Abstract
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.
Patients with severe-to-profound hearing loss may benefit from management with cochlear implants. These patients need a referral to a cochlear implant team for further assessment and possible ...surgery. The referral pathway may result in varied access to hearing healthcare. This study aimed to explore referral patterns and whether there were any socioeconomic or ethnic associations with the likelihood of referral. The primary outcome was to determine factors influencing referral for implant assessment. The secondary outcome was to identify factors impacting whether healthcare professionals had discussed the option of referral.
A multicentre multidisciplinary observational study was conducted in secondary care Otolaryngology and Audiology units in Great Britain. Adults fulfilling NICE (2019) audiometric criteria for implant assessment were identified over a 6-month period between 1 July and 31 December 2021. Patient- and site-specific characteristics were extracted. Multivariable binary logistic regression was employed to compare a range of factors influencing the likelihood of implant discussion and referral including patient-specific (demographics, past medical history, and degree of hearing loss) and site-specific factors (cochlear implant champion and whether the hospital performed implants). Hospitals across all 4 devolved nations of the UK were invited to participate, with data submitted from 36 urban hospitals across England, Scotland, and Wales. Nine hospitals (25%) conducted cochlear implant assessments. The majority of patients lived in England (n = 5,587, 86.2%); the rest lived in Wales (n = 419, 6.5%) and Scotland (n = 233, 3.6%). The mean patient age was 72 ± 19 years (mean ± standard deviation); 54% were male, and 75·3% of participants were white, 6·3% were Asian, 1·5% were black, 0·05% were mixed, and 4·6% were self-defined as a different ethnicity. Of 6,482 submitted patients meeting pure tone audiometric thresholds for cochlear implantation, 311 already had a cochlear implant. Of the remaining 6,171, 35.7% were informed they were eligible for an implant, but only 9.7% were referred for assessment. When adjusted for site- and patient-specific factors, stand-out findings included that adults were less likely to be referred if they lived in more deprived area decile within Indices of Multiple Deprivation (4th (odds ratio (OR): 2·19; 95% confidence interval (CI): 1·31, 3·66; p = 0·002), 5th (2·02; 1·21, 3·38; p = 0·05), 6th (2·32; 1·41, 3·83; p = 0.05), and 8th (2·07; 1·25, 3·42; p = 0·004)), lived in London (0·40; 0·29, 0·57; p < 0·001), were male (females 1·52; 1·27, 1·81; p < 0·001), or were older (0·97; 0·96, 0·97; p < 0·001). They were less likely to be informed of their potential eligibility if they lived in more deprived areas (4th (1·99; 1·49, 2·66; p < 0·001), 5th (1·75; 1·31, 2·33, p < 0·001), 6th (1·85; 1·39, 2·45; p < 0·001), 7th (1·66; 1·25, 2·21; p < 0·001), and 8th (1·74; 1·31, 2·31; p < 0·001) deciles), the North of England or London (North 0·74; 0·62, 0·89; p = 0·001; London 0·44; 0·35, 0·56; p < 0·001), were of Asian or black ethnic backgrounds compared to white patients (Asian 0·58; 0·43, 0·79; p < 0·001; black 0·56; 0·34, 0·92; p = 0·021), were male (females 1·46; 1·31, 1·62; p < 0·001), or were older (0·98; 0·98, 0·98; p < 0·001). The study methodology was limited by its observational nature, reliance on accurate documentation of the referring service, and potential underrepresentation of certain demographic groups.
The majority of adults meeting pure tone audiometric threshold criteria for cochlear implantation are currently not appropriately referred for assessment. There is scope to target underrepresented patient groups to improve referral rates. Future research should engage stakeholders to explore the reasons behind the disparities. Implementing straightforward measures, such as educational initiatives and automated pop-up tools for immediate identification, can help streamline the referral process.
Background
Endoscopic sinus surgery is performed for medically recalcitrant chronic rhinosinusitis. There is no universally accepted strategy regarding post-operative antibiotics despite the high ...rates of usage worldwide. The aim of this study was to analyse patient-reported and objective outcomes behind antibiotic use following endoscopic sinus surgery.
Methods
A search of electronic databases was performed. Eligible randomised controlled trials (RCTs) and observational trials were included. The primary outcome was patient reported outcome measures. Secondary outcomes were local infections, endoscopy scores and adverse events. Meta-analysis was performed.
Results
Of 1045 publications identified, 7 were included in the qualitative synthesis and 5 RCTs were included in meta-analysis. Antibiotic regimens varied between studies in terms of antibiotic selection, timing commenced and duration of use. Meta-analysis suggested no significant difference between placebo and antibiotics in patient reported outcome measures (standardised mean difference (SMD) –0.215, 95% confidence interval (CI) –0.637 to 0.207) or endoscopic scores (SMD –2.86, 95% CI –0.846 to 0.273). There was no consistent definition in reporting of infection; therefore, this outcome cannot be comprehensively considered. No severe adverse events were attributable to antibiotics.
Conclusions
From the studies analysed, there is no level 1 evidence to suggest that antibiotics improved patient outcomes following sinus surgery. However, there was significant heterogeneity in outcome measures and no clear data exists regarding the effects of antibiotics on postoperative infections. The available evidence at present is not enough to make a recommendation in either direction. Further designed larger RCTs are required to investigate these questions in more detail.
