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At least 289 records · Page 16Linked to original sources
PubMed2005

A hybrid cutting approach for hysteroscopy simulation.

An integral element of every surgical simulator is the ability to interactively cut tissue. A number of approaches have been suggested in the past, the most important being mesh subdivision by introducing new elements and mesh adaptation by adjusting existing topology. In this paper we combine these two methods and optimize them for our training system of hysteroscopic interventions. The basic methodology is introduced in 2D, a first extension to 3D is presented and finally the integration into the simulator described.

Computer Simulation↗
PubMed2004

Randomized clinical trial of virtual reality simulation for laparoscopic skills training.

BACKGROUND: This study examined the impact of virtual reality (VR) surgical simulation on improvement of psychomotor skills relevant to the performance of laparoscopic cholecystectomy. METHODS: Sixteen surgical trainees performed a laparoscopic cholecystectomy on patients in the operating room (OR). The participants were then randomized to receive VR training (ten repetitions of all six tasks on the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR)) or no training. Subsequently, all subjects performed a further laparoscopic cholecystectomy in the OR. Both operative procedures were recorded on videotape, and assessed by two independent and blinded observers using predefined objective criteria. Time to complete the procedure, error score and economy of movement score were assessed during the laparoscopic procedure in the OR. RESULTS: No differences in baseline variables were found between the two groups. Surgeons who received VR training performed laparoscopic cholecystectomy significantly faster than the control group (P=0.021). Furthermore, those who had VR training showed significantly greater improvement in error (P=0.003) and economy of movement (P=0.003) scores. CONCLUSION: Surgeons who received VR simulator training showed significantly greater improvement in performance in the OR than those in the control group. VR surgical simulation is therefore a valid tool for training of laparoscopic psychomotor skills and could be incorporated into surgical training programmes.

Cholecystectomy, Laparoscopic↗
PubMed1998

Force interactions in laparoscopic simulations: haptic rendering of soft tissues.

Research in the area of computer assisted surgery and surgical simulation has mainly focused on developing 3D geometrical models of the human body from 2D medical images, visualization of internal structures for educational and preoperative surgical planning purposes, and graphical display of soft tissue behavior in real time. Conveying to the surgeon the touch and force sensations with the use of haptic interfaces has not been investigated in detail. We have developed a set of haptic rendering algorithms for simulating "surgical instrument--soft tissue" interactions. Although the focus of the study is the development of algorithms for simulation of laparoscopic procedures, the developed techniques are also useful in simulating other medical procedures involving touch and feel of soft tissues. The proposed force-reflecting soft tissue models are in various fidelities and have been developed to simulate the behavior of elastically deformable objects in virtual environments. The developed algorithms deal directly with geometry of anatomical organs, surface and compliance characteristics of tissues, and the estimation of appropriate reaction forces to convey to the user a feeling of touch and force sensations.

Algorithms↗
PubMed2001

3-D simulation of craniofacial surgical procedures.

An integrated system for simulating craniofacial surgical procedures is presented. The system computes nonlinear soft-tissue deformation due to bone realignment. It is capable of simulating bone cutting and bone realignment with integrated interactive collision detection. Furthermore, soft-tissue deformation and cutting due to surgical instruments can be visualized. The system has been tested with several individual patient data sets. Simulation processes are based on a 3-D model of a patient's preoperative bone structure of the skull derived from a computer tomography scan and on a 3-D, photorealistic model of the patient's preoperative appearance obtained by a laser range scanner. The multi-layer soft-tissue model is represented by nonlinear springs. Very fast and robust prediction of nonlinear soft-tissue deformation is computed by optimizing a nonlinear cost function.

Cephalometry↗
PubMed2006

A virtual reality surgery simulation of cutting and retraction in neurosurgery with force-feedback.

A virtual-reality surgical simulator aimed at neurosurgery is presented. The simulator utilises boundary element (BE) technology to develop real-time realistic deformable models of the brain. The simulator incorporates the simulation of surgical prodding, pulling and cutting. Advanced features include the separation the cut surfaces by retractors and post-cutting deformations. The experience of virtual surgery is enhanced by implementing 3D stereo-vision and the use of two hand-held force-feedback devices.

Neurosurgery↗
PubMed2000

Hidden Markov models of minimally invasive surgery.

A crucial process in surgical education is to evaluate the level of surgical skills. For laparoscopic surgery, skill evaluation is traditionally preformed subjectively by experts grading a video of a procedure performed by a student. By its nature, this process is preformed using fuzzy criteria. The objective of the current study was to develop and assess a skill scale using Discrete Hidden Markov Models (DHMM). Ten surgeons (5 Novice Surgeons--NS; 5 Expert Surgeons--ES) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper equipped with a three-axis force/torque sensor was used to measure the forces/torques at the hand/tool interface synchronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis and a vector quantization algorithm, defined force/torque signatures for 14 types of tool/tissue interactions. From each step of the surgical procedures, two DHMM were developed representing the performance of 3 surgeons randomly selected from the 5 in the ES and NS groups. The data obtained by the remaining 2 surgeons in each group were used for evaluating the performance scale. The final result was a surgical performance index which represented a ratio of statistical similarity between the examined surgeon's DHMM and the DHMM of NS and ES. The difference between the performance index value, for a surgeon under study, and the NS/ES boundary, was considered to indicate the level of expertise in the surgeon's own group. Using this index, 87.5% of the surgical procedures were correctly classified into the NS and ES groups. The 12.5% of the procedures that were misclassified were preformed by the ES and classified as NS. However, in these cases the performance index values were very close to the NS/ES boundary. Preliminary data suggest that a performance index based on DHMM and force/torque signatures provides an objective means of distinguishing NS from ES. In addition this methodology can be further applied to evaluate haptic virtual reality surgical simulators for improving realism in surgical education.

