Developing an Evidence-Based Surgical Curriculum: Learning from a Randomized Controlled Trial of Surgical Rehearsal in Virtual Reality.

BACKGROUND: Surgical rehearsal - patient-specific preoperative surgical practice - can be provided by virtual reality simulation. This study investigated the effect of surgical rehearsal on cortical mastoidectomy performance and procedure duration. METHODS: University students (n=40) were randomized evenly into a rehearsal and control group. After watching a video tutorial on cortical mastoidectomy, participants completed the procedure on a virtual reality simulator as a pre-test. Participants completed a further 8 cortical mastoidectomies on the virtual reality simulator as training before drilling two 3-dimensional (3D) printed temporal bones. The rehearsal group received 3D printed bones they had previously operated on in virtual reality, while the control group received 2 new bones. Cortical mastoidectomy was assessed by 3 blinded graders using the Melbourne Mastoidectomy Scale. RESULTS: There was high interrater reliability between the 3 graders (intraclass correlation coefficient, r=0.8533, P < .0001). There was no difference in the mean surgical performance on the two 3D printed bones between the control and rehearsal groups (P=.2791). There was no significant difference in the mean procedure duration between the control and rehearsal groups for both 3D printed bones (P=.8709). However, there was a significant decrease in procedure duration between the first and second 3D printed bones (P < .0001). CONCLUSION: In this study, patient-specific virtual reality rehearsal provided no additional advantage to cortical mastoidectomy performance by novice operators compared to generic practice on a virtual reality simulator. Further, virtual reality training did not improve cortical mastoidectomy performance on 3D printed bones, highlighting the impact of anatomical diversity and changing operating modalities on the acquisition of new surgical skills.

Creation of an incus recess for a middle-ear microphone using a drill or laser ablation: a comparison of equivalent noise level and middle ear transfer function.

PURPOSE: Studies have assessed the trauma and change in hearing function from the use of otological drills on the ossicular chain, but not the effects of partial laser ablation of the incus. A study of the effectiveness of a novel middle-ear microphone for a cochlear implant, which required an incus recess for the microphone balltip, provided an opportunity to compare methods and inform a feasibility study of the microphone with patients. METHODS: We used laser Doppler vibrometry with an insert earphone and probe microphone in 23 ears from 14 fresh-frozen cadavers to measure the equivalent noise level at the tympanic membrane that would have led to the same stapes velocity as the creation of the incus recess. RESULTS: Drilling on the incus with a diamond burr created peak noise levels equivalent to 125.1-155.0 dB SPL at the tympanic membrane, whilst using the laser generated equivalent noise levels barely above the baseline level. The change in middle ear transfer function following drilling showed greater variability at high frequencies, but the change was not statistically significant in the three frequency bands tested. CONCLUSIONS: Whilst drilling resulted in substantially higher equivalent noise, we considered that the recess created by laser ablation was more likely to lead to movement of the microphone balltip, and therefore decrease performance or result in malfunction over time. For patients with greatly reduced residual hearing, the greater consistency from drilling the incus recess may outweigh the potential benefits of hearing preservation with laser ablation.

Electrocochleography triggered intervention successfully preserves residual hearing during cochlear implantation: Results of a randomised clinical trial.

