Fundamentals of Neurosurgery: Virtual Reality Tasks for Training and Evaluation of Technical Skills

Background

Technical skills training in neurosurgery is mostly done in the operating room. New educational paradigms are encouraging the development of novel training methods for surgical skills. Simulation could answer some of these needs. This article presents the development of a conceptual training framework for use on a virtual reality neurosurgical simulator.

Methods

Appropriate tasks were identified by reviewing neurosurgical oncology curricula requirements and performing cognitive task analyses of basic techniques and representative surgeries. The tasks were then elaborated into training modules by including learning objectives, instructions, levels of difficulty, and performance metrics. Surveys and interviews were iteratively conducted with subject matter experts to delimitate, review, discuss, and approve each of the development stages.

Results

Five tasks were selected as representative of basic and advanced neurosurgical skill. These tasks were: 1) ventriculostomy, 2) endoscopic nasal navigation, 3) tumor debulking, 4) hemostasis, and 5) microdissection. The complete training modules were structured into easy, intermediate, and advanced settings. Performance metrics were also integrated to provide feedback on outcome, efficiency, and errors. The subject matter experts deemed the proposed modules as pertinent and useful for neurosurgical skills training.

Conclusions

The conceptual framework presented here, the Fundamentals of Neurosurgery, represents a first attempt to develop standardized training modules for technical skills acquisition in neurosurgical oncology. The National Research Council Canada is currently developing NeuroTouch, a virtual reality simulator for cranial microneurosurgery. The simulator presently includes the five Fundamentals of Neurosurgery modules at varying stages of completion. A first pilot study has shown that neurosurgical residents obtained higher performance scores on the simulator than medical students. Further work will validate its components and use in a training curriculum.

Introduction

Technical skills proficiency is an essential component of a surgeon's competency. An important aspect in cranial neurosurgery is microsurgical skill. Typically, a neurosurgeon must execute precise and delicate manipulations through small openings on magnified structures, performed under the operating microscope (25). Injury to critical areas could lead to major postoperative deficits or fatal outcomes (33). As is the case for many surgical disciplines, neurosurgery is becoming less invasive. The range of procedures that can be done endoscopically is steadily expanding, introducing new and increasingly sophisticated tools to surgeons and ultimately widening the already considerable scope of skills that a trainee must master.

Concerns for patient safety and reduced resident duty hours have limited the time available to train in the operating room (OR) (28). This restriction is at odds with learning new and added techniques; encouraging the development of novel training methods for surgical skills outside of the OR. Current curricula include laboratory sessions with hands-on components such as cadaveric dissection and animal surgeries (40). Cadavers are useful for learning surgical anatomy; however, dynamic properties, such as bleeding or pulsing organs, are missing. In live animal surgeries, the anatomy might differ. None of these alternatives are able to incorporate the anatomic variability and pathology seen during live training in the OR. Surgical simulation is emerging as a potential answer. These systems can consist of task box trainers, mannequins, virtual reality (VR), and hybrid systems 5, 24. A benefit of VR simulation is that in addition to complementing training in the OR, it can serve as an assessment tool by providing immediate objective feedback to the trainee through automated performance scores (47). VR simulation can allow autonomous skills training. It can also incorporate the different techniques, anatomies, and pathologies required for a variety of surgical specialties. Using advanced graphics and haptics, simulation is striving toward realistic, dynamic tissue behavior.

Systems are being developed for neurosurgery by research teams, including simulators for ventriculostomy (35), brain tissue manipulation and dissection 21, 49, endoscopic surgery 38, 39 and cranial bone drilling 1, 31, 50. To our knowledge, there is no commercially available VR simulator specific to neurosurgery. The end goal for a given VR simulator is acceptance by the medical community. A lesson that has been learned during first generation development of these simulators is that the technology should not be constructed before determining the needs of the end user 11, 23. Proper simulator design facilitates its integration into surgical training curricula. The first step is the identification of the educational requirements. Next, face and content validity are subjective measures used to respectively establish that the simulator is realistic and targets training the skills that are required to be trained 9, 18. The scores obtained in simulation should correlate with actual operative technical skill by discriminating novices from experts, demonstrated through construct validation studies 9, 18. Finally, concurrent validation is required to establish that the skills acquired from training on the simulator are transferable to the OR 9, 18, 22, 32, 43.

The National Research Council Canada (NRC) is currently developing NeuroTouch, a VR surgical simulator for cranial neurosurgery (Figure 1). NeuroTouch is an integrated platform simulating both the stereovision and ergonomics of an OR microscope as well as the two-dimensional indirect view of an endoscopic procedure. The system is equipped with two haptic devices, providing tactile feedback for each hand and permitting interaction with virtual soft tissue. An array of interchangeable physical handles is available (suction tool, ultrasonic aspirator, bipolar forceps, microscissors, and endoscope). The developed software allows physics-based simulation of tissue–tool interaction and bleeding. Further details on the system extend beyond the scope of this article. For a comprehensive description of NeuroTouch, the reader is referred to a work that introduces the technology (13).

A conceptual framework for training was defined before developing NeuroTouch. The present article describes the efforts undertaken to define the content for simulation with the input of surgeons. For basic skills training, we took inspiration from the Fundamentals of Laparoscopic Surgery (FLS) manual skills exercises 14, 16 to draft the Fundamentals of Neurosurgery (FNS) tasks targeting neurosurgical oncology. The objective of the FNS is to facilitate the acquisition of psychomotor skills. Consensus was reached to define only five main tasks as a starting point for fundamental skills training.