Animals↗
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↗
PubMed2001

Virtual reality based surgical assistance and training system for long duration space missions.

Access to medical care during long duration space missions is extremely important. Numerous unanticipated medical problems will need to be addressed promptly and efficiently. Although telemedicine provides a convenient tool for remote diagnosis and treatment, it is impractical due to the long delay between data transmission and reception to Earth. While a well-trained surgeon-internist-astronaut would be an essential addition to the crew, the vast number of potential medical problems necessitate instant access to computerized, skill-enhancing and diagnostic tools. A functional prototype of a virtual reality based surgical training and assistance tool was created at our center, using low-power, small, lightweight components that would be easy to transport on a space mission. The system consists of a tracked, head-mounted display, a computer system, and a number of tracked surgical instruments. The software provides a real-time surgical simulation system with integrated monitoring and information retrieval and a voice input/output subsystem. Initial medical content for the system has been created, comprising craniofacial, hand, inner ear, and general anatomy, as well as information on a number of surgical procedures and techniques. One surgical specialty in particular, microsurgery, was provided as a full simulation due to its long training requirements, significant impact on result due to experience, and likelihood for need. However, the system is easily adapted to realistically simulate a large number of other surgical procedures. By providing a general system for surgical simulation and assistance, the astronaut-surgeon can maintain their skills, acquire new specialty skills, and use tools for computer-based surgical planning and assistance to minimize overall crew and mission risk.

Aerospace Medicine↗
PubMed2005

Surgical robot setup simulation with consistent kinematics and haptics for abdominal surgery.

Preoperative simulation and planning of surgical robot setup should accompany advanced robotic surgery if their advantages are to be further pursued. Feedback from the planning system will plays an essential role in computer-aided robotic surgery in addition to preoperative detailed geometric information from patient CT/MRI images. Surgical robot setup simulation systems for appropriate trocar site placement have been developed especially for abdominal surgery. The motion of the surgical robot can be simulated and rehearsed with kinematic constraints at the trocar site, and the inverse-kinematics of the robot. Results from simulation using clinical patient data verify the effectiveness of the proposed system.

Biomechanical Phenomena↗
PubMedDate not supplied

Initial evaluation of a shoulder arthroscopy simulator: establishing construct validity.

Formal evaluation of surgical simulators is essential before their introduction into training programs. We report our assessment of the Mentice Corp Procedicus shoulder arthroscopy simulator. This study tests the hypothesis of construct validity that experienced surgeons will score better on the simulator than individuals with minimal to no experience with the technique. Thirty-five subjects were stratified into three groups (novice, intermediate, and expert) based on their past 5 years' experience with shoulder arthroscopies. Each subject had an identical session on the simulator and completed anatomic identification, hook manipulations, and scope navigation exercises. We found statistically significant differences among the three groups in hook manipulation and scope navigation exercises, with the expert group performing the exercises more quickly (P =.013) and more accurately (P =.002) than the other two groups. No statistically significant differences were found among the groups in the identification of anatomic landmarks. Experts rated the simulator as an effective teaching tool, giving it a mean score of 4.22 and 4.44 (maximum, 5) for teaching instrument control and triangulation, respectively.

Arthroscopy↗
PubMed2004

Use of a virtual reality simulator for ureteroscopy training.

PURPOSE: Virtual reality surgical simulators may shorten operative time and reduce the potential for iatrogenic injury by providing training outside the operating room. We hypothesized that training on a virtual ureteroscopy (VU) simulator would allow novice endoscopists to overcome the initial learning curve before entering the operating room. MATERIALS AND METHODS: We evaluated 16 medical students on their ability to perform specific ureteroscopic tasks on a VU simulator. The students trained on the simulator for a total of 5 hours over multiple sessions using different training modules and then were retested on the initial module. Likewise, 16 urology residents with varying degrees of endoscopic experience were assessed on the same test module twice, without additional simulator training. RESULTS: The students improved task completion time from 17.4 to 8.7 minutes (p <0.05), while the residents performed the task in 7.6 minutes at baseline and 6.7 minutes at the second trial. Stratification of residents by years of urology training revealed that the mean completion time for the students after training did not differ statistically from that of first year residents who had performed a median of 14 clinical ureteroscopies. Furthermore, the subjective performance scores of the students were comparable to those of the first year residents. CONCLUSIONS: Novice medical students trained on a VU simulator improved task completion time by 50% after training, and performed comparably to residents who had completed nearly 1 year of urology training. VR training may allow beginning urology residents to shorten the initial learning curve associated with ureteroscopy training, although this hypothesis requires further validation.

Adult↗
PubMed2005

A bioresorbable molding mesh for impaction grafting revision hip surgery.

Impacted morselized allografts are used to treat bone loss in revision surgery. This technique depends on adequate mechanical support of the graft. Metal support devices function well, but there are disadvantages associated with the use of steel meshes. In this cadaveric, surgical simulation model we investigated the surgical and mechanical suitability of a bioresorbable molding mesh for use in impaction grafting revision surgery. Surgical feasibility was assessed, and mechanical deformation of the mesh during the surgical procedure and postoperative cyclic loading of the specimens were measured with strain gauges. All meshes were surgically usable. The exterior surface deformation of the meshes during the surgical procedure and postoperative mechanical loading did not exceed 4500 microm/m, although the meshes were not damaged in a four-point bending test in which deformations higher than 19,000 microm/m were reached. Therefore, results of this study suggest that this type of bioresorbable mesh seems to have sufficient initial mechanical properties to warrant additional preclinical in vivo study.

Arthroplasty, Replacement, Hip↗