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%.

Directional sensitivity of bone conduction stimulation on the otic capsule in a finite element model of the human temporal bone.

Sound transmission to the human inner ear by bone conduction pathway with an implant attached to the otic capsule is a specific case where the cochlear response depends on the direction of the stimulating force. A finite element model of the temporal bone with the inner ear, no middle and outer ear structures, and an immobilized stapes footplate was used to assess the directional sensitivity of the cochlea. A concentrated mass represented the bone conduction implant. The harmonic analysis included seventeen frequencies within the hearing range and a full range of excitation directions. Two assessment criteria included: (1) bone vibrations of the round window edge in the direction perpendicular to its surface and (2) the fluid volume displacement of the round window membrane. The direction of maximum bone vibration at the round window edge was perpendicular to the round window. The maximum fluid volume displacement direction was nearly perpendicular to the modiolus axis, almost tangent to the stapes footplate, and inclined slightly to the round window. The direction perpendicular to the stapes footplate resulted in small cochlear responses for both criteria. A key factor responsible for directional sensitivity was the small distance of the excitation point from the cochlea.

The New Semisynthetic TORP: A Prosthesis for Ossicular Reconstruction Both With the Absence and the Presence of the Stapes Superstructure.

OBJECTIVES: To describe the new semisynthetic total ossicular replacement prosthesis (New-SSTORP) and to evaluate the New-SSTORP ossiculoplasty results both with the presence and absence of the stapes superstructure. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. METHODS: From April 2023 to May 2023, 18 New-SSTORP ossiculoplasties were performed by the first author. In all patients, the New-SSTORP was interposed between the footplate and the eardrum. The study group was divided into two groups (group A and group B). Group A included 13 patients with the absence of stapes superstructure. Group B included five patients with the presence of stapes superstructure. A successful reconstruction was defined as a postoperative air-bone gap ABG ≤20 dB. For all patients of groups A and B, the last audiometric control considered was performed in January 2024. The mean follow-up was 8½ months. The χ2 test was used to compare results. p < 0.05 was considered significant. MAIN OUTCOME MEASURES: Mean postoperative ABG ≤20 dB. RESULTS: At the end of follow-up, the overall success rate (ABG ≤20 dB) of New-SSTORP ossiculoplasty was obtained in 88.8% (n = 16 of 18) of cases. In group A, the success rate of New-SSTORP ossiculoplasty occurred in 84.6% (n = 11 of 13) of cases, and in group B, the success rate of New-SSTORP ossiculoplasty occurred in 100% (n = 5 of 5) of cases. There was no audiological statistically significant difference between groups A and B (Fisher value is 1; p < 0.05). In all cases, the time for positioning of New-SSTORP was about 5 minutes. CONCLUSION: The New-SSTORP has a minimal technical challenge for building and placement. The New-SSTORP ossiculoplasty results are very good both with the presence and absence of SS.

Audiologic Outcomes After Vestibulotomy in Patients With Congenital Absence of the Oval Window.

OBJECTIVE: To examine the clinical features and surgical outcomes in patients with congenital absence of the oval window (CAOW), and to investigate the potential factors that affect audiologic results. STUDY DESIGN: A retrospective chart review. SETTING: A tertiary academic center. PATIENTS AND INTERVENTION: A total of 17 ears among 16 patients were confirmed to have CAOW. Among them, 13 ears underwent vestibulotomy for hearing reconstruction. Clinical parameters associated with the hearing outcomes were analyzed. MAIN OUTCOME MEASURES: A mean air-bone gap (ABG) after 6-month and long-term follow-up was compared with preoperative measurements. RESULTS: Intraoperative findings showed that anomalies of the malleus or incus were observed in 11 ears (64.7%), stapes anomalies were present in all ears (100%), and facial nerve anomalies were present in 10 ears (58.8%). Because of unfavorable facial nerve anomalies, hearing reconstruction was aborted in four cases (23.5%). In the hearing reconstruction group, the mean ABG at 6 months postoperation was significantly reduced after compared with the preoperative value (44.0 ± 8.4 dB versus 58.8 ± 9.1 dB, p = 0.006). After dividing ears into a success subgroup (ABG ≤ 30 dB, seven ears) and non-success subgroup (ABG > 30 dB, six ears), the use of a drill during vestibulotomy was significantly related to a poor hearing outcome (100% versus 16.7%, p = 0.015). The long-term follow-up result (mean, 60 mo) revealed no deterioration compared with the 6-month postoperative result. Five ears (29.4%) underwent revision surgery, and three of them showed ABG improvements. No serious complications were reported. CONCLUSION: Vestibulotomy is an effective and safe option for hearing restoration in patients with CAOW, particularly when the use of a drill is not required. The long-term audiologic outcome is also reliable.

