Virtual temporal bone simulators and their use in surgical training: a narrative review.

OBJECTIVE: Temporal bone dissection is a difficult skill to acquire, and the challenge has recently been further compounded by a reduction in conventional surgical training opportunities during the coronavirus disease 2019 pandemic. Consequently, there has been renewed interest in ear simulation as an adjunct to surgical training for trainees. We review the state-of-the-art virtual temporal bone simulators for surgical training. MATERIALS AND METHODS: A narrative review of the current literature was performed following a Medline search using a pre-determined search strategy. RESULTS AND ANALYSIS: Sixty-one studies were included. There are five validated temporal bone simulators: Voxel-Man, CardinalSim, Ohio State University Simulator, Melbourne University's Virtual Reality Surgical Simulation and Visible Ear Simulator. The merits of each have been reviewed, alongside their role in surgical training. CONCLUSION: Temporal bone simulators have been demonstrated to be useful adjuncts to conventional surgical training methods and are likely to play an increasing role in the future.

Transtympanic Visualization of Cochlear Implant Placement With Optical Coherence Tomography: A Pilot Study.

OBJECTIVE: This study aimed to evaluate the ability of transtympanic middle ear optical coherence tomography (ME-OCT) to assess placement of cochlear implants (CIs) in situ. PATIENT: A 72-year-old man with bilateral progressive heredodegenerative sensorineural hearing loss due to work-related noise exposure received a CI with a slim modiolar electrode for his right ear 3 months before his scheduled checkup. INTERVENTION: A custom-built swept source ME-OCT system (λo = 1550 nm, ∆λ = 40 nm) designed for transtympanic middle ear imaging was used to capture a series of two- and three-dimensional images of the patient's CI in situ. Separately, transtympanic OCT two-dimensional video imaging and three-dimensional imaging were used to visualize insertion and removal of a CI with a slim modiolar electrode in a human cadaveric temporal bone through a posterior tympanotomy. MAIN OUTCOME MEASURE: Images and video were analyzed qualitatively to determine the visibility of implant features under ME-OCT imaging and quantitatively to determine insertion depth of the CI. RESULTS: After implantation, the CI electrode could be readily visualized in the round window niche under transtympanic ME-OCT in both the patient and the temporal bone. In both cases, characteristic design features of the slim modiolar electrode allowed us to quantify the insertion depth from our images. CONCLUSIONS: ME-OCT could potentially be used in a clinic as a noninvasive, nonionizing means to confirm implant placement. This study shows that features of the CI electrode visible under ME-OCT can be used to quantify insertion depth in the postoperative ear.

Optical Clearing Agents for Optical Imaging Through Cartilage Tympanoplasties: A Preclinical Feasibility Study.

HYPOTHESIS: Optical clearing agents (OCAs) can render cartilage tympanoplasty grafts sufficiently transparent to permit visualization of middle ear structures in an operated ear using optical coherence tomography (OCT) imaging. METHODS: Pieces of human tragal cartilage were treated with glycerol, a commonly used OCA. A reference reflector was imaged with OCT through the tympanoplasty as it cleared and the optical attenuation of the graft was measured. The reversibility of clearing and the dimensional changes associated with glycerol absorption were also measured. In a separate experiment, a human cadaveric temporal bone was prepared to simulate an ossiculoplasty surgery with cartilage replacement of the tympanic membrane. A partial ossicular replacement prosthesis (PORP) inserted in the ear was imaged with OCT through a 0.4mm cartilage graft optically cleared with glycerol. MAIN OUTCOME MEASURE: The optical attenuation of 0.4mm cartilage grafts decreased at 2.3+/-1.1 dB/min following treatment with glycerol, reaching a total decrease in attenuation of 13.6+/-5.9 dB after 7 minutes. The optical and dimensional effects of glycerol absorption were reversable following saline washout. In the temporal bone preparation, treatment of a cartilage graft with glycerol resulted in a 13 dB increase in signal-to-noise ratio and a 13 dB increase in contrast for visualizing the PORP through the graft with OCT. CONCLUSIONS: Optical clearing agents offer a potential pathway towards optical coherence tomography imaging of the middle ear in post-surgical ears with cartilage grafts.

Emerging artificial intelligence applications in otological imaging.

