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.

[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.

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.

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.

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.

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.

Skeletal anatomy of the early Permian parareptile Delorhynchus with new information provided by neutron tomography.

Detailed description of the holotype skeleton of Delorhynchus cifellii, made possible through the use of neutron tomography, has yielded important new information about the cranial and postcranial anatomy of this early Permian acleistorhinid parareptile. Hitherto unknown features of the skull include a sphenethmoid, paired epipterygoids and a complete neurocranium. In addition, the stapes has been exposed in three dimensions for the first time in an early parareptile. Postcranial material found in articulation with the skull in this holotype allows for the first detailed description of vertebrae, ribs, shoulder girdle and humerus of an acleistorhinid parareptile, allowing for a reevaluation of the phylogenetic relationships of this taxon with other acleistorhinids, and more broadly among parareptiles. Results show that Delorhynchus is recovered as the sister taxon of Colobomycter, and 'acleistorhinids' now include Lanthanosuchus.

Content Validity of a High-Fidelity Surgical Middle Ear Simulator: A Randomized Prospective International Multicenter Trial.

OBJECTIVE: After demonstration of face validity of a surgical middle ear simulator (SMS) previously, we assessed the content validity of the simulator with otolaryngology residents. STUDY DESIGN: Multicenter randomized prospective international study. SETTING: Four academic institutions. METHODS: Novice participants were randomized into control, low-fidelity (LF), and high-fidelity (HF) groups. Control and LF produced 2 recordings from 2 attempts, and HF produced 4 recordings from 10 attempts, with trials 1, 4, 7, and 10 used for scoring. Three blinded experts graded videos of the simulated stapedectomy operation using an objective skills assessment test format consisting of global and stapedotomy-specific scales. RESULTS: A total of 152 recordings from 61 participants were included. Baseline characteristics did not differ significantly between groups. Depending on the step of the operation, inter-rater reliability ranged from 24 to 90%. For LF and HF, years of training was significantly associated with improved scores in certain objective skills assessment test subparts. HF outperformed the control group on stapes and global scores ( p < 0.05). The HF group demonstrated improvement in global score over trials, but plateaued after four trials. Scores varied greatly for participants from different institutions in certain operative steps, such as transecting incudostapedial joints, likely due to differences in instrumentation and time elapsed since manufacture. CONCLUSION: Practice with SMS led to better performance in both global and stapes-specific scores. Further studies are needed to examine construct validity and to create otology-appropriate grading systems. Variables like instrumentation and decline in flexibility of the simulator after 12 months greatly affect performance on the simulator.

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.

The tetrapod fauna of the upper Permian Naobaogou Formation of China: 10. Jimusaria monanensis sp. nov. (Dicynodontia) shows a unique epipterygoid.

Jimusaria is the first reported Chinese dicynodont, previously only known from Xinjiang. Here we refer two specimens from the Naobaogou Formation, Nei Mongol, China to Jimusaria based on the following features: squamosal separated from supraoccipital by tabular, tabular contacting opisthotic, sharp and thin lateral dentary shelf expanding anteriorly into a thick swelling, nasals fused as single element, rod-like medial bar formed by footplate of epipterygoid connecting to the parabasisphenoid and periotic medially. A new species, J. monanensis, is named based on the diagnostic characters on these two specimens such as distinct caniniform buttress lacking posteroventral furrow, naso-frontal suture forming an anterior directed sharp angle, and converging ventral ridges on posterior portion of anterior pterygoid rami. In Jimusaria, the epipterygoid posteromedially contacts the parabasisphenoid and the periotic as a rod-like bar, a unique morphology unknown in any other dicynodonts. This structure probably increases the stability of the palatal complex. A similar structure might also appear in other dicynodonts as a cartilage connection. The new occurrence of Jimusaria increases the diversity of the tetrapod assemblage from the Naobaogou Formation, and further strengthens the connection between the tetrapod faunas from Nei Mongol and Xinjiang. Based on the current record, Jimusaria is one of the few tetrapod genera which survived in the end-Permian mass extinction.

Comparison of dislocation rates of Teflon and Titanium stapes prostheses: a retrospective survival analysis on 855 patients.

