Training in Paranasal Sinus Surgery: A Review of Current Modalities and What the Future May Hold

Abstract

Pathology affecting the paranasal sinuses can have a myriad of negative effects on patients who suffer from chronic symptoms which may significantly impact their quality of life. In most patients who fail medical treatment, surgical options can be explored. Endoscopic sinus surgery has become a mainstay of managing paranasal sinus disease ranging from chronic rhinositis, nasal polyposis, and sinonasal tumours. Surgery in this anatomical area can be challenging due to the proximity to important structures and adequate training is needed. Trainees especially in the UK have less exposure to relevant cases due to time constraints, service provision and a shift towards consultant led care. Traditional methods of training such as cadaveric dissection and 2D simulators are still relevant but may not be the most effective in the modern day. Other alternative methods of learning and teaching using technology such as VR, AR/MR and telemedicine may provide a shift in the way paranasal surgical education is delivered. Future work is needed to develop these tools further and to validate them as effective tools for surgical trainees.

1. Introduction

Paranasal sinus surgery plays an important role in addressing a myriad of nasal and sinus pathologies that can significantly impact patient’s quality of life. Conditions such as chronic sinusitis, sinonasal tumours, structural abnormalities and persistent infections are among those than can be addressed with surgical management. Surgery offers individuals grappling with chronic symptoms such as nasal congestion, facial pain, and anosmia a glimmer of hope when medical management has failed.

Endoscopic surgery in all domains have continued to gain popularity due to the replacement of large incisions into non-invasive procedures. A better view of the anatomy and access to small orifices mean that endoscopic approaches can be better than traditional approaches to surgery. Additional benefits include improved patient safety, quicker post operative recovery, reduced operative times and lower costs. The use of endoscopy in paranasal surgery dates to the early twentieth century when a cystoscope was used to examine the sinuses [1]. However endoscopic sinus surgery was not regularly performed until the 1970s [2]. The use of external approaches using a headlight were routinely performed until technological advancements led to the modern development of functional endoscopic sinus surgery (FESS) which is now a mainstay of sinonasal and skull base surgery [3]. The main reason being the improvement in symptoms of patients undergoing FESS as well as the overall low complication rates when compared to traditional procedures [4].

The paranasal sinuses are situated within the bones of the facial skeleton and play a crucial role in respiratory function, immune response and maintaining the integrity of the skull. The interplay of various structures, such as the ethmoid, frontal, maxillary and sphenoid sinuses demand a comprehensive understanding of anatomy as well as the variations among these structures [5]. Performing any type of procedure within this domain requires precise knowledge but also the understanding of the challenges posed by the proximity of critical structures, the potential for complications and the variation in patient presentations [6]. Although complication rates are low in endoscopic surgery, they can be significant such as vision loss, CSF leak and haemorrhage.

The complexity of paranasal sinus surgery underscores the critical importance of well-trained surgeons. Effective training equips surgeons with the proficiency to navigate complex anatomical structures, make informed decisions during procedures, and anticipate potential complications [7]. As the demand for surgical expertise in this domain grows, it becomes imperative to explore the diverse training modalities available to aspiring surgeons and identify avenues for improving and innovating these methods.

This chapter aims to provide a comprehensive overview of the existing training modalities in paranasal surgery. We aim to outline traditional methods such as cadaveric workshops, while also exploring new modalities of learning such as virtual reality simulations, augmented/mixed reality, and telemedicine driven platforms. It is important to understand the current state of training in order to improve upon these methods to equip modern day surgeons with the tools they need to master the intricate art of paranasal sinus surgery.

2. Current training modalities

2.1 Training overview

In the UK there are various routes into specialist otolaryngology training with the aim leading to consultancy. Typically the current training programme comprises of 2 years of foundation training after medical school. Following on from this there is a competitive national selection process to enter a 2 year ‘Core Surgical Training’ programme which can be themed based on the trainee’s specialty of choice. This is then followed by a second competitive national selection process for specialty training which typically lasts for 6 years (ST3 – 8) but can be extended if any research, academia, fellowships or less than full time training occurs. The outcome then leads to a Certificate of Completion of Training (CCT) allowing appointment to consultant posts [8].

