes superstructure would enable the surgeon to make a timely decision to provide surgical intervention before progression to severe stapes destruction, thereby maintaining long-term satisfactory hearing.

Comparison of the efficacy of cochlear implantation and stapes surgery in far advanced otosclerosis: a meta-analysis study.

OBJECTIVE: This study is to compare the hearing outcomes and complications of stapes surgery and cochlear implantation (CI) in patients with far-advanced otosclerosis (FAO). DATA SOURCES: A comprehensive electronic search of PubMed/MEDLINE, Scopus, Web of science and Cochrane Library was conducted in June 2021 for articles in the literature till this year. STUDY SELECTION: Studies are published in English language, conducted on human subjects, concerned with comparison of CI and stapes surgery in the management of FAO, not Laboratory study and not Opinion study. The current review followed the guidelines of preferred reporting items for systematic reviews and meta-analysis statement 2009 (PRISMA). DATA EXTRACTION: Twenty-six studies were included with 334 patients in CI group and 241 patients in stapes surgery group. Comparison between both groups was done in terms of postoperative complications, audiological outcomes, rete of revision surgery and patients' satisfaction rate. RESULTS: Postoperative complications rate was significantly lower in CI (13.6%) than stapes surgery (18.6%). CI had a significantly lower rate of revision surgery (8.1%) than stapes surgery (16.4%). CI had a better mean for pure tone average (29.1 dB) than stapedectomy (52.3 dB) while stapes surgery had a higher mean for recognition of monosyllables and disyllables than CI. CI had significantly higher satisfaction rate than stapes surgery. CONCLUSION: Both Stapes surgery and CI are reliable treatment options for FAO with close success rates. Statistics of CI are greater than stapes surgery and CI has a consistent improvement in audiometric outcomes in comparison to stapes surgery.

"Hot" vs "Cold" endoscopic stapes surgery: a matched case-control study.

PURPOSE: To compare hearing results and complication rates between two groups of patients operated on by endoscopic stapes surgery (ESS) for otosclerosis, either with CO2 fiber laser or microdrill. METHODS: A case-control study was performed. All consecutive cases of CO2 fiber laser ESS operated at a single center during the period 2017-2020 (case group) were matched to a control group of patients operated by traditional technique, according to year of surgery, preoperative mean air-bone gap, sex and age. Audiological data from preoperative and postoperative examinations and complication rates were compared. RESULTS: 46 cases were included. Mean operative time was significantly longer in the laser cohort (65 min) than in the drill one (45 min) (p = 0.003). Similar results were found in the two groups regarding the mean postoperative BC-PTA. The high-frequency bone conduction resulted significantly higher in the laser group (p = 0.002), suggesting an overclosure effect in the laser group. Consistently, a significant improvement of the BC-PTA threshold at 2000 Hz postoperatively was found in the laser group (p = 0.034). The postoperative AC-PTA significantly improved in both groups at all frequencies (p < 0.05), except for the AC threshold at 8 kHz. Similar rates of complications were found in the two groups. CONCLUSION: This study is the first to compare hearing results and complications between CO2 fiber laser and microdrill in ESS. Our results demonstrated similar functional outcomes between the two groups, confirming ESS as safe and effective, regardless of the technique used.

Comparison of endoscopic vs microscopic ossiculoplasty: a study of 157 consecutive cases.

PURPOSE: The relatively new technique of trans-canal endoscopic ear surgery (TEES) when compared to microsurgery for ossiculoplasty has advantages of better visualization and no external incision but also has the disadvantage of being a one-handed procedure. Our study aimed to compare audiometric outcomes following ossiculoplasty performed via TESS with results of microsurgery. MATERIALS AND METHODS: Data from a prospective audit of 157 consecutive patients who underwent ossiculoplasty by a single otologist from 2009 to 2018 was analyzed. TEES was introduced in the department in 2014; therefore, all patients before this period underwent microsurgery. Patients were classified by surgical approach, TEES, or microsurgery. Audiological outcomes were recorded at 3 and 12 months postoperatively and compared to pre-operative levels. Other variables included were the condition of stapes and reconstruction material used. RESULTS: Of the 157 cases, 50 were TEES and 107 were microsurgery (81 microscope only and 27 combined with endoscope). There was statistically significant improvement (p < 0.001) in AC (43.4 dB pre-operatively, 36.2 dB postoperatively), BC (20.3 dB pre-operatively, 17.6 dB postoperatively), and ABG (21.8 dB pre-operatively, 16.7 dB postoperatively) in the total cohort. Both groups achieved an ABG better than 20 dB; 72% in TEES, 73% in the microscopic group, and there was no significant difference. There was no change in hearing at 12 months when compared to 3 months. No statistically significant difference was noted based on stapes condition, type of material used for ossiculoplasty, or tympanic membrane graft. CONCLUSION: TEES is safe and as effective as microsurgery in ossiculoplasty with possibly much less pain and morbidity.

