3D printed biomimetic cochleae and machine learning co-modelling provides clinical informatics for cochlear implant patients.

Cochlear implants restore hearing in patients with severe to profound deafness by delivering electrical stimuli inside the cochlea. Understanding stimulus current spread, and how it correlates to patient-dependent factors, is hampered by the poor accessibility of the inner ear and by the lack of clinically-relevant in vitro, in vivo or in silico models. Here, we present 3D printing-neural network co-modelling for interpreting electric field imaging profiles of cochlear implant patients. With tuneable electro-anatomy, the 3D printed cochleae can replicate clinical scenarios of electric field imaging profiles at the off-stimuli positions. The co-modelling framework demonstrated autonomous and robust predictions of patient profiles or cochlear geometry, unfolded the electro-anatomical factors causing current spread, assisted on-demand printing for implant testing, and inferred patients' in vivo cochlear tissue resistivity (estimated mean = 6.6 kΩcm). We anticipate our framework will facilitate physical modelling and digital twin innovations for neuromodulation implants

Acute otitis externa: Consensus definition, diagnostic criteria and core outcome set development.

OBJECTIVE: Evidence for the management of acute otitis externa (AOE) is limited, with unclear diagnostic criteria and variably reported outcome measures that may not reflect key stakeholder priorities. We aimed to develop 1) a definition, 2) diagnostic criteria and 3) a core outcome set (COS) for AOE. STUDY DESIGN: COS development according to Core Outcome Measures in Effectiveness Trials (COMET) methodology and parallel consensus selection of diagnostic criteria/definition. SETTING: Stakeholders from the United Kingdom. SUBJECTS AND METHODS: Comprehensive literature review identified candidate items for the COS, definition and diagnostic criteria. Nine individuals with past AOE generated further patient-centred candidate items. Candidate items were rated for importance by patient and professional (ENT doctors, general practitioners, microbiologists, nurses, audiologists) stakeholders in a three-round online Delphi exercise. Consensus items were grouped to form the COS, diagnostic criteria, and definition. RESULTS: Candidate COS items from patients (n = 28) and literature (n = 25) were deduplicated and amalgamated to a final candidate list (n = 46). Patients emphasised quality-of-life and the impact on daily activities/work. Via the Delphi process, stakeholders agreed on 31 candidate items. The final COS covered six outcomes: pain; disease severity; impact on quality-of-life and daily activities; patient satisfaction; treatment-related outcome; and microbiology. 14 candidate diagnostic criteria were identified, 8 reaching inclusion consensus. The final definition for AOE was 'diffuse inflammation of the ear canal skin of less than 6 weeks duration'. CONCLUSION: The development and adoption of a consensus definition, diagnostic criteria and a COS will help to standardise future research in AOE, facilitating meta-analysis. Consulting former patients throughout development highlighted deficiencies in the outcomes adopted previously, in particular concerning the impact of AOE on daily life

Models of Cochlea Used in Cochlear Implant Research: A Review.

Funder: Evelyn Trust; doi: http://dx.doi.org/10.13039/501100004282Funder: Royal College of Surgeons and the Anatomical SocietyFunder: W.D. Armstrong Fund (UK)Funder: Turkish Ministry of National Education (TR)As the first clinically translated machine-neural interface, cochlear implants (CI) have demonstrated much success in providing hearing to those with severe to profound hearing loss. Despite their clinical effectiveness, key drawbacks such as hearing damage, partly from insertion forces that arise during implantation, and current spread, which limits focussing ability, prevent wider CI eligibility. In this review, we provide an overview of the anatomical and physical properties of the cochlea as a resource to aid the development of accurate models to improve future CI treatments. We highlight the advancements in the development of various physical, animal, tissue engineering, and computational models of the cochlea and the need for such models, challenges in their use, and a perspective on their future directions

Corrigendum: Cochlear Size Assessment Predicts Scala Tympani Volume and Electrode Insertion Force- Implications in Robotic Assisted Cochlear Implant Surgery.

