The role of low- and high-fidelity simulations in training tomorrow’s neurovascular surgeons: a mini review based on the experience of King’s NeuroLab

Introduction

Neurosurgical training, like neurosurgical practice, has undergone rapid evolution in recent decades. The evolution of training has followed changes in practice, such as the increasing endovascular management of aneurysms following the International Subarachnoid Aneurysm Trial (ISAT) (1), but the nature of training has also adapted in response to workforce changes, such as reduced residency hours (2) and the European Working Time Directive (3). The aim of training—to produce competent and confident surgeons of tomorrow—remains, but surgical training opportunities in neurovascular surgery, in particular, have diminished due to reduced operative caseloads, accelerating the development of innovative training methods to address this skill gap. This has included those taking on a neurovascular consultant role, typically undertaking a post-certificate of completion of training (CCT) fellowship, but more recently simulation-based training. This review will discuss the role of simulation training with a particular emphasis on neurovascular surgical training. We also review our experience integrating high-fidelity cadaveric training and low-fidelity simulation training to enhance the learning curve for neurosurgery trainees.

The neurovascular caseload—the fall

Following the seminal ISAT study, an increasing number of anterior circulation aneurysms are managed endovascularly, with a smaller proportion managed surgically. A review of inpatient statistics in the United States from 2002 to 2011 demonstrated a dramatic shift from decades past, with endovascular treatment more common than surgical clipping for a ruptured aneurysm (4), reflecting a reduction in training opportunities for neurosurgical trainees. Consequently, a higher proportion of surgically treated aneurysms are complex and challenging (5).

Other neurovascular pathologies, such as arteriovenous malformations (AVMs), may also be treated with alternative methods, such as stereotactic radiosurgery or endovascular treatments. Although these changes are not unique to neurovascular surgery, when coupled with dwindling open case volumes, they result in fewer operations per trainee and less autonomy per case. Indeed, several neurosurgical curricula no longer require trainees to be competent in the operative management of aneurysm clipping for accreditation (6). Nevertheless, reduced exposure to operative neurovascular cases results in a steeper learning curve, and it remains the role of surgical trainers and healthcare systems to identify ways to safely shorten it to ensure the best outcomes for patients.

Simulation training—the rise

Simulation training has emerged as a key tool for enhancing the learning curve (7), allowing trainees to develop their surgical skills in a safe environment before transferring them to a clinical setting. Simulation technologies, including those based on virtual reality, artificial models, and animal and cadaveric tissues, are increasingly used and have been integrated into the surgical curriculum since 2012 (8) to offset the training disadvantages arising from reduced operative caseload. These tools may aid the learning curve for acquiring basic skills amongst neurosurgical trainees. However, they are not anticipated to replace operative experience for advanced skill development, which remains the gold standard of surgical training.

Simulation training is now recognised as a key part of surgical training, with the Improving Surgical Training proposals by the Royal College of Surgeons of England (9) recommending that simulation be embedded within the surgical curricula, with sufficient resources to ensure its availability to all trainees. Furthermore, it suggests that each phase of training should be preceded by an induction period where technical and non-technical skills are taught and developed in a simulated environment.

High-fidelity training, including cadaveric training, provides trainees with a realistic, risk-free environment to practice complex procedures and hone skills, and studies suggest that high-fidelity simulation can improve technical proficiency and reduce error rates as trainees transition to clinical work (10). High-fidelity simulation may involve animal and cadaveric specimens, synthetic surgical models, or virtual reality, all of which offer anatomical accuracy and real-time feedback; it may be delivered in a laboratory or mock operating theatre environment. Cadaveric training remains an essential component of surgical education, bridging the gap between simulation on models and operating on patients. Whilst virtual reality and surgical models have progressed, the majority lack the tactile feedback of real human tissue.

