Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.181556
Source of Support: None, Conflict of Interest: None
Neurosurgery is one of the most technically demanding medical professions that warrants a high level of expertise. In the present context of competitive medical practice, high societal expectations regarding quality of patient care and medicolegal and financial constraints, there are fewer opportunities for a trainee to achieve competency in standard neurosurgical, microsurgical, and operative techniques. Practice on simulation models like cadavers has been a trend since antiquity; however, recent development of newer models with their strategic modifications has given simulation education a new dimension. It has allowed trainees to acquire and improve surgical skills and knowledge in specifically fabricated and controlled settings with no risk to real patients. Simulation also offers the opportunity for deliberate practice and repetition unlimited number of times so that psychomotor skills can be automated. There is ever-growing evidence showing the positive impact of simulation on resident training in various areas of health care. Advances in computer technology and imaging, development of sophisticated virtual reality simulators with haptic feedback and the recent addition of three-dimensional printing technology, have opened a wide arena for the development of high-fidelity patient-specific models to complement current neurosurgical training. Simulation training in neurosurgery in India is still elementary since its inception at the All India Institute of Medical Sciences, New Delhi. A structured modular training program has been developed which is yet to be implemented at a multi-institutional level. Stringent efforts are needed to establish a uniform resident training curriculum where simulators can be used to complement current neurosurgical training.
Keywords: Curriculum; neurosurgery; simulation; skills training; virtual reality
Neurosurgery is one of the most technically demanding medical professions. It ranks as the most liable specialty amongest all the medical subspecialties to malpractice suits, with 19.1% of neurosurgeons in the US facing a claim a year. In spite of requirement of such a high level of technical expertise, with any error leading to severe consequences, there are even fewer opportunities for younger trainees to practice on complicated cases. Their exposure is also decreasing day-by-day with a decrease in the resident work hours, a dramatic increase in the number of residents in surgical disciplines, the proliferation of neurosurgical techniques, and the increasing societal expectations regarding the quality of patient care. In this context, simulation has evolved as a potential solution to provide basic training on various skills without risking the lives of real patients.
Simulation is defined as “the technique of imitating the behavior of some situations or processes by means of a suitable analogous situation or apparatus, especially for the purpose of study or personnel training.” Since antiquity, simulation has been used by novices and experts as a method to practice difficult techniques. Learning through simulation has historical roots dating back to the ancient Roman Empire when soldiers prepared for war by using simulated figures of their enemies. War games like Petteia (played by Greeks as early as in 500 BC), chess (a game believed to have originated in India in the 6th century or perhaps earlier, from the Indian Chaturanga) [Figure 1], and Kriegsspiel (Prussian army war game) have been used for centuries to demonstrate war tactics, and to improve the power of judgment and execution in the battlefield. By providing real-life situations to tackle and reduce errors, simulation has transformed itself into a new learning method. It has shown its efficacy in various nonmedical fields, especially in those carrying a high risk and cost in the event of errors. These include training of military personnel, airplane pilots, automobile designers, and nuclear power plant operators. This artificial environment (simulation) allows both the novice and the expert to be placed in situ ations that often mimic a crisis, where they can gain critical experience with no additional risk.
