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At least 217 records · Page 12Linked to original sources
PubMed2005

Comparison of training on two laparoscopic simulators and assessment of skills transfer to surgical performance.

BACKGROUND: Several studies have investigated the transfer of surgical trainees' skills acquired on surgical simulators to the operating room setting. The purpose of this study was to compare the effectiveness of two laparoscopic surgery simulators by assessing the transfer of skills learned on simulators to closely matched surgical tasks in the animal laboratory. STUDY DESIGN: In this post-test-only Control group study design, 46 surgically naive medical student volunteers were randomly assigned to one of three groups: Tower Trainer group (n = 16), LapSim group (n = 17), and Control group (n = 13). Outcomes measures included both time and accuracy scores on three laparoscopic tasks (Task 1: Grasp and Place; Task 2: Run the Bowel; Task 3: Clip and Cut) performed on live anesthetized pigs, and a global rating of overall performance as judged by four experienced surgeons. RESULTS: The Tower Trainer group performed significantly better than the Control group on 1 of 7 outcomes measures-Task 3: Time (p < 0.032), although the LapSim group performed significantly better than the Control group on 2 of 7 measures-Task 3: Time (p < 0.008) and Global score (p < 0.005). In comparing the two simulators, the LapSim group performed significantly better than the Tower Trainer group on 3 of 7 outcomes measures-Task 2: Time (p < 0.032), Task 2: Accuracy (p < 0.030) and Global score (p < 0.005), although the Tower Trainer group did not perform significantly better than the LapSim group on any measure. CONCLUSIONS: This study demonstrated that naive subjects trained on a virtual-reality part-task trainer performed better on live surgical tasks in a porcine model as compared with those trained with a traditional box trainer. These findings could aid in selection of appropriate training methodologies.

Adult↗
PubMed2000

A more efficient method of texture use in surgical robot simulation.

Texture mapping is a crucial supplement to modeling in 3D graphic simulation technology. Relatively small objects in a simulation environment can be represented with textures rather than by modeling, which helps economize on precious data storage space. Textures also lend some surfaces a more realistic appearance, both for the user and the viewer. The production of a texture, however, is a very complex process of repeated trial-and-error approximations. This inspired the idea of using mathematical formulas to determine the optimal texture so that the desired simulation environment is achieved with maximum effect and efficiency. In this paper the mathematical formulas for producing optimal texture are described. The results are presented as applied in a surgical robot simulation environment in an operating room.

Computer Graphics↗
PubMed2002

First experience with a public domain computer-aided surgical system.

The outcome of complex craniofacial operations is critically dependent on careful and accurate preoperative planning. Recent advances in computer technology enable the surgeon to do surgical simulations directly on to a computer terminal. We describe the clinical application of a public domain-based computer-aided system in craniofacial surgery. Operation planning was based on clinical investigations and radiological images, with particular use of a virtual three-dimensional surgical simulation. Three patients with complex craniofacial malformations were admitted for orbital correction. Surgical simulation defined numerically the extent of bone movements and the extent of resection areas. Operations were guided by the virtual planning. The outcome was compared with the planning to assess the accuracy of the operative correction. Our first experience confirms that computer-assisted simulation is a reliable and useful tool that improves surgical planning and helps to evaluate the surgical outcome.

Adult↗
PubMed1997

Computerized cephalometric evaluation of orthognathic surgical precision and stability in relation to maxillary superior repositioning combined with mandibular advancement or setback.

