Simulation in Neurosurgery: Possibilities and Practicalities: Foreword

Limbrick, David D. Jr MD, PhD*,§; Dacey, Ralph G. Jr MD

Section Editor(s): Harrop, James S. MD; Bendok, Bernard R. MD

doi: 10.1227/NEU.0000000000000094

*Department of Neurological Surgery;

Barnes-Jewish Hospital, Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri;

§St. Louis Children's Hospital, St. Louis, Missouri

Correspondence: Ralph G. Dacey, Jr, MD, Department of Neurological Surgery, Barnes-Jewish Hospital, Washington University School of Medicine, 660 S Euclid, Campus Box 8057, St. Louis, MO 63110. E-mail: or

Article Outline

The convergence of several key factors—resident duty hour limitations chief among them—has resulted in marked changes in the surgical training environment in recent years. Additional looming factors imposed by healthcare reform, including outcomes-based reimbursement, increased scrutiny of healthcare quality, and the widespread dissemination of physician-specific data, threaten to further challenge traditional paradigms of surgical training. Balancing the competing priorities of educating the next generation of neurosurgeons and achieving clinical performance metrics in the context of increasing oversight and regulation will require thoughtful and creative modifications to the traditional methodologies used in neurosurgical training.1

Although the hours that trainees spend in the hospital, the educational methodologies, and even resident roles in surgical procedures may be changing, the summative result of neurosurgical training must not. By the end of their training, today’s trainees must be well-trained, competent neurosurgeons. However, to achieve excellence in the current environment, educators need to look toward further change and additional structure in the neurosurgical training. The core components of surgical training—establishing a fundamental knowledge base, demonstrating proficiency in diagnosing neurological and relevant medical disorders, developing surgical technical skills, and accumulating experience in surgery and patient care2—remain unchanged in general terms, but the means to achieve them must indeed change.

Given current duty hour limitations, ensuring that each neurosurgical trainee achieves all of these core components must be an active process. It is clear that the model of sustained immersion and exposure in neurosurgery, as effective as it was in training past generations of neurosurgeons, is not possible today.2 Over the past several years, the American Board of Neurological Surgery, the Residency Review Committee, and the Society for Neurological Surgeons, in conjunction with the Accreditation Council for Graduate Medical Education, have worked to advance our approach to neurosurgical education. Perhaps the most apparent recent example pertains to standardizing evaluations for resident experience and performance via the Milestones project, in which neurosurgery had a leadership role. However, attention is increasingly being focused on the curriculum itself to streamline the learning process for residents to acquire the necessary knowledge base, diagnostic proficiency, and surgical technical skills. In this, simulation promises to be transformative.

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In its most basic sense, simulation has been in use as an educational tool for physicians and surgeons for hundreds, perhaps thousands, of years. Cadaveric human dissection can be traced to the Greek physician Galen (AD 129-c. 216) and later Vesalius (1514-1564), whose meticulous monographs formed the basis of modern human anatomic studies.3 Therefore, cadaveric dissections have historically been considered the ultimate anatomic simulators and continue to play an indispensable role in current surgical training. Yet despite providing definitive anatomic detail and permitting demonstration of elegant surgical approaches, cadavers poorly replicate living tissues and thus are an inadequate surrogate for preparing surgical trainees for real-life, dynamic operative scenarios. Although rodent or other animal preparations may assist in modeling living tissues, there are obvious limitations in size, scale, and anatomy.1

Recent years have seen an explosion of simulation-based medical education. From the introduction of standardized patients in medical school curricula to ever-more-lifelike high-fidelity manikins, simulation may now be used to teach trainees everything from appropriate responses to clinical crises to complex procedural skills to interpersonal skills. Seventy percent of medical schools include at least some elements of simulation in medical education, and other procedure-based specialties such as general surgery, vascular surgery, otolaryngology, and anesthesia include simulation as a major component in residency training.4 Among surgical specialties, general surgery has acquired the most extensive experience with simulation and has amassed a large body of literature supporting the use of simulation in residency training. Laparoscopic simulators, for example, have repeatedly been shown to improve technical performance in the operating room while decreasing procedure time.5,6

Particularly compelling for surgical education are the technology-based advances in virtual reality simulators that combine 3-dimensional graphic renderings with haptic feedback to model operative scenarios. Early surgical simulators using these technologies were largely limited to laparoscopic and endoscopic paradigms, in which the degrees of freedom were inherently limited and the haptic modeling was relatively simple. With increasing computational power, however, advanced algorithms that permit simulation of real-time free-hand procedures in a complex 3-dimensional anatomic space are emerging. At present, simulators exist for many neurosurgical procedures, including ventriculostomy, tumor resection, microvascular decompression, aneurysm clipping, endovascular procedures, spinal instrumentation, and numerous others.4,7

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Simulation is likely to have its most pivotal impact on early learners in neurosurgery. Indeed, since 2010, the Society for Neurological Surgeons has used both technical and behavioral simulation in its postgraduate year 1 resident boot camp courses, with 100% participation by all entering postgraduate year 1 residents in Accreditation Council for Graduate Medical Education–accredited US neurosurgery programs in 2011. In this supplement, Selden et al8 report their results from an analysis of course surveys over 3 years as simulation paradigms (physical, image- or mannequin-based, clinical scenarios) underwent iterative modifications based participant critique. Course evaluations suggested that the participants found simulations useful, particularly for those procedures they were most apt to perform in the coming year.

