Over the last several decades, the science of medicine has undergone rapid advancement and expansion as a result of significant technological innovations. These changes have affected many facets of society, resulting in drastic adjustments in medicine and in the realm of patient care. Particular attention has focused on the quality of treatment patients receive through the development and analysis of patient outcome metrics. This philosophical change has been illustrated through numerous government initiatives and changes in patients’ and physicians’ attitudes and perceptions. One area that has been significantly influenced by these changes is medical education, in particular the training of surgical residents and procedures. The Congress of Neurological Surgeons (CNS), with a stated mission of improving education, noticed these changes and formed a committee in 2010 to specifically address “how to maximize neurosurgical education to improve patient outcomes with the greatest efficiency and safety.” This committee has evolved over the past 3 years and currently is known as the CNS Simulation Committee. The mission of the CNS Simulation Committee is to develop a comprehensive neurosurgical simulation initiative that will redefine the methodology of training neurosurgery residents and serve as the benchmark for future program development.
THE DIFFICULTIES WITH NEUROSURGERY EDUCATION
The educational algorithms and paradigms of the surgical subspecialties were originally modeled after apprenticeship protocols set by our forefathers. However, recent analysis of medical education, in particular resident education, has illustrated numerous areas of potential improvement.1 Some specific questions in terms of maximizing resident proficiency and patient safety included the following: How many cases does a resident need to perform before he or she is “competent?” How many cases need to be completed before a surgeon is proficient? What is the optimal length of a surgical training program? Do all individuals learn at the same fixed rate? How can we best measure surgical technical skills? After reviewing these questions and answers, it becomes apparent that although many training programs have defined educational goals, there is no standardization of training or of these educational protocols. Furthermore, no objective criteria have been established to measure educational outcomes.
As a result of these observations, it is clear that optimizing medical education presents several significant and distinct challenges. The central nervous system anatomy of the cerebrum and spinal cord has a very complex 3-dimensional pattern that is challenging for novices to comprehend. Furthermore, several neurosurgical procedures are unique and infrequently performed, which limits the resident’s exposure to these rare cases. Additionally, there has been a limitation on the neurosurgical resident’s educational experience with the introduction of the 80-hour workweek. These fewer hours for education present a challenge to train residents in neurosurgical subspecialties, in particular, with the continual expansion of neurosurgical procedures.
OPPORTUNITIES FOR NEUROSURGERY EDUCATION
After review of these difficulties, there has been a significant focus on maximizing neurosurgical education and learning. Assessment of learning strategies reveals that to maximize learning and education, students should be taught with methods that use multimodality senses such as sight, hearing, and tactile sensation simultaneously.2-5 In the education of otolaryngology residents, the use of multimodality learning strategies has illustrated improvement of endoscopy skills. Deutsch et al5 used lectures, an animal laboratory, high-fidelity manikins, virtual bronchoscopy simulation, and standardized patients and had residents compare their experience among these various teaching methods. These authors noted that alternative learning modalities were perceived to have different educational values but concluded they could be used in a complementary manner. Furthermore, educators must acknowledge that individuals have different learning styles. Baykan and Naçar3 noted in a large cohort of medical students that learning styles did not differ between male and female students, and no statistically significant difference was determined between the first-semester grade point averages and learning styles.
Educational curriculums require repetition and continual refocusing on a learned task to enhance education and to maximize efficiency. These principles are exemplified in the Kolb experiential learning mode (Figure), which has been used in medical education.6-10 In this model, the learner has a continuum of educational experiences. Typically, the participant first has a concrete educational experience. After reflection on this concrete experience, a transition is made into an observation period. Over a period of time, an abstract conceptualization develops that then transitions into active experimentation. This restarts the educational cycle, and the learner then has another concrete experience but enters into this experience with a greater knowledge and insight.
The review of the above educational difficulties with particular focus on neurosurgical issues and theories on how to maximize education resulted in the CNS Simulation Committee’s examination of successful medical and nonmedical educational models. It became apparent that education through simulation models was a standard component of numerous nonmedical fields, including the airplane industry, military and commercial vehicle control, and mechanical system maintenance. Furthermore, simulation educational techniques have recently been illustrated to have been successfully incorporated into several and a diverse group of medical fields.11-17
Simulation models have the advantage over other educational algorithms such as an apprentice program in that they provide training in a specifically fabricated and controlled setting. This artificial environment affords the trainee an opportunity to be placed in difficult clinical situations that often mimic a crisis. The trainee gains critical experience with no risk to potential patients. Thus, this training model allows trainees to gain insightful experience in a controlled environment.
