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The Attitudes Toward Male Nurses Scale was modified and then administered to a stratified-by-sex sample of 149 members of a state chapter of the National Association of Social Workers. Analysis suggests suitable internal consistency for the modified 15-item measure and provides empirical support for the scale's convergent-discriminant validity.

Maize (Zea mays L.) performance can vary widely between different production systems. The need for high-performing hybrids for organic systems with wide adaptation to various macroenvironments is becoming increasingly important. The goal of this study was to characterize inbred lines developed by distinct breeding programs for their combining ability and hybrid yield performance across diverse organic environments. Parent lines were selected from five different breeding programs to give a sample of publically available germplasm with potential for use in organic production systems with expired plant variety protection (Ex-PVP) and current commercial inbreds as benchmarks. A North Carolina Design II mating design was used to produce all possible cross combinations between seven lines designated as males and seven lines designated as females. A significantly positive general combining ability for the female inbred UHF134 suggests that it performs well in hybrid combination. Significant general combining ability was not observed for any male inbred line in this study. Several significantly positive specific combining abilities suggest that nonadditive genetic effects play an important role in determining yield in this germplasm. Further analysis revealed that hybrids containing either an Ex-PVP line or a commercial inbred line were on average superior to hybrids containing only inbreds developed by the cooperators of this study. This demonstrates the utility of testing inbreds from diverse sources when developing hybrids for organic production systems. [ABSTRACT FROM AUTHOR]

Development of the cotylocidium within its egg has only been described for a limited number of trematodes in the Aspidogastridae. The objectives of this study were: (1) to determine the location of cotylocidium development within the egg for Cotylaspis insignis; and (2) to establish a time line for developmental stages of this larva within the egg. Unembryonated, ectolecithal eggs in the uterus of the adult worm showed a large, centrally located zygote surrounded by vitelline cells. Eggs shed within the host, Lampsilas radiata luteola, and eggs released into surrounding water from the host contained zygotes or embryos undergoing early (i.e., 3 blastomeres) cleavage. This indicated that subsequent cotylocidial development within the egg proceeded outside the host in the external environment. These subsequent developmental stages of the cotylocidium larvae within the egg are described over the next 36 d in vitro at 20°C, culminating with the hatching of a motile larva. Our findings are compared with those previously reported for other aspidogastrean species. [ABSTRACT FROM AUTHOR]

The objectives of the present study were: (1) to establish the identity of Cotylaspis insignis in fat mucket, Lampsilis radiata luteola, specimens collected during the summer of 2014 from North Elkhorn Creek, Scott County, Kentucky, U.S.A.; (2) to assess host histopathology; and (3) to determine the prevalence and mean intensity of C. insignis in this mussel based on host sex and size/shell length. Whole mounts and histological sections of this worm revealed 19-20 peripheral alveoli and 9 central alveoli in the ventral sucker, as well as 19 marginal bodies, confirming the identification of this species. Specimens prepared for histological sectioning readily detached from host tissue in fixative, and no host pathology was observed. Eighty-one of 86 L. r. luteola harbored C. insignis infections, resulting in an overall prevalence of 94.2% and a mean intensity of infection of 9.31 ± 6.93. Results of statistical tests showed no significant differences in either the prevalence or mean intensity of infection when compared by host shell length or host sex. These results are compared to prior surveys of this trematode in freshwater mussels within the United States. [ABSTRACT FROM AUTHOR]

The aspidogastrid Cotylaspis insignis is normally found as an ectoparasite at the junction of the gills and visceral mass in freshwater mussels from a variety of species. It is not known if the osmotic environment at this site more closely approximates that found in stream/pond water or mollusk blood/hemolymph. The objectives of this study were to assess the in vitro effect of osmolality on adult C. insignis egg production and survivorship over 3 and 14 d, respectively, at 20°C. Worms recovered from the fat mucket, Lampsilas radiata luteola, and maintained in artificial snail water/hemolymph (ASW; 102 mOsm) showed a trend for greater survivorship than in artificial pond water (APW; 15 mOsm), though a significant difference was only noted on day 2 postexposure (PE). The mean ± SE eggs shed from adult worms in the controlled osmotic conditions over days 1-3 PE exceeded the number of eggs initially present within adults on day 0, indicating that egg production continued by adult worms in vitro. Egg production was much reduced after day 1 PE, but worms released significantly more eggs in ASW than in APW on days 2 and 3 PE. These results suggest that the osmolality at the gill visceral mass junction more closely approximates that of ASW rather than APW. [ABSTRACT FROM AUTHOR]

