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Results for “Surgical simulation”

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At least 379 records · Page 21Linked to original sources

PubMed2003

Can tonic accommodation predict surgical performance?

BACKGROUND: Pilots undergo many visual tests for both selection and assessment, and we know that there are many similarities between pilots and surgeons. Hence, it would not be unreasonable to bring similar visual tests into surgery. Tonic accommodation (TA) is a stable parameter that is adopted by the eye in the absence of any stimulation. Over recent years, surgery has undergone change from traditional open surgery to minimally invasive procedures, bringing many advantages. However, not every surgeon has the ability to perform under conditions where the operative field is represented on a flat monitor. METHOD: We determined the TA values in medical students and then correlated this with their performance on a virtual reality surgical simulator. RESULTS: We found that TA values predicted the number of errors made with the dominant hand, accounting for 27% of the variance. CONCLUSION: The data suggest that TA may play a role in the individual differences that are noted when surgeons perform laparoscopic surgery. Further studies are needed to evaluate the exact role of TA in surgical performance.

Accommodation, Ocular↗

PubMed2006

The effect of surgical resection in the region of the retromolar trigone.

Tumours in the mucosa of the retromolar trigone (RMT) are rare, but develop insidiously and spread rapidly into surrounding structures. Resection may require radical dissection beginning usually on the medial side of the mandible. Such surgery can put important structures at risk. The normal anatomy of the RMT and its relations has been studied together with simulated surgical incisions and resections. Tissue removed was processed by histological techniques in order to demonstrate structures excised or damaged by the operation. The simulated incision showed that the lingual nerve, submandibular duct and palatoglossus were at particular risk. This could affect sensation, speech, swallowing and movements of the tongue. The findings pose immediate concerns for surgeons operating in this area. Although cancer surgery often involves sacrificing tissue, care should be taken to preserve structures vital to the patient's oral function without compromising oncological principles.

Humans↗

PubMed2005

Designing a virtual reality model for aesthetic surgery.

BACKGROUND: Aesthetic surgery deals in large part with the manipulation of soft-tissue structures that are not amenable to visualization by standard technologies. As a result, accurate three-dimensional depictions of relevant surgical anatomy have yet to be developed. This study presents a method for the creation of detailed virtual reality models of anatomy relevant to aesthetic surgery. METHODS: Two-dimensional histologic sections of a cadaver from the National Library of Medicine's Visible Human Project were imported into Alias's Maya, a computer modeling and animation software package. These two-dimensional data were then "stacked" as a series of vertical planes. Relevant anatomy was outlined in cross-section on each two-dimensional section, and the resulting outlines were used to generate three-dimensional representations of the structures in Maya. RESULTS: A detailed and accurate three-dimensional model of the soft tissues germane to aesthetic surgery was created. This model is optimized for use in surgical animation and can be modified for use in surgical simulators currently being developed. CONCLUSIONS: A model of facial anatomy viewable from any angle in three-dimensional space was developed. The model has applications in medical education and, with future work, could play a role in surgical planning. This study emphasizes the role of three-dimensionalization of the soft tissues of the face in the evolution of aesthetic surgery.

Computer Simulation↗

PubMed2005

Correlating motor performance with surgical error in laparoscopic cholecystectomy.