The impact of size on middle-ear sound transmission in elephants, the largest terrestrial mammal.

Elephants have a unique auditory system that is larger than any other terrestrial mammal. To quantify the impact of larger middle ear (ME) structures, we measured 3D ossicular motion and ME sound transmission in cadaveric temporal bones from both African and Asian elephants in response to air-conducted (AC) tonal pressure stimuli presented in the ear canal (PEC). Results were compared to similar measurements in humans. Velocities of the umbo (VU) and stapes (VST) were measured using a 3D laser Doppler vibrometer in the 7-13,000 Hz frequency range, stapes velocity serving as a measure of energy entering the cochlea-a proxy for hearing sensitivity. Below the elephant ME resonance frequency of about 300 Hz, the magnitude of VU/PEC was an order of magnitude greater than in human, and the magnitude of VST/PEC was 5x greater. Phase of VST/PEC above ME resonance indicated that the group delay in elephant was approximately double that of human, which may be related to the unexpectedly high magnitudes at high frequencies. A boost in sound transmission across the incus long process and stapes near 9 kHz was also observed. We discuss factors that contribute to differences in sound transmission between these two large mammals.

Measurement of stapes footplate thickness using ultra-high-resolution computed tomography: stapes axial plane correlates better with otosclerosis than lateral semicircular canal plane.

BACKGROUND, AIMS: Stapes footplate thickness measurement using ultra-high-resolution CT has been described only in the lateral semicircular canal plane. The purpose of this study was to compare stapes footplate thickness between the lateral semicircular canal and stapes axial planes in patients with otosclerosis compared to controls. MATERIAL AND METHODS: We performed a retrospective single-center study of patients undergoing high-resolution temporal bone CT. Two radiologists measured stapes footplate thickness in both the lateral semicircular canal and stapes axial planes. RESULTS: Between February 2020 and October 2022, we collected 81 ears from 49 patients (75% of women; mean age 51.22 ± 16.6 years, 17 otosclerosis, and 64 controls). In the stapes axial plane, there was a significant anterior thickening in otosclerosis patients (Reader 1: 0.52 ± 0.12 [0.3-0.7] vs. 0.41 ± 0.08 [0.3-0.6], p = 0.001; Reader 2: 0.54 ± 0.06 [0.5-0.7] vs. 0.39 ± 0.08 [0.2-0.6], P < 0.001) compared to controls. These differences were not significant using the lateral semicircular canal plane. CONCLUSION: The stapes footplate was thickened at its AC in otosclerosis patients using only the stapes axial plane. SIGNIFICANCE: We propose to use the stapes axial plane instead of the lateral semicircular canal plane when analyzing the stapes.

Analysis of the effect of reconstructing the ossicular chain under otoendoscopy with and without a stapes superstructure.

BACKGROUND: Numerous studies have been conducted on the effect of the stapes superstructure after ossicular chain reconstruction, but the findings are not uniform. OBJECTIVE: To compare the hearing outcomes of ossicular chain reconstruction with partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP) under otoendoscopy. MATERIALS AND METHODS: The records of 111 patients diagnosed with chronic suppurative otitis media were retrospectively analyzed. These patients were divided into PORP group (n = 57) and TORP group (n = 54). They were further subdivided into subgroups PORP-a (with a malleus handle) and PORP-b (without a malleus handle), subgroups TORP-a and TORP-b. Pre- and postoperative audiometric results were analyzed. RESULTS: The mean postoperative air conduction hearing thresholds improvement, mean air-bone gap improvement, and the success rate of reconstruction were significantly higher in the PORP group than in the TORP group (p < .05). The mean postoperative air conduction hearing thresholds improvement and the success rate of reconstruction were significantly higher in the PORP-a group than in the TORP-a group (p < .05); and similar results were concluded in comparison of the PORP-b group and the TORP-b group. CONCLUSIONS AND SIGNIFICANCE: The stapes superstructure has an important positive effect on the postoperative outcome of endoscopic ossicular chain reconstruction.

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.

[The application of endoscope and microscope in the stapes surgeries].