In the medical field, cadaveric dissection was probably the earliest effort at simulation since the 6th century BC, during the era of Alcmaeon of Croton, a Greek philosopher. Aelius Galenus (AD 129–c. 200/c. 216) was a Greek physician, who gave many anatomical descriptions (sometimes erroneous) based on his dissections of live and dead animals, mostly pigs and primates, that were considered as standard till Leonardo da Vinci (1452–1519) produced his anatomical drawings with accurate descriptions., Later, Andreas Vesalius (1514–1564) rectified many inaccuracies regarding the human anatomy in his publication “De humani corporis fabrica” from his extensive work on human cadavers. Limitations of cadaveric models due to the prevalent social stigma, legal and religious misconceptions, and monetary problems encouraged the development of physical models for medical education. Intricate waxworks illustrating human anatomy were developed in the 18th century. However, no further significant development in the field of medical simulation occured until Asmund Laerdal, a Norwegian publisher and toy manufacturer in the 1950s, developed the “Resusci-Anne” mannequin for cardiopulmonary resuscitation., Subsequently, complex and composite mannequins were developed for simulating real situations like the Human Patient Simulator (METI, Sarasota, FL, USA) for training on anesthesia and advanced resuscitation skills and the Trauma Man System (SimuLab, Seattle, Washington, USA) for rehearsing trauma resuscitation as well as other minor procedures, including a cricothyroidotomy and a chest tube placement., The concept of simulation in medicine evolved with the maturation of educational theories and understanding of teaching philosophies and began to influence the surgical fields in particular, in a substantial way. With the growing evidence of positive impact of simulation on surgical training, several surgical simulators have been designed, ranging from physical models to sophisticated virtual reality (VR) systems. However, in neurosurgery, the development of simulation platforms other than the cadaveric dissection modules has been relatively slow.
Recent years have seen a dramatic change in the simulation training with incorporation of new modules and modifications in a wide array of models as well as methods of training [Table 1] and [Table 2]. The majority of neurosurgical simulators are of physical and virtual reality (VR) subtypes. In a review article by Kirkman on the use of simulation in neurosurgical education in 2014, the most common simulated procedure was ventriculostomy followed by carotid angioplasty and stenting. Immersive Touch was the initial widely used simulator, followed by the Procedicus Vascular Intervention System Training (VIST; Mentice AB) and the rat model.
This includes cadaver models, live animal models, and synthetic models. In spite of many developments, cadaveric dissection has been the gold standard for neurosurgical training, especially for the practicing of various cranial and spinal procedures with a great degree of realism. Most of the physical models are dedicated partial task-based models for practice of basic skills of neurosurgery such as microsurgery, drilling, neuroendoscopy, spinal decompression, and instrumentation. Microsurgical training is probably the most discussed and practiced simulation which involves synthetic models such as silastic sheets, silicon tubes,,, and realistic models of skull, dura, and brain; dead tissue models such as chicken wing artery  and porcine heart; living animal models like rats.,, Cadavers and mannequins have been used in many centers to practice the drilling techniques as well as ventricular and nasal endoscopy [Figure 2] and [Figure 3].,,,,
Virtual reality simulators
After the introduction of computer-generated graphics in the 1980s, surgical simulation entered a new era with the capability to recreate human anatomy in a virtual space, thus obviating the need for physical models. It was further boosted by the introduction of computed tomography (CT) and magnetic resonance imaging (MRI), which provided images for designing three-dimensional (3D) models. Utilizing computer graphics, CT, and MRI data along with photographs of 1 mm slices of an actual human cadaver, the National Library of Medicine was able to create a volumetric digitized model of the human body in 1994 known as the 'Visible Man Project' which eventually formed the basis for numerous computer-based anatomic simulations. Given the complicated anatomy of the central nervous system, these tools are extremely useful for a better understanding of the normal three dimensional (3D) orientation of anatomical structures as well as for a visual rehearsal of different and complex cranial and spinal procedures [Figure 4].
Simplified virtual reality system
This is the most basic form of VR consisting of only a computer-user interface without any sensory interaction by the user. The basic example is the 'Visible Human Project' with a compilation of 3D anatomic data that can be used to create a digital representation of anatomic space. It can be further classified into first- and second-order environments and are discussed as follows:
Augmented virtual reality system
This enables the computer-user interface to be interactive and digitally manipulable by some degree of primary sensory input/outputs, which are mostly derived from the use of external props, for example, virtual brain reality software-based audio-visual ventriculostomy simulator, the 'Robo-Sim-Endoscopic neurosurgical simulator'. Similarly, patient-specific data can also be integrated into the Dextroscope to plan different surgical approaches. Using this platform, numerous other applications have been developed, for example, the virtual temporal bone dissector, the planning of surgical approaches and the clip ligation of intracranial aneurysms.
Immersive virtual reality systems
These provide a perception of the physical presence in a virtual world created by maximal primary sensory input/output, including haptic and kinesthetic modalities producing an “artificial environment.”