BACKGROUND: Preservation of natural hearing during cochlear implantation is associated with improved speech outcomes, however more than half of implant recipients lose this hearing. Real-time electrophysiological monitoring of cochlear output during implantation, made possible by recording electrocochleography using the electrodes on the cochlear implant, has shown promise in predicting hearing preservation. Sudden drops in the amplitude of the cochlear microphonic (CM) have been shown to predict more severe hearing losses. Here, we report on a randomized clinical trial investigating whether immediate surgical intervention triggered by these drops can save residual hearing. METHODS: A single-blinded placebo-controlled trial of surgical intervention triggered when CM amplitude dropped by at least 30% of a prior maximum amplitude during cochlear implantation. Intraoperative electrocochleography was recorded in 60 adults implanted with Cochlear Ltd's Thin Straight Electrode, half randomly assigned to a control group and half to an interventional group. The surgical intervention was to withdraw the electrode in ½-mm steps to recover CM amplitude. The primary outcome was hearing preservation 3 months following implantation, with secondary outcomes of speech-in-noise reception thresholds by group or CM outcome, and depth of implantation. RESULTS: Sixty patients were recruited; neither pre-operative audiometry nor speech reception thresholds were significantly different between groups. Post-operatively, hearing preservation was significantly better in the interventional group. This was the case in absolute difference (median of 30 dB for control, 20 dB for interventional, χ² = 6.2, p = .013), as well as for relative difference (medians of 66% for the control, 31% for the interventional, χ² = 5.9, p = .015). Speech-in-noise reception thresholds were significantly better in patients with no CM drop at any point during insertion compared with patients with a CM drop; however, those with successfully recovered CMs after an initial drop were not significantly different (median gain required for speech reception score of 50% above noise of 6.9 dB for no drop, 8.6 for recovered CM, and 9.8 for CM drop, χ² = 6.8, p = .032). Angular insertion depth was not significantly different between control and interventional groups. CONCLUSIONS: This is the first demonstration that surgical intervention in response to intraoperative hearing monitoring can save residual hearing during cochlear implantation.

Noise Exposure on Human Cochlea During Cochleostomy Formation Using Conventional and a Hand Guided Robotic Drill.

OBJECTIVE: To investigate the disturbance induced in the cochlea during cochleostomy using conventional drill and a hand guided robotic drill. STUDY DESIGN: The study is based on experimental measurements using the Laser Doppler Vibrometer during the drilling processes converted to Sound Pressure Levels (SPL) for comparison. SETTING: The study is based on experimental results of three sets of cochleostomies on human cadaver heads. MAIN OUTCOME MEASURE(S): Robotic drilling, in comparison to the conventional drilling method, creates a consistently lower level of disturbance in cochlea across the hearing frequency range. RESULTS: Robotic drilling, in comparison to the conventional drilling method, creates a consistently lower level of disturbance in cochlea across the hearing frequency range. CONCLUSIONS: It is reasonable to conclude that robotic drilling has a lower possibility of creating acoustic trauma in cochlea that endangers the residual hearing of patients.

The Melbourne Mastoidectomy Scale: Validation of an end-product dissection scale for cortical mastoidectomy.

INTRODUCTION: Cortical mastoidectomy is a common otolaryngology procedure and represents a compulsory part of otolaryngology training. As such, a specific validated assessment score is needed for the progression of competency-based training in this procedure. Although multiple temporal bone dissection scales have been developed, they have all been validated for advanced temporal bone dissection including posterior tympanotomy, rather than the task of cortical mastoidectomy. METHODS: The Melbourne Mastoidectomy Scale, a 20-item end-product dissection scale to assess cortical mastoidectomy, was developed. The scale was validated using dissections by 30 participants (10 novice, 10 intermediate and 10 expert) on a virtual reality temporal bone simulator. All dissections were assessed independently by three blinded graders. Additionally, all procedures were graded with an abbreviated Welling Scale by one grader. RESULTS: There was high inter-rater reliability between the three graders (r = .9210, P < .0001). There was a significant difference in scores between the three groups (P < .0001). Additionally, there was a large effect size between all three groups: the differences between the novice group and both the intermediate group (P = .0119, η2  = 0.2482) and expert group (P < .001, η2  = 0.6356) were significant. The difference between the intermediate group and expert group again had a large effect size (η2  = 0.3217), but was not significant. The Melbourne Mastoidectomy Scale correlated well with an abbreviated Welling Scale (r = .8485, P < .0001). CONCLUSION: The Melbourne Mastoidectomy Scale offers a validated score for use in the assessment of cortical mastoidectomy.

Four-point impedance as a biomarker for bleeding during cochlear implantation.

Cochlear implantation has successfully restored the perception of hearing for nearly 200 thousand profoundly deaf adults and children. More recently, implant candidature has expanded to include those with considerable natural hearing which, when preserved, provides an improved hearing experience in noisy environments. But more than half of these patients lose this natural hearing soon after implantation. To reduce this burden, biosensing technologies are emerging that provide feedback on the quality of surgery. Here we report clinical findings on a new intra-operative measurement of electrical impedance (4-point impedance) which, when elevated, is associated with high rates of post-operative hearing loss and vestibular dysfunction. In vivo and in vitro data presented suggest that elevated 4-point impedance is likely due to the presence of blood within the cochlea rather than its geometry. Four-point impedance is a new marker for the detection of cochlear injury causing bleeding, that may be incorporated into intraoperative monitoring protocols during CI surgery.

