Physics-based models for catheter, guidewire and stent simulation.

For over 20 years, interventional methods have improved the outcomes of patients with cardiovascular disease or stroke. However, these procedures require an intricate combination of visual and tactile feedback and extensive training periods. An essential part of this training relates to the manipulation of diagnostic and therapeutic devices such as catheters, guidewires, or stents. In this paper, we propose a physics-based model of wire-like structures that can be used as a core representation for the real-time simulation of various devices. Our approach is computationally efficient, and physically realistic. A catheter/guidewire is simulated using a composite model, which can dynamically adapt its material properties to locally describe a combination of both devices. We also show that other devices, such as stents, can be modeled from the same core representation.

Accelerating Surgical Simulation Development via OpenSurgSim: Burr Hole Trainer.

The first complete simulation based on OpenSurgSim (OSS) is used as a case study for analyzing how the toolkit can accelerate the development of surgical simulations. The Burr Hole Trainer (BHT) is designed to train non-neurosurgeons to drill holes in the skull to relieve intracranial pressure, and the majority of its simulation functionality is provided by OSS. Based on code size, using OSS cut the development time in half, reduced the necessary size of the development team by two-thirds, and saved millions of US dollars.

Open Surgical Simulation (OSS) - A Community Resource.

The OpenSurgSim system (www.opensurgsim.org) has been in development for the past 18 months. This open-source system is designed to provide the foundation for development of surgical simulators. The system combines years of learning the ins and outs of simulator design with best practices from other successful open-source projects.

Interactive contacts resolution using smooth surface representation.

Accurately describing interactions between medical devices and anatomical structures, or between anatomical structures themselves, is an essential step towards the adoption of computer-based medical simulation as an alternative to traditional training methods. However, while substantial work has been done in the area of real-time soft tissue modeling, little has been done to study the problem of contacts occurring during tissue manipulation. In this paper we introduce a new method for correctly handling complex contacts between various combination of rigid and deformable objects. Our approach verifies Signorini's law by combining Lagrange multipliers and the status method to solve unilateral constraints. Our method handles both concave and convex surfaces by using a displacement subdivision strategy, and the proposed algorithm allows interactive computation times even in very constrained situations. We demonstrate the efficiency of our approach in the context of interventional radiology, with the navigation of catheters and guidewires in tortuous vessels and with the deployment of coils to treat aneurysms.

Tumor-associated leukemia inhibitory factor and IL-6 skew monocyte differentiation into tumor-associated macrophage-like cells.

Tumor-associated macrophages (TAMs), the most abundant immunosuppressive cells in the tumor microenvironment, originate from blood monocytes and exhibit an IL-10(high)IL-12(low) M2 profile. The factors involved in TAM generation remain unidentified. We identify here leukemia inhibitory factor (LIF) and IL-6 as tumor microenvironmental factors that can promote TAM generation. Ovarian cancer ascites switched monocyte differentiation into TAM-like cells that exhibit most ovarian TAM functional and phenotypic characteristics. Ovarian cancer ascites contained high concentrations of LIF and IL-6. Recombinant LIF and IL-6 skew monocyte differentiation into TAM-like cells by enabling monocytes to consume monocyte-colony-stimulating factor (M-CSF). Depletion of LIF, IL-6, and M-CSF in ovarian cancer ascites suppressed TAM-like cell induction. We extended these observations to different tumor-cell line supernatants. In addition to revealing a new tumor-escape mechanism associated with TAM generation via LIF and IL-6, these findings offer novel therapeutic perspectives to subvert TAM-induced immunosuppression and hence improve T-cell-based antitumor immunotherapy efficacy.