Surgical training in the UK is generally overseen by the Royal College of Surgeons in England or Edinburgh and Glasgow in Scotland. The Joint Committee on Surgical Training (JCST) via Specialty Advisory Committees (SACs) then provide and oversee the surgical curriculum as well as quality indicators for each specialty in order to monitor and assess trainees’ progress [8, 9]. Trainees are then expected to complete work-based assessments (WBAs) and record them on the Intercollegiate Surgical Curriculum Programme (ISCP) portal [10] and log their operations on the eSurgical Logbook [11]. Trainees are then subjected to a rigorous assessment process via the Fellowship of the Royal College of Surgeons Exams which occurs in the latter stages of specialist training. A summary overview of the ISCP curriculum for paranasal surgery is provided in Table 1 [10].

Foundation level	1.Introduction to paranasal surgery	Basics of paranasal anatomy and physiology
		Overview of common sinus pathologies and surgical indications
	2.Clinical assessment and diagnosis	Learning to take thorough patient histories and perform physical examinations
		Diagnostic tools like imaging (CT, MRI) and endoscopy for accurate assessment
	3.Medical management	Understanding non-surgical treatments for sinus pathologies (e.g., medications, nasal sprays, irrigation)
Intermediate level	1.Surgical techniques	Introduction to endoscopic procedures for sinus surgery
		Hands-on training in instrumentation, navigation, and endoscope usage
	2.Surgical anatomy	In-depth study of paranasal sinus anatomy and variations
		Understanding critical landmarks and potential complications
	3.Common surgical procedures	Detailed instruction on procedures like functional endoscopic sinus surgery (FESS), sinus drainage, and polypectomy
		Post-operative care and management
	4.Complications and management	Recognising and managing intraoperative and postoperative complications
		Strategies to prevent and address adverse events
Advanced level	1.Complex cases and techniques	Advanced surgical techniques for complicated sinus pathologies
		Management of challenging cases, such as revision surgeries or tumours
	2.Multidisciplinary collaboration	Collaborating with radiologists, anesthesiologists, and other specialists
		Participation in multidisciplinary teams for complex cases
	3.Research and innovation	Introduction to research methodologies relevant to paranasal sinus surgery
		Exploring innovative techniques and technologies
	4.Professional development	Ethical considerations in paranasal surgery.
		Communication skills, patient interaction, and informed consent
Assessment and certification	1.Formative assessments	Regular assessments to track trainee progress and provide feedback
		Evaluations of surgical skills, clinical knowledge, and professionalism
	2.Summative assessments	Final examinations to assess overall competency
		Objective Structured Clinical Examinations (OSCEs) and practical assessments
	3.Certification	Successful completion leads to certification in paranasal sinus surgery
		Eligibility to practice independently in the field

Table 1.

ISCP curriculum overview for paranasal surgery.

As outlined above, the training requirements for paranasal sinus surgery is extensive and one of the primary challenges in surgical training is ensuring trainees receive adequate exposure to a diverse range of cases. This allows the trainee surgeon to appreciate the variability in anatomy and pathology and allows a broad spectrum of experiences to develop their skill set. Not only are trainees able to perform procedures, but they are also able to observe experienced surgeons operate which can also help increase their knowledge base when faced with similar cases or challenges. Unfortunately ensuring adequate exposure can be problematic due to availability of suitable cases as well as time considerations such as the EWTD which was implemented in 2009 within the UK’s healthcare. Trainees are limited to working 48 hours per week over a 6-month period with a change towards shift-based rotas [8]. The Temple report published in 2010 also identified concerns regarding the EWTD severely impacting training due to the reduced number of hours available for supervised learning [8, 12]. This has meant trainees have had to turn to other modalities of learning such as courses in order to gain knowledge and surgical skills such as via cadaveric dissection.