At present, virtual simulators exist for almost all neurosurgical procedures and operations, including endovascular coiling and stenting, pedicle screw placement, percutaneous rhizotomy, cranial microsurgery, ventriculostomy, and neuroendoscopy procedures. However, they are still far behind in providing a realistic interface. To provide an environment with realistic visual and haptic feedback, Bova et al., have developed a set of mixed-reality platforms, also known simply as mixed simulators. These mixed simulators provide the user with all of the essential cues necessary for real-world training. Bova et al., integrated a patient-specific physical model, a virtual radiographic and fluoroscopic model, an image-guided workstation, and infrared and electromagnetic probe tracking. They have developed a ventriculostomy simulator, a spinal instrumentation simulator, and a simulator for radiofrequency lesion probe insertion for the treatment of trigeminal neuralgia. It has gained appreciation from both trainees and practicing neurosurgeons in that it provides a realistic analog with appropriate real-world visual and haptic feedback. Currently, they are creating pediatric mixed-reality models.
Web-based surgical simulation
New advances in computer technology and convenient access to the internet led Phillips and John to develop a web-based surgical simulation model for ventricular catheterization. This model allowed trainee surgeons to practice the procedure with varying degrees of visual feedback without any risk to the patient. It allowed them to understand the relevant anatomy and master the technique along with the feasibility of assessment while performing the procedure. The only feedback to the user from this simulation was visual. The lack of tactile or haptic feedback was a concern but they deliberately compromised it to allow the application to remain small and thus useful over the web. Web-based VR training simulator exists for pedicle screw fixation and percutaneous rhizotomy.
Three-dimensional printing technology in neurosurgery
It is emerging as a new tool for the development of 3D high-fidelity neurosurgical simulator models. Multi-material 3D printers have the capability to fabricate high-fidelity multitexture models for planning and training of operative procedures [Figure 5]. They will enable the neurosurgeons to develop a clear visualization of the operative anatomy, thus improving operative planning through interaction with a patient-specific model. Based on this 3D printing technology, Tai et al., developed a neurosurgical simulator for external ventricular drain (EVD) placement, which was able to provide a realistic feedback with visualization of the trajectory of catheter placement. Similarly, Breimer et al., have recently introduced a synthetic brain simulator for ETV based on 3D printing technology with advantages such as a low cost, portability, reusability, and lack of special maintenance.
Virtual presence in neurosurgery
The concept of virtual presence has been derived from the innovations in telecommunication which allows an expert surgeon to virtually assist or guide a trainee without being physical present in the operative room utilizing teleconferencing and robotic technology. This has been made possible by the virtual presence software, VIPAA (Virtual Interactive Presence and Augmented Reality, Birmingham, AL, USA). With bidirectional video communication, the trainee can visualize the directions and techniques of the expert and perform the surgery in real time. However, this has limitations in its applicability with potential risk to real patients.
Till date, most of the simulation training has been widely utilized and evaluated in laparoscopic surgery. Recently, the benefits have been realized and applied in the neurosurgical fields also. The Society of Neurological Surgeons now sponsors regional boot camps for all the first year neurosurgery residents in the US for minor procedures like EVD placements, shunt taps, lumbar drain placements, etc. Similarly, a Congress of Neurological Surgeons (CNS) simulation committee has been formed in 2010 by the CNS to develop a comprehensive neurosurgical curriculum and methodology to maximize education and skills training.
It is becoming increasingly clear that without the standard assessment criteria, implementation and development of a training curriculum is incomplete. Apart from assessing the skill levels of trainees, it can be useful to evaluate the impact of the training module and program in the overall skill acquisition. Assessment tools can be categorized into subjective evaluation or feedback surveys, knowledge-based written tests, objective evaluations like global rating scale, objective structured assessment of technical skills, Northwestern Objective Microanastomosis Assessment Tool, etc. Almost all available studies using various training models have demonstrated clear improvement in skills with training; however, it is difficult to grade any one model as being superior to the other. Most of the simulators are applicable to individual task-based rehearsals rather than a practice of the whole procedure. Fidelity in simulation training has always been an important factor, which has largely been revolutionized by computer-based simulations producing an almost real operative environment; however, till date, none of the simulators has proven to be totally immersive to provide a perfect virtual environment. Yet another concern that has recently been discussed is whether the skills acquired from training on these models really replicate the real-life situation in the operative room. Finally, the most important factor that hinders development and the practical use of recent simulators is their high cost, which most of the institutions and training organizations across the world can barely afford.
