High hydrostatic pressure treatment for advanced tissue grafts in reconstructive head and neck surgery.

The increasing importance of regenerative medicine has resulted in a growing need for advanced tissue replacement materials in head and neck surgery. Allo- and xenogenic graft processing is often time-consuming and can deteriorate the extracellular matrix (ECM). High hydrostatic pressure (HHP)-treatment could allow specific devitalization while retaining the essential properties of the ECM. Porcine connective tissue and cartilage were HHP-treated at 100-400 MPa for 10 min. Structural modifications following HHP-exposure were examined using electron microscopy, while devitalization was assessed through metabolism and cell death analyses. Furthermore, ECM alterations and decellularization were evaluated by histology, biomechanical testing, and DNA content analysis. Additionally, the inflammatory potential of HHP-treated tissue was evaluated in vivo using a dorsal skinfold chamber in a mouse model. The devitalization effects of HHP were dose-dependent, with a threshold identified at 200 MPa for fibroblasts and chondrocytes. At this pressure level, HHP induced structural alterations in cells, with a shift toward late-stage apoptosis. HHP-treatment preserved ECM structure and biomechanical properties, but did not remove cell debris from the tissue. This study observed a pressure-dependent increase of markers suggesting the occurrence of immunogenic cell death. In vivo investigations revealed an absence of inflammatory responses to HHP-treated tissue, indicating a favorable biological response to HHP. In conclusion, application of HHP devitalizes fibroblasts and chondrocytes at 200 MPa while retaining the essential properties of the ECM. Prospectively, HHP may simplify the preparation of allo- and xenogenic tissue replacement materials and increase the availability of grafts in head and neck surgery.

The Predictive Value of Preoperative Measurements of Cochlear Nerve Diameters From MRT and Postoperative Speech Perception in Adult Patients With Cochlear Implant.

OBJECTIVE: The current study aims to investigate whether objective measurements of the cochlear nerve (CN), derived from preoperative MRI images, correlate with postoperative speech perception in CI patients. STUDY DESIGN: Retrospective cohort study. SETTING: University Medical Center, tertiary academic referral center. PATIENTS: Patients undergoing a cochlear implant surgery including MED-EL (Synchrony 2, FLEX electrode series; MED-EL, Innsbruck, Austria) Cochlear (slim straight electrodes; Cochlear Ltd., Sydney, Australia), Advanced Bionics (HiRes Ultra 3D CI, HiFocus SlimJ electrodes; Sonova, Zürich, Switzerland), and Oticon (Neuro Zti EVO; Oticon A/S, Smørum, Denmark) between 2020 and 2023. INTERVENTION: Preoperative MRI images were utilized to measure the volume of the modiolus (VM), the cross-sectional areas of the CN (ACN), and for normalization, the area of the facial nerve (AFN) and the area of the internal ear canal (AIEC). Postoperative speech perceptions were assessed through word recognition scores (WRS) at several stages following the first fitting (FF) of the CI processor: immediately after FF, 1 month, 3 months, and 6 months after FF. MAIN OUTCOME MEASURES: Sixty-eight patients were enrolled in this study. A statistically significant positive correlation between the ratio between ACN and AFN (ACN/AFN) and WRSFF was identified (R = 0.36, p < 0.003). However, this correlation disappeared in subsequent follow-up tests. Moreover, upon grouping patients based on their degree of asymmetrical hearing loss, it was observed that the correlation was primarily driven by patients with moderate to severe asymmetrical hearing loss (AHLm) on the contralateral side (R = 0.62, p = 0.0003). CONCLUSION: The present results suggest that assessing the size of the CN through MRI has limited predictive utility for postoperative speech perceptions during CI consultations. This limitation seems to be particularly relevant for AHLm patients and is confined to the initial activation period.

The curvature quantification of wave I in auditory brainstem responses detects cochlear synaptopathy in human beings.