Objectives:
The primary aim was to measure the volume of the scala tympani (ST) and the length of the straight portion of the cochlear basal turn from micro-computed tomography (μCT) images. The ...secondary aim was to estimate the electrode insertion force based on cochlear size and insertion speed. Both of these objectives have a direct clinical relevance in robotic assisted cochlear implant (CI) surgery.
Methods:
The ST was segmented in thirty μCT datasets to create a three-dimensional (3D) model and calculate the ST volume. The diameter (A-value), the width (B-value), and the straight portion of the cochlear basal turn (S-value) were measured from the oblique coronal plane. Electrode insertion force was measured in ST models of two different sizes, by inserting FLEX24 (24 mm) and FLEX28 (28 mm) electrode arrays at five different speeds (0.1, 0.5, 1, 2, and 4 mm/s).
Results:
The mean A-, B-, and S-values measured from the 30 μCT datasets were 9.0 ± 0.5, 6.7 ± 0.4, and 6.9 mm ± 0.5, respectively. The mean ST volume was 34.2 μl ± 7 (range 23–50 μl). The ST volume increased linearly with an increase in A- and B-values (Pearson's coefficient
r
= 0.55 and 0.56, respectively). The A-value exhibited linear positive correlation with the B-value and S-value (Pearson's coefficient
r
= 0.64 and
r
= 0.66, respectively). In the smaller of the two ST models, insertion forces were higher across the range of insertion speeds during both array insertions, when compared to the upscaled model. Before the maximum electrode insertion depths, a trend toward lower insertion force for lower insertion speed and vice-versa was observed.
Conclusion:
It is important to determine pre-operative cochlear size as this seems to have an effect upon electrode insertion forces. Higher insertion forces were seen in a smaller sized ST model across two electrode array lengths, as compared to an upscaled larger model. The ST volume, which cannot be visualized on clinical CT, correlates with clinical cochlear parameters. This enabled the creation of an equation capable of predicting ST volume utilizing A- and B-values, thus enabling pre-operative prediction of ST volume.
(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.
Abstract Objectives 1. To investigate the feasibility of performing case-specific surgical rehearsal using a virtual reality temporal bone simulator. 2. To identify potential clinical applications in ...temporal bone surgery. Design Prospective assessment study. Setting St Mary's Hospital, Imperial College NHS Trust, London UK. Participants Sixteen participants consisting of a trainer and trainee group. Method Twenty-four cadaver temporal bones were CT-scanned and uploaded onto the Voxelman simulator. Sixteen participants performed a 90-min temporal bone dissection on the generic simulation model followed by 3 dissection tasks on the case simulation and cadaver models. Case rehearsal was assessed for feasibility. Clinical applications and usefulness were evaluated using a 5-point Likert-type scale. Results The upload process required a semi-automated system. Average time for upload was 20 min. Suboptimal reconstruction occurred in 21% of cases arising when the mastoid process and ossicular chain were not captured ( n = 2) or when artefact was generated ( n = 3). Case rehearsal rated highly (Likert score >4) for confidence (75%), facilitating planning (75%) and training (94%). Potential clinical applications for case rehearsal include ossicular chain surgery, cochlear implantation and congenital anomalies. Case rehearsal of cholesteatoma surgery is not possible on the current platform due to suboptimal soft tissue representation. Conclusion The process of uploading CT data onto a virtual reality temporal bone simulator to perform surgical rehearsal is feasible using a semi-automated system. Further clinical evaluation is warranted to assess the benefit of performing patient-specific surgical rehearsal in selected procedures.
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.
Abstract Introduction Various “scarless” approaches have been described for thyroid and parathyroid surgery. The objective of the current study was to investigate patients' perception of neck scar ...cosmesis, its impact on quality of life (QoL) and evaluate patient preference with regards to scar location. Methods 120 patients undergoing thyroid or parathyroid surgery were followed-up over a 5-year period (2008–2013). Validated tools were used to assess scar perception and its impact on QoL. These were evaluated against sex, age, ethnicity, operation type, histopathology, time following surgery and scar length. Results Mean follow-up was 2.6 ± 3.8 years. One of the most common post-operative problems was scar-related (n = 18). Caucasian patients and those with benign histology expressed a lower impact on QoL (p < 0.001, p = 0.038). Sex and scar length did not significantly affect patients' perception for scar cosmesis (p > 0.05). Clinicians tended to score scar cosmesis higher than patients (p = 0.02). Most participants (75%) expressed a clear preference for an extracervical “scar-less in the neck” approach. Discussion Scar-related issues are frequently reported following thyroid and parathyroid surgery. The negative impact, often underestimated by clinicians, is more apparent amongst Asian and Afro-Caribbean patients and can significantly impact on their QoL. This, combined with the lack of correlation between scar length and patient satisfaction, indicates the need to divert research from miniaturising neck scars to concealing them in extracervical sites. Conclusion Patients prefer a scar-less in the neck approach when given the option. A prospective comparative study is required to compare the cervical and extracervical approaches.
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