2.2 Cadaveric dissection courses

Cadaveric dissection has been the mainstay for anatomy teaching in the medical curriculum since the seventeenth century [13]. Human cadaveric dissection helps students understand the relationships between various anatomical structures when compared to textbooks and lecture-based learning [14]. Due to the unparalleled realism it offers, it has also been the mainstay of postgraduate surgical education. It offers trainees the opportunity to perform surgical procedures in a simulated environment where patient safety is not compromised [15]. Trainees can then apply what they have learned into an operative setting.

The opportunity to practice performing procedures on real human tissue helps to increase confidence and improve surgical skills to help them perform procedures independently. Trainers have been found to also have more confidence in their trainees and provide them with greater autonomy in the operating theatre [16]. Trainees who have been through cadaveric dissection courses were also found to have increased knowledge of procedural steps as well as a greater appreciation of complications which then contributes to a higher level of confidence when performing procedures [17].

In terms of paranasal sinus surgery, there are multiple courses that offer dissection—based learning for trainees globally. In the UK itself, courses such as these are funded by the training body and delegates are encouraged to attend in order to improve their technical skills. A multi-centre study surveyed 133 participants in seven centres across Germany, Switzerland and Australia regarding their experiences of endoscopic sinus surgery cadaveric dissection courses and almost all participants reported that the course had improved their anatomical knowledge and confidence [18]. The majority of participants considered infundibulotomy and anterior ethmoidectomy as the easiest step in the procedure while frontal sinus surgery appeared to be the most challenging regardless of their level of training. They identified that more emphasis on anatomy as well as self-directed learning during their surgical training years would be of greatest benefit [18].

Although cadaveric dissection courses have shown to be effective for training surgeons, there are certain factors that must be considered when running these courses. Cadaveric courses are expensive and require approval from the Human Tissue Authority in order to make sure cadavers are being used appropriately and safely [19, 20]. There are also ethical considerations involved and costs when handling cadavers related to donor consent, respect for human remains, and cultural sensitivities. Courses must be hosted in facilities that have the legal and health and safety requirements for cadavers. These factors not only increase the costs for running the course as well for attendees but also limits where and when courses can be run [21]. Balancing the educational value of cadaveric training with these ethical and financial concerns requires careful planning and consideration. Due to the issues highlighted above, the need for developing other means of training has been important such as using simulation or utilisation of phantom and animal models.

2.3 Simulation in paranasal surgery

Simulators have been widely used and developed in all domains of surgery. These systems all vary in their levels of realism, task specificity and training modality [21]. There are several simulators which have been developed for endoscopic sinus surgery reported in literature and these range from ‘low fidelity’ gelatine or 3D printed models to realistic ‘high fidelity’ anatomical models along with animal ovine models [22]. The fidelity of these simulations refer to the extent to which the models reflect real tissue properties and their anatomical accuracy of various structures. The simulators also vary in cost based on fidelity as well as the material used for production.

A detailed comparison of the various types of simulators available is beyond the scope of this chapter but it is interesting to observe that even with low-cost simulators, a significant improvement in skills has been noted [23]. This study utilised a low-cost sinus surgery task trainer to evaluate 52 medical students who had no sinus surgery experience by asking them to perform five specific sinus surgery tasks. Pre- and post-training videos were recorded of nasal endoscopy and surgical skills, and their performance was evaluated via a checklist and global rating scale. They found that even in novices, repeated practice using the skills trainer resulted in an improvement in performance [23].

Another study focused on assessing whether an intermediate fidelity FESS training model was effective and measured data comparing 12 medical students against 10 otolaryngology residents in the United States by asking them to perform distinct tasks on the simulator. They found that both groups were found to have gained a statistically significant improvement in skills and time taken to complete each task. They also found that the improvement was retained by testing them again after 2 weeks. Delegates were also found to have increased their accuracy in performing tasks through repetition which helped illustrate that practicing outside the operating theatre repeatedly can help improve surgical skills when performing FESS [24].