DEVELOPMENT OF A SIMULATION-BASED CURRICULUM
Establishment of a novel educational program such as simulation-based training must begin with development of a curriculum. In 2003, the Accreditation Council for Graduate Medical Education (ACGME) introduced 6 core competencies that must be addressed in every resident training program (ACGME 2007). These include patient care, medical knowledge, practice-based learning and improvement, interpersonal and communication skills, professionalism, and systems-based practice. The CNS conceived the design of the resident simulation curriculum to address educational objectives in each of these categories. Skills in patient care and medical knowledge would be assessed via written and hands-on practical skill tests. Practice-based learning and improvement and system-based practice would be addressed via precourse and postcourse evaluations by trainees that required them to conduct an analysis of their case-based experiences in residency training. Interpersonal skills and professionalism would be addressed through a combined analysis of directed questions during the written test and teaching by course faculty during the hands-on section of the course.
Additionally, during the development of the CNS simulation curriculum, an evaluation of several simulation centers was performed to assess methods that would be most successful in developing the CNS simulation program. The National Capital Area Simulation Center, Walter Reed Army Medical Center, Duke Medical Center, University of Illinois—Chicago, University of Florida—Jacksonville, and Royal College of Physicians and Surgeons simulation center in Canada were among the centers evaluated. From these assessments, we learned that course-based symposia that integrated multimodality simulators were among the most effective to establish a simulation-based training program that demonstrated validated improvement in the surgical skills of trainees. The CNS thus developed the first full-length practical course to train residents in simulation-based techniques. The curriculum for the CNS course was designed to address training needs for each of the 6 ACGME core competencies for resident education using the multimedia and multimodality approach that had been most successful at well-established training centers. The development of a simulation-based curriculum was, in fact, the most important focus in the development of the CNS simulation program. We chose this approach instead of designing the training platform around simulators that would be considered to be novel or interesting or to have a high degree of fidelity to actual surgeries. This allowed more readily quantifiable metrics-based validation of the utility of the simulation course to improve resident surgical skills.
NEUROSURGERY SIMULATOR MODELS
There are 4 major categories or types of simulator models:
1. Physical models, which provide direct manipulation and contact of the device;
2. Virtual reality (VR) simulators, typically computer-generated images controlled through computer haptic/tactile feedback devices;
3. Web-based simulators; and
4. Hybrid models or a combination of the other 3 types.
Physical models have been used in neurosurgical education for a number of years. Some basic examples are spine sawbones and cadaver dissection. More complex models have been developed, including the cervical laminectomy and foraminotomy simulator discussed elsewhere in this supplement. Despite the advantage of these devices providing actual manipulation and tactile feedback, a major limitation is that they tend not to be reusable because, during part of the dissections, the structural integrity of the model is disrupted and subsequently destroyed. This can result in a significant cost to continually replace these models.
To lower costs and to permit unlimited use of simulators, VR-based models have been introduced over the last several decades. The conception and use of these models have rapidly accelerated recently as a result of the rapid expansion of computer technology with a concurrent decline in the cost of VR model development. Additionally, improvements in haptic feedback for VR-based systems have led to improvements in the fidelity of these models, allowing more accurate representation of the surgical procedure they are designed to teach. Examples of VR-based simulators in neurosurgery include aneurysm clipping; craniotomy for trauma, tumor, and skull base dissection; posterior fossa decompression; and placement of external ventricular devices (see articles in this supplement).18-21 The benefits of these devices include their reusability and the ability to continually modify and update the models. Limitations include the initial cost for the purchase of computer and software, which tends to be much greater (10-100 times) than physical models. Although haptics have improved in recent years, VR-based models remain inferior to physical models in truly reproducing the surgical experience. Interestingly, in a post-CNS simulation course evaluation, neurosurgery residents reported a much greater appreciation and fondness for physical model simulators over VR devices.
Web-based computer simulators have become very common because of the growth of the Internet and World Wide Web infrastructure. The CNS has readily accepted and implemented this technology into its educational curriculum through the development of the CNS self-assessment in neurosurgery module. These Web-based computer programs and approaches are aimed at educating and evaluating neurosurgeons’ clinical problem solving, judgment, and decision-making skills. Web-based simulators such as the self-assessment in neurosurgery module provide an important adjunct to neurosurgical education but do not offer haptic controls or tactile feedback present with physical or VR-based models. These devices are beneficial in that they use currently available computer technology and thus are less expensive. However, there can be significant costs in development, depending on the software design requirements.