BACKGROUND: Analysis of motor performance in minimally invasive surgery (MIS) is a new field with applications in surgical training, surgical simulators, and robotics. Force/torque and derivatives of tool tip position (velocity, acceleration, and jerk) are examples of measures of motor performance (MMPs). Few studies have measured MMPs or have correlated MMPs with surgical performance during MIS on humans. The objectives of this study were to determine the feasibility of a novel multimodal system to quantify MMPs in laparoscopic cholecystectomy and to attempt to correlate MMPs with the magnitude of error as a measure of surgical performance. METHODS: Novice and expert surgeons performed laparoscopic cholecystectomies in two groups of three patients each. MMPs were obtained using a combination of optical and electromagnetic tool tip tracking and a force/torque sensor on a modified Maryland dissector. Error scores for laparoscopic cholecystectomy were calculated using a previously validated system. Novice and expert measurements were compared, and correlations were made between error scores and MMPs. RESULTS: Error scores were similar between novices and experts. Novice surgeons had a significantly greater mean velocity (566 +/- 83 vs 85 +/- 32 mm/s, p = 0.006) and acceleration (2,600 +/- 760 vs 440 +/- 174 mm/s2, p = 0.050) compared to expert surgeons. Force (16.5 +/- 4.6 vs 18.3 +/- 6.0 N, p = 0.829), position (121 +/- 25 vs 135 +/- 72 mm, p = 0.863), and jerk (19,600 +/- 7,410 vs 2,430 +/- 367 mm/s3, p = 0.138) were similar between groups. A positive correlation was found in novice surgeons between error score and jerk (Pearson correlation, 0.999; p = 0.035). CONCLUSIONS: It is feasible to quantify MMPs in laparoscopic cholecystectomy. Novice and expert surgeons can be differentiated by MMPs; moreover, there may be a positive correlation between jerk and error score in novice surgeons.

Adult↗

PubMed2004

[Computer-assisted simulation and clinical application of custom-produced nose implant].

OBJECTIVE: Surgery to reshape the nose with an implant has been a regular procedure for enhancing a patient's appearance and self-confidence. The purpose of this study was to establish a three-dimensional surgical simulation system. which can provide the patients with realistic prediction of their own postoperative appearance in computer and specifically produce a nose implant for an individual patient. METHODS: Preoperative CT data and image-processing techniques were employed to generate a three dimensional template of the papatient' s face. Three-dimensional morphing processes were then applied to predict and compare the outcome of plastic procedures on a patient-specific nose surface, according to the patient' s expectation. By comparing and revising the changes before and after simulation, digital prototypes of the nose implants could be generated. The templates to create custom-made silicone implants were than produced by a computer controlled device. RESULTS: Accurately regeneration of 3-D images and realistic operative simulations could be achieved with this system. The implants produced exactly conformed to the results of simulation. No curving and reshaping were needed during operating. The clinical results extremely matched with the simulations. CONCLUSION: The system enhances surgeon-patient communication and facilitates preoperative planning. It is especially desirable for implant surgery with less guesswork of size, contour, and orientation of the implant. The best chance of optimal results could be achieved.

Adolescent↗

PubMed2004

Stereo-assisted landmark detection for the analysis of changes in 3-D facial shape.

In this paper, a semi-automated approach to 3-D landmark digitization of the face is described which uses a combination of active shape model-driven feature detection and stereophotogrammetric analysis. The study aims to assess whether the proposed method is capable of detecting statistically significant changes in facial soft tissue shape due to mandibular repositioning in a cross-sectional patient sample. A hybrid stereophotogrammetric and structured-light imaging system is used for acquiring 3-D face models in the first instance. A landmark-based statistical analysis of facial shape change is then carried out using procrustes registration, principal component analysis and thin plate spline warping on the 2-D facial midline profiles and automatically digitized 3-D landmarks. The proposed method is validated both statistically and visually by characterizing shape changes induced by mandibular repositioning in a heterogeneous cross-sample of 20 orthodontic patients. It is shown that the method is capable of distinguishing between changes in facial morphology due to simulated surgical correction and changes due to other factors such as growth and normal variation within the patient sample. The study shows that the proposed method may be useful for auditing outcomes of clinical treatment or surgical intervention which result in changes to facial soft tissue morphology.

Adolescent↗

PubMed2003

Validation of medical modeling & simulation training devices and systems.