Similarly, the Congress of Neurological Surgeons formed a simulation committee to explore the use of simulation in neurosurgical training. In this supplement, Harrop et al describe the systematic implementation of simulation curriculum in a course held at the 2011 Congress of Neurological Surgeons Annual Meeting.9 The course included predominantly a combination of physical and virtual reality models (grouped into vascular, cranial, spinal modules) tailored to teach a range of skills to residents, from ventriculostomy placement to vascular bypass. On the basis of feedback from participants, the authors advanced a structured course algorithm to include a course outline with clear objectives, a written pretest, a didactic session, a review of the simulator before each module, hands-on training with faculty, and a written posttest and evaluation. This course design makes intuitive and pedagogical sense, and it will be interesting to see further results regarding the effect of these simulations on resident performance.

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This supplement to Neurosurgery explores the application of simulation-based approaches to education, training, and innovation in neurosurgery. In dedicating an entire supplemental volume to this topic, Neurosurgery and its editors send a strong message regarding the potential value of simulation in the current training environment. The supplement highlights much of the important research being conducted in this area, beginning with a historical background and providing information on current models and early integration into resident boot camps and neurosurgical educational curricula.

Significant advances have been made in the simulation of vascular, particularly endovascular, neurosurgery. Fargen et al10 describe their initial experience with a program piloting a cerebral angiography simulator that coupled virtual reality with angiography wires and catheters (“augmented” reality). Residents who completed the learning module scored higher on both a written posttest and an instructor-graded practical evaluation. Complex open vascular procedures such as aneurysm clipping and intracranial bypass have also been modeled.11,12 Using synthetic vessels and a validated scoring system, El Ahmadieh et al12 show that completing a bypass simulation resulted in improved posttest scores and improved performance on the task.

The complexity and variability of cranial procedures make simulation challenging, but significant progress has been made in recent years. From basic procedures such as ventriculostomy13,14 to cranial trauma surgery,15 simulation has shown early success in helping junior residents learn the fundamentals of each operation, plan the approach, and rehearse the procedure.16,17 Advanced physical and virtual reality simulation paradigms have also enabled the creation of realistic models for intracranial endoscopy,18,19 tumor resection,20 and complex skull base approaches,21 which may be useful in training more senior trainees and even attending surgeons in new or less familiar surgeries.

A number of simulation-based spine surgery training modules have been developed to teach trainees approaches for spinal decompression, instrumentation, and even complication management.22,23 In this supplement, Harrop et al24 report early results of a posterior cervical decompression model that was created using 3-dimensional printing and included synthetic dura and neural elements. Pressure sensors were included to estimate potential injury during the simulated procedure. Piloted at the 2012 Congress of Neurological Surgeons Annual Meeting, the posterior cervical decompression module increased participants’ understanding and performance of posterior cervical decompression. A more simplified physical model was used at the same meeting to teach the technique for anterior cervical diskectomy and fusion,25 and although the performance assessment was not used in all cases, posttest scores indicated that the model helped residents learn key elements of the operative approach. Minimally invasive spine surgery, pedicle screw placement in particular, is another skill set ideally suited for simulation with computer models, virtual reality, and advanced haptics.26 When evaluated in a pilot study, trainees performed better on both didactic testing and technical evaluation after a simulation-based education program.27

Introducing simulation modules into the traditional neurosurgical curriculum will require substantial effort and significant capital expenditure. On the basis of their own experience, Gasco et al28 estimate an initial investment of approximately $340 000 and annual operating expenses of $28 000 (1 resident per year). They note a positive impact of resident perceptions on the training experience, but additional studies are required to evaluate whether resident perception translated into improved outcomes, patient safety, or other objective metrics.28 Overall, the authors feel that incorporating simulation scenarios into their curriculum was feasible and useful in resident education.

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With increasingly lifelike simulators and dynamic operative and clinical crisis training, simulation promises to be a transformative tool for neurosurgical training. As these methodologies are used more and more in courses and in basic neurosurgical curricula, simulation will enable trainees to rehearse operative procedures or clinical scenarios many times, reinforcing key principles or steps.9,11 Furthermore, as trainee evaluations are standardized through the Milestones project (Accreditation Council of Graduate Medical Education) and additional performance evaluations are required for selected index cases (as part of the Society for Neurological Surgeons’ Matrix), simulation may provide both a method for residents to practice and learn and a means for resident assessment.4,29

Although simulation may be most immediately relevant to early learners, it may also represent a valuable tool to be used throughout more senior levels of training and even woven into curricula for lifelong learning. Simulation in these groups may focus not just on operative skills, novel procedures, and clinical scenarios but also on approaches to enhance patient safety and healthcare quality.

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The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article.

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