GROWTH OF MEDICAL SIMULATOR MODELS
The ACGME has noted the positive benefits of simulation in the medical education. Currently, several medical subspecialties (general surgery, anesthesiology, geriatrics, obstetrics and gynecology) require simulation as part of their educational requirements for residency training programs. The general surgery field was the first to accept and use this technology. One initial field was laparoscopic surgery where simulation was used to teach attendings and residents a “new” procedure or technique. The use of simulators to teach operative techniques in laparoscopic surgery has been shown to improve technique, performance, and the time needed to perform the procedure.22,23 Seymour et al23 noted in a prospective, randomized, blinded study that residents trained on VR simulators were 29% faster with laparoscopic gallbladder dissection. The non–VR-trained residents were 9 times more likely to fail to make progress and 5 times more likely to injure the gallbladder or to burn nontargeted tissue. In addition, the mean errors were 6 times more likely to occur in a non–VR-trained group. Therefore, these simulators appear to make training safer and more efficient in terms of time to educate. Medical simulation can provide evidence-based training in a controlled environment.
At the 2011 CNS Annual Meeting in Washington, DC, the first CNS simulation curriculum was initiated. The course was divided into 3 main categories: vascular, spinal, and cranial procedures (Table 1). The vascular model consisted of a simulation-based angiography model, later adding a vascular bypass simulator. Spinal disorders consisted of a cerebrospinal fluid dural repair model designed and validated by Paul Anderson, MD (orthopedic surgeon),24 a posterior cervical laminectomy model, and a minimally invasive spine lumbar pedicle screw physical model. In the cranial area, a posterior temporal VR model, posterior temporal physical model, VR ventriculostomy model designed and validated by ImmersiveTouch and the University of Illinois–Chicago Medical Center, a cranial flap computer-based design, and a VR tumor resection model were integrated into the curriculum.25 As part of this experience, numerous models and educational algorithms were assessed by questionnaires, surveys, and direct insights sought from the resident participants. Summary of this feedback concluded that the participants preferred a predefined course algorithm, as was instituted in the vascular angiography simulator model, with predefined course objectives and goals. Residents noted a preference for the physical models over VR simulators. Furthermore, trainees noted a need for a greater allocation of time to learn and perform tasks (> 60-90 minutes).
REDEFINING NEUROSURGICAL SIMULATION
In 2012, after numerous conference calls, discussions, and adaptation of the course design based on observation, assessments, and comments from the initial course, the educational curriculum was altered and standardized. To increase resident time with specific tasks, the modules were increased to 120 minutes. The residents were then assigned 3 specific simulation procedures, 1 from cranial, 1 from vascular, and 1 from spine. The 2-hour curricular blocks had a standardized outline (see Table 2) and included a written pretest on arrival, a quick didactic session, review of the simulator device, a practical pretest on arrival, hands-on training with faculty, a written posttest, and a posttest evaluation.
All modules were designed in a case-based fashion and had clearly defined goals and objectives. The simulators had a premodule test consisting of 10 to 15 multiple-choice questions designed to be procedure specific. The test was retaken at the end of the course as a posttest and used to measure improvement. Furthermore, a didactic session was incorporated, along with the technical component of the procedure. To standardize the grading and technical components, the objective-structured assessments of technical skill were used.26 The objective-structured assessments of technical skill were designed to quantitatively measure surgical technical skills though a 5-scale measurement and have been shown to be a valid and reliable metric. These metrics were adapted to each simulator module and based on the preassigned surgical objectives. In addition to establishing a defined and standardized curriculum for the simulation models, the course was expanded with the addition of several new simulators: a vascular anastomosis model, an anterior cervical discectomy and fusion model, and a skull fracture and epidural hematoma simulator.
Neurosurgery simulation models and education need to be further incorporation into residency education to maximize proficiency in the most efficient manner. It is the goal of the CNS Simulation Committee to establish an educational platform from which simulators can be used to complement current neurosurgical resident training goals and objectives. Such a platform would allow the residents or students to perform the procedures numerous times and would reinforce the educational objectives. This important concept of repetition is essential and required for the incorporation of learned skills. Expansion of the CNS resident simulation program to multiple centers will allow further validation studies to be performed to continue to refine the simulation curriculum to meet the goals of resident education in neurosurgery.
Dr Rezai is currently the President of the Congress of Neurological Surgeons. 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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