Audiological outcome after stapes surgery in relation to prosthesis type.

PURPOSE: Different techniques are used to fix crimp and CliP® Piston stapes prostheses to the long process of the incus (LPI). The CliP® Piston provides a stiff connection in contrast to the static bended loop of the crimp prosthesis, which imitates the physiological incudostapedial joint (ISJ) and thereby potentially leads to different hearing outcome. METHODS: In a retrospective single-center study of German-speaking one hundred and ninety patients who underwent stapes surgery CliP® Piston or crimp prostheses between the years of 2016 and 2019 by the same surgeon and in the same setting. Pre- and postoperative bone- (BC) and air-conduction (AC) pure-tone thresholds, pre- and postoperative air-bone gap (ABG) for 0.5, 1, 1.5, 2, 3, 4 kHz and the surgery time were examined. RESULTS: The postoperative bone conduction thresholds were significantly lower in the frequencies between 0.5 and 3 kHz and the mean ABG was < 10 dB in most cases independent of the prosthesis used. Crimp prosthesis showed a significantly better closure of the ABG at 0.5 kHz. CONCLUSIONS: The audiological outcome after stapes surgery is dependent on the type of prosthesis used, as reflected by the frequency-specific air-bone gap. The better ABG closure with the crimp prosthesis might be the result of the connection to the LPI imitating the physiological ISJ. The crimp prosthesis may be the better choice if use of hearing aids is expected postoperatively.

Creation of an incus recess for a middle-ear microphone using a drill or laser ablation: a comparison of equivalent noise level and middle ear transfer function.

PURPOSE: Studies have assessed the trauma and change in hearing function from the use of otological drills on the ossicular chain, but not the effects of partial laser ablation of the incus. A study of the effectiveness of a novel middle-ear microphone for a cochlear implant, which required an incus recess for the microphone balltip, provided an opportunity to compare methods and inform a feasibility study of the microphone with patients. METHODS: We used laser Doppler vibrometry with an insert earphone and probe microphone in 23 ears from 14 fresh-frozen cadavers to measure the equivalent noise level at the tympanic membrane that would have led to the same stapes velocity as the creation of the incus recess. RESULTS: Drilling on the incus with a diamond burr created peak noise levels equivalent to 125.1-155.0 dB SPL at the tympanic membrane, whilst using the laser generated equivalent noise levels barely above the baseline level. The change in middle ear transfer function following drilling showed greater variability at high frequencies, but the change was not statistically significant in the three frequency bands tested. CONCLUSIONS: Whilst drilling resulted in substantially higher equivalent noise, we considered that the recess created by laser ablation was more likely to lead to movement of the microphone balltip, and therefore decrease performance or result in malfunction over time. For patients with greatly reduced residual hearing, the greater consistency from drilling the incus recess may outweigh the potential benefits of hearing preservation with laser ablation.

Assessment of the ability of the radiological incudo-stapedial angle to predict the stapedotomy technique type: a prospective case-series study.

PURPOSE: This study aimed to propose a radiological classification of the incudo-stapedial angle by preoperative high-resolution computed tomography (HRCT) images and to highlight its importance for predicting the use of reversal-steps stapedotomy (RSS) rather than the traditional non-reversal technique. METHODS: We included 83 candidates for stapedotomy operation. Two physicians measured the radiological incudo-stapedial joint angle in the preoperative HRCT. According to this measurement, the radiological incudo-stapedial joint was classified into three types: obtuse, right, and acute. In addition, this radiological classification was correlated with the intraoperative use of the stapedotomy technique, either reversal or non-reversal. RESULTS: The RSS technique was used in forty-two (97.7%) cases with an obtuse angle and twenty-six (89.7%) with a right angle. At the same time, the traditional non-reversal technique was used in all patients with an acute angle. The three groups differed significantly regarding the method used for stapedotomy (P value < 0.001). Moreover, Spearman's correlation coefficient revealed a significant correlation between the used technique and the radiological type of the incudo-stapedial angle (P value < 0.001). CONCLUSIONS: This prospective study proposed a preoperative radiological classification of the incudo-stapedial angle. This classification was significantly correlated with the type of stapedotomy technique. The RSS technique was feasible in most cases with an obtuse and right radiological incudo-stapedial angle. In contrast, the non-reversal method was used in all patients with an acute radiological incudo-stapedial angle. This radiological classification could predict the choice for the stapedotomy technique with an accuracy of 95.18%, a sensitivity of 73.33%, and a specificity of 100%.