Objective:To compare the application of endoscope and microscope in all kinds of stapes surgeries. Methods:Fifty-nine stapes surgeries have been collected from April 2020 to May 2023 in Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School. Hearing level, hospital stay post-operation, times of hospital visit post-operation, etc. have been compared between the endoscopic group and microscopic group. Patients who were failed to place the stapes prosthesis because of the poor exposure of the oval window have been analyzed. Results:Otosclerosis was the most common diagnosis in both groups. There was 1（1/23） middle ear malformation in the endoscopic group and 5（5/36） middle ear malformations in the microscopic group. There were 2 Van Der Hover syndromes and 4 Treacher Collins syndromes in the microscopic group. In the endoscopic group ABG of 10 ears（43.5%） ≤ 10 dB, and ABG of 21 ears（91.3%） ≤20 dB.In the microscopic group ABG of 13 ears（41.9%） ≤ 10 dB, and ABG of 28 ears（90.3%） ≤ 20 dB. There was no statistic difference between 2 groups. Times of hospital visit post-operation in the endoscopic group was less than in the microscopic group（P<0.01）. There was no facial palsy, tympanic perforation or profound sensorineural hearing loss in both groups. Conclusion:Endoscope is more suitable for patients who are evaluated with no severe stapes malformation, or less manipulation of drilling the bone. It could also reduce the hospital visit post-operation. Patients with narrow ear canal or severe middle ear malformation are recommended to perform the surgery with microscope, because it provides the chance of manipulation with 2-hands of surgeons.

Ultra-high-resolution CT of the temporal bone: Comparison between deep learning reconstruction and hybrid and model-based iterative reconstruction.

PURPOSE: The purpose of this study was to evaluate the ability of ultra-high-resolution computed tomography (UHR-CT) to assess stapes and chorda tympani nerve anatomy using a deep learning (DLR), a model-based, and a hybrid iterative reconstruction algorithm compared to simulated conventional CT. MATERIALS AND METHODS: CT acquisitions were performed with a Mercury 4.0 phantom. Images were acquired with a 1024 × 1024 matrix and a 0.25 mm slice thickness and reconstructed using DLR, model-based, and hybrid iterative reconstruction algorithms. To simulate conventional CT, images were also reconstructed with a 512 × 512 matrix and a 0.5 mm slice thickness. Spatial resolution, noise power spectrum, and objective high-contrast detectability were compared. Three radiologists evaluated the clinical acceptability of these algorithms by assessing the thickness and image quality of the stapes footplate and superstructure elements, as well as the image quality of the chorda tympani nerve bony and tympanic segments using a 5-point confidence scale on 13 temporal bone CT examinations reconstructed with the four algorithms. RESULTS: UHR-CT provided higher spatial resolution than simulated conventional CT at the penalty of higher noise. DLR and model-based iterative reconstruction provided better noise reduction than hybrid iterative reconstruction, and DLR had the highest detectability index, regardless of the dose level. All stapedial structure thicknesses were thinner using UHR-CT by comparison with conventional simulated CT (P < 0.009). DLR showed the best visualization scores compared to the other reconstruction algorithms (P < 0.032). CONCLUSION: UHR-CT with DLR results in less noise than UHR-CT with hybrid iterative reconstruction and significantly improves stapes and tympanic chorda tympani nerve depiction compared to simulated conventional CT and UHR-CT with iterative reconstruction.

Linear transmission between malleus and stapes in cases with incus necrosis.

OBJECTIVE: The outcome of cartilage interposition ossiculoplasty was assessed in cases of incus necrosis after posterior malleus repositioning in the plane of the stapes, in terms of hearing gain after ossicular reconstruction. METHODS: A retrospective observational study was conducted of 30 patients admitted to an Ain Shams University hospital from March 2021 to September 2021. All patients with ossicular disruption due to chronic suppurative otitis media and hearing loss of more than 40 dB were included in the study. Pure tone audiometry was conducted for each patient after three months, six months and one year post operation. RESULTS: The audiogram showed a post-operative air-bone gap of 20 dB or less in 83.33 per cent of patients (n = 25) at three months post-operatively and in 80 per cent of patients after six months; after one year, the results remained the same. CONCLUSION: The use of cartilage interposition after malleus posterior mobilisation represents an excellent partial ossicular replacement technique.

The TORP-PORP: A Tympanoplasty Technique for Isolated Defects of the Stapes Suprastructure.

OBJECTIVE: Investigating the outcomes of a surgical approach to treat isolated defects of the stapes suprastructure, using a modified total ossicular replacement prosthesis (TORP) prosthesis as a PORP between the footplate and the incus, effectively creating a TORP-PORP configuration. PATIENTS: Eleven patients (mean age, 37.2 years; 36% male and 64% female) between the years 2007 and 2022. INTERVENTIONS: Therapeutic (ossiculoplasty). MAIN OUTCOME MEASURES: Hearing gain (in dB) in air conduction thresholds at 0.5, 1, 2, 3, and 4 kHz, stability of bone conduction, revision rate. RESULTS: Significant improvement in air conduction between the preoperative and the postoperative cohorts (p = 0.002) with a mean postoperative hearing level of 30.00 ± 5.25 dB. The bone conduction remained stable. We encountered no perioperative complications, and there were no revisions surgery. CONCLUSIONS: The described ossiculoplasty procedure is a safe and effective approach to treat isolated defects of the stapes suprastructure.