PURPOSE: Patients with age-related hearing loss complain often about reduced speech perception in adverse listening environment. Studies on animals have suggested that cochlear synaptopathy may be one of the primary mechanisms responsible for this phenomenon. A decreased wave I amplitude in supra-threshold auditory brainstem response (ABR) can diagnose this pathology non-invasively. However, the interpretation of the wave I amplitude in humans remains controversial. Recent studies in mice have established a robust and reliable mathematic algorithm, i.e., curve curvature quantification, for detecting cochlear synaptopathy. This study aimed to determine whether the curve curvature has sufficient test-retest reliability to detect cochlear synaptopathy in aging humans. METHODS: Healthy participants were recruited into this prospective study. All subjects underwent an audiogram examination with standard and extended high frequencies ranging from 0.125 to 16 kHz and an ABR with a stimulus of 80 dB nHL click. The peak amplitude, peak latency, curvature at the peak, and the area under the curve of wave I were calculated and analyzed. RESULTS: A total of 80 individuals with normal hearing, aged 18 to 61 years, participated in this study, with a mean age of 26.4 years. Pearson correlation analysis showed a significant negative correlation between curvature and age, as well as between curvature and extended high frequency (EHF) threshold (10-16 kHz). Additionally, the same correlation was observed between age and area as well as age and EHF threshold. The model comparison demonstrated that the curvature at the peak of wave I is the best metric to correlate with EHF threshold. CONCLUSION: The curvature at the peak of wave I is the most sensitive metric for detecting cochlear synaptopathy in humans  and may be applied in routine diagnostics to detect early degenerations of the auditory nerve.

Rise in complications of acute otitis media during and after the COVID-19 pandemic.

PURPOSE: After the lifting of nonpharmaceutical interventions (NPIs) during the COVID-19 pandemic, clinical observation showed an increase in complications of acute otitis, followed by a rise in the number of mastoidectomies performed. The aim of this study was to record the number of mastoidectomies performed before, during and after the COVID-19 pandemic as an indicator for complications of acute otitis media. METHODS: Data were collected from a tertiary hospital in a university setting, as well as from four major public health insurance companies in Germany. The data of 24,824,763 German citizens during a period from 2014 until 2023 were analyzed. RESULTS: According to the data, during the COVID-19 pandemic, the number of mastoidectomies performed dropped by 54% for children aged 0-6 and by 62% for children aged 7-18. For adults, there were 30% fewer mastoidectomies performed between 2020 and 2022. After the lifting of most NPI's in the season from July 2022 to June 2023, there was a sharp increase in the number of mastoidectomies performed on patients of all ages. CONCLUSIONS: During the COVID-19 pandemic, a decrease in the number of mastoidectomies performed was seen, suggesting a lower incidence of complicated acute otitis, most likely linked to the general decrease of upper airway infections due to NPI's. In contrast, a sharp increase in the incidence of complicated otitis occurred after the hygiene measures were lifted. The current development causes a more frequent performance of mastoidectomies, thus entailing a change in the challenges for everyday clinical practice.

[Multidimensional formats of surgical anatomy in otorhinolaryngology student teaching-a comparison of effectivity]. / Multidimensionale Formate chirurgischer Anatomie in der studentischen Ausbildung der HNO-Heilkunde ­ ein Effektivitätsvergleich.

BACKGROUND: Technological change in healthcare and the digital transformation of teaching require innovations in student teaching in medicine. New technologies are needed to enable the delivery and use of diverse teaching and learning formats by educational institutions independent of time and place. The aim of this study is to analyze the effectiveness of different multidimensional formats in student teaching in surgical ENT medical anatomy. MATERIALS AND METHODS: During the summer semester 2022 and winter semester 2022/2023, the digital teaching and learning program was expanded by testing different visualization formats (3D glasses, cardboards, or VR glasses) with students in the context of a highly standardized surgical procedure, namely cochlear implantation. A pre- and post-intervention knowledge assessment was carried out in all groups, followed by an evaluation. RESULTS: Of 183 students, 91 students fully participated in the study. The post-intervention knowledge assessment showed a significant increase in correct answers regardless of visualization format. In a direct comparison, the operating room (OR) group answered correctly significantly more often than the cardboard group (p = 0.0424). The majority of students would like to see 3D teaching as an integral part of the teaching program (87.9%) and more streaming of live surgeries (93.4%). They see the use of the various technologies as a very good addition to conventional surgical teaching (72.5%), as good visualization (89%) increases retention (74.7%) and motivation (81.3%). CONCLUSION: Application and use of new visualization technologies in everyday clinical practice is a promising approach to expanding student training. Mobile, interactive, and personalized technical formats can be adapted to the learning behavior of students. Last but not least, the use of new media influences learning motivation. An expansion of digital teaching and learning formats can be expressly recommended on the basis of this study.