The authors examine the need for wireless and pervasive communications for improved healthcare services in the U.S. They call for innovation in information and communications technology in order to facilitate reliable, comprehensive and high quality clinical care service. They highlight the use of mobile software services in mobile phones and personal digital assistants (PDAs) to track the health conditions of patients.

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 1/16th the cost of the Lapsim. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 24x7. 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. [ABSTRACT FROM AUTHOR]

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described. [ABSTRACT FROM AUTHOR]

The European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is a major pest of maize, Zea mays L., in many temperate parts of the world. Genotype-by-environment interaction effects can make relative performance unpredictable and may hamper selection for resistance to European corn borer. The objective of this study was to determine the effect of environment on genotypic reaction to European corn borer resistance in maize. A set of 12 maize inbred lines was chosen to represent a range of European corn borer responses. Eleven testing environments ranged from Delaware, Ohio, Illinois, Iowa, Nebraska, Missouri, to Mississippi. For length of stalk tunneling, environmental and genotypic main effects (estimated by restricted maximum likelihood) were >20- and 10-fold larger than their interaction effect, respectively. Length of tunneling means for genotypes (across environments) ranged from 10.1 to 35.4 cm. Several putatively resistant genotypes grouped with the susceptible checks, B73 and Mo17. By breaking factors and the interaction into single degree of freedom components, we observed that GEMS-0001 had significant crossover interactions toward less susceptibility in both Mississippi and the Nebraska environments. Environments displaying several crossover interactions indicated that European corn borer screening at these sites would not necessarily apply to other locations, whether due to small differences in experimental conduct and/or environmental effects. The five most resistant genotypes were fairly consistent across environments. Because all environments except Illinois used larvae from the same insectary, and these environments differed in damage intensity and rankings, it is unlikely that insect biotype was a factor contributing to genotype-by-environment effects. [ABSTRACT FROM AUTHOR]

Learning anatomy and surgical procedures requires both a conceptual understanding of three-dimensional anatomy and a hands-on manipulation of tools and tissue. Such virtual resources are not available widely, are expensive, and may be culturally disallowed. Simulation technology, using high-performance computers and graphics, permits realistic real-time display of anatomy. Haptics technology supports the ability to probe and feel this virtual anatomy through the use of virtual tools. The Internet permits world-wide access to resources. We have brought together high-performance servers and high-bandwidth communication using the Next Generation Internet and complex bimanual haptics to simulate a tool-based learning environment for wide use. This article presents the technologic basis of this environment and some evaluation of its use in the gross anatomy course at Stanford University. [ABSTRACT FROM PUBLISHER]