For almost a decade, research has been conducted in many areas of science to develop medical simulation training devices and even comprehensive training systems. To propel the field, the Telemedicine and Advanced Technology Research Center (TATRC), an agency of the United States Army Medical Research Materiel Command (USAMRMC), has been managing a portfolio of research projects in the area of Medical Modeling and Simulation (MM&S) since 1999. Significant progress has made to identify and harness enabling technologies. Generally, these developments can be categorized in four areas: (1) PC-based interactive multimedia, (2) Digitally Enhanced Mannequins, (3) Virtual Workbench, or "part-task", simulators, and (4) Total Immersion Virtual Reality (TIVR). Many medical simulation-training systems have shown great potential to improve medical training, but the potential shown has been based largely on anecdotal feedback from informal user studies. Formal assessment is needed to determine the degree to which simulator(s) train medical skills and the degree to which skills learned on a simulator transfer to the practice of care. A robust methodology is required as a basis for these assessments. Several scientific workshops sponsored in 2001 focused on algorithm and metrics development in support of surgical simulation. Also in 2001, TATRC chartered a Simulation Working Group (SWG) to develop a robust methodology upon which to base an assessment of the effectiveness of simulation training devices and systems. After the terrorist attacks of September 11, 2001, attention was redirected for a period, and progress was delayed. In the summer of 2002, TATRC chartered a follow-on group called the Validation, Metrics and Simulation (VMAS) Committee. The poster will highlight and summarize the development of the methodology and identify validation studies to be conducted (supported by various funding sources and research programs). The interaction between TATRC and the National Capital Area Medical Simulation Center (NCAMSC) will be noted.

Computer Simulation↗

PubMed1994

The European Association for Endoscopic Surgery recommendations for training in laparoscopic surgery.

A questionnaire among surgeons in Europe on minimal access surgery (MAS) was carried out. 96% of the responders were of the opinion that the resident or trainee should take training courses before embarking on MAS. 81% recognized a need for basic training and 96.5% for advanced courses. Registrars should be trained in MAS according to 96% of the responders. The recommendations of the European Association of Endoscopic Surgery (E.A.E.S.) for training and privileging in MAS are presented. In one of the centres that fulfills the requirements of the E.A.E.S. there were 602 surgeons from January 1992 to March 1993 who attended teaching courses in laparoscopic surgery. They came from all European countries (except Iceland) and participated in courses in basic and advanced MAS. The courses were rated with high marks and may serve as a model for similar courses elsewhere in Europe. In Europe, standardised and well organised teaching in MAS is currently available, both for surgeons and registrars. Skills laboratories will play an important role in teaching MAS. In the future, training in virtual reality surgical simulations will become central in teaching MAS and with this development, the need for animals for training will be reduced. Preceptorship and proctoring is becoming established. Still, the apprenticeship system remains the cornerstone of surgical training also in MAS.

Curriculum↗

PubMed1995

Ophthalmic microsurgical robot and associated virtual environment.

An ophthalmic virtual environment has been developed as part of a teleoperated microsurgical robot built to perform surgery on the eye. The virtual environment is unique in that it incorporates a detailed continuum model of the anatomical structures of the eye, its mechanics and optical properties, together with a less detailed geometric-mechanical model of the face. In addition to providing a realistic visual display of the eye being operated on, the virtual environment simulates tissue properties during manipulation and cutting and the forces involved are determined by solving a mechanical finite element model of the tissue. These forces are then fed back to the operator via a force reflecting master and so the surgeon can experience both the visual and mechanical sensations associated with performing surgery. The virtual environment can be used to enhance the images produced by the camera on the microsurgical slave robot during surgery and as a surgical simulator in which it replaces these images with computer graphics generated from the eye model.

Computer Graphics↗

PubMed2006

Decreasing glenoid inclination improves function in shoulders with simulated massive rotator cuff tears.