[Interactive electronic visualization formats in student teaching]. / Interaktive elektronische Visualisierungsformate in der studentischen Ausbildung.

BACKGROUND: In the context of contact restrictions, conventional teaching is currently in need of optimization and expansion. The range of digital teaching formats in student training is very heterogeneous and their effectiveness uncertain. This study aims to investigate the extent to which an electronic ward round can be used as an alternative to the conventional ENT attendance practical course, and whether the use of electronic teaching formats has an influence on the quality of teaching. MATERIALS AND METHODS: Instead of regular attendance practicals, bedside teaching took place once a week in real time as a video stream via tablet. A total of 43 students in the seventh semester (winter semester 2020/2021) were included in the prospective study. Evaluation forms were used to examine the subjective didactic value of different visualization formats for the students. Examination results from previous years were used for comparison. RESULTS: The majority of students reported knowledge gain from the electronic rounds (93.02%) and that they were a good alternative to the traditional attendance clerkship (69.77%). The quality of the video and audio transmission as well as the comprehensibility of the case studies presented were consistently rated as good to very good. The students' examination results tended to be slightly worse in the test group compared to the control students of previous years. CONCLUSION: Integration of innovative interactive visualization options into teaching shows promising prospects as a supplement to conventional face-to-face teaching. The results of this study can contribute to the further expansion of digital teaching. Scaling up this model could be considered especially in countries with limited availability of face-to-face teaching.

Transimpedance Matrix Can Be Used to Estimate Electrode Positions Intraoperatively and to Monitor Their Positional Changes Postoperatively in Cochlear Implant Patients.

OBJECTIVE: Accurate positioning of the electrode array during cochlear implant (CI) surgery is crucial for achieving optimal hearing outcomes. Traditionally, postoperative radiological imaging has been used to assess electrode position. Transimpedance matrix (TIM) measurements have also emerged as a promising method for assessing electrode position. This involves utilizing electric field imaging to create an electric distance matrix by analyzing voltage variations among adjacent electrodes. This study aimed to investigate the feasibility of using intraoperative TIM measurements to estimate electrode position and monitor postoperative changes. STUDY DESIGN: Retrospective cohort study. SETTING: University Medical center, tertiary academic referral center. PATIENTS: Patients undergoing CI (CI622) surgery between January 2019 and June 2022. INTERVENTION: CI electrode positions and maximal angular insertion depths (maxAID) were determined using X-ray imaging according to Stenvers' projection. The mean gradient phase (MGP) was extracted from the TIM, and a correlation between the MGP and maxAID was examined. A model was then built to estimate the maxAID using the MGP, and changes in electrode location over time were assessed using this model. MAIN OUTCOME MEASURES: Twenty-four patients were included in this study. A positive correlation between the maxAID and the MGP ( R = 0.7, p = 0.0001) was found. The established model was able to predict the maxAID with an accuracy of 27.7 ± 4.4°. Comparing intraoperative and postoperative TIM measurements, a decrease of 24.1° ± 10.7° in maxAID over time was observed. CONCLUSION: TIM measurements are useful for estimating the insertion depth of the electrode and monitoring changes in the electrode's position over time.

Tone Decay Reconsidered: Preliminary Results of a Prospective Study in Hearing-Aid Users with Moderate to Severe Hearing Loss.

