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At least 199 records · Page 11Linked to original sources
PubMed2006

Generation of variable anatomical models for surgical training simulators.

The generation of variable surgical scenes is a key element for effective training with surgery simulators. Our current research aims at a high fidelity hysteroscopy simulator which challenges the trainee with a new surgical scene in every training session. We previously reported on methods able to generate a broad range of pathologies within an existing healthy organ model. This paper presents the methods necessary to produce variable models of the healthy organ. In order to build a database of uteri, a volunteer study was conducted. The segmentation was carried out interactively, also covering the establishment of an anatomically meaningful correspondence between the individual organs. The variability of the shape parameters has been characterized by principal component analysis. A new method has been developed and tested, allowing the derivation of realistic new instances based on the stochastic model and complying with non-linear shape constraints which are defined and interactively controlled by medical experts.

Computer Graphics↗
PubMed2001

Bimanual haptic workstation for laparoscopic surgery simulation.

Realistic laparoscopic surgical simulators will require real-time graphic imaging and tactile feedback. Our research objective is to develop a cost-effective haptic workstation for the simulation of laparoscopic procedures for training and treatment planning. The physical station consists of a custom-built frame into which laparoscopic trocars and surgical tools may be attached/inserted and which are continuously adjustable to various positions and orientations to simulate multiple laparoscopic surgical approaches. Instruments inserted through the trocars are attached to end effectors of two haptic devices and interfaced to a high speed PC with fast graphics capability. The haptic device transduces 3D motion of the two manually operated surgical instruments into slave maneuvers in virtual space. The slave instrument tips probe the simulated organ. Simulations currently in progress include: 1) Surface-only renderings, deformation, and haptic interactions with elements in the gall gladder surgical field; 2) Voxel-based simulations of the bulk manipulation of tissue; 3) laparoscopic herniorrhaphy. This system provides force feed-forward from the grasped tools to the contact tissue in virtual space, with deformation of the tissue by the virtual probe, and force feedback from the deformed tissue to the operator's hands.

Computer Graphics↗
PubMed2000

The role of simulation in surgical training.

Surgical training has undergone many changes in the last decade. One outcome of these changes is the interest that has been generated in the possibility of training surgical skills outside the operating theatre. Simulation of surgical procedures and human tissue, if perfect, would allow complete transfer of techniques learnt in a skills laboratory directly to the operating theatre. Several techniques of simulation are available including artificial tissues, animal models and virtual reality computer simulation. Each is discussed in this article and their advantages and disadvantages considered.

Computer Simulation↗
PubMed2003

Self-assessment in simulation-based surgical skills training.

BACKGROUND: Simulation-based training provides minimal feedback and relies heavily on self-assessment. Research has shown medical trainees are poor self-assessors. The purpose of this study was to examine trainees' ability to self-assess technical skills using a simulation-trainer. METHODS: Twenty-one medical students performed 10 repetitions of a simulated task. After each repetition they estimated their time and errors made. These were compared with the simulator data. RESULTS: Task time (P < 0.0001) and errors made (P < 0.0001) improved with repetition. Both self-assessment curves reflected their actual performance curves (P < 0.0001). Self-assessment of time did not improve in accuracy (P = 0.26) but error estimation did (P = 0.01) when compared with actual performance. CONCLUSIONS: Novices demonstrated improved skill acquisition using simulation. Their estimates of performance and accuracy of error estimation improved with repetition. Clearly, practice enhances technical skill self-assessment. These results support the notion of self-directed skills training and could have significant implications for residency training programs.

Clinical Competence↗
PubMed1999

Three-dimensional facial model reconstruction and plastic surgery simulation.

Facial model reconstruction and surgical simulation are essential to plastic surgery in today's medicine. Both can help surgeons to design appropriate repair plans and procedures prior to actual surgery. In this paper, we exploit a metamorphosis technique in our new design. First, using metamorphosis and vision techniques, we can establish three-dimensional facial models from a given photo. Second, we design several morphing operators, including augmentation, cutting, and lacerating. Experiments show that the proposed algorithms can successfully create acceptable facial models and generate realistically visual effects of surgical simulation.

Computer Simulation↗
PubMed2005

Dynamic generation of surgery specific simulators -- a feasibility study.

Most of the current surgical simulators rely on preset anatomical virtual environments (VE). The functionality of a simulator is typically fixed to anatomy-based specific tasks. This rigid design principle makes it difficult to reuse an existing simulator for different surgeries. It also makes it difficult to simulate procedures for specific patients, since their anatomical features or anomalies cannot be easily replaced in the VE. In this paper, we demonstrate the reusability of a modular skill-based simulator, LapSkills, which allows dynamic generation of surgery-specific simulations. Task and instrument modules are easily reused from LapSkills and the three-dimensional VE can be replaced with other anatomical models. We build a nephrectomy simulation by reusing the simulated vessels and the clipping and cutting task modules from LapSkills. The VE of the kidney is generated with our anatomical model generation tools and then inserted into the simulation (while preserving the established tasks and evaluation metrics). An important benefit for the created surgery and patient-specific simulations is that reused components remain validated. We plan to use this faster development process to generate a simulation library containing a wide variety of laparoscopic surgical simulations. Incorporating the simulations into surgical training programs will help collect data for validating them.