[This corrects the article on p. 723897 in vol. 8, PMID: 34660676.]

Multidisciplinary Tracheostomy Quality Improvement in the COVID-19 Pandemic : Building a Global Learning Community

Objectives: To report experience with a global multidisciplinary tracheostomy e-learning initiative Methods: An international multidisciplinary panel of experts convened to build a virtual learning community for tracheostomy care, comprising a web-based platform, five distance learning (interactive webinar) sessions, and professional discourse over 12 months. Structured pre- and post-webinar surveys were disseminated to global participants including otolaryngologists, intensivists, nurses, allied health professionals, and patients/caregivers. Data were collected on audio-visual fidelity, demographics, and pre- and post-tutorial assessments regarding experience and skill acquisition. Participants reported confidence levels for NICU, pediatric, adult, and family care, as well as technical skills, communication, learning, assessment, and subdomains. Results: Participants from 197 institutions in 22 countries engaged in the virtual education platform, including otolaryngologists, speech pathologists, respiratory therapists, specialist nurses, patients, and caregivers. Significant improvements were reported in communication (P < .0001), clinical assessments (P < .0001), and clinical governance (P < .0001), with positive impact on pediatric decannulation (P = .0008), adult decannulation (P = .04), and quality improvement (P < .0001). Respondents reported enhanced readiness to integrate knowledge into practice. Barriers included time zones, internet bandwidth, and perceived difficulty of direct clinical translation of highly technical skills. Participants rated the implementation highly in terms of length, ability for discussion, satisfaction, applicability to professional practice, and expertise of discussants (median scores: 4, 4, 4, 4 and 5 out of 5). Conclusions: Virtual learning has dominated the education landscape during COVID-19 pandemic, but few data are available on its effectiveness. This study demonstrated feasibility of virtual learning for disseminating best practices in tracheostomy, engaging a diverse, multidisciplinary audience. Learning of complex technical skills proved a hurdle, however, suggesting need for hands-on experience for technical mastery. While interactive videoconferencing via webinar affords an engaging and scalable strategy for sharing knowledge, further investigation is needed on clinical outcomes to define effective strategies for experiential online learning and virtual in-service simulations

Impact of Scala Tympani Geometry on Insertion Forces during Implantation.

Funder: Royal College of Surgeons and the Anatomical Society(1) Background: During a cochlear implant insertion, the mechanical trauma can cause residual hearing loss in up to half of implantations. The forces on the cochlea during the insertion can lead to this mechanical trauma but can be highly variable between subjects which is thought to be due to differing anatomy, namely of the scala tympani. This study presents a systematic investigation of the influence of different geometrical parameters of the scala tympani on the cochlear implant insertion force. The influence of these parameters on the insertion forces were determined by testing the forces within 3D-printed, optically transparent models of the scala tympani with geometric alterations. (2) Methods: Three-dimensional segmentations of the cochlea were characterised using a custom MATLAB script which parametrised the scala tympani model, procedurally altered the key shape parameters (e.g., the volume, vertical trajectory, curvature, and cross-sectional area), and generated 3D printable models that were printed using a digital light processing 3D printer. The printed models were then attached to a custom insertion setup that measured the insertion forces on the cochlear implant and the scala tympani model during a controlled robotic insertion. (3) Results: It was determined that the insertion force is largely unaffected by the overall size, curvature, vertical trajectory, and cross-sectional area once the forces were normalised to an angular insertion depth. A Capstan-based model of the CI insertion forces was developed and matched well to the data acquired. (4) Conclusion: By using accurate 3D-printed models of the scala tympani with geometrical alterations, it was possible to demonstrate the insensitivity of the insertion forces to the size and shape of the scala tympani, after controlling for the angular insertion depth. This supports the Capstan model of the cochlear implant insertion force which predicts an exponential growth of the frictional force with an angular insertion depth. This concludes that the angular insertion depth, rather than the length of the CI inserted, should be the major consideration when evaluating the insertion force and associated mechanical trauma caused by cochlear implant insertion

