A new model of electrosurgical tissue damage for neurosurgery simulation.

BACKGROUND: Bipolar hemostasis electrocoagulation is a fundamental procedure in neurosurgery. A precise electrocoagulation model is essential to enable realistic visual feedback in virtual neurosurgical simulation. However, existing models lack an accurate description of the heat damage and irreversible tissue deformation caused by electrocoagulation, thus diminishing the visual realism. This work focuses on the electrocoagulation model for neurosurgery simulation. METHOD: In this paper, a position-based dynamics (PBD) model with a bioheat transfer and damage prediction (BHTDP) method is developed for simulating the deformation of brain tissue caused by electrocoagulation. The presented BTHDP method uses the Arrhenius equation to predict thermal damage of brain tissue. A deformation model with energy and thermal damage constraints is developed to characterize soft tissue deformation during heat absorption before and after thermal injury. Visual effect of damaged brain tissue is re-rendered. RESULT: To evaluate the accuracy of the proposed method, numerical simulations were conducted and compared with commercial finite element software. The maximum normalized error of the proposed model for predicting midpoint temperature is 10.3 % and the maximum error for predicting the thermal damage is 5.4 %. The contraction effects of heat-exposed anisotropic tissues are also simulated. The results indicate that the presented electrocoagulation model provides stable and realistic visual effects, making it applicable for simulating the electrocoagulation process in virtual neurosurgery.

Modeling of connective tissue damage for blunt dissection of brain tumor in neurosurgery simulation.

We introduce a new model for connective tissue damage in blunt dissection, which is a very important process in neurosurgery simulation. Specifically, the tool-tissue interaction between the instrument and connective tissue is incorporated into the model of connective tissue damage. This damage develops with the evolution criterion due to the effect of the external load. The tetrahedral mesh in the soft tissue model is removed for the representation of rupture as the damage accumulates to the threshold value. Analysis and experiments show that the connective tissue damage model provides stable, visually realistic results for the simulation of the connective tissue rupture process. The stiffness of the connective tissue decreases as the damage accumulates. The proposed model for connective tissue damage was incorporated into the development of a neurosurgery simulator, in which blunt dissection of a brain tumor was simulated.

Roadmap for Developing Complex Virtual Reality Simulation Scenarios: Subpial Neurosurgical Tumor Resection Model.

BACKGROUND: Advancement and evolution of current virtual reality (VR) surgical simulation technologies are integral to improve the available armamentarium of surgical skill education. This is especially important in high-risk surgical specialties. Such fields including neurosurgery are beginning to explore the utilization of virtual reality simulation in the assessment and training of psychomotor skills. An important issue facing the available VR simulation technologies is the lack of complexity of scenarios that fail to replicate the visual and haptic realities of complex neurosurgical procedures. Therefore there is a need to create more realistic and complex scenarios with the appropriate visual and haptic realities to maximize the potential of virtual reality technology. METHODS: We outline a roadmap for creating complex virtual reality neurosurgical simulation scenarios using a step-wise description of our team's subpial tumor resection project as a model. RESULTS: The creation of complex neurosurgical simulations involves integrating multiple modules into a scenario-building roadmap. The components of each module are described outlining the important stages in the process of complex VR simulation creation. CONCLUSIONS: Our roadmap of a stepwise approach for the creation of complex VR-simulated neurosurgical procedures may also serve as a guide to aid the development of other VR scenarios in a variety of surgical fields. The generation of new VR complex simulated neurosurgical procedures, by surgeons for surgeons, with the help of computer scientists and engineers may improve the assessment and training of residents and ultimately improve patient care.

Neurosurgical Skills Assessment: Measuring Technical Proficiency in Neurosurgery Residents Through Intraoperative Video Evaluations.

OBJECTIVES: Although technical skills are fundamental in neurosurgery, there is little agreement on how to describe, measure, or compare skills among surgeons. The primary goal of this study was to develop a quantitative grading scale for technical surgical performance that distinguishes operator skill when graded by domain experts (residents, attendings, and nonsurgeons). Scores provided by raters should be highly reliable with respect to scores from other observers. METHODS: Neurosurgery residents were fitted with a head-mounted video camera while performing craniotomies under attending supervision. Seven videos, 1 from each postgraduate year (PGY) level (1-7), were anonymized and scored by 16 attendings, 8 residents, and 7 nonsurgeons using a grading scale. Seven skills were graded: incision, efficiency of instrument use, cauterization, tissue handling, drilling/craniotomy, confidence, and training level. RESULTS: A strong correlation was found between skills score and PGY year (P < 0.001, analysis of variance). Junior residents (PGY 1-3) had significantly lower scores than did senior residents (PGY 4-7, P < 0.001, t test). Significant variation among junior residents was observed, and senior residents' scores were not significantly different from one another. Interrater reliability, measured against other observers, was high (r = 0.581 ± 0.245, Spearman), as was assessment of resident training level (r = 0.583 ± 0.278, Spearman). Both variables were strongly correlated (r = 0.90, Pearson). Attendings, residents, and nonsurgeons did not score differently (P = 0.46, analysis of variance). CONCLUSIONS: Technical skills of neurosurgery residents recorded during craniotomy can be measured with high interrater reliability. Surgeons and nonsurgeons alike readily distinguish different skill levels. This type of assessment could be used to coach residents, to track performance over time, and potentially to compare skill levels. Developing an objective tool to evaluate surgical performance would be useful in several areas of neurosurgery education.

Simulation in Neurosurgery-A Brief Review and Commentary.

Neurosurgery is one of the most technically demanding and liable of all medical professionals. More than 75% of neurosurgical errors are deemed as preventable and technical in nature. Yet in a specialty that requires such high level of technical expertise, with large consequences for error, there are even fewer opportunities for residents in training to practice on the most complicated cases. Although there is no replacement for actual experiences in the operating room, interpersonal mentorship, coaching, and training, there is room to supplement residency education through simulation. Here we review the evidence to support surgical simulation, describe the strengths and weaknesses of existing technologies in direct neurosurgery specific and indirect simulation applications, and advocate for the development of more neurosurgery-specific applications using emerging kinetic technologies.