As evident in the literature, there are a multitude of simulators available to help trainees learn how to perform paranasal surgery and it is also interesting to observe that even though fidelity is important, it does not make a large difference when it comes to attaining skills in endoscopic surgery. In order to address the differences in fidelity and their effectiveness, 34 first year medical students were randomised into three groups and taught basic anatomy and instrumentation. Two groups were allocated to receive training with either a high-fidelity training model or a low fidelity training model with the last group serving as a control. The control group received no simulator exposure. The groups were then tested with cadaveric specimens and sessions were recorded and graded by an expert. It was interesting to note that there was no statistical difference in performance between the three groups in relation to identification of anatomy, endoscopic competency or completion of basic tasks however those who underwent training in either a high or low fidelity simulator did show improvement in time taken to complete various tasks [22].

In terms of validation of these simulators as an educational tool, a systematic review performed in 2018 aimed to analyse the evidence for validated endoscopic sinus surgery (ESS) simulation. They found that although several ESS simulators have been comprehensively validated, the majority lack standardisation in terms of outcome reporting which makes it difficult to compare the various types of simulators [25]. Despite the lack of uniformisation and standardisation of outcomes, literature has still shown that simulation is effecting in allowing junior trainees to acquire skills and practice in non-clinical environments where patient safety is not negatively affected [26]. Simulators in general allow the development of hand-eye coordination and dexterity when performing surgical tasks and are potentially a cost-effective means for teaching and learning surgical skills [27].

Although simulators have been shown to be effective, they are still not equivalent to cadaveric models in terms of immersion and realism which has been shown to be an important facet for skills acquisition [28]. A robust platform that is easily accessible to ENT trainees is also lacking and in order to address these differences and achieve the same level of realism as being within the operating theatre, virtual reality (VR) simulators have been in development over the last three decades [29, 30].

2.4 Virtual reality simulation in paranasal surgery

Advancements in technology have brought virtual reality and simulation to the forefront of surgical training. VR platforms create immersive environments where trainees can practice surgical techniques on realistic 3D models of the paranasal sinuses. One of the most popular simulators has been the ES3 developed by Lockheed Martin in 1997. This tool provides a virtual surgical environment where the trainee can manipulate an endoscope and other instruments inside the nasal cavity of a mannequin with varying levels of haptic feedback affordable via the surgical instruments [31]. The ES3 has been validated extensively as a learning tool and shown to be effective in addressing training needs in terms of procedural skills. In a prospective, multi-institute controlled trial, 12 ES3 trained novice ENT residents in the United States were compared with 13 novice residents who did not undergo training in the VR simulator. It was found that those who had used this training tool demonstrated more skill during instrument manipulation and made fewer technical errors when compared to the control group [32]. Although this tool has been extensively validated, it is no longer in production due to development costs making the simulator very expensive [31].

Based on the effectiveness of the ES3, other VR simulators have also been in development, and these include the CardinalSim, VOXEL-MAN SinuSurg, Nasal Endoscopy Simulator (NES), Dextroscope, Virtual Endoscopic Simulation of Transsphenoidal Endoscopic Pituitary Surgery (STEPS), Flinders Sinus Surgery Simulator, NeuroTouch Endo, and the McGill Simulator for ESS [31]. Although many of these tools are validated, they are still faced with issues surrounding accuracy of anatomical models as well as the real-life applicability of the haptic feedback afforded from the surgical instruments used in each of the respective VR simulators [31]. Additionally, there are concerns around assessment and achievement of competence for trainees as there is no uniformity across various training programmes due to the affordability and accessibility of the various simulators [31]. It is also important to note that although the tools mentioned above are classed as VR simulators, they are not ‘true’ VR which we will cover in the next section of this chapter.

3. Potential future training modalities

3.1 ‘True VR’

In ‘true VR’, a user is exposed to a computer-generated environment which is completely segregated from normal reality. Immersive VR (iVR) systems are different to the VR simulators described in the previous section due to the need for a head mounted display which then allows a 360° appreciation of the virtual environment. This differs from simulators such as the ES3 whereby the virtual environment is displayed on a screen display rather than offering true immersion.

Utilisation of 360° video also allows users to experience an immersive environment though unlike true VR, users are unable to move within or interact directly with objects in the virtual environment unless there are hotspots or clickable content added to the video [21, 33, 34]. With the user taken out of the real-world environment, they can be transported to any virtual environment that has been developed which allows for true immersion. This shift in visuospatial understanding is a major factor in how beneficial virtual 3D environments can be for learners.