Are there differences in revision stapes surgery outcomes between university and county clinics? A study from the quality register for otosclerosis surgery in Sweden.

PURPOSE: The aim of the study was to investigate hearing outcomes in stapes revision surgery with regard to the type of clinic (university clinic or county clinic). Furthermore, the aim was to investigate the risk of complications with a focus on tinnitus, hearing deterioration, and taste disturbance 1 year after surgery. METHODS: The study is based on data from the Swedish Quality Register for Otosclerosis Surgery (SQOS). Two study protocols were completed by the surgeon, and a questionnaire was distributed to the patients 1 year after surgery. A total of 156 revisions were available for analysis with both preoperative and postoperative audiometry data. RESULTS: Seventy-five percent of the patients reported better to much better hearing 1 year after revision surgery. An air bone gap ≤ 20 dB postoperatively was seen in 77% of the patients. Four percent had hearing deterioration ≥ 20 dB PTA4 AC. Eleven percent had worsened or newly developed tinnitus, 5% had taste disturbance, and 3% had dizziness 1 year after surgery. Preoperative and postoperative hearing did not differ between patients operated on in university vs. county clinics. CONCLUSIONS: Revision surgery in otosclerosis is a challenge for otologists, but no differences in hearing outcomes between university and county clinics were found in this nationwide study. The risk of hearing deterioration and deafness is higher than in primary stapes surgery, and revision surgery should be recommended primarily in cases with a large air-bone gap and moderate to severe preoperative hearing loss.

Relative importance and interactions of parameters of finite-element models of human middle ear.

In the last decades, finite-element models of the middle ear have been widely used to predict the middle-ear vibration outputs. Even with the simplest linear assumption for material properties of the structures in the middle ear, these models need tens of parameters. Due to the complexities of measurements of material properties of these structures, accurate estimations of the values of most of these parameters are not possible. In this study, we benefited from the stochastic finite-element model of the middle ear we had developed in the past, to perform global sensitivity analysis. For this aim, we implemented Sobol' sensitivity analysis which ranks the importance of all uncertain parameters and interactions among them at different frequencies. To decrease the computational costs, we found Sobol' indices from surrogate models that we created using stochastic finite-element results and the polynomial chaos expansion method. Based on the results, the Young's modulus and thickness of the tympanic membrane, Young's modulus and damping of the stapedial annular ligaments, and the Young's modulus of ossicles are among the parameters with the greatest impacts on vibrations of the umbo and stapes footplate. Furthermore, the most significant interactions happen between the Young's modulus and thickness of the tympanic membrane.

Comparison between incus short process and long process coupling of the vibrant soundbridge in human temporal bones.

OBJECTIVE: The Vibrant Soundbridge (VSB) is one of the most widely used implantable hearing devices. It consists of a vibrating floating mass transducer (FMT) that is connected to a middle ear structure. The standard coupling devices for sensorineural hearing loss are short process (SP) or long process (LP) couplers. DESIGN AND STUDY SAMPLE: This study directly compared the electro-mechanical performance of the SP- and LP-coupled FMT of the VSB in the same temporal bone specimen (n = 10). We measured velocity magnitudes and total harmonic distortions (THD) of the stapes (ST) and the round window (RW) using laser Doppler Vibrometry (LDV). RESULTS: Comparison shows a maximally 10 dB higher magnitude for the LP coupler at ST and RW for frequencies below 600 Hz, whereas the SP coupler shows a maximally 20 dB higher magnitude at the ST and RW for frequencies above 600 Hz. THD show similar behaviour with less distortion at 500 Hz for the LP coupler and less distortions for the SP coupler in higher frequencies. CONCLUSIONS: Our experiments showed that the SP coupling may be mechanically favourable, in terms of magnitude and distortion, for the transmission of FMT vibrations at higher frequencies.

Persistent Stapedial Artery, Oval Window Atresia and Congenital Stapes Agenesis-Case Report.

Background: The persistent stapedial artery (PSA) is a rare congenital vascular malformation involving the middle ear. It is usually associated with pulsatile tinnitus and/or conductive hearing loss and can account for multiple risks during middle ear surgery. Case Report: we present a case of a 9-year-old male child with conductive hearing loss and persistent stapedial artery in his right ear, who was admitted to our ENT Department for hearing loss. During surgery, we discovered PSA along with congenital stapes agenesis and oval window atresia, as well as an abnormal trajectory of the mastoid segment of the facial nerve. After ossicular reconstruction (transcanal total ossicular replacement prosthesis) with cochleostomy, no surgical complications were recorded and hearing improvement was monitored by pre- and postoperative audiometry. Conclusion: Stapedial artery is a rare anatomical middle ear abnormality that can prevent proper surgical hearing restoration and can be associated with other simultaneous temporal bone malformations.