Techniques of Endoscopic Ossiculoplasty.

The utilization of endoscopes in modern otology has evolved from diagnostic purposes to the development of exclusive endoscopic ear surgery. This technique offers a panoramic view of the middle ear and provides an optimal magnification of the oval window region, the stapes' suprastructure, and the footplate, allowing great precision in prosthesis positioning during ossiculoplasty (OPL). Various techniques for ossicular chain reconstruction have been described in the literature. Either autologous or synthetic materials can be used for reconstruction. The use of a patient's own tissue minimizes the risk of implant rejection or extrusion of the prosthesis through the tympanic membrane. On the other hand, synthetic materials like titanium are light and rigid and do not require time-consuming prosthesis remodeling. The main objective of this article is to present a comprehensive step-by-step guide that serves as a surgical manual for exclusive endoscopic OPL. This guide will explain various forms of OPL using synthetic and autologous materials. The goal is to provide a comprehensive understanding of the various surgical techniques and support the integration into clinical practice.

Performance of personalised prosthesis under static pressure: Numerical analysis and experimental validation.

This study investigates the performance of personalised middle ear prostheses under static pressure through a combined approach of numerical analysis and experimental validation. The sound transmission performances of both normal and reconstructed middle ears undergo changes under high positive or negative pressure within the middle ear cavity. This pressure fluctuation has the potential to result in prosthesis displacement/extrusion in patients. To optimise the design of middle ear prostheses, it is crucial to consider various factors, including the condition of the middle ear cavity in which the prosthesis is placed. The integration of computational modelling techniques with non-invasive imaging modalities has demonstrated significant promise and distinct prospects in middle ear surgery. In this study, we assessed the efficacy of Finite Element (FE) analysis in modelling the responses of both normal and reconstructed middle ears to elevated static pressure within the ear canal. The FE model underwent validation using experimental data derived from human cadaveric temporal bones before progressing to subsequent investigations. Afterwards, we assessed stapes and umbo displacements in the reconstructed middle ear under static pressure, with either a columella-type prosthesis or a prosthetic incus, closely resembling a healthy incus. Results indicated the superior performance of the prosthetic incus in terms of both sound transmission to the inner ear and stress distribution patterns on the TM, potentially lowering the risk of prosthesis displacement/extrusion. This study underscores the potential of computational analysis in middle ear surgery, encompassing aspects such as prosthesis design, predicting outcomes in ossicular chain reconstruction (OCR), and mitigating experimental costs.

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.

Quantifying the effect of shoulder size on operation duration: an analysis of stapes surgery outcomes.

OBJECTIVE: To investigate the effect of body mass index on hearing outcomes, operative time and complication rates following stapes surgery. METHOD: This is a five-year retrospective review of 402 charts from a single tertiary otology referral centre from 2015 to 2020. RESULTS: When the patient's shoulder was adjacent to the surgeon's dominant hand, the average operative time of 40 minutes increased to 70 minutes because of a significant positive association between higher body mass index and longer operative times (normal body mass index group (<25 kg/m2) r = 0.273, p = 0.032; overweight body mass index group (25-30 kg/m2) r = 0.265, p = 0.019). Operative times were not significantly longer upon comparison of low and high body mass index groups without stratification by laterality (54.9 ± 19.6 minutes vs 57.8 ± 19.2 minutes, p = 0.127). CONCLUSION: There is a clinically significant relationship between body mass index and operating times. This may be due to access limitations imposed by shoulder size.

Anatomic and morphometric examination of auditory ossicles in sheep.

It is important to know the morphometry of the auditory ossicles for middle ear surgical applications. The present study aims to investigate the morphometric measurements of sheep auditory ossicles and the relationship between these ossicles. In this study, 100 malleus, incus and stapes of 50 Akkaraman sheep were examined using at trinocular stereo microscope and a total of 19 morphometric measurements were taken. The mean values of the morphometric measurements were obtained, and correlation analysis was performed between each part of each auditory ossicle. Similarities were found between the measurements of the lengths of the malleus, manubrium mallei and incus, and the width of the base of the stapes with morphometric measurements in human auditory ossicles. A significant positive correlation was found between the length of the malleus with the length of the manubrium mallei, between the length of the incus with the lengths of the long crus and corpus incudis, between the length of the stapes with the lengths of the rostral crus, caudal crus, caput stapedis, and the length and width of the intercrural foramen. Due to the anatomic similarities between sheep and human auditory ossicles, it was concluded that the auditory ossicles of sheep are suitable for use in the training of human ear surgery applications.