A successful example of how 360 videos can be used for surgical education is the work and development done by Virtual Reality in Medicine and Surgery (VRiMs, vrims.net) and Brighton and Sussex Medical School (BSMS). They were the first medical school in the UK to have live streamed footage of cadaveric dissection using 360 videos [21]. Trainees across the UK were invited to attend a five-day course covering a range of specialities including ENT procedures. The delivery of content was via a combination of 360VR footage of clinical examination, assessment and surgical techniques as well as live streamed cadaveric dissection. The added benefit of the course was that content could be accessed via a smartphone and cardboard headset which made it cost effective. The course was accessed by over 500 trainees across the UK with 129 responding to the post course survey where 90% either agreed or strongly agreed that this training tool would be of value [21].

Although ENT operations were included within the 360° library, the majority of operations that were taught were emergency operations such as front of neck access and drainage of deep neck space infections. The positive feedback received in relation to 360° videos and their usefulness in surgical training should potentially be a basis for 360 video content creation in relation to paranasal surgery which has not yet been reported in the literature.

A further step in utilisation of immersive VR would be to develop simulations utilising ‘true VR’ and six degrees of freedom (6DOF). This technology forms the basis of gaming platforms offered by headsets such as Meta Quest 2 and Pro, Apple’s Vision Pro, PICO 3 as well HTC Vive. Although not reported in the literature, there are ongoing developments by VR companies to push through medical simulations which include surgical procedures. Examples of these companies include Touch Surgery and Fundamental Surgery. The latter is already recognised by the American Academy of Orthopaedic Surgeons as well as the Royal College of Surgeons of England, but many simulations are focused on general surgery and orthopaedic procedures.

The benefit of utilising this technology would be to fully immerse delegates within an operative environment which not only helps increase the realistic nature of the simulation compared to real life, but also can mimic various surgical scenarios. Specifically, for paranasal surgery, a simulation that offers complications such as a catastrophic bleed, or CSF leak could allow trainees to learn how to correct these adverse events intra-operatively in a situation that mimics reality.

The additional benefit of utilising this technology would be the potential ability to measure competence. In traditional surgical training, an assessment is made by the senior consultant or attending on when a trainee is ready for the next step or first unsupervised steps when performing a procedure [35]. This is usually a subjective assessment, and it is difficult to standardise this across all trainees in various training programmes across the globe. Psychological fidelity is the extent or degree to which a simulation replicates the cognitive demands of the real task and eye tracking has been shown to be a potential assessment tool for this domain [21, 36]. Eye tracking tools are offered in the majority of new headsets and can measure gaze as well as other metrics such as fixation frequency, pupil dilatation and dwell time. The differences in these parameters have shown to help differentiate novices versus experts when performing tasks [21, 36, 37]. In one study focusing on endoscopic sinus surgery, 16 residents performed FESS training over 18 sessions which were split into three surgical steps. Eye movements were measured, and results indicated performance improvements in terms of completion time and surgical performance [35]. There was also a significant change in cognitive load and average fixation duration towards the last step of training [35]. Eye movements and cognitive load also differed between residents of different levels, and it was found that eye tracking is a helpful objective measuring tool in FESS.

True VR may potentially help solve some of the issues identified when using cadaveric dissection as there is no need for any human tissue to be obtained. It may also solve some of the issues with 2D VR simulators whereby standardisation and assessment have not been possible due to the differences in availability of various simulators across different units. There is also the added cost benefit where although the initial start-up costs can be significant, once a headset is obtained and programmed, simulations can be run repeatedly and potentially from a trainee’s own home.

Although True VR may be a novel approach, it does not address the issue with the lack of appropriate haptic feedback which is where augmented reality and mixed reality solutions may be of benefit.

3.2 Augmented and mixed reality

Augmented reality is where a user is presented with a computer – generated image superimposed onto a part of normal reality. This is different to true VR described above as the user is not segregated from reality, but rather digital elements are overlayed onto the real world. Mixed reality on the other hand is where a view of the physical world is overlayed with digital elements, but these elements can interact with each other [21]. Within otolaryngology, this technology has most commonly been used to explore intra-operative guidance and surgical planning with minimal work done currently on procedural simulations [38].