PURPOSE: A computerized, cephalometric, orthognathic surgical program (TIOPS) was applied in orthognathic surgical simulation, treatment planning, and postoperatively to assess precision and stability of bimaxillary orthognathic surgery. PATIENTS AND METHODS: Forty consecutive patients with dentofacial deformities requiring bimaxillary orthognathic surgery with maxillary superior repositioning combined with mandibular advancement or setback were included. All patients were managed with rigid internal fixation (RIF) of the maxilla and mandible and without maxillomandibular fixation (MMF). Preoperative cephalograms were analyzed and treatment plans produced by computerized surgical simulation. Planned, 5-week postoperative and 1-year postoperative maxillary and mandibular cephalometric-positions were compared. RESULTS: In the mandibular advancement group, the anterior maxilla was placed too far superiorly, with an inaccuracy of 0.4 mm. The posterior maxilla and the anterior mandible were placed in the planned positions. The lower posterior part of the mandibular ramus was placed too far anteriorly, with an inaccuracy of 2.0 mm. However, the mandibular condyles were accurately placed. In the setback group, the anterior maxilla was placed too far superiorly and posteriorly, with a vertical and sagittal inaccuracy of 1.0 mm and 0.7 mm, respectively. The posterior part of the maxilla was placed in a posterior position with an inaccuracy of 1.9 mm. The anterior mandible was placed too far anteriorly with an inaccuracy of 0.9 mm. The lower posterior part of the mandibular ramus was placed in a posterior position with an inaccuracy of 0.9 mm. However, the mandibular condyles were accurately placed. The statistical analysis of the 1-year stability data showed that the maxilla had moved 0.3 mm posteriorly in the advancement group and the lower incisors had moved 0.8 mm superiorly. No other significant positional maxillary or mandibular changes were found. In the setback group, the maxilla had moved 0.5 mm posteriorly, the anterior mandible 0.5 mm anteriorly, and the lower incisors 0.7 mm superiorly. No significant positional changes were seen in the mandibular ramus. CONCLUSION: The TIOPS computerized, cephalometric, orthognathic program is useful in orthognathic surgical simulation, planning, and prediction, and in postoperative evaluation of surgical precision and stability. The simulated treatment plan can be transferred to model surgery and finally to the orthognathic surgical procedures. The results show that this technique yields acceptable postoperative precision and stability.

Adolescent↗
PubMed2000

Modelling of soft tissue deformation for laparoscopic surgery simulation.

Virtual reality based surgical simulator systems offer a very elegant solution to the development of endoscopic surgical trainers. While the graphical performance of commercial systems already makes PC-based simulators viable, the real-time simulation of soft tissue deformation is still the major obstacle in developing simulators for soft-tissue surgery. The goal of the present work is to develop a framework for the full-scale, real-time, finite element simulation of elastic tissue deformation in complex systems such as the human abdomen. The key for such a development is the proper formulation of the model, the development of scalable parallel solution algorithms, and special-purpose parallel hardware. The developed techniques will be used for the implementation of a gynecological laparoscopic VR-trainer system.

Computer Simulation↗
PubMed2003

Effective use of human simulators in surgical education.

BACKGROUND: We initiated a teaching module utilizing a human simulator midway through 2001-2002 to improve student skills specific to the evaluation of patients in shock during a required clerkship in surgery for fourth-year medical students. We tested the hypothesis that student skills would improve after implementation of this module and identified factors that predicted student performance. MATERIALS AND METHODS: Students (n = 86) chose one of two hospital sites for a clerkship that focuses on the care of acutely ill surgical patients. A case-based lecture focusing on the diagnosis and management of a patient in shock was replaced midway through the academic year by a simulator session with a computerized life-sized mannequin. A standardized clinical final evaluation (OSCE) was used to assess student skills. We evaluated the effect of the simulator session and other factors on student exam performance using univariate and multivariate analysis. RESULTS: The site of the clerkship and the simulator session were significant factors affecting the OSCE score identified by ANOVA, P < 0.05. A stepwise multiple regression analysis testing the effect of simulator module, site, time of year, prior NBME subject exam, and prior OSCE during the third year clerkship identified that the simulator module was the only independent factor that modeled performance on all shock stations, P < 0.01. CONCLUSIONS: In a clerkship that already emphasized faculty facilitated case-based learning, the use of a teaching module employing a human simulator significantly improved test scores. This study supports the efficacy of human simulators to improve student skills related to the management of complex critically ill patients.

