What is virtual reality?

Virtual reality is an object, series of objects or three-dimensional environment generated by computer software.² It can be interacted with by one or many concurrent users, in a convincing, physical way. The interaction between the user and the virtual world usually requires a head-mounted display, replacing the user's field of view, and some form of controller in one or both hands.

Virtual reality technology falls into a series of emerging technologies known as ‘extended reality’, or ‘XR’ as it is colloquially and commonly known.^{Reference Sabbagh, Bajunaid, Alarifi, Winkler-Schwartz, Alsideiri and Al-Zhrani3} Augmented reality and mixed reality are the main components of extended reality technology, in addition to virtual reality. Augmented reality is the superimposition of computer processed images onto a real-world view. Mixed reality is a combination of virtual reality and augmented reality technology. This technology blends real and virtual objects, allowing both to be manipulated in a physical way. It enhances augmented reality by allowing the user to interact with the digital object, in three dimensions, whilst maintaining complete awareness and the ability to interact with the real world.

History of virtual reality within surgical education

Over the last 25 years, significant advances have been made in optical, haptic, computing and graphical capabilities.^{Reference Kuo, Delvecchio and Preminger4} As these advancements have been introduced and the cost of the technology has concurrently fallen, we have seen wider applications for virtual reality within the context of medical simulation.

Today, the literature depicts a variety of specialties (including both medicine and surgery) developing simulators grounded upon virtual reality paradigms. Specialties that have tested true virtual reality surgical simulators include: neurosurgery,^{Reference Bernardo5} urology,^{Reference Hamacher, Whangbo, Kim and Chung6} cardiothoracic surgery^{Reference Bernardo5,Reference Jensen, Ringsted, Hansen, Petersen and Konge7} and orthopaedics.^{Reference Bartlett, Lawrence, Stewart, Nakano and Khanduja8} General surgery has enthusiastically adopted the technology, focusing on laparoscopic and endoscopic procedures.^{Reference Mahmood, Scaffidi, Khan and Grover9,Reference Ko, Cheung, Pun and Tung10} Mahmood et al. suggest introducing virtual reality simulation as a mandatory education activity prior to real-world endoscopy, thus mitigating a disadvantage of the apprenticeship model of procedural training.^{Reference Mahmood, Scaffidi, Khan and Grover9}

Within the field of otolaryngology, uptake in virtual reality simulation technology has been comparatively slow. Virtual reality simulators are limited to only two specific areas: endoscopic sinus surgery and temporal bone surgery.^{Reference Lui and Hoy11,Reference Al-Noury12} Whilst the evidence for these simulators is promising, the current technology is staggeringly expensive and therefore out of reach for most training institutions.

As the equipment has become more advanced in terms of resolution, interactivity, responsiveness and graphical fidelity, the experiences being produced are becoming dramatically more immersive.^{Reference Winkler, Röthke, Siegfried and Benlian13} The immersion created in virtual reality applications lends itself well to potential emergency scenario based, algorithmic training simulation. Simulated emergency scenarios exist only in anaesthetics, paediatrics (including paediatric ENT) and emergency medicine.^{Reference Luigi Ingrassia, Ragazzoni, Carenzo, Colombo, Ripoll Gallardo and Della Corte14,Reference Reznek, Harter and Krummel15} Currently, these potential methods of emergency training remain largely untested. Coupled with emergency scenario simulation, non-technical skills training would lend itself to virtual reality, given the high level of immersion. Non-technical skills virtual reality simulators have been described, but the direct acquisition of non-technical skills has yet to be statistically demonstrated.^{Reference Bracq, Michinov and Jannin16}

It is clear that the development of extended reality technology is rapidly progressing, with potential applications broadening as the technology matures. In response to the Covid-19 pandemic, the use of digital technology for education has increased exponentially, and it remains likely that the ongoing need for social distancing will prompt further investment into high-quality, alternative methods of surgical education.

Main advantages of virtual reality educational tools

With the introduction in the UK of the 2016 junior doctor contract, surgical trainees are seeing a further reduction in contact hours.¹⁷ In addition, updates in the otolaryngology surgical training curriculum may see competency based progression and further shortening of training time.¹⁸ In light of these developments, adoption of simulation training is likely to increase, to support ‘hands-on’ training.

Traditional simulation training is currently delivered in a variety of settings. These can be characterised as high- or low-fidelity.^{Reference Hegland, Aarlie, Stromme and Jamtvedt19} High-fidelity simulation utilises advanced mannequin technology, human role-playing or even cadavers to recreate complex case scenarios or procedures. Low-fidelity simulation is less resource intensive, and may utilise part-task trainers (e.g. bronchoscopy mannequins), online learning packages, videos and written material.

Although there is good evidence to suggest the benefit of high-fidelity simulation centres and cadaveric simulation as education tools, there are some significant limitations, as follows. High-fidelity simulation centres require a significant upfront investment. The operation of these centres requires an extensive team of expert staff and incurs large running costs.^{Reference van de Ven, van Baaren, Fransen, van Runnard Heimel, Mol and Oei20} Cadaveric simulation has extremely high running costs and ethical implications when using cadavers.^{Reference Yiasemidou, Gkaragkani, Glassman and Biyani21} Both of these educational tools require the learner to attend a course on a specific date and generally run through the scenario just once. These courses or educational activities, to be maximally effective, may need to be repeated, thus incurring repeated similar costs.

A virtual reality simulator is relatively inexpensive, requires little space and, depending on the educational model, no supervision.^{Reference Berg and Steinsbekk22} There is an initial upfront investment for the development of the product, but once established it can be limitlessly replayed, helping to maintain competency. The equipment required (head-mounted display and hand input controls) are safely portable, and can be transferred across divisions, specialties and levels of seniority.

Most medical specialty doctors have to be prepared to deal with a variety of high-pressure, low-frequency scenarios. ENT surgery is an example of a specialty with many of these scenarios, ranging from emergency paediatric and adult airway compromise, aerodigestive tract bleeding, and emergencies related to a tracheostomy tube. Simulation training is the most effective way to train and prepare for such ‘rare’ and potentially life-threatening events.

The Covid-19 pandemic has prompted ENT governing bodies such as ENT-UK, the British Society of Otology and the British Association of Head and Neck Oncologists to publish extensive guidelines on how to manage some of these emergency scenarios during a pandemic. Fundamentally, these societies are motivated by the acknowledged high risk of aerosol exposure inherent in many ENT procedures. An area of commonality is the suggestion that emergencies (operative and clinical) should be led by a senior doctor, with efforts made to minimise the aerosol exposure of additional non-integral staff (including junior trainees).^{23,Reference ENT24}

Current limitations

Extended reality technology, whilst promising, does currently have recognised limitations that need to be addressed. One can categorise the limitations into three main groups: limitation of the technology, comfort and cost of development.

Future applications and adoption of virtual reality

It has been predicted that the global market for virtual reality technology will approximately double in the next three years.³⁰ The increased investment will likely push research and development forward to address the recognised limitations. Immersion will evolve in parallel with improvements in optics, processing power, virtual environment physics and graphical fidelity.