Among hearing aid (HA) users, there is a considerable variability in word recognition scores (WRSs). This variability is most pronounced among individuals with moderately severe to severe hearing loss. The variability cannot be adequately explained by factors such as pure-tone audiogram, audiogram type or age. This prospective study was designed to investigate the relationship between tone decay (TD) and WRS in a group of HA users with corresponding pure-tone hearing loss. The study population included 22 patients with hearing loss between 50 and 80 dB HL. Aided WRS, unaided WRS and TD were assessed for both ears. TD was found to be frequency-dependent. TD and WRS were correlated, with up to R = -0.66. The TD test was revealed to be a feasible method for explaining variability in WRS among HA users with hearing loss below 80 dB. This may contribute to improved differential diagnostics. The TD test may thus offer a better understanding of the limitations of HA use in the context of cochlear implant candidacy assessment for HA users.

Comparing linear and non-linear models to estimate the appropriate cochlear implant electrode array length-are current methods precise enough?

PURPOSE: In cochlear implantation with flexible lateral wall electrode arrays, a cochlear coverage (CC) range between 70% and 80% is considered ideal for optimal speech perception. To achieve this CC, the cochlear implant (CI) electrode array has to be chosen according to the individual cochlear duct length (CDL). Here, we mathematically analyzed the suitability of different flexible lateral wall electrode array lengths covering between 70% and 80% of the CDL. METHODS: In a retrospective cross-sectional study preoperative high-resolution computed tomography (HRCT) from patients undergoing cochlear implantation was investigated. The CDL was estimated using an otosurgical planning software and the CI electrode array lengths covering 70-80% of the CDL was calculated using (i) linear and (ii) non-linear models. RESULTS: The analysis of 120 HRCT data sets showed significantly different model-dependent CDL. Significant differences between the CC of 70% assessed from linear and non-linear models (mean difference: 2.5 mm, p < 0.001) and the CC of 80% assessed from linear and non-linear models (mean difference: 1.5 mm, p < 0.001) were found. In up to 25% of the patients none of the existing flexible lateral wall electrode arrays fit into this range. In 59 cases (49,2%) the models did not agree on the suitable electrode arrays. CONCLUSIONS: The CC varies depending on the underlying CDL approximation, which critically influences electrode array choice. Based on the literature, we hypothesize that the non-linear method systematically overestimates the CC and may lead to rather too short electrode array choices. Future studies need to assess the accuracy of the individual mathematical models.

Effects of Intraoperative Cochlear Implant Electrode Conditioning on Impedances and Electrically Evoked Compound Action Potentials.

OBJECTIVE: The current study investigates whether, during a Cochlear Implant (CI) surgery, conditioning (i.e. applying short bursts of electrical stimulation) within a saline solution can have positive effects on subsequent intra-operative measurements. We hypothesize that, based on previous research, the impedance values will be reduced, and that the reproducibility of Electrically Evoked Compound Action Potentials (ECAPs) is improved as a result of conditioning. METHODS: We conditioned half of the electrode contacts, within a saline solution, before CI insertion, using 23 MED-EL implants. Impedance was measured for both the conditioned and non-conditioned groups at five time points. Repeated ECAP recordings were measured and compared between the conditioned and non-conditioned groups. RESULTS: Impedance of the electrode contacts were reduced by 31% after conditioning in saline solution; however, there were no clinically relevant differences after the implantation of the electrode array. The hypothesis that measurement reproducibility would be increased after conditioning could not be confirmed with our data. Within the saline solution, we observed that 44% of the electrode contacts were covered with air bubbles, which most disappeared after implantation. However, these air bubbles limited the effectiveness of the conditioning within the saline solution. Lastly, the effect of conditioning on the reference electrode stimulation was approximately 16% of the total reduction in impedance. CONCLUSION: Our data does not suggest that intraoperative conditioning is clinically required for cochlear implantation with MED-EL implants. Additionally, an in-vivo ECAP recording can be considered as a method of conditioning the electrode contacts. SIGNIFICANCE: We confirm that the common clinical practice does not need to be changed.

Head and Neck Cancer: A Study on the Complex Relationship between QoL and Swallowing Function.