Incomplete Partition Type-II Cochlear Malformations: Delineating the 3D Structure from Digitised Human Histopathological Specimens

Hypothesis There are clinically-relevant differences in scalae anatomy and spiral ganglion neuron (SGN) quantity between incomplete partition type II (IP-II) and normal cochleae. Background IP-II is a commonly implanted cochlear malformation. Detailed knowledge of intracochlear three dimensional (3D) morphology may assist with cochlear implant (CI) electrode selection/design and enable optimization of audiologic programming based on SGN maps. Methods IP-II (n=11) human temporal bone histological specimens were identified from the NIDCD National Temporal Bone Registry and digitised. The cochlear duct, scalae, and surgically-relevant anatomy were reconstructed in 3D. A machine learning algorithm was applied to map the location and number of SGNs. Results 3D scalae morphology of the basal turn was normal. Scala tympani (ST) remained isolated for 540° before fusing with scala vestibuli (SV). Mean ST volume reduced below 1mm2 16 after the first 340°. Scala media was a distinct endolymphatic compartment throughout; mean cochlear duct length was 18 28mm+/-3mm SD. SGNs were reduced compared to age-matched norms (mean 48%, range 5-90%). In some cases, SGNs failed to ascend Rosenthal’s canal, remaining in an abnormal basalward modiolar location. Two forms of IP-II were seen: type A and type B. The majority (98-100%) of SGN were located in the basal modiolus in type B IP-II, compared to 76-85% in type A. Conclusion Hallmark features of IP-II cochleae include: (1) fusion of the ST and SV at a mean of 540°, (2) highly variable and overall reduced SGN quantity compared to normative controls (3) abnormal SGN distribution with cell bodies failing to ascend Rosenthal’s canalRoyal College of Surgeons (England) (CS), Anatomical Society (CS), Baroness de Turckheim fund (CS), Wellcome Trust Developing Concept Fund (RG93172/BANCE/40181, MLB), the Biomedical Research Centre Cambridge (MLB), NIH/NIDCD U24DC013983 (AMQ, MZ) and U24DC020849 (AMQ), Research Foundation Flanders (1SD3322N;V414121N, AG)

Detecting and managing partial shorts in Cochlear implants: A validation of scalp surface potential testing.

Funder: Advanced BionicsFunder: Anatomical Society; Id: http://dx.doi.org/10.13039/100012070Funder: Cambridge Hearing TrustFunder: Cochlear; Id: http://dx.doi.org/10.13039/100008626Funder: MED‐EL Medical ElectronicsFunder: MRC Confidence in Concept FundFunder: Oticon Medical; Id: http://dx.doi.org/10.13039/501100020045OBJECTIVE: To investigate the value of scalp surface potentials to identify and manage partial short circuits to ground in cochlear implant electrodes. DESIGN: A retrospective review of patients with suspected partial short circuits. MAIN OUTCOME MEASURE: Electrical output of individual electrodes was measured using scalp surface potentials for patients reporting a change in hearing function. Electrical output was compared to functional performance and impedance measurements to determine if devices with suspected partial short circuits were experiencing a decrease in performance as a result of reduced electrical output. Electrical output was checked in an artificial cochlea for two implants following explant surgery to confirm scalp surface potential results. RESULTS: All patients with suspected partial short circuits (n = 49) had reduced electrical output, a drop in impedances to approximately ½ of previously stable measurements or to below 2 kΩ, an atypical electrical field measurement (EFI) and a decline in hearing function. Only devices with an atypical EFI showed reduced electrical output. Results of scalp based surface potentials could be replicated in an artificial cochlea following explantation of the device. All explant reports received to date (n = 42) have confirmed partial short circuits, with an additional four devices failing integrity tests. CONCLUSION: Surface potential measurements can detect partial shorts and had 100% correlation with atypical EFI measurements, which are characteristic of a partial short to ground in this device. Surface potentials can help determine the degree to which the electrode array is affected, particularly when behavioural testing is limited or not possible