The medical education in India dates back to the era of Atreya and Sushruta with dedicated training at the Universities of Taxila and Kasi. However, the neurosurgical training started only in the postindependence period due to the initial efforts by Jacob Chandy., Despite multilevel advancements in neurosurgical education in the Western world, where simulation models and education are being incorporated into the residency programs to maximize proficiency in the most efficient manner, we are still following the footsteps of our forefathers, i.e., the traditional apprenticeship model of neurosurgical education.,,, We have yet to establish an uniform neurosurgical resident training curriculum and develop an educational platform where simulators can be used to complement the currently practised neurosurgical training. The earliest attempt to incorporate simulation training in neurosurgical education was taken up by the All India Institute of Medical Sciences (AIIMS), New Delhi, by establishing the Neurosurgery Education and Training School (NETS).,
The NETS was established in 2008 at AIIMS, funded by the Department of Science and Technology, Department of Bio-Technology, Indian Council of Medical Research, and Department of Health Research, Government of India. It has an intra-institutional collaboration between the Departments of Neurosurgery, Anatomy, Forensic Medicine and Central Animal Facility; inter-institutional collaboration with the Indian Institute of Technology, Delhi;, and, an international collaboration with the Department of Neurosurgery, Hospital Barmherzige Bruder, Trier, Germany. The facility consists of laboratories well equipped with operating microscopes, endoscopes, microscopic and endoscopic instrument sets, drills, image intensifier, and high-definition cameras and monitors with recording and storage devices., 16, ,,,, In due course, this neurosurgery laboratory has developed many modules on the fundamental skills that are dedicated towards neurosurgical training [Figure 2],[Figure 3],[Figure 4],[Figure 5],[Figure 6]. The training curriculum provides modular hands-on training on synthetic models and live animal models along with practice of different cranial approaches on cadavers.,,,,,, However, it is still in its inception phase and is currently using physical models for simulation training. Further plans are underway to incorporate similar training schools in the central institutes followed by state medical colleges in India and develop a uniform curriculum to supplement neurosurgical residency programs in India. Implementation of simulation programs for training of residents at multiple centers will help in further validation of its efficacy along with development of a curriculum that can meet the goals of resident education in neurosurgery.
Advances in computer technology and imaging, development of sophisticated VR simulators with haptic feedback, and the recent addition of 3D printing technology, have opened a wide arena for the development of high-fidelity patient-specific models to complement current neurosurgical training. However, simulation training in India is still in its infancy stage. It is high time that we realize the potential benefits of simulation training in neurosurgery and incorporate this novel tool into the current neurosurgical curriculum.
We would like to acknowledge the efforts of scientific, technical, and application specialists from Neurosurgery Skills Training Facility, Neurosurgery Education and Training School, All India Institute of Medical Sciences, New Delhi, India. We would also like to thank Mr. Ramandeep Singh, Mrs. Britty Baby, Mr. Vinkle Srivastshav, Mr. Subhas Bora, Mr. Ajab Singh, Mr. Ram Niwas, Mr. Shashi Shekhar, Mr. Trivendra Yadav Mr. Suresh Kothari, Mr. Vikram Singh, and Mr. Satish Kumar for their untiring valuable support.
We thank the funding agencies for extramural grants - Indian Council of Medical Research, Department of Health Research, Ministry of Health and Family Welfare, Government of India - Project Number: 5/4-5/70/Neuro/TF/2011-NCD-1); Department of Science and Technology, Ministry of Science and Technology, Government of India - Project Number: SR/FST/LSII-029/2012.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]