Head and neck squamous cell carcinoma (HNSCC) is linked to significant morbidity, adversely affecting survival and functional capacity. Post-treatment challenges such as pain, dysphonia, and dysphagia are common, prompting increased attention in survivorship research. Quality of Life (QoL) questionnaires, especially the MD Anderson Dysphagia Inventory (MDADI), are prevalent outcome measures in clinical studies but often lack parallel objective swallowing function evaluations, leading to potential outcome discrepancies. This study aimed to illuminate the relationship between subjective QoL (EQ-5D-5L and MDADI) measures and objective swallowing function (evaluated via Fiberoptic Endoscopic Evaluation of Swallowing, FEES) in patients with HNSCC. The analysis revealed a notable discordance between objective measures of swallowing function, such as the Penetration-Aspiration Scale (PAS) and residue ratings in the vallecula or piriform sinus, and patients' subjective QoL assessments (p = 0.21). Despite the lack of correlation, swallowing-related QoL, as measured by the MDADI, was more indicative of disease severity than generic QoL assessments. Generic QoL scores did not demonstrate substantial variation between patients. In contrast, MDADI scores significantly declined with advancing tumor stage, multimodal therapy, and reliance on feeding tubes. However, the clinical significance of this finding was tempered by the less than 10-point difference in MDADI scores. The findings of this study underline the limitations of QoL measures as standalone assessments in patients with HNSCC, given their reliance on patient-perceived impairment. While subjective QoL is a crucial aspect of evaluating therapeutic success and patient-centric outcomes, it may fail to capture critical clinical details such as silent aspirations. Consequently, QoL assessments should be augmented by objective evaluations of swallowing function in clinical research and practice to ensure a holistic understanding of patient well-being and treatment impact.

Establishing safe high hydrostatic pressure devitalization thresholds for autologous head and neck cancer vaccination and reconstruction.

High hydrostatic pressure specifically devitalizes cells and tissues without major changes in their molecular structure. Hence, high hydrostatic pressure may enhance the development of whole-cell anti-tumor vaccines, representing tumor heterogeneity and thus (neo-) antigen diversity. Moreover, safe devitalization of tumor-infiltrated supporting tissue may facilitate reimplantation for functional reconstruction. However, precise high hydrostatic pressure thresholds for safe cancer cell killing are unknown. Here, we show that high hydrostatic pressure of at least 450 MPa is necessary to safely devitalize head and neck squamous cell cancer. A pressure of 300 MPa, which has been used frequently in cancer vaccine preparation, resulted in partial devitalization with 27% live cells in flow cytometry and 4% remaining autofluorescence in cell culture after one week. The remaining cells could form vital tumors in the chorioallantoic membrane assay. In contrast, 450 MPa killed all cells in vitro and prevented tumor outgrowth in ovo. The effectiveness of 450 MPa was attributed to the induction of DNA double-strand breaks, independent of apoptosis, autophagy, or methuosis. Furthermore, 450 MPa continued to induce immunogenic cell death. Our results demonstrate that 450 MPa of high hydrostatic pressure induces safe and sustained devitalization of head and neck cancer cells and tissues. Because of the heterogeneity in pressure resistance, we propose our approach as a starting point for determining the precise thresholds for other cancer entities. Further studies on head and neck cancer should focus on immunological co-cultures, combinations of immune checkpoint inhibition, and accurate anatomical reconstruction with pressure-treated autografts.

Accuracy of Preoperative Cochlear Duct Length Estimation and Angular Insertion Depth Prediction.

