We present a discrete treatment of adapted framed curves, parallel transport, and holonomy, thus establishing the language for a discrete geometric model of thin flexible rods with arbitrary cross section and undeformed configuration. Our approach differs from existing simulation techniques in the graphics and mechanics literature both in the kinematic description---we represent the material frame by its angular deviation from the natural Bishop frame---as well as in the dynamical treatment---we treat the centerline as dynamic and the material frame as quasistatic. Additionally, we describe a manifold projection method for coupling rods to rigid-bodies and simultaneously enforcing rod inextensibility. The use of quasistatics and constraints provides an efficient treatment for stiff twisting and stretching modes; at the same time, we retain the dynamic bending of the centerline and accurately reproduce the coupling between bending and twisting modes. We validate the discrete rod model via quantitative buckling, stability, and coupled-mode experiments, and via qualitative knot-tying comparisons.

/pdf/discrete-elastic-rods-1p72w8wrc9.pdf

Discrete elastic rods

This review paper discusses the role of haptics within virtual medical training applications, particularly, where it can be used to aid a practitioner to learn and practice a task. The review summarizes aspects to be considered in the deployment of haptics technologies in medical training. First, both force/torque and tactile feedback hardware solutions that are currently produced commercially and in academia are reviewed, followed by the available haptics-related software and then an in-depth analysis of medical training simulations that include haptic feedback. The review is summarized with scrutiny of emerging technologies and discusses future directions in the field.

The Role of Haptics in Medical Training Simulators: A Survey of the State of the Art

SOFA is an Open Source framework primarily targeted at real-time simulation, with an emphasis on medical simulation. It is mostly intended for the research community to help develop newer algorithms, but can also be used as an efficient prototyping tool. Based on an advanced software architecture, it allows to: * create complex and evolving simulations by combining new algorithms with algorithms already included in SOFA * modify most parameters of the simulation - deformable behavior, surface representation, solver, constraints, collision algorithm, etc. - by simply editing an XML file * build complex models from simpler ones using a scene-graph description * efficiently simulate the dynamics of interacting objects using abstract equation solvers * reuse and easily compare a variety of available methods

https://hal.inria.fr/inria-00319416/document

SOFA--an open source framework for medical simulation.

Haptics is a valuable tool in minimally invasive surgical simulation and training. We discuss important aspects of haptics in MISST, such as haptic rendering and haptic recording and playback. Minimally invasive surgery has revolutionized many surgical procedures over the last few decades. MIS is performed using a small video camera, a video display, and a few customized surgical tools. In procedures such as gall bladder removal (laparoscopic cholesystectomy), surgeons insert a camera and long slender tools into the abdomen through small skin incisions to explore the internal cavity and manipulate organs from outside the body as they view their actions on a video display. Because the development of minimally invasive techniques has reduced the sense of touch compared to open surgery, surgeons must rely more on the feeling of net forces resulting from tool-tissue interactions and need more training to successfully operate on patients.

Haptics in minimally invasive surgical simulation and training

An endoscopic solo surgery simulator was designed to quantitatively evaluate human-machine interface in robotic camera positioning systems. Our simulator can assess not only the quantitative efficiency of laparoscopic cameraworks but also the influence of cameraworks upon the accuracy of surgical actions. Two human-machine interfaces: a face motion navigation system and a voice activated system were developed and compared. As a result, the face control interface was more efficient in cameraworks than the voice control, even under a stress to control the instruments. However, it was also found that the face motion may have bad influence on precise surgical actions.

Medical Image Computing and Computer-Assisted Intervention — MICCAI 2002

The real-time simulation of rope, and knot tying in particular, raises difficult issues in contact detection and management. Some practical knots can only be achieved by complicated crossings of the rope, yielding multiple simultaneous contacts, especially when the rope is pulled tight. This paper describes a graphical simulator that allows a user to grasp and smoothly manipulate a virtual rope and to tie arbitrary knots, including knots around other objects, in real time. A first component of the simulator computes the global configuration of the rope based on user interactions. Another component of the simulator precisely detects self-collisions in the rope as well as collisions with other objects. Finally, a third component manages collisions to prevent penetration, while making the rope slide with some friction along itself and other objects, so that knots can be pulled tight in a realistic manner. An additional module uses recent results from knot theory to identify, also in real time, which topological knots have been tied. This work was motivated by surgical suturing, but simulation in other domains, such as sailing and rock climbing, could also benefit from it.

/pdf/real-time-knot-tying-simulation-1k9xgvgp3n.pdf

Real-time knot-tying simulation

Presents algorithms for animating deformable objects in real time. We focus on computing the deformation of an object subject to external forces and detecting collisions among deformable and rigid objects. The targeted application domain is surgical training. This application relies more on visual realism than exact, patient-specific deformation, but requires that computations be performed in real time. This is in contrast with pre-operative surgical planning, where computations may be done offline but must provide accurate results. To achieve real-time performance, the proposed algorithms take advantage of the fact that most deformations are local, human-body tissues are well damped, and motions of surgical instruments are relatively slow. They have been integrated into a virtual reality system for simulating the suturing of small blood vessels (microsurgery).

/pdf/real-time-simulation-of-deformable-objects-tools-and-243qalho6v.pdf

Real-time simulation of deformable objects: tools and application

We describe the implementation details of a real-time surgical simulation system with soft-tissue modeling and multi-user, multi-instrument, networked haptics. The simulator is cross-platform and runs on various Unix and Windows platforms. It is written in C++ with OpenGL for graphics; GLUT, GLUI, and MUI for user interface; and supports parallel processing. It allows for the relatively easy introduction of patient-specific anatomy and supports many common file formats. It performs soft-tissue modeling, some limited rigid-body dynamics, and suture modeling. The simulator interfaces to many different interaction devices and provides for multi-user, multi-instrument collaboration over the Internet. Many virtual tools have been created and their interactions with tissue have been implemented. In addition, a number of extra features, such as voice input/output, real-time texture-mapped video input, stereo and head-mounted display support, and replicated display facilities are presented.

http://cynthia.code404.com/assets/pubs/mmvr_spring_paper.pdf

Spring: a general framework for collaborative, real-time surgical simulation.

Algorithmic tools for real-time microsurgery simulation.

Computer systems for surgical planning and training are poised to greatly impact the traditional versions of these tasks. These systems provide an opportunity to learn surgical techniques with lower costs and lower risks. We have developed a virtual environment for the graphical visualization of complexsu rgical objects and real-time interaction with these objects using real surgical tools. An application for microsurgical training, in which the user sutures together virtual blood vessels, has been developed. This application demonstrates many facets of our system, including deformable object simulation, tool interactions, collision detection, and suture simulation. Here we present a broad outline of the system, which can be generalized for any anastomosis or other procedures, and a detailed look at the components of the microsurgery simulation.

/pdf/a-microsurgery-simulation-system-4aqofeznrp.pdf

Joel Brown

Papers

Real-time knot-tying simulation

Real-time simulation of deformable objects: tools and application

Spring: a general framework for collaborative, real-time surgical simulation.

Algorithmic tools for real-time microsurgery simulation.

A Microsurgery Simulation System