Role of virtual simulation in surgical training.

The comparison of the developments obtained by training for aviation with the ones obtained by training for surgery highlights the efforts that are still required to define shared and validated training curricula for surgeons. This work focuses on robotic assisted surgery and the related training systems to analyze the current approaches to surgery training based on virtual environments. Limits of current simulation technology are highlighted and the systems currently on the market are compared in terms of their mechanical design and characteristics of the virtual environments offered. In particular the analysis focuses on the level of realism, both graphical and physical, and on the set of training tasks proposed. Some multimedia material is proposed to support the analysis and to highlight the differences between the simulations and the approach to training. From this analysis it is clear that, although there are several training systems on the market, some of them with a lot of scientific literature proving their validity, there is no consensus about the tasks to include in a training curriculum or the level of realism required to virtual environments to be useful.

GPU-based physical cut in interactive haptic simulations.

PURPOSE: Interactive, physics based, simulations of deformable bodies are a growing research area with possible applications to computer-aided surgery. Their aim is to create virtual environments where surgeons are free to practice. To ensure the needed realism, the simulations must be performed with deformable bodies. The goal of this paper is to describe the approach to the development of a physics-based surgical simulator with haptic feedback. METHOD: The main development issue is the representation of the organ behavior at the high rates required by haptic realism. Since even high-end computers have inadequate performance, our approach exploits the parallelism of modern Graphics Processing Units (GPU). Particular attention is paid to the simulation of cuts because of their great importance in the surgical practice and the difficulty in handling topological changes in real time. RESULTS: To prove the correctness of our approach, we simulated an interactive, physically based, virtual abdomen. The simulation allows the user to interact with deformable models. Deformable models are updated in real time, thus allowing the rendering of force feedback to the user. The method is optimized to handle high quality scenes: we report results of interactive simulation of two virtual tools interacting with a complex model. CONCLUSIONS: The integration of physics-based deformable models in simulations greatly increases the realism of the virtual environment, taking into account real tissue properties and allowing the user to feel the actual forces exerted by organs on virtual tools. Our method proves the feasibility of exploiting GPU to simulate deformable models in interactive virtual environments.

Preoperative workflow for lymph nodes staging.

PURPOSE: Accurate staging of lymph nodes relies mainly on surgical exploration and manual palpation. We present a new non-invasive diagnostic approach: simulated palpation through virtual laparoscopic instruments. METHODS: We set up a diagnostic process to extract lymph nodes shape and position from CTs and to analyze the trend of pixels intensities to determine tissue properties in order to feedback the force information. RESULTS: We have integrated the model, obtained from both the morphological information and stiffness values, in our laparoscopy simulator and surgeons can virtually palpate, with a haptic device, the lymph nodes. We evaluated the workflow extracting lymph nodes from a case study: the feedback provided through the simulator greatly helps the surgeon in the correct staging. CONCLUSIONS: Results show the feasibility of the approach and in the future we will clinically evaluate this new diagnostic methodology. We are studying the possibility to integrate CTs with other imaging systems to increase the accuracy.