OBJECTIVE: In cochlear implantation with flexible lateral wall electrodes, a cochlear coverage of 70% to 80% is assumed to yield an optimal speech perception. Therefore, fitting the cochlear implant (CI) to the patient's individual anatomy has gained importance in recent years. For these reasons, the optimal angular insertion depth (AID) has to be calculated before cochlear implantation. One CI manufacturer offers a software that allows to visualize the AID of different electrode arrays. Here, it is hypothesized that these preoperative AID models overestimate the postoperatively measured insertion angle. This study aims to investigate the agreement between preoperatively estimated and postoperatively measured AID. STUDY DESIGN: Retrospective cross-sectional study. SETTING: Single-center tertiary referral center. PATIENTS: Patients undergoing cochlear implantation. INTERVENTION: Preoperative and postoperative high-resolution computed tomography (HRCT). MAIN OUTCOME MEASURES: The cochlear duct length was estimated by determining cochlear parameters ( A value and B value), and the AID for the chosen electrode was (i) estimated by elliptic circular approximation by the software and (ii) measured manually postoperatively by detecting the electrode contacts after insertion. RESULTS: A total of 80 HRCT imaging data sets from 69 patients were analyzed. The mean preoperative AID estimation was 662.0° (standard deviation [SD], 61.5°), and the mean postoperatively measured AID was 583.9° (SD, 73.6°). In all cases (100%), preoperative AID estimation significantly overestimated the postoperative determined insertion angle (mean difference, 38.1°). A correcting factor of 5% on preoperative AID estimation dissolves these differences. CONCLUSIONS: The use of an electrode visualization tool may lead to shorter electrode array choices because of an overestimation of the insertion angle. Applying a correction factor of 0.95 on preoperative AID estimation is recommended.

[Health-related quality of life in chronic otitis media-measurement methods and their application in surgical therapy]. / Gesundheitsbezogene Lebensqualität bei der chronischen Otitis media ­ Messmethoden und deren Anwendung bei chirurgischen Therapien.

BACKGROUND: Chronic otitis media (COM) can lead to significant impairment of health-related quality of life (HRQoL) due to symptoms such as otorrhea, pain, hearing loss, tinnitus, or dizziness. A systematic assessment of HRQoL in COM is becoming increasingly important as it complements (semi-)objective outcome parameters in clinical practice and research. HRQoL is measured by means of patient-reported outcome measures (PROMs). There are two disease-specific validated PROMs available for COM in German-the Chronic Otitis Media Outcome Test (COMOT-15) and the Zurich Chronic Middle Ear Inventory (ZCMEI-21)-which have become increasingly popular in recent years. OBJECTIVE: The purpose of this narrative review is to present the current state of research on measuring HRQoL in COM before and after surgical procedures. RESULTS AND CONCLUSION: Hearing is the most important factor influencing HRQoL in COM. Surgical procedures usually result in a clinically relevant improvement in HRQoL in COM with or without cholesteatoma. However, if cholesteatoma is present, its extent does not correlate with HRQoL. While HRQoL plays a secondary role in establishment of the indication for surgical therapy in COM with cholesteatoma, it plays an important role in terms of relative surgical indications, e.g., a symptomatic open mastoid cavity after resection of the posterior canal wall. We encourage the regular use of disease-specific PROMs preoperatively as well as during follow-up to assess HRQoL in COM in individual patients, in research, and in the context of quality monitoring.

Continuous intraoperative perfusion monitoring of free microvascular anastomosed fasciocutaneous flaps using remote photoplethysmography.

Flap loss through limited perfusion remains a major complication in reconstructive surgery. Continuous monitoring of perfusion will facilitate early detection of insufficient perfusion. Remote or imaging photoplethysmography (rPPG/iPPG) as a non-contact, non-ionizing, and non-invasive monitoring technique provides objective and reproducible information on physiological parameters. The aim of this study is to establish rPPG for intra- and postoperative monitoring of flap perfusion in patients undergoing reconstruction with free fasciocutaneous flaps (FFCF). We developed a monitoring algorithm for flap perfusion, which was evaluated in 15 patients. For 14 patients, ischemia of the FFCF in the forearm and successful reperfusion of the implanted FFCF was quantified based on the local signal. One FFCF showed no perfusion after reperfusion and devitalized in the course. Intraoperative monitoring of perfusion with rPPG provides objective and reproducible results. Therefore, rPPG is a promising technology for standard flap perfusion monitoring on low costs without the need for additional monitoring devices.

Internal auditory canal volume in normal and malformed inner ears.