Clinical Clerkship↗
PubMed2006

Telecontrolled micromanipulator system (NeuRobot) for minimally invasive neurosurgery.

BACKGROUND: To perform less invasive neurosurgery, a telecontrolled micromanipulator system has been developed and applied to clinical situations. Basic experiments for telesurgery have also been conducted. METHOD: A cadaver head was used to carry out surgical simulation of the opening of the sylvian fissure and third ventriculostomy. After obtaining permission from the Ethical Committee of Shinshu University School of Medicine, part of the recurrent meningioma in a 45-year-old man was removed. As basic experiment for telesurgery, surgical simulation was also conducted in a rat brain with the operating console transported to a hospital 40 km distant from the University. FINDINGS: Opening of the sylvian fissure and third ventriculostomy were accurately performed. Tumour removal in a patient with recurrent meningioma was safely achieved. Surgical simulation in the rat brain was accurately and correctly carried out, operated on from a hospital 40 km distant. CONCLUSIONS: The NeuRobot, telecontrolled micromanipulator system, can be used as a tool for less invasive neurosurgery.

Animals↗
PubMed2003

Comparing a simplified FEM approach with the mass-spring model for surgery simulation.

Virtual reality based surgical simulators offer a very elegant approach to enhancing traditional training in endoscopic surgery. In this context a realistic soft tissue model is of central importance. The most accurate procedures for modeling elastic deformations of tissue use the Finite Element Method (FEM) to solve the governing mechanical equations. An alternative are mass-spring models which are a crude approximation of the real physical behavior. The main reason given when using the mass-spring approach is the computational complexity of FEM. In this study we show that an optimized linear FEM model requires computation time similar to the mass-spring approach, while giving better results.

Computer Simulation↗
PubMed2001

Virtual reality simulators for dermatologic surgery: measuring their validity as a teaching tool.

Surgical simulation is increasingly being considered for training, testing, and possibly credentialing in medicine and surgery. At the University of Washington we have been developing a virtual reality (VR) suturing simulator. In the course of development it must be realized that expensive new technologies should bear the burden of proof of their effectiveness and reliability before they are put into training programs. The purpose of this article is to define the concept of surgical skill and to discuss how it can be measured in the context of validating VR surgical simulators. Specific measures of validity and reliability are reviewed and discussed.

Computer Simulation↗
PubMed2003

An animal model for surgical anesthesia and analgesia: characterization with isoflurane anesthesia and remifentanil analgesia.

UNLABELLED: With a traditional clamp test alone, quantitative evaluation of the level of surgical anesthesia/analgesia is not easy. We have developed a rabbit model that allows for repeated quantification of the varying level of surgical anesthesia/analgesia using both mechanical and electrical stimulation as simulated surgical stimuli. After tracheostomy and intravascular cannulations under isoflurane anesthesia, eight rabbits were placed on a sling that allowed for free movement of the head and extremities. The inspired isoflurane concentration was reduced from 3% to 1.5% and then to 0%. Remifentanil was then infused at 4 graded infusion rates (0.1-0.8 microg. kg(-1) x min(-1)). At each drug dose, analgesic variables were determined including the number of animals behaviorally unresponsive to clamping the forepaw (nonresponders) and threshold voltage of subcutaneous electrical stimulation (2 Hz, 5 Hz, and 50 Hz) required to evoke the head lift (HLT, pain detection/arousal threshold) and escape movement responses (EMT, pain tolerance threshold). With increasing drug doses, HLTs and EMTs at 5 Hz increased dose-dependently and most proportionately to increases in the number of nonresponders, a standard indicator of the anesthetic/analgesic level. Therefore, using the HLT and EMT at 5 Hz combined with a clamp test, this rabbit model allows for quantitative evaluation of the varying level of surgical anesthesia/analgesia. IMPLICATIONS: We have developed a rabbit model of surgical anesthesia and analgesia using both mechanical and electrical stimulation as simulated surgical stimuli, which allows for repeated, quantitative, and qualitative evaluation of the varying level of surgical anesthesia and analgesia, differentiation between sedative/hypnotic and analgesic components of drug actions, and simultaneous monitoring of all the clinically relevant physiological variables including cardiovascular and respiratory variables.