In our experience, mesh-cutting methods can be distinguished by how their solutions address the following major issues: definition of the cut path, primitive removal and re-meshing, number of new primitives created, when re-meshing is performed, and representation of the cutting tool. Many researches have developed schemes for interactive mesh cutting with the goals of reducing the number of new primitives created, creating new primitives with good aspect ratios, avoiding a disconnected mesh structure between primitives in the cut path, and representing the path traversed by the tool as accurately as possible. The goal of this paper is to explain how, by using a very simple framework, one can build a generalized cutting scheme. This method allows for any arbitrary cut to be made within a virtual object, and can simulate cutting surface, layered surface or tetrahedral objects using a virtual scalpel, scissors, or loop cautery tool. This method has been implemented in a real-time, haptic-rate surgical simulation system allowing arbitrary cuts to be made on high-resolution patient-specific models. Published in 2002 by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Background: In the management of morbid obesity by laparoscopic adjustable gastric banding (LAGB), careful patient preparation and attentive follow-up have been shown to produce the best long-term results. Methods: Between November 2002 and August 2007, prospective data were collected on 2,411 consecutive patients, 84% of whom underwent LAGB at our freestanding outpatient surgery center, staffed by our dedicated multidisciplinary bariatric team. Outcomes reported include changes in mean body mass index (BMI), percentage excess body weight loss (%EBWL), and incidence of complications at 1 year, as well as the slippage rate up to 3 years. Results: A total of 2,003 (83%) female and 409 (17%) male patients with a mean age of 44.1 years (range 15–76 yrs) and a BMI (mean ± SD) of 45.7 ± 7.9 kg/m2 (range 29.1–83.1 kg/m2) underwent LAGB. In 2,027 patients (84%), LAGB was performed as an outpatient procedure, with 1 (0.04%), conversion from a laparoscopic to an open procedure. The majority of operations were completed in less than 1 hour, using the pars flaccida technique. One-year weight loss data were available in 1,144 patients (47%). BMI decreased to 36.9 ± 7.4 kg/m2 (−8.8). Mean %EBWL at 1 year (± 60 days) was 41.0% ± 18.1% (range 0.7%–113.9%). Complications occurred in 241 of 2,411 (10%) patients. There was 1 death (0.04%). Cumulative slippage at 1, 2, and 3 years, respectively, was 0.4%, 2.4%, and 10%. There were 56 (2.3%) port-related problems, and 13 band explantations (0.54%). Conclusions: With extensive staff experience and patient preparation, LAGB can be performed safely as an outpatient procedure for select patients. Close follow-up is crucial in order to optimize LAGB outcomes for the long term. [Copyright &y& Elsevier]

Today, there is growing interest in computer surgical simulation to enhance surgeons’ training. This paper presents a simulation system based on novel algorithms for animating instruments interacting with deformable tissue in real-time. The focus is on computing the deformation of a tissue subject to external forces, and detecting collisions among deformable and rigid objects. To achieve real-time performance, the algorithms take advantage of several characteristics of surgical training: (1) visual realism is more important than accurate, patient-specific simulation; (2) most tissue deformations are local; (3) human-body tissues are well damped; and (4) surgical instruments have relatively slow motions. Each key algorithm is described in detail and quantitative performance-evaluation results are given. The specific application considered in this paper is microsurgery, in which the user repairs a virtual severed blood vessel using forceps and a suture (micro-anastomosis). Microsurgery makes it possible to demonstrate several facets of the simulation algorithms, including the deformations of the blood vessel and the suture, and the collisions and interactions between the vessel, the forceps, and the suture. Validation of the overall microsurgery system is based on subjective analysis of the simulation’s visual realism by different users. [Copyright &y& Elsevier]

Objective: Bariatric surgery is an effective treatment for the reduction of weight in obese patients (BMI ≥ 40 kg/m(2) or 30 kg/m(2) with ≥1 comorbidities), who are refractory to behavioral and medical therapies. This study examined the effect of the adjustable gastric band (AGB) system on changes in gastroesophageal reflux disease (GERD) and patient-reported outcomes, including measures of quality of life., Methods: Two-year interim analysis of patients (N = 171) in the 5 year, prospective APEX study who reported GERD prior to the AGB procedure. An unrecorded number of hiatal hernia repairs were conducted during the APEX study., Results: At baseline, 171 of 395 patients (43%) reported GERD requiring daily medical therapy. After 2 years, 122 patients had sufficient data to assess outcome (71%). Complete resolution of GERD was reported in 98 patients (80%), improvement in 13 (11%), no change in 9 (7%), and worsening in 2 (2%). Overall, 91% of GERD patients experienced resolution and/or improvement of GERD. Baseline BMI was not significantly different among the GERD response categories (resolved, improved, and stable/worse), p = 0.4581. Mean ΔBMI and percentage excess weight loss (%EWL) were: -8.8 kg/m(2)/-0.9%, -11.4 kg/m(2)/-53.9%, -6.4 kg/m(2)/-36.1%, and -7.1 kg/m(2)/-31.2%, respectively. There were no significant differences in reductions in BMI or %EWL between responder groups (resolved versus stable/worse ΔBMI p = 0.1031, %EWL p = 0.0667 OR resolved/improved versus stable/worse ΔBMI p = 0.0918, %EWL p = 0.0552). After 2 years, resolution or improvement occurred in pre-existing comorbidities: type 2 diabetes (96%), hypertension (91%), hyperlipidemia (77%), obstructive sleep apnea (86%), osteoarthritis (93%), and depression (75%). Patient satisfaction with AGB was assessed as: very satisfied/satisfied (87%), very satisfied (50%), dissatisfied (5.0%). Quality of life measured by the Obesity and Weight-Loss Quality of Life Instrument (GERD patients) significantly improved from baseline., Conclusion: Obese patients with GERD had meaningful improvement in patient-reported outcomes with the AGB system. In addition, other obesity-related comorbidities and measures of quality of life improved.