High-fidelity simulation, particularly immersive training in an operating theatre environment, can help trainees build procedural memory (11) and reduce cognitive workload by allowing them to practice the case from start to finish in a low-risk environment. The “rehearsal” of an operation in a simulation environment should facilitate a trainee’s progression through real operative cases more efficiently and reduce cognitive workload, enabling them to respond to dynamic aspects of the surgery, such as complications and distractions. Such training provides trainees with opportunities to make mistakes and learn from them in a low-risk environment. By addressing these mistakes in a controlled, low-risk setting, trainees can avoid repeating them during live surgeries, thereby improving patient safety (10).

Low-fidelity simulations offer other distinct advantages, especially for practising and finessing basic techniques such as suturing and anatomical dissection, and consolidating core concepts and knowledge. The key benefit of low-fidelity simulation lies in its accessibility and cost-effectiveness (8), enabling trainees to practice key skills frequently and build procedural memory and dexterity. The combination of low- and high-fidelity simulations within a spiral curriculum that revisits key concepts ensures trainees are better prepared for more complex surgeries and can gain key operative competencies before delivering this care to patients.

Parallels have been drawn between surgery and elite athletics, with high-performance athletes known to use mental rehearsal as part of their training (12). Whilst the focus of simulation is often to develop skills, another significant benefit is the development of procedural memory that the trainee can use as a basis for future mental rehearsals. Mental rehearsal of a case may be easier if one has personal experience of the case, and for surgical trainees, performing cases in a high-fidelity mock operating theatre on a cadaver provides the optimal opportunity to build procedural memory through a “motor rehearsal” ahead of a real operative case.

The King’s NeuroLab experience—spiral learning through simulation

The King’s NeuroLab training programme integrates both low-fidelity simulation and high-fidelity cadaveric training to accelerate the inherent procedural learning curve for neurosurgery trainees across all subspecialties. King’s NeuroLab started its programme during the COVID-19 pandemic to ensure trainees continued to develop surgical skills despite a reduced elective caseload. In its low-fidelity form, trainees were encouraged to practice tasks such as suturing under the microscope and drilling exercises (Figure 1A,1B). This has since developed to training on both high-fidelity models and cadavers in a mock operating theatre, with the curriculum designed to revisit topics in a spiral fashion (13).

Figure 1 The spiral method, as it applies to learning the use of the drill in neurosurgery, developing skills on low-fidelity models such as eggs (A) and progressing to using the drill in high-fidelity spinal surgical simulators (B). (C) A view of the mock operating theatre where King’s NeuroLab, where simulation training is delivered.

Our high-fidelity simulation is delivered in a mock operating theatre that features an operating microscope, image navigation, and other adjuncts (Figure 1C). Training in such an environment allows trainees to progress through the entire case, starting with patient positioning and surgical planning. This may be followed by practising the relevant approach, progressing to more complex tasks such as performing an anterior clinoidectomy and splitting the Sylvian fissure. Learning in a high-fidelity mock operating theatre also provides trainees with the ability to learn in a familiar and realistic environment whilst protecting them from the distractions of clinical work and service provision. Trainees who have participated in our training have commented that the protected environment helped them feel safer and more able to learn whilst the high-fidelity environment meant that “it felt like real surgical practice”. Our learning model reflects the dynamics of a real operating theatre and supports learning through the “protégé effect” (14). Examples of this include a senior trainee taking a junior colleague through an interfascial dissection on a cadaver.

By following a spiral learning model (13) (Figure 2), we revisit topics at increasing levels of complexity at frequent intervals, thus consolidating prior knowledge and building upon participants’ foundational understanding. In our experience, a spiral learning structure is particularly well-suited to surgical training. This model ensures that trainees can progressively reinforce and refine their skills and revisit critical concepts and techniques (15)—both in low- and high-fidelity situations, and alongside their clinical exposure. For example, the skill of using a drill with a cutting burr to fashion a burr hole may be acquired using a low-fidelity simulation model and then refined in a real operating theatre during external ventricular drain (EVD) insertion. The same trainee may then utilise these drilling skills in more complex manoeuvres, for example, when drilling the sphenoid wing and performing an anterior clinoidectomy—firstly in a simulated setting using a model or a cadaver before progressing to performing these steps on a patient. By revisiting and finessing surgical skills in tandem, both in daily surgical practice and in simulation training, trainees will progress more rapidly, enabling them to participate safely in more advanced surgical procedures, such as clipping a ruptured aneurysm. We encourage trainees to inform us in advance of the session what skills they would like to develop, and give them in-session feedback with group debriefs at the end of each session.