Inappropriate Use of the "Rosowski Criteria" and "Modified Rosowski Criteria" for Assessing the Normal Function of Human Temporal Bones.

Important research by Rosowski et al. [Twenty-Seventh Meeting of the Association for Research in Otolaryngology, 2004, p. 275] has led to a standard practice by the American Society for Testing Materials [West Conshohocken: ASTM International; 2014] to assess normal function of temporal bones used in the development of novel middle ear actuators and sensors. Rosowki et al. [Audiol Neurotol. 2007; 12(4): 265-76] have since suggested that the original criteria are too restrictive and have proposed modified criteria. We show that both the original and modified criteria are inappropriate for assessing individual temporal bones. Moreover, we suggest that both the original and modified Rosowski criteria should be applied with caution when assessing whether mean data from a study are within physiological norms because the multiple comparisons resulting from verification at each frequency will lead to very liberal rejection. The standard practice, however, has led to the collection of more extensive and consistent data. We suggest that it is now opportune to use these data to further modify the Rosowski criteria.

The Future of Cochlear Implant Design.

This chapter discusses the multifaceted future of cochlear implant design. Current research is focused on novel strategies relating to the electrode array, aiming to improve the neuronal health and spatial selectivity, and reduce the power consumption. Future design iterations will most likely improve the neuronal health by reducing insertion trauma, minimizing the inflammatory pathway that follows electrode insertion or through the use of neurotrophins or stem cells. Improvements in spatial selectivity and in speech recognition in difficult listening environments can be achieved through changes in the electrode/neural interface. Designing an array that brings the electrodes closer to neural tissue, or changing the method of stimulation with current steering or even optical or piezoelectric stimulation are discussed. Increasing the MRI compatibility is an important consideration, and devices allowing remote programming have a huge impact on worldwide provision. Technology exists to realize the elusive goal of a fully implantable cochlear implant, allowing continuous and invisible hearing. Ultimately, future technologies will be integrated to allow tailoring of implant design to the individual, thereby addressing the broad variability in user performance. At the same time, there is an urgent requirement for a high quality, low cost, mass-produced implant for the developing world.

Percutaneous pedestals in cochlear implantation.

Percutaneous pedestals have been integral to the development of cochlear implants since 1969. By enabling direct electrical access to implanted electrodes or other devices, they allow optimization of control of stimulation strategies. Similarly, technology not validated for implantable use can be safely tested. These advantages have facilitated the development of cochlear implants and also resulted in their inclusion in trials investigating electronic implants developed for other organs. Surgery is straightforward, but post-operative care, in particular, skin-care is crucial to ensure complications are minimized. This review discusses the history of percutaneous pedestal use in cochlear implants and other electronic devices. Surgical technique, aftercare, and complications of surgery are discussed along with possibilities for future development.

A hand-guided robotic drill for cochleostomy on human cadavers.

BACKGROUND: An arm supported robotic drill has been recently demonstrated for preparing cochleostomies in a pilot research clinical trial. In this paper, a hand-guided robotic drill is presented and tested on human cadaver trials. METHODS: The innovative smart tactile approach can automatically detect drilling mediums and decided when to stop drilling to prevent penetrating the endosteum. The smart sensing scheme has been implemented in a concept of a hand guided robotic drill. RESULTS: Experiments were carried out on two adult cadaveric human bodies for verifying the drilling process and successfully finished cochleostomy on three cochlea. The advantage over a system supported by a mechanical arm includes the flexibility in adjusting the trajectory to initiate cutting without slipping. Using the same concept as a conventional drilling device, the user will also be benefit from the lower setup time and cost, and lower training overhead. CONCLUSION: The hand-guided robotic drill was recently developed for testing on human cadavers. The robotic drill successfully prepared cochleostomies in all three cases.

Implantable microphones as an alternative to external microphones for cochlear implants.