PURPOSE: A narrow bony internal auditory canal (IAC) may be associated with a hypoplastic cochlear nerve and poorer hearing performances after cochlear implantation. However, definitions for a narrow IAC vary widely and commonly, qualitative grading or two-dimensional measures are used to characterize a narrow IAC. We aimed to refine the definition of a narrow IAC by determining IAC volume in both control patients and patients with inner ear malformations (IEMs). METHODS: In this multicentric study, we included high-resolution CT (HRCT) scans of 128 temporal bones (85 with IEMs: cochlear aplasia, n = 11; common cavity, n = 2; cochlear hypoplasia type, n = 19; incomplete partition type I/III, n = 8/8; Mondini malformation, n = 16; enlarged vestibular aqueduct syndrome, n = 19; 45 controls). The IAC diameter was measured in the axial plane and the IAC volume was measured by semi-automatic segmentation and three-dimensional reconstruction. RESULTS: In controls, the mean IAC diameter was 5.5 mm (SD 1.1 mm) and the mean IAC volume was 175.3 mm3 (SD 52.6 mm3). Statistically significant differences in IAC volumes were found in cochlear aplasia (68.3 mm3, p < 0.0001), IPI (107.4 mm3, p = 0.04), and IPIII (277.5 mm3, p = 0.0004 mm3). Inter-rater reliability was higher in IAC volume than in IAC diameter (intraclass correlation coefficient 0.92 vs. 0.77). CONCLUSIONS: Volumetric measurement of IAC in cases of IEMs reduces measurement variability and may add to classifying IEMs. Since a hypoplastic IAC can be associated with a hypoplastic cochlear nerve and sensorineural hearing loss, radiologic assessment of the IAC is crucial in patients with severe sensorineural hearing loss undergoing cochlear implantation.

Volumetry improves the assessment of the vestibular aqueduct size in inner ear malformation.

OBJECTIVES: Enlarged vestibular aqueduct (EVA) is a common finding associated with inner ear malformations (IEM). However, uniform radiologic definitions for EVA are missing and various 2D-measurement methods to define EVA have been reported. This study evaluates VA volume in different types of IEM and compares 3D-reconstructed VA volume to 2D-measurements. METHODS: A total of 98 high-resolution CT (HRCT) data sets from temporal bones were analyzed (56 with IEM; [cochlear hypoplasia (CH; n = 18), incomplete partition type I (IPI; n = 12) and type II (IPII; n = 11) and EVA (n = 15)]; 42 controls). VA diameter was measured in axial images. VA volume was analyzed by software-based, semi-automatic segmentation and 3D-reconstruction. Differences in VA volume between the groups and associations between VA volume and VA diameter were assessed. Inter-rater-reliability (IRR) was assessed using the intra-class-correlation-coefficient (ICC). RESULTS: Larger VA volumes were found in IEM compared to controls. Significant differences in VA volume between patients with EVA and controls (p < 0.001) as well as between IPII and controls (p < 0.001) were found. VA diameter at the midpoint (VA midpoint) and at the operculum (VA operculum) correlated to VA volume in IPI (VA midpoint: r = 0.78, VA operculum: r = 0.91), in CH (VA midpoint: r = 0.59, VA operculum: r = 0.61), in EVA (VA midpoint: r = 0.55, VA operculum: r = 0.66) and in controls (VA midpoint: r = 0.36, VA operculum: r = 0.42). The highest IRR was found for VA volume (ICC = 0.90). CONCLUSIONS: The VA diameter may be an insufficient estimate of VA volume, since (1) measurement of VA diameter does not reliably correlate with VA volume and (2) VA diameter shows a lower IRR than VA volume. 3D-reconstruction and VA volumetry may add information in diagnosing EVA in cases with or without additional IEM.

The Dorsal Skinfold Chamber as a New Tympanic Membrane Wound Healing Model: Intravital Insights into the Pathophysiology of Epithelialized Wounds.