Figure 2 The spiral learning model in the King’s NeuroLab experience.

Enhanced neurovascular simulation

King’s NeuroLab has recognised the need for targeted neurovascular training by investing in high-fidelity simulation models, such as SurgeonsLab’s SurgTrain. This has been used in conjunction with the established cadaveric training. As described, the cadaveric training allows residents to learn anatomical structures and even Sylvian dissection. The SurgTrain model allowed for reproduction of factors not easily reproduced in cadavers—including the haptic feedback of a pulsating aneurysm and the sense of realism and anxiety associated with this (Figure 3). King’s NeuroLab embedded SurgTrain in our mock operating theatre facility to incorporate anaesthetic and scrub staff components of the theatre experience, adding to the workflow and cognitive workload of multi-disciplinary teams required when managing this pathology, especially in the context of an aneurysmal rupture. We feel this offers the highest tier of training outside the operating room.

Figure 3 Simulation at King’s NeuroLab. (A) The King’s NeuroLab control room from where the high-fidelity operating theatre can be controlled and observed, (B) with the SurgeonsLab aneurysm simulation in action.

Equity of access

It is essential to consider the personal financial cost of training borne by each surgical trainee. In the United Kingdom, this personal cost is estimated to be £21,625.50 for neurosurgical trainees over the course of training (16). It is therefore imperative to maintain access to training opportunities as fair and equitable as possible. Simulation that incorporates high-fidelity and cadaveric models increases delivery costs, but all trainees must have equal access to the best learning opportunities. At King’s NeuroLab, we have developed a sustainable funding model through our close partnership with King’s College London and effective engagement with industry.

Limitations

This mini review covers the King’s NeuroLab experience, and whilst our model has been well received by our trainees. Its generalisability is not known, but we hope this adds to the existing literature on different simulation training techniques and how to integrate these. As we develop more trainees through the King’s NeuroLab, future outcomes will assess skill retention and transfer from the simulation lab to the operating theatre.

Conclusions

Surgical training, whether delivered in an operating theatre or in simulation, should consolidate key knowledge, enhance procedural memory and reduce cognitive workload, enabling a trainee to learn to perform a particular operation with skill and confidence. The reduced operative caseload and increasing complexity of neurovascular operations require a steeper learning curve to ensure we deliver the best outcomes for patients. Simulation training will never replace operative surgical training in the theatre, but it can enhance learning by reducing the learning curve and helping new surgical skills be acquired. Whilst this paper summarises our experience, it does not cover the full scope of simulation training, such as virtual reality and augmented reality in neurovascular surgery and other surgical specialities, which are well addressed in the literature (17,18).

By revisiting key concepts and skills as part of a structured spiral curriculum, simulation training allows progressive mastery and a low-risk experience in which surgical errors can be corrected and learnt from, with no risk to a patient. Simulation training using both low- and high-fidelity models is a complementary means of effectively supplementing our armamentarium for training the neurovascular surgeons of tomorrow.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editor (Christos Tolias) for the series “State of Neurovascular Surgery. The Way Forward” published in AME Surgical Journal. The article has undergone external peer review.

Peer Review File: Available at https://asj.amegroups.com/article/view/10.21037/asj-25-78/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://asj.amegroups.com/article/view/10.21037/asj-25-78/coif). The series “State of Neurovascular Surgery. The Way Forward” was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the noncommercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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