Utility of machine learning for identifying stapes fixation on ultra-high-resolution CT.

PURPOSE: Imaging diagnosis of stapes fixation (SF) is challenging owing to a lack of definite evidence. We developed a comprehensive machine learning (ML) model to identify SF on ultra-high-resolution CT. MATERIALS AND METHODS: We retrospectively enrolled 109 participants (143 ears) and divided them into the training set (115 ears) and test set (28 ears). Stapes mobility (SF or non-SF) was determined by surgical inspection. In the ML analysis, rectangular regions of interest were placed on consecutive axial slices in the training set. Radiomic features were extracted and fed into the training session. The test set was analyzed using 7 ML models (support vector machine, k nearest neighbor, decision tree, random forest, extra trees, eXtreme Gradient Boosting, and Light Gradient Boosting Machine) and by 2 dedicated neuroradiologists. Diagnostic performance (sensitivity, specificity and accuracy, with surgical findings as the reference) was compared between the radiologists and the optimal ML model by using the McNemar test. RESULTS: The mean age of the participants was 42.3 ± 17.5 years. The Light Gradient Boosting Machine (LightGBM) model showed the highest sensitivity (0.83), specificity (0.81), accuracy (0.82) and area under the curve (0.88) for detecting SF among the 7 ML models. The neuroradiologists achieved good sensitivities (0.75 and 0.67), moderate-to-good specificities (0.63 and 0.56) and good accuracies (0.68 and 0.61). This model showed no statistical differences with the neuroradiologists (P values 0.289-1.000). CONCLUSIONS: Compared to the neuroradiologists, the LightGBM model achieved competitive diagnostic performance in identifying SF, and has the potential to be a supportive tool in clinical practice.

The Stapes Head Coupler-A Flexible and Safe Option for Vibroplasty.

OBJECTIVE: To investigate the surgical approach and the audiological outcome of a stapes head coupler in active middle ear implant surgery. STUDY DESIGN: Retrospective data analysis. SETTING: Tertiary referral center with a large active middle ear implant program. PATIENTS: Twelve patients with active middle ear implant surgery. INTERVENTIONS: Therapeutic surgical approach for hearing rehabilitation in human subjects. MAIN OUTCOME MEASURES: Auditory brainstem response, sound field thresholds, vibrogram, speech perception in the Freiburger monosyllabic word test. RESULTS: The stapes head was attached safely in different coupling situations. Audiological outcomes were similar to the audiological performance of established vibroplasty couplers presented in the literature. CONCLUSION: The stapes head coupler is a new and safe tool for vibroplasty with a good audiological outcome.

Endoscopic Findings on Facial Nerve Anatomy During Exclusive Endoscopic Stapedotomy: Clinical Considerations and Impact on Surgical Results.

BACKGROUND: Variations along the facial nerve (FN) course present considerable challenges in the surgical treatment of otosclerosis, often complicating the procedure. Existing knowledge of its tympanic tract and its implications primarily comes from microscopical procedures. This study aims to assess endoscopic findings of FN anatomy in a healthy tympanic cavity and its impact on the stapedotomy procedure, focusing on the risk of complications and functional hearing outcomes. METHODS: A retrospective study on exclusive endoscopic stapedotoplasties between October 2014 and October 2021 at our Otorhinolaryngology University Department was carried out. An evaluation of intraoperative endoscopic findings reviewed in surgical descriptive and/or video records was conducted to assess their potential negative impact on the surgery. Demographic data, preoperative and postoperative hearing thresholds, as well as intraoperative and postoperative complications were analyzed. RESULTS: One hundred fifty-seven subjects were included. A FN partially overhanging the oval window was observed in 7.3% (n=12): 10 prolapsing with bony canal dehiscence and 2 without any detected dehiscence. Each procedure was successfully completed without any issues related to the anomalous anatomy, and in no case, switching to the microscope for the handling of the prosthesis near the dehiscent nerve was required. No facial paralysis occurred, with an early- or long-term postoperative House-Brackman grade of 1 (n=157, 100%). Only 3/157 patients (1.9%) showed a sensorineural threshold reduction of ≥20 dB HL, but a significant air-bone gap improvement was observed (mean closure of 18.36 dB HL, P -lt; .0001). CONCLUSION: The endoscope promotes a concrete description of tympanic FN anatomy, and endoscopic stapes surgery appears to be a safe and viable option when dehiscent or prolapsed FNs reduce the footplate's exposure.