A virtual-reality real-time simulation of surgical operations that incorporates the inclusion of a hard tumour is presented. The software is based on Boundary Element (BE) technique. A review of the BE formulation for real-time analysis of two-domain deformable objects, using the pre-solution technique, is presented. The two-domain BE software is incorporated into a surgical simulation system called VIRS to simulate the initiation of a cut on the surface of the soft tissue and extending the cut deeper until the tumour is reached.

Virtual reality (VR) simulators have been created for various surgical specialties. The common theme is extensive use of graphics, confined spaces, limited functionality and limited tactile feedback. A development team at the University of Nottingham, UK, consisting of computer scientists, mechanical engineers, graphic designers and a neurosurgeon, set out to develop a haptic, e.g. tactile simulator for neurosurgery making use of boundary elements (BE). The relative homogeneity of the brain, allows boundary elements, e.g. 'surface only' rendering, to simulate the brain structure. A boundary element simplifies the computing equations saves computing time, by assuming the properties of the surface equal the properties of the body. A limited audit was done by neurosurgical users confirming the potential of the simulator as a training tool. This paper focuses on the application of the computational method and refers to the underlying mathematical structure. Full references are included regarding the mathematical methodology.

A virtual reality real-time simulation of surgical operations has been developed using the boundary element (BE) method. Other numerical techniques and related approaches to real-time modelling of deformable objects are briefly reviewed. The challenges raised by a key application – the simulation of neurosurgery – are identified. A brief review of the BE method is presented followed by a description of its implementation for three basic actions of prodding, pinching and cutting deformable objects. An initial implementation of these techniques is described in which haptic and visual feedbacks are generated when these operations are carried out on simple deformable objects.

A review of the field of virtual reality (VR) in surgery simulation is presented. The incorporation of computational mechanics techniques, namely the finite element (FE) and boundary element (BE) methods, in surgical simulations is discussed. Recent work on the development of a BE-based visual and haptic surgical simulator is presented. Advanced features of the BE simulator are highlighted; these include real-time tissue manipulation, surgical cutting, post-cutting deformations and self-contact. The experience of VR surgery is enhanced through the use of a purpose-built set-up with an angled projection through a semi-silvered mirror, two haptic force-feedback hand-held devices and Three-dimensional stereovision glasses.

Boundary element (BE) analysis is well known as a tool for assessing the stiffness and strength of engineering components, but, along with finite element (FE) techniques, it is also finding new applications as a means of simulating the behaviour of deformable objects within virtual reality simulations since it exploits precisely the same kind of surface-only definition used for visual rendering of three-dimensional solid objects. This paper briefly reviews existing applications of BE and FE within virtual reality, and describes recent work on the BE-based simulation of aspects of surgical operations on the brain, making use of commercial hand-held force-feedback interfaces (haptic devices) to measure the positions of the virtual surgical tools and provide tactile feedback to the user. The paper presents an overview of the project then concentrates on recent developments, including the incorporation of simulated tumours in the virtual brain.

A virtual-reality surgical simulator aimed at neurosurgery is presented. The simulator utilises boundary element (BE) technology to develop real-time realistic deformable models of the brain. The simulator incorporates the simulation of surgical prodding, pulling and cutting. Advanced features include the separation the cut surfaces by retractors and post-cutting deformations. The experience of virtual surgery is enhanced by implementing 3D stereo-vision and the use of two hand-held force-feedback devices.

The first page of this article is displayed as the abstract.

We present the design, demonstration and preliminary evaluation of a VR simulator for neurosurgical training. We describe the typical process of neurosurgery that we wish to simulate which involves the surgeon using diathermic forceps to incrementally cut into the brain, making a series of many small incisions. We describe our technique for simulating small cuts and also prodding, pinching and pulling actions on a VR model of the brain. This is based upon the boundary element method, rather than the more widespread finite element method. We present a demonstration implementation that provides both haptic and stereo graphical feedback to users. Preliminary evaluation shows that expert users believe that this approach has the potential to be useful in VR training but also raises issues that need to be addressed by future development.