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Evaluation was performed on a prototype low-cost virtual-reality motor-skills simulator (VRMSS) created at the Telehealth Research Institute, John A. Burns School of Medicine, in conjunction with the National Biocomputation Center, Stanford University. The VRMSS is specifically designed to teach baseline fine-motor skills used in surgery that are based on a matrix of elemental technical skills that comprise the tenets of surgical technique. Fifty-seven participants were randomly assigned to one of three groups (VRMSS, box trainer or no training). After training each group was evaluated using the LapSim from Surgical Sciences. The VRMSS and box trainer were similar in performance, but significantly better than the no training control group. The VRMSS has significant advantages over the box trainer, in that the VRMSS can provide scoring on several parameters of the task without the need of an instructor and the VRMSS is approximately 1/16(th) the cost of the Lapsim.

Virtual reality simulators have the capability to automatically record user performance data in an unbiased, cost effective manner that is also less error prone than manual methods. Centralized data recording simplifies proficiency evaluation even more; however is not commonly available to date for surgical skills trainers. We will detail our approach in implementing a framework for distributed score recording over the Internet using a database for persistent storage.

We present a particle-based smoke simulation and a particle-based fluid simulation in an interactive environment with rigid and deformable objects. Many smoke and fluid simulations offer high physical and visual accuracy, but the underlaying models are to complex to run in real-time while performing soft-tissue simulation, collision detection, and haptic device support at the same time. Our algorithms are based on simple models that allow the surgery simulation to run in real-time.

Computer-based surgical simulation systems have produced tremendous benefits and demonstrated validity as a better method for many areas of surgical skills acquisition. However, despite these benefits, broad proliferation of these systems has continued to be elusive. While in large part this lag in adoption of this technology is due to social factors (organizational momentum, curriculum integration difficulties, etc), the cost of computer-based simulation systems has certainly remained a major deterrent toward broad deployment. Instead, what if it were possible to eliminate the cost of the large computer completely from the system, yet provide a much more extensive and detailed simulation than currently available? Finally, what if a simulation with even greater detail over a wider anatomical area were possible?This is the genesis of Project Hydra- a shared simulation supercomputer were made available for free and all that is required to access it is a low-end Internet-connected computer and, optionally, interaction/haptics devices as needed for the particular task. This would enable supercomputer-class simulation at every desktop with much greater fidelity than any user could individually afford and provide an online community for simulation research and application. Further, Internet-based simulation provides for many other benefits as well. By the user merely plugging optional, additional hardware into their existing, low-end PC and using the Internet as a means of simulation dissemination, distribution, and delivery means that the user can have immediate access to simulation updates/upgrades and download/access new content (didactic curriculum and cases). Further, this ease of access and use could lead to accelerated adoption and use of simulation within the medical curriculum and this access is provided anywhere in the world 24 x 7. In addition, once connected, a server-based simulation system would be a natural point for performing easy, automated clinical studies of surgical performance and skills.

Access to the laboratory component of a class is limited by resources, while lab training is not currently possible for distance learning. To overcome the problem a solution is proposed to enable hands-on, interactive, objectively scored and appropriately mentored learning in a widely accessible environment. The proposed solution is the Virtual-Reality Motor-Skills trainer to teach basic fine-motor skills using Haptics for touch and feel interaction as well as a 3D virtual reality environment for visualization.

The telementoring of surgical procedures is currently achieved via a wired infrastructure that usually requires sophisticated videoconference systems. This project represents the first step in assessing the potential for using handheld computers as a mobile alternative to current telementoring systems. Specifically, this project compares a handheld computer to a standard CRT monitor regarding their capability to accurately display video images from an endoscopic procedure. Video images from two previously recorded endoscopic procedures were transmitted from a standard VCR to: 1) a handheld computer (iPAQ 3670 running Pocket PC) via a wireless LAN and 2) a standard CRT monitor via a wired analog connection. The software-used on the handheld device was custom designed to allow 320 X 240 pixel video images to be broadcast in real time. Twenty-three surgical residents who had completed an endoscopy rotation were randomized to watch one of the two videotaped endoscopic procedures on the hand held computer or on the CRT monitor. After viewing the procedure, a ten-question quiz was used to assess the ability of each participant to recognize several anatomic landmarks. The result of each questionnaire was expressed as the percentage of correct responses. Using a crossover design, each participant then viewed the other videotaped procedure using the alternate device and completed a second quiz. The mean test score for each device was calculated, and these data was analyzed using a Student T test. The observed difference between the mean test score associated with the handheld device (77.93 +/- 11.26) and the CRT monitor (81.30 +/- 12.54) was not statistically significant (p<0.41). In addition, regardless of the device used, scores corresponding to video tape one were significantly higher than those recorded for video tape two (84.35 +/- 9.92 vs. 74.35 +/- 11.61; p < 0.01) All participants were able to recognize anatomic landmarks equally well when viewing broadcasted endoscopic procedures on a handheld display or a standard CRT monitor. Handheld computers may have a role in telementoring residents who are performing endoscopic procedures. Further research is needed to evaluate the integration of handheld devices into telementoring and robotic system to perform surgical procedures.

The objective of this project was to develop a computer-based surgical simulation system for cleft lip planning and repair. This system allows the user to interact with a virtual patient to perform the traditional steps of cleft-lip repair. The system interfaces to force-feedback (haptic) devices to track the user's motion and provide feedback during the procedure, while performing real-time soft-tissue simulation. An eleven-day old unilateral cleft-lip and palate patient was previously CT scanned for ancillary diagnostic purposes using standard imaging protocols and 1mm slices. High-resolution 3D meshes were automatically generated from this data using the ROVE software created in our lab. The resulting 3D meshes of bone and soft-tissue were instilled with physical properties of soft tissues for purposes of simulation. Once these preprocessing steps were completed, the patient's bone and soft-tissue data are presented on the computer screen in stereo and the user can freely view, rotate, and otherwise interact with the patient's data in real-time. The user is prompted to select anatomical landmarks on the patient data for preoperative planning purposes, then their locations are compared against that of a "gold standard" and a score, derived from their deviation from that standard and time required, is generated. The user can then move a haptic stylus and guide the motion of the virtual cutting tool. The soft tissues can thus be incised using this virtual cutting tool, moved using virtual forceps, and fused in order to perform any of the major procedures for cleft-lip repair. Real-time soft tissue deformation of the mesh realistically simulates normal tissues and haptic-rate (>1kHz) force-feedback is provided. The surgical result of the procedure can then be immediately visualized and the entire training process can be repeated at will. A short evaluation study was also performed. Two groups (nonmedical and plastic surgery residents) of six-people each performed the anatomical marking task of the simulator four times. Results showed that the plastic surgery residents scored consistently better than the people without medical background. Every person's score increased with practice, and the length of time needed to complete the eleven markings decreased. The data was compiled and showed which specific markers consistently took users the longest to identify as well as which locations were hardest to accurately mark. Our findings suggest that the simulator is a valuable training tool, giving residents a way to practice anatomical identification for cleft lip surgery without the risks associated with training on a live patient. Educators can also use the simulator to examine which markers are consistently problematic, and modify their training to address these needs.

The proliferation of surgical simulators would be increased if a common framework and set of virtual instruments existed for use by the application developer. We describe such a framework consisting of a powerful abstraction of a user interaction device, a functional taxonomy of surgical instruments, and a method for linking these components together. A series of example virtual instruments is also provided.

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.