The unavailability of a flexible system for realtime testing of decision-support algorithms in a pre-hospital clinical setting has limited their use. In this study, we describe a plug-and-play platform for real-time testing of decision-support algorithms during the transport of trauma casualties en route to a hospital. The platform integrates a standard-of-care vital-signs monitor, which collects numeric and waveform physiologic time-series data, with a rugged ultramobile personal computer. The computer time-stamps and stores data received from the monitor, and performs analysis on the collected data in real-time. Prior to field deployment, we assessed the performance of each component of the platform by using an emulator to simulate a number of possible fault scenarios that could be encountered in the field. Initial testing with the emulator allowed us to identify and fix software inconsistencies and showed that the platform can support a quick development cycle for real-time decision-support algorithms.

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.

The American Telemedicine Association (ATA) held the Global Forum on Telemedicine: Connecting the World Through Partnerships in September 2007 with sponsorship by the Telemedicine and Advanced Technology Research Center (TATRC), U.S. Army Medical Research and Materiel Command (USAMRMC). The goal was to bring together key stakeholders in global healthcare outreach to explore a flexible framework and sustainable business model that can leverage telemedicine and information technology (IT) to expand healthcare services internationally. Dr. Hon S. Pak, President of the ATA, opened the forum with a call for collaboration and partnership, and encouraged continued international dialogue to create a framework that leverages the telemedicine community to improve global disparity in healthcare. Keynote addresses included speakers from the World Health Organization (UN) and United Nations (UN) Global Alliance for Information and Communities Technologies and Development (GAID). Presentations from 15 government and nongovernment aid organizations (NGOs) and 12 international programs covered 5 key areas: (1) NGO perspective; (2) governmental/military programs; (3) financial sustainability; (4) disaster response; and (5) emerging opportunities. The forum resulted in an International Roadmap for Action that was developed by the authors based on the presentations and interactions from the 335 attendees and establishing a set of priorities and actions to improve healthcare using telemedicine and IT. Recommendations include: (1) continued dialogue in creating a telemedicine framework; (2) identification and leverage of resources; (3) provision of education to funding organization and expand training programs to build competency in the healthcare workforce; (4) alignment of international policy to support integration of telemedicine into country plans and support cross-country partnerships; (5) development of communications infrastructure; and (6) integration of telemedicine into disaster relief programs.

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.

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.

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 present schemes for real-time generalized interactions such as probing, piercing, cauterizing and ablating virtual tissues. These methods have been implemented in a robust, real-time (haptic rate) surgical simulation environment allowing us to model procedures including animal dissection, microsurgery, hysteroscopy, and cleft lip repair.

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.

We present schemes for real-time generalized mesh cutting. Starting with the a basic example, we describe the details of implementing cutting on single and multiple surface objects as well as hybrid and volumetric meshes using virtual tools with single and multiple cutting surfaces. These methods have been implemented in a robust surgical simulation environment allowing us to model procedures ranging from animal dissection to cleft lip correction.