Totally implantable cochlear implants may be able to address many of the problems cochlear implant users have around cosmetic appearances, discomfort, and restriction of activities. The major technological challenges that need to be solved to develop a totally implantable device relate to implanted microphone performance. Previous attempts at implanting microphones for cochlear implants have not performed as well as conventional cochlear implant microphones, and in addition have struggled with extraneous body or surface contact noise. Microphones can be implanted under the skin or act as sensors in the middle ear; however, evidence from middle ear implants suggest body and contact noise can be overcome by converting ossicular chain movements into digital signals. This article reviews implantable microphone systems and discusses the technology behind them.

Quality of Information Available Via the Internet for Patients With Otological Conditions.

OBJECTIVE: Evaluate the type, content, and quality of information available via the Internet for patients with common otological conditions. METHODS: The Google search engine was used to generate responses for the following search terms: glue ear, otitis media, otosclerosis, Ménière's disease, cholesteatoma, and ear perforation. The first 10 websites for each search term were selected for analysis. Websites were evaluated with the validated DISCERN instrument (Institute of Health Sciences, University of Oxford, UK), the LIDA tool (Minervation Ltd, Oxford, UK), the Flesch Readability Formula, the Simple Measure Of Gobbledygook (SMOG) readability score, and against the Journal of the American Medical Association (JAMA) criteria. Comparisons were made with a similar study assessing quality of information in nonotological conditions. RESULTS: Mean SMOG score was 12.19 years of education (range, 6.2-22.8). The health on the net (HON) symbol appeared on 15 of 49 websites (30.61%). Pearson's r was used to identify interactions between variables and demonstrated a significant correlation between LIDA score and Google ranking (R = -0.1195, p = 0.002); between university/hospital affiliation and JAMA score (R = -1.7889, p = 0.0182) and commercial affiliation and JAMA score (R = 1.0561; p = 0.01). Multivariate linear regression analysis showed LIDA to be the strongest predictor of Google ranking (Page rank decreasing by 0.10572 per LIDA score; p = 0.01). CONCLUSION: As websites with better Google ranking were only weakly associated with higher quality rankings patients would benefit from being directed to reliable websites by clinicians. There is currently a gap in the available resources for a high quality repository of otological information aimed at patients.

Quality of information available via the internet for patients with head and neck cancer: are we improving?

This study aimed to evaluate the type, content, accessibility and quality of information available via the internet for patients with head and neck cancer. The Google search engine was used to generate lists of the first 100 websites for general head and neck cancer and the first ten for head and neck cancers by anatomical location (160 total). Websites were evaluated with the validated DISCERN and LIDA instruments, the SMOG (Simple measure of gobbledygook) readability score and against the JAMA (Journal of the American Medical Association) criteria. 40 of the 160 websites ranked by Google were suitable for analysis. Seven websites (17.5%) partially or fully achieved all four JAMA benchmarks and only one (2.5%) site achieved none. 28 (70%) included reference to quality of life factors. Correlations were identified between Google site rank and all four of our appraisal tools; LIDA (-0.966, p = 0.006), JAMA (-5.93, p = 0.028), DISCERN (-0.568, p = 0.037) and SMOG (4.678, p = 0.04). Google site rank and both government run sites (-35.38, p = 0.034) and sites run by universities or hospitals (-27.32, p = 0.016) also showed an association. Comparing our observations with those of Riordain in 2008, there has been little improvement in the quality of head and neck cancer information available online over this time. Given the variability in quality of information online, patients would benefit from being directed to reliable websites by clinicians.

Torrential epistaxis in the third trimester: a management conundrum.

Although epistaxis is common during pregnancy, large volume epistaxis is rare. Many standard epistaxis management options are limited in pregnancy due to absolute or relative contraindications. Ear, nose and throat surgeons need to be aware of what options can be used safely and effectively. We present a case of a 32-year-old woman, 32 weeks pregnant, who was admitted with heavy epistaxis refractive to conservative management. Several potential interventions including bismuth iodoform paraffin paste (BIPP) and Floseal were contraindicated or involved additional risk in pregnancy necessitating unorthodox management. This challenging case highlights suitable alternatives for managing large volume epistaxis during pregnancy, as well as discussing the differential diagnosis and relevant investigations.