BACKGROUND: Stapes prosthesis dislocation is the first cause of revision stapes surgery. To our knowledge, there is no data about stability of the incus attachment of manual crimped prosthesis of different materials. This study aimed to compare the dislocation incidence between titanium and fluoroplastic stapes prostheses. METHOD: A monocentric retrospective cohort study was conducted between January 2013 and June 2022 in a tertiary-care center. All patients that underwent a primary stapes surgery with manually crimped fluoroplastic or titanium prostheses were included. Prosthesis dislocation from the incus was identified intraoperatively or with CT scan. The incidence of stapedial prosthesis dislocation over time was estimated using the Kalbfleisch and Prentice survival analysis method. Other indications for revision surgery prior to prosthesis dislocation were considered as competing events. Differences in the cumulative incidence functions between the fluoroplastic group and the titanium group was assessed using the Gray's test. RESULTS: Eight hundred and fifty-five patients underwent primary stapes surgery during the study period. Fluoroplastic prosthesis was used in 758 (88.7%) cases and titanium prosthesis in 97 (11.3%) cases. Median follow-up was 51.7 months (28.4-80.1). Dislocation was observed in 23 (3.0%) patients with fluoroplastic prosthesis and none (0.0%) in the titanium group. The probability of prosthesis dislocation at two years after surgery was 3.5% in the Teflon group and 0.0% in the Titanium group. No significant difference was found in the cumulative incidence of prosthesis dislocation between the fluoroplastic group and the titanium group (p = 0.12). CONCLUSIONS: Despite lack of statistical power, our results suggest a trend in a more stable incus attachment of manually crimped titanium stapes prosthesis compared to fluoroplastic over time. Further prospective randomized studies could be valuable to assess our findings.

High-resolution computerized tomography for ossicular replacement prostheses

Introduction To study the accuracy of high-resolution computed tomography (HRCT) for assessing the ossicular structures in cadaveric temporal bone by the distance between temporal bone elements is of great interest. Objectives To record the distances between the malleal neck and both the stapedial head and footplate by HRCT. Further, after partially opening the temporal bone toward the ossicular structure, to record the actual distances between those structures during surgical dissection. Material and methods This study compared actual and HRCT measurements of cadaveric temporal bone. We studied, measured, and recorded distances within and between various structural elements. All data are reported as means and were analyzed to prove the accuracy of HRCT to assess ossicular structure from the temporal bone. Results This study included the temporal bones of 10 male and 10 female cadavers (mean age, 70.4 years). By surgical dissection, the distances between the malleal neck and the stapedial head and footplate were 3.40 and 5.30 mm, respectively (measured from the bone); by HRCT, the corresponding values were 3.35 and 5.29 mm. The intraclass correlation coefficients for assessing ossicular structure in contrast to the actual measurements were 0.901 (malleal neck to stapedial head) and 0.923 (malleal neck to stapedial footplate) (p < 0.05). There were no differences between the actual malleal neck to stapedial head (p = 0.793) or footplate (p = 0.242) measurements. Conclusion HRCT produced statistically comparable, reliable, and accurate measurements compared with actual measurements in cadaveric temporal bone. (AU)

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.

Otosclerosis under the magnifying glass.

Otosclerosis is a bone condition affecting the stapes bone within the otic capsule, and its exact cause is still unknown. It is characterized by a lack of proper remodeling of newly formed vascular and woven bone, leading to the development of abnormal osteons and the formation of sclerotic bone. Bilateral otosclerosis is seen in 80% of patients and 60% of otosclerosis patients have a family history of the condition. The etiology of this disease is still unknown, there are lots of theories to explain it. The histopathological (HP) studies of otosclerosis showed that osteoblasts, osteoclasts, vascular proliferation, fibroblasts, and histiocytes were observed in the stapes footplate. The onset of the symptoms occurs by the early third decade of life, usually it doesn't start later. In otosclerosis, the energy exerted by sound at the level of the tympanic membrane is reduced in the inner ear due to the fixation and rigidity of the ossicular chain, leading to hearing loss, especially for low frequencies. The primary clinical symptom of otosclerosis is conductive hearing loss but it is important to note that sensorineural hearing loss and mixed hearing loss can also occur as secondary symptoms of the condition. Another symptom present in patients with otosclerosis is tinnitus. The paper carried out a retrospective study of 70 patients diagnosed with otosclerosis in the Department of Otorhinolaryngology of Emergency City Hospital, Timisoara, Romania, between January 2021 to December 2022. Tissue fragments were processed at Service of Pathology by standard Hematoxylin-Eosin staining. The HP diagnosis was completed using Masson's trichrome staining, Giemsa histochemical staining, and immunohistochemical (IHC) reactions with anti-cluster of differentiation (CD)20, anti-CD3, anti-CD4, anti-CD8, anti-CD34, and anti-CD31 antibodies. The microscopic examination showed a chronic diffuse inflammatory infiltrate that consisted predominantly of mature T-lymphocytes, immunohistochemically positive for CD3, CD4 and CD8. There were also present rare CD20-positive B-lymphocytes. Among the lymphocytes, relatively numerous mast cells were identified, highlighted histochemically by the Giemsa staining. They had numerous purple-violet intracytoplasmic granules. In the connective tissue support, a relatively rich vascular network was identified, consisting of hyperemic capillaries, highlighted immunohistochemically with anti-CD31 and anti-CD34 antibodies. Bone tissues trabeculae showed extensive areas of fibrosis. The collagen fibers were highlighted by Masson's trichrome staining, being stained in green, blue, or bluish green.

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.