PURPOSE OF REVIEW: To highlight the recent literature on artificial intelligence (AI) pertaining to otological imaging and to discuss future directions, obstacles and opportunities. RECENT FINDINGS: The main themes in the recent literature centre around automated otoscopic image diagnosis and automated image segmentation for application in virtual reality surgical simulation and planning. Other applications that have been studied include identification of tinnitus MRI biomarkers, facial palsy analysis, intraoperative augmented reality systems, vertigo diagnosis and endolymphatic hydrops ratio calculation in Meniere's disease. Studies are presently at a preclinical, proof-of-concept stage. SUMMARY: The recent literature on AI in otological imaging is promising and demonstrates the future potential of this technology in automating certain imaging tasks in a healthcare environment of ever-increasing demand and workload. Some studies have shown equivalence or superiority of the algorithm over physicians, albeit in narrowly defined realms. Future challenges in developing this technology include the compilation of large high quality annotated datasets, fostering strong collaborations between the health and technology sectors, testing the technology within real-world clinical pathways and bolstering trust among patients and physicians in this new method of delivering healthcare.

Current management of necrotising otitis externa in the UK: survey of 221 UK otolaryngologists.

INTRODUCTION: Necrotising otitis externa (NOE) is a rare infection causing skull base osteomyelitis. The evidence regarding NOE consists mostly of case series. Hence, there is a limited evidence base to guide decision-making. This survey aims to report the experience of 221 otolaryngologists in this condition. MATERIALS AND METHODS: Internet survey administered to the membership of the British Association of Otorhinolaryngology - Head and Neck Surgery (ENT UK). RESULTS: Respondents' detailed replies on diagnosis, treatment and follow up are presented. One third of respondents reported increasing incidence of NOE. Over 80% diagnosed NOE based on pre-existing risk factors, severe pain, non-resolution of infection and CT scan. Most respondents managed NOE with intravenous antibiotics (90%) and blood sugar control (82%). There was less agreement in certain aspects of management including the role of surgery and the nature and duration of follow up. CONCLUSIONS: Our survey provides a picture of NOE management in the UK. While there is consensus in some aspects of NOE management, other aspects attract widely differing answers. This may reflect the lack of strong evidence in the literature. Future work should aim to address this.

Clinical applications of Telerobotic ENT-Head and Neck surgery.

OBJECTIVE: To review the published clinical data in Telerobotic ENT-Head and Neck surgery, evaluate the benefit of existing clinical applications and identify areas for potential development. METHODS: A qualitative review was performed of publications in PubMed, Medline and the Cochrane Database identified from the following keyword searches: Telerobotic/Robotic ENT, Otorhinolaryngology, Head and Neck surgery, Thyroid and Parathyroid surgery. Preclinical studies and non-clinical review articles were excluded. RESULTS: Forty-five publications were identified including 7 review articles. Transoral robotic surgery (TORS) was reported in 20 clinical studies, robotic-assisted thyroidectomy in 13 studies, parathyroidectomy in 4 studies and skull base surgery in 1 study. The majority of TORS publications relate to oropharyngeal malignancy which were Stage III and IV. Clinical benefits include avoidance or dose reduction of adjuvant chemoradiotherapy and improved swallow function. The primary clinical advantage of robotic-assisted neck surgery is the avoidance of a neck scar. The learning curve for robotic thyroidectomy is 50 cases. Body habitus is an important factor for assessment of robotic feasibility in transoral and neck surgery. CONCLUSION: The application of robotic-assisted parathyroidectomy, thyroidectomy and TORS suggests promising improvements in patient care. Randomised control trials are needed to assess clinical outcome, cost effectiveness and patient benefit in the existing applications. Continued development of robotic technology will expand the viable clinical applications in this specialty.

Ear microbiology reports: a need for better communication with the microbiologists.

Most ENT surgeons treat discharging ears with topical antibiotics but many may not routinely utilise ear microbiology specimens. One reason could be that ear microbiology reports may not reflect their usual therapeutic options. This paper explores how microbiology departments in England process ear swabs. We carried out a telephone questionnaire of 104 microbiology departments in England. Results were obtained from 95 hospitals. Various culture methods are used, with sensitivity testing for up to 51 different antibiotics. Only five are licensed for topical use. Systemic antibiotics seemed to be preferentially tested for over topical antibiotics. Anaerobes and fungus are routinely tested. Many microbiology departments do not routinely report on all sensitivities tested. Antibiotic sensitivity testing for various micro-organisms cultured from ear swabs seemed to be guided by protocols for systemic infections. Microbiologists may not fully appreciate ENT surgeons' preferential usage of topical antibiotics in treating discharging ears, albeit there are other factors in their consideration for antibiotics to test. To gain better guidance from swab results, and to reduce needless lab costs, discussion with the microbiologists may be of benefit.