Computer Simulation↗
PubMed2003

Virtual reality surgery: neurosurgery and the contemporary landscape.

OBJECTIVE: Virtual reality-simulated environments have been used for the training of personnel, most notably for military applications, for more than 35 years. The advantages conferred by being able to train novice personnel in a low- to no-risk simulated environment have long been appreciated by the medical community. The recent availability of affordable gigahertz-range microprocessors (once the exclusive domain of the Cray supercomputer) has made photorealistic graphical rendering and manipulation of virtual surgical substrates a reality. Concomitant advances in artificial intelligence systems and the portability of patient-specific magnetic resonance imaging, computed tomographic scanning, and angiographic image data presage the emergence of the surgical simulator as a modern surgical training adjunct. An overview of the status of surgical simulation with regard to its adaptability to current surgical training regimens is presented. METHODS: Extensive MEDLINE, Internet, and other database searches spanning the years 1960 to 2002 were conducted in an effort to delineate the status of simulated surgical environments. RESULTS: As would be expected, most articles addressing surgical simulation as their primary focus have been published in the past decade. A review of this literature demonstrates the broadest application in the field of endoscopic (and laparoscopic) procedures, most likely as a result of the reduced engineering burden with respect to incorporation of a haptic interface. CONCLUSION: The realization of ergonomically acceptable haptic interfaces remains elusive. Improvements in graphical rendering and the incorporation of artificial intelligence functions signal the certain emergence of surgical simulators as a viable supplement to the Halstedian method of surgical training.

Humans↗
PubMed2003

In-vivo and in-situ compressive properties of porcine abdominal soft tissues.

Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic feedback. Surgical simulation technology has progressed rapidly but lacks a comprehensive database of soft tissue mechanical properties with which to incorporate. Simulators are often designed purely based on what "feels right;" quantitative empirical data are lacking. A motorized endoscopic grasper was used to test abdominal porcine tissues in-vivo and in-situ with cyclic and static compressive loadings. An exponential constitutive equation was fit to the resulting stress-strain curves, and the coefficients were compared for various conditions. Stress relaxation for liver and small bowel were also examined. Differences between successive squeezes and between in-vivo and in-situ conditions were found.

Abdomen↗
PubMed1997

ENT endoscopic surgical training simulator.

This paper describes work in progress on the design and development of a prototype simulator for minimally invasive otolaryngology surgical training. The anatomy of the paranasal sinuses is geometrically complex and dangerously close to the brain and orbits, making this procedure challenging to practice and difficult to learn. We discuss the potential role of computer simulation to enhance and accelerate acquisition of surgical skills. The design goals of the prototype include high-fidelity simulation of the endoscopic imagery and haptic cues of surgical palpation. The prototype enables endoscopic navigation and limited interactive tissue manipulation and dissection tasks on a virtual patient using realistic replicas of surgical tools. We present an overview of the system architecture with a discussion of the technological challenges, design issues and current status of the efforts.

Computer Simulation↗
PubMed2002

Computer-controlled motorized endoscopic grasper for in vivo measurement of soft tissue biomechanical characteristics.

Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic devices. Surgical simulation technology has progressed rapidly but without a large database of soft tissue mechanical properties with which to incorporate. The device described here is a computer-controlled, motorized endoscopic grasper capable of applying surgically relevant levels of force to tissue in vivo and measuring the tissue's force-deformation properties.

Abdomen↗
PubMed2006

Dimensional accuracy of a binder jet model produced from computerized tomography data for dental implants.

A full-scale model produced by multislice helical computerized tomography (CT) was made by using the binder jet method and applied for presurgical diagnosis, surgical simulation, and the production of surgical templates for dental implant treatment. In this study, accuracy of the full-scale model with plaster powder was assessed by shifting the binary threshold values. A step phantom was made from bone-equivalent material. When it was placed in water, the CT imaging was performed with a multislice helical CT unit. Three-dimensional (3-D) images were reconstructed by 3-D visualization software. Using 4 different threshold values, full-scale models were produced by a binder jet method with plaster powder. All sides of the full-scale models were directly measured, and their values were compared with that of the step phantom. The mean difference was approximately 0.1 mm in the axial plane when the setting was 0.75 for the threshold. In total, the mean difference was approximately 0.2 mm when the setting was 0.50 for the threshold. It is suggested this full-scale model could be applied for presurgical diagnosis, surgical simulation, and the production of surgical templates in dental implant treatment.

Computer-Aided Design↗
PubMed2006

Surgical residents' perception of simulation training.