One example of a mixed/augmented reality system that could be used for paranasal surgery training is the UpSurgeOn Transsphenoidal (TNS) Box which has been used in a neurosurgical setting for the endoscopic endonasal transsphenoidal approach to the pituitary fossa [39, 40]. The TNS box is a high-fidelity simulator and comprises of a nasal cavity with a 3D face overlay and is made of silicone via 3D printing. The model allows trainees to explore the nasal cavity, identify anatomical landmarks and resect pituitary tumours endoscopically. Currently there are no validated studies for this tool which led to a study looking at 15 neurosurgeons of which 10 were novices and 5 were intermediate and experts in their field. The participants were subjected to a survey as well as task specific technical skills and given a score. The results demonstrated that the model was a valid training tool as a simulator for the endoscopic endonasal transsphenoidal approach although improvements to the system could also be made [39]. These included the addition of neuro-vascular anatomy and arachnoid mater to stimulate bleeding vessels and CSF leak as well as improving the materials used to make the model more realistic.

Although the TNS box is tailored to paranasal approaches to access the pituitary fossa, there is the potential for further development of similar tools to simulate other paranasal surgical procedures. The TNS box also allows for haptic feedback whilst giving the user a superimposed image on their telephone mimicking an endoscopic view. Although initial costs may be deemed high, the repeatability of the simulation can possibly make this augmented/mixed reality simulator implementable across multiple training units across the UK and the globe.

3.3 Telemedicine

Telemedicine could be one method of adapting training methods considering the decrease in exposure to cases that are faced by trainees. Using technology to provide remote medical care and consultations remotely, this can be adapted to also provide teaching as well as access to real time learning experiences. Telemedicine allows trainees to remotely observe live surgeries by skilled surgeons across the world which allows further exposure to various techniques, approaches and patient scenarios. Vice versa, trainees could also perform procedures in a simulated or real life setting with ongoing observations from experts who can offer and comment on the techniques being performed which allows the trainee to learn in real time. Surgeons could potentially guide trainees through procedures, and provide step by step instructions, highlight critical landmarks, as well as offer immediate feedback. One such example is Proximie who are utilising their innovative platform to live stream operations or teaching sessions remotely while offering the educator the capability to annotate ‘on screen’ while trainees are watching the procedure being performed. Proximie’s platform also allows for the editing of recorded content to be packaged into educational videos which can be accessed by trainees in their own time. Currently the platform has been used by several surgical bodies across the globe but it’s application within paranasal surgery is not published in literature.

However, a successful venture to help facilitate remote training of FESS was completed in 2021 by a group based in Japan and Australia utilising novel 3D printed sinus models and telemedicine software [41]. Three otolaryngologists in Hokkaido, Japan were trained to perform frontal sinus dissections on 3D sinus models of increasing difficulty by two rhinologists in Adelaide, Australia. The models were printed using CT scans of patients with chronic rhinosinusitis. They utilised Zoom and the Quintree telemedicine platform to first lecture the Japanese surgeons followed by supervising them in real time as they performed the frontal sinus dissections. This teaching session was streamed to over 200 otolaryngologists worldwide. The Japanese surgeons were asked to complete a questionnaire afterwards and the time taken to complete the tasks were recorded. It was found that the time taken to identify the frontal sinus reduced significantly despite the increasing difficulty of the 3D models. Feedback was also mainly positive from the dissectors and the worldwide audience which may help illustrate how this can be implemented within surgical training.

4. Conclusions

The landscape of surgical training is shifting towards alternative and novel methods to deliver education. These changes are driven by factors which can impact trainee’s exposure to diverse cases due to time constraints as well as other factors such as service provision and a shift towards consultant led care. Traditional approaches such as cadaveric dissection and 2D simulation to learn how to perform paranasal surgery still have a place but other innovative approaches such as VR, AR/MR and telemedicine may prove to be effective in training surgeons of the future.