BACKGROUND: A massive rotator cuff tear leads to poor shoulder function as evidenced by diminished glenohumeral abduction and superior translation of the humeral head compared to its normal position. The inclination angle of the glenoid has been associated with rotator cuff tears. The objective of this study was to quantify the effect of a decreased glenoid inclination angle on glenohumeral kinematics during active abduction in shoulders with a simulated, massive rotator cuff tear. METHODS: Eight fresh-frozen full upper extremities were tested using a dynamic shoulder testing apparatus. After recording the kinematics of the intact shoulder, a massive rotator cuff tear was surgically simulated. An osteotomy of the glenoid was then performed and the inclination angle was decreased by 30 degrees . The translation of the humeral head during abduction and the maximum abduction angle were recorded. FINDINGS: With an intact rotator cuff minimal humeral head translation on the glenoid occurred and the maximum abduction angle was mean 85.5 degrees (SD 7.4 degrees ). A massive rotator cuff tear resulted in superior translation of the humeral head with impingement on the acromion. The maximum abduction angle was mean 15.5 degrees (SD 9.4 degrees ). Decreasing the inclination angle of the glenoid resulted in a significant reduction of superior humeral head translation during abduction and there was no impingement on the acromion. The maximum abduction achieved was mean 28.5 degrees (SD 17.0 degrees ). INTERPRETATION: From a clinical perspective the reduced superior translation may decrease shoulder pain since the humeral head no longer impinges on the acromion. Further investigations are necessary to assess if the improvement in abduction is clinically significant.

Cadaver↗

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↗

PubMedDate not supplied

Computer-assisted neurosurgery system: Wayne State University hardware and software configuration.

Computer-assisted neurosurgery uses the latest technological advancements in imaging, computers, mechanics, and electronics to improve the accuracy and reduce the invasiveness and risk of neurosurgical procedures. We describe the Wayne State University, Detroit, Michigan, computer-assisted neurosurgical system with the emphasis on software and discuss the theory guiding the development of this system and its application in real-time position tracking systems. Our system consists of the Neurological Surgery Planning System (NSPS) software which we developed at our medical center and three types of position tracking systems: the Zamorano-Dujovny (Z-D) are digitizer for frame-based procedures, an articulated arm, and an infrared-based digitizer for frameless procedures. The NSPS software is designed to offer neurosurgeons a safe and accurate method to approach intracranial lesions by preoperatively planning a surgical trajectory. Software consisting of the most advanced technologies in computer vision, computer imaging/graphics, and stereotactic numeric analysis forms the core of the system. Capabilities for correlating data from imaging studies to facilitate image reconstruction, image mapping, and three-dimensional (3D) visualization of target volumes enable the neurosurgeon to simulate surgical procedures into a preoperative protocol to be used during surgery, both to follow the preplanned trajectory and to track the position of surgical instruments in real-time on the computer monitor. The tracking systems position and orient the surgical instruments relative to the patient's head. With these devices, the display of the surgical instruments together with the virtual images create an excellent intraoperative tool.

Algorithms↗

PubMed2000

Skills evaluation in minimally invasive surgery using force/torque signatures.

BACKGROUND: One of the more difficult tasks in surgical education is to teach the optimal application of instrument forces and torques necessary to facilitate the conduct of an operation. For laparoscopic surgery, this type of training has traditionally taken place in the operating room, reducing operating room efficiency and potentially affecting the safe conduct of the operation. The objective of the current study was to measure and compare forces and torques (F/T) applied at the tool/hand interface generated during laparoscopic surgery by novice (NS) and experienced (ES) surgeons using an instrumented laparoscopic grasper and to use this data for evaluating the skill level. METHODS: Ten surgeons (five-NS, five-ES) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper with interchangeable standard surgical tips equipped with a three-axis F/T sensor located at the proximal end of the grasper tube was used to measure the F/T at the hand/tool interface. In addition, one axis force sensor located at the grasper's handle was used to measure the grasping force. F/T data synchronized with visual view of the tool operative maneuvers were collected simultaneously via a novel graphic user interface incorporated picture-in-picture video technology. Subsequent frame-by-frame video analysis of the operation allowed a definition of states associated with different tool/tissue interactions within each step of the operation. F/T measured within each state were further analyzed using vector quantization (VQ). The VQ analysis defines characteristic sets of F/T in the database that were defined as F/