Laparoscopic surgical simulation is a valuable and validated training tool. We examined its perception and use among general surgery residents at our institution. Questionnaires were sent to all 29 general surgery residents with a 93 per cent response rate. Residents were divided into junior residents (JR; PGY 1-2) and senior residents (SR; PGY 3-5). JR spent more hours in the simulation center and completed their assigned tasks faster than SR (14 vs 52 days). Thirty-three per cent of SR felt that simulation training should be limited to JR in contrast to only 8 per cent of JR. However, 93 per cent of residents agreed that the program improved their laparoscopic skills. Most residents feel that simulation training is essential and mandatory in current surgical residency (75% of JR and 67% of SR) and needs to be extended to open surgery (67% JR and 60% SR). Seventy-five per cent of JR, but only 13 per cent of SR, feel that residents' involvement in procedures should be based on performance in surgical simulation. JR ranked simulation training first in useful ways to learn new skills, whereas SR ranked proctorship highest. JR have a higher use of simulation training and a higher perception of its utility.

Attitude of Health Personnel↗
PubMed2004

Realistic simulation of surgical cutting of soft tissues in real time with force feedback.

In this paper we present a geometrically efficient algorithm coupled with a physically based numerical scheme using a meshfree approach for the simulation of surgical procedures including surgical cutting in multimodal virtual environments. Progressive cutting, without the generation of new primitives, is achieved by snapping the nearest nodes to the interaction point between the cutting tool and the underlying polygon edge. The realism of the simulations is enhanced by employing a local subdivision algorithm in the vicinity of the tool-tissue interaction region and a cutting gutter to display the interior structure of the soft tissue as the cut opens up. A meshfree method is used to compute the deformation fields and interaction forces.

Algorithms↗
PubMed1996

Assessing a virtual reality surgical skills simulator.

The Institute for Defense Analyses (IDA) was contracted to perform a military standard task analysis of laparoscopic cholecystectomy, and to study the effectiveness of a virtual reality surgical skills simulator as a tool for surgical training and as a method for recording psychomotor behavior. This report describes the purpose of the study, its design, initial results, and implications for the field of medical education.

Cholecystectomy, Laparoscopic↗
PubMed1995

Virtual reality, telesurgery, and the new world order of medicine.

We are seeing the emergence of medical applications for virtual reality (VR). These include telepresence surgery, three-dimensional (3-D) visualization of anatomy for medical education, VR surgical simulators, and virtual prototyping of surgical equipment and operating rooms. Today, approximately 90% of the knowledge a physician requires can be obtained through electronic means, such as diagnostic sensors and imaging modalities, directly seeing the patient with a video camera for medical consultation, or using electronic medical records. In addition, with telepresence, a therapy can be effected electronically, regardless of the physical location of the patient. Therefore, it makes sense to send the electronic information or manipulation, rather than sending the patient or blood samples, to obtain tests or to produce a cure. In that these applications are mediated through the computer interface, they are the embodiment of VR as the major force for change in the field of medicine. The Green Telepresence Surgery System consists of two components, the surgical workstation and the remote worksite. At the remote site are a 3-D camera system and responsive manipulators with sensory input. At the workstation are a 3-D monitor and dexterous handles with force feedback. The next generation in medical education can learn anatomy from a new perspective by "flying" inside and around the organs, using sophisticated computer systems and 3-D visualization. The VR surgical simulator is a stylized recreation of the human abdomen with several essential organs. Using this, students and surgeons can practice surgical procedures with virtual scalpels and clamps. To support these advanced technologies, the operating room and hospital of the future will first be designed and tested in virtual reality, allowing multiple iterations of equipment and surgical rooms before they are actually built. Insofar as all these technologies are based on digital information, they are the building blocks for the digital physician of the 21st century.

Computer Simulation↗
PubMed1997

Acute coronary artery deficiency treatment process. Managing scarce resources and maintaining a level of service with the help of computer simulation.

Surgical treatment can be planned well in advance or arrive in a near emergency. If careful control is not exercised there is always the possibility that patients may suffer as a result. Discrete event simulation is an effective tool which can be used to find the most efficient ways of managing such a service's timetable. Examines the application of a desktop computer simulation package to model the work of a cardiac diagnosis and treatment system. The simulation package suggests how efficiency might be improved by moderating times taken to complete activities and staff and other resources required to perform the activities. Suggests the principles outlined can be readily expanded into a more complex model.

Acute Disease↗
PubMed2005

Comparison of the sensitivity of physical and virtual laparoscopic surgical training simulators to the user's level of experience.

BACKGROUND: The recent focus on quality of care and patient safety has been accompanied by increased interest in standardizing the training for laparoscopic surgeons. Studies have shown that laparoscopic simulators can be used to train surgical skills. Therefore, we designed an experiment to compare the effectiveness of two popular training systems. One system was based on a physical model, whereas the other used a virtual reality model. METHODS: A total of 32 medical students and residents were tested on both simulators. Time required for task completion and number of errors committed were recorded and compared. RESULTS: The physical training system differentiated among experience levels on three of the five tasks when time was used as a measure and four of five tasks when score was used, whereas the virtual reality system yielded statistically significant results in eight of 13 tasks for time and in five of 13 tasks for score. CONCLUSION: The physical model is more sensitive than the virtual reality one in detecting differences in levels of laparoscopic surgical experience.

Computer Simulation↗