BACKGROUND: Tympanic membrane perforations (TMPs) are a common complication of trauma and infection. Persisting perforations result from the unique location of the tympanic membrane. The wound is surrounded by air of the middle ear and the external auditory canal. The inadequate wound bed, growth factor, and blood supply lead to circular epithelialization of the perforation's edge and premature interruption of defect closure. Orthotopic animal models use mechanical or chemical tympanic membrane laceration to identify bioactive wound dressings and overcome premature epithelialization. However, all orthotopic models essentially lack repetitive visualization of the biomaterial-wound interface. Therefore, recent progress in 3D printing of customized wound dressings has not yet been transferred to the unique wound setup of the TMP. Here, we present a novel application for the mice dorsal skinfold chamber (DSC) with an epithelialized full-thickness defect as TMP model. METHODS: A circular 2-mm defect was cut into the extended dorsal skinfold using a biopsy punch. The skinfold was either perforated through both skin layers without prior preparation or perforated on 1 side, following resection of the opposing skin layer. In both groups, the wound was sealed with a coverslip or left unclosed (n = 4). All animals were examined for epithelialization of the edge (histology), size of the perforation (planimetry), neovascularization (repetitive intravital fluorescence microscopy), and inflammation (immunohistology). RESULTS: The edge of the perforation was overgrown by the cornified squamous epithelium in all pre-parations. Reduction in the perforation's size was enhanced by application of a coverslip. Microsurgical preparation before biopsy punch perforation and sealing with a coverslip enabled repetitive high-quality intravital fluorescence microscopy. However, spontaneous reduction of the perforation occurred frequently. Therefore, the direct biopsy punch perforation without microsurgical preparation was favorable: spontaneous reduction did not occur throughout 21 days. Moreover, the visualization of the neovascularization was sufficient in intravital microscopy. CONCLUSIONS: The DSC full-thickness defect is a valuable supplement to orthotopic TMP models. Repetitive intravital microscopy of the epithelialized edge enables investigation of the underlying pathophysiology during the transition from the inflammation to the proliferation phase of wound healing. Using established analysis procedures, the present model provides an effective platform for the screening of bioactive materials and transferring progress in tissue engineering to the special conditions of tympanic membrane wound healing.

Effect of Cochlear Implant Electrode Insertion Depth on Speech Perception Outcomes: A Systematic Review.

Objective: The suitable electrode array choice is broadly discussed in cochlear implantation surgery. Whether to use a shorter electrode length under the aim of structure preservation versus choosing a longer array to achieve a greater cochlear coverage is a matter of debate. The aim of this review is to identify the impact of the insertion depth of a cochlear implant (CI) electrode array on CI users' speech perception outcomes. Databases Reviewed: PubMed was searched for English-language articles that were published in a peer-reviewed journal from 1997 to 2022. Methods: A systematic electronic search of the literature was carried out using PubMed to find relevant literature on the impact of insertion depth on speech perception. The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines of reporting. Studies in both, children and adults with pre- or postlingual hearing loss, implanted with a CI were included in this study. Articles written in languages other than English, literature reviews, meta-analyses, animal studies, histopathological studies, or studies pertaining exclusively to imaging modalities without reporting correlations between insertion depth and speech outcomes were excluded. The risk of bias was determined using the "Risk of Bias in Nonrandomized Studies of Interventions" tool. Articles were extracted by 2 authors independently using predefined search terms. The titles and abstracts were screened manually to identify studies that potentially meet the inclusion criteria. The extracted information included: the study population, type of hearing loss, outcomes reported, devices used, speech perception outcomes, insertion depth (linear insertion depth and/or the angular insertion depth), and correlation between insertion depth and the speech perception outcomes. Results: A total of 215 relevant studies were assessed for eligibility. Twenty-three studies met the inclusion criteria and were analyzed further. Seven studies found no significant correlation between insertion depth and speech perception outcomes. Fifteen found either a significant positive correlation or a positive effect between insertion depth and speech perception. Only 1 study found a significant negative correlation between insertion depth and speech perception outcomes. Conclusion: Although most studies reported a positive effect of insertion depth on speech perception outcomes, one-third of the identified studies reported no correlation. Thus, the insertion depth must be considered as a contributing factor to speech perception rather than as a major decisive criterion. Registration: This review has been registered in PROSPERO, the international prospective register of systematic reviews (CRD42021257547), available at https://www.crd.york.ac.uk/PROSPERO/.