Search PubMed⌕ Search

Biomedical subjects

Kevin Montgomery

Publications and source records attributed to Kevin Montgomery.

14 recordsLinked to original sources
PubMed2006

A surgical and fine-motor skills trainer for everyone? Touch and force-feedback in a virtual reality environment for surgical training.

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.

Computer Simulation↗
PubMed2006

Project hydra--a new paradigm of internet-based surgical simulation.

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.

Computer Simulation↗
PubMed2005

A surgical simulator for planning and performing repair of cleft lips.

UNLABELLED: The objective of this project was to develop a computer-based surgical simulation system for planning and performing cleft lip repair. This system allows the user to interact with a virtual patient to perform the traditional steps of cleft-lip repair (rotation-advancement technique). MATERIALS AND METHODS: 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 11-day-old unilateral cleft lip, alveolus 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 developed in-house. 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's 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 (>1 kHz) 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 (non-medical and plastic surgery residents) of six persons each performed the anatomical marking task of the simulator four times. RESULTS: Results showed that the plastic surgery residents scored consistently better than the persons without medical background. Every person's score increased with practice, and the length of time needed to complete the 11 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. CONCLUSION: These 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.

Cleft Lip↗
PubMed2004

The fundamental manipulations of surgery: a structured vocabulary for designing surgical curricula and simulators.

A structured vocabulary is proposed for supporting the design and development of advanced surgical simulators. Nine fundamental surgical instrument-tissue actions or manipulations are defined and common synonyms provided. The vocabulary focuses on "target skills" that are familiar to surgeons, in comparison with "enabling skills" from the lexicon of instructional designers and psychometricians. The adoption of this vocabulary can facilitate communication among surgeons and bioengineers developing "high-fidelity" surgical simulators.

Computer Simulation↗
PubMed2004

Effect of environment on resistance to the European corn borer (Lepidoptera: Crambidae) in maize.

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 Mol7. 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.

Animals↗
PubMed2004

The personal digital assistant (PDA) as a tool for telementoring endoscopic procedures.

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.

Computers, Handheld↗
PubMed2003

A surgical simulator for cleft lip planning and repair.

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.

Cleft Lip↗
PubMed2003

Virtual instruments: a generalized implementation.

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.

Computer Simulation↗
PubMed2002

Algorithmic tools for real-time microsurgery simulation.

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.

Algorithms↗
PubMed2002

Generalized interactions using virtual tools within the spring framework: cutting.

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.

Biomechanical Phenomena↗
PubMed2002

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

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.

Computer Communication Networks↗
PubMedDate not supplied

User interface paradigms for patient-specific surgical planning: lessons learned over a decade of research.

This paper covers work in virtual reality-based, patient-specific surgical planning over the past decade. It aims to comprehensively examine the user interface paradigms and system designs during that period of time and to objectively analyze their effectiveness for the task. The goal is to provide useful feedback on these interface and implementation paradigms to aid other researchers in this field. First, specialized systems for specific clinical use were produced with a limited set of visualization tools. Later, through collaboration with NASA, an immersive virtual environment was created to produce high-fidelity images for surgical simulation, but it underestimated the importance of collaboration. The next system, a networked, distributed virtual environment, provided immersion and collaboration, but the immersive paradigm was found to be of a disadvantage and the uniqueness of the framework unwieldy. A virtual model, workbench-style display was then created using a commercial package, but limitations of each were soon apparent. Finally, a specialized display, with an integrated visualization and simulation system is described and evaluated. Lessons learned include: surgical planning is an abstract process unlike surgical simulation; collaboration is important, as is stereo visualization; and that high-resolution preoperative images from standard viewpoints are desirable, but interaction is truly the key to planning.

Patient-Centered Care↗
PubMedDate not supplied

Simulated medical learning environments on the Internet.

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.

Anatomy↗