Analgesia↗
PubMed2006

Enhancing the visual realism of hysteroscopy simulation.

Visualization is a very important part of a high fidelity surgical simulator. Due to modern computer graphics hardware, which offers more and more features and processing power, it is possible to extend the standard OpenGL rendering methods with advanced visualization techniques to achieve highly realistic rendering in real-time. For an easy and efficient use of these new capabilities, a stand-alone graphics engine has been implemented, which exploits these advanced rendering techniques and provides an interface in order to ensure the interoperability with a software framework for surgical simulators.

Computer Simulation↗
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↗
PubMed2001

Measurement of in-vivo local shear modulus by combining multiple phase offsets mr elastography.

To provide realistic surgical simulation, haptic feedback is important. In the existing surgical simulators, the fidelity of the deformation and haptic feedback is limited because they are based on the subjective evaluation of the expert-user and not on an objective model-based evaluation. To obtain elastic modulus of in-vivo human tissues, magnetic resonance elastography (MRE) was developed. MRE is a phase-contrast- based method that can visualize propagating strain waves in materials. The quantitative values of shear modulus can be calculated by estimating the local wavelength of the wave pattern. Low frequency mechanical motion must be used for soft tissue-like materials, because strain waves rapidly attenuate at higher frequency. Therefore, wavelength in MRE is long. It is difficult to estimate local wavelength with high spatial resolution especially from noisy MRE. In the MRE sequence, motion-sensitizing gradient (MSG) are synchronized with the mechanical cyclic motion. MRE with multiple initial phase offsets can be generated with increasing delays between the MSG and mechanical excitation. In this paper, we describe a method of measuring local wavelength with high spatial resolution by combining multiple phase offsets MRE. To confirm the reliability of this method, a computer simulation and phantom study were performed. The shear modulus measured with various elastic objects was well consistent with the value obtained by MRE and the mechanical method. The shear moduli of excised porcine liver and in-vivo human calf muscle were also analyzed by this method. on the subjective evaluation of an expert-user and not on objective model-based methods.

Acoustic Stimulation↗
PubMed2005

Virtual reality simulators in orthopedic surgery: what do the surgeons think?

BACKGROUND: There is increasing pressure to develop virtual reality surgical simulation that can be used in surgical training. However, little is known of the attitudes of the surgical community toward such simulation, and which aspects of simulation are most important. MATERIALS AND METHODS: A postal survey on attitudes to surgical simulation was sent to all New Zealand orthopedic surgeons and advanced trainees. This comprised of 44 questions in 10 sections, using either a visual analogue scale (0 to 10) or free text box replies. Results were analyzed for two sub-groups; surgeons qualified before 1990 and those qualified in or after 1990 or still in training. RESULTS: Of the 208 possible responses, 142 were received, a response rate of 68%. Only four respondents had tried a surgical based simulator. Earlier qualified surgeons were more likely to agree that simulation was an effective way to practice surgical procedures, median score 7.7 versus 5.6 (P = 0.03). Both groups thought the most important task for simulation was practicing angulation/spatial orientation (median score 8.4/10), while a realistic view of the operation was the most important requirement (median score 9/10). Both groups were unconvinced that simulation would impact on their practice in the next 5 years, with this statement being scored lower by later qualified surgeons, median score 2.4 versus 4.1 (P = 0.04). CONCLUSIONS: Orthopedic surgeons in New Zealand are supportive of surgical simulation but do not expect simulation to have an impact in the near future. Intriguingly, later qualified surgeons and trainees are more skeptical than their earlier qualified colleagues.

Adult↗
PubMed2006

Physics-based simulation of surgical fields for preoperative strategic planning.

Although careful planning of surgical approach is a key for success of surgery, conventional planning and simulation tools cannot support detailed discussion. This issue is derived from the difficulty of estimating complex physical behavior of soft tissues provided by a series of surgical procedures like cutting and deformation. This paper proposes an adaptive physics-based framework that simulates both interactive cutting and accurate deformation on virtual bodies, and performs preoperative planning for supporting strategic discussion. We focus on limited use of the two models: A particle-based model and an FEM-based model considering required quality and performance in different situations. FEM-based deformation of incision accurately produces estimated surgical fields. Based on the framework, a strategic planning system was developed for supporting decision of surgical approach using 3D representation of the surgical fields. We applied clinical CT dataset of an aortic aneurysm case to the system. Some experiments and usability tests confirmed that the system contributes to grasping 3D shape and location of the target organs and performs detailed discussion on patient-specific surgical approaches.

Aortic Aneurysm↗
PubMed2005

The effects of previously acquired skills on sinus surgery simulator performance.

OBJECTIVE: The Endoscopic Sinus Surgery Simulator is currently being studied as a tool for otolaryngology resident training. While examining performance patterns on the simulator, we sought to define any relationships that may exist between students' previously acquired skills and their performance on the simulator. METHODS: Twenty-six medical students were enrolled in our study. After completing their trials, they were asked to complete a 28-item questionnaire. This questionnaire included yes/no questions as well as 10-point Likert scale instruments. RESULTS: Only 4 students did not respond to the questionnaire. Significant contributions to simulator performance were elucidated for a number of previously learned skills, but most were short-lived. For example, experienced video gamers were significantly better at hazard avoidance in the simulator's novice mode (P = .03), but their advantage dissipated as they advanced to intermediate mode trials. In addition, students' handedness contributed to simulator performance for only the first 3 trials (P = .04), but this relationship, too, was no longer statistically significant in later trials. CONCLUSIONS: Some study students had skills and characteristics that significantly aided them in their ability to perform surgery on the simulator. However, these benefits were short-lived, and these results suggest that practicing plays a more important and long-standing role than other factors in surgical simulator performance. It follows that surgical simulation should play a more prominent role in surgical education because residents who practice on simulators such as this are, in turn, practicing for the reality of the operating room.

Adult↗
PubMed2001

The use of electromagnetic motion tracking analysis to objectively measure open surgical skill in the laboratory-based model.

BACKGROUND: Technical performance has traditionally been assessed subjectively within the operating theater, with few successful attempts at objective analysis. The Imperial College Surgical Assessment Device (ICSAD) has already been shown to be a valid quantitative measure of dexterity in laparoscopic surgical simulation. We describe its application to the assessment of open surgical procedures. STUDY DESIGN: Fifty-one participants were recruited from four different levels of general surgical experience: basic surgical trainees (n = 12), junior specialist registrars (n = 13), senior specialist registrars (n = 13), and consultants (n = 13). They completed two tasks: a small bowel anastomosis and a vein patch insertion into an artery. Surgical performance was measured with the Imperial College Surgical Assessment Device, a motion analysis system that measures the number of hand movements made and time taken to complete a task. The four groups were compared statistically using the Kruskal-Wallis test (K-W). Pairwise group comparisons used the Mann-Whitney U test and p values were adjusted for multiple comparisons to determine the statistical significance of these comparisons. RESULTS: Mean values for number of movements and time (secs) for small bowel anastomosis were 2,080/1,236 (basic surgical trainees), 1,673/1,016 (junior specialist registrars), 1,375/862 (senior specialist registrars), and 1,337/782 (consultants), respectively. Comparison of the medians by K-W revealed a p < 0.001 for each variable (No. of movements, time), respectively. Mean vein patch insertion results were 1,653/1,258, 1,297/1,006, 1,090/912, and 925/736 for each of the four groups. Again, comparison of the medians by K-W revealed a p < 0.001 for each variable. CONCLUSIONS: These findings suggest that hand motion analysis may be an effective objective measure of dexterity in open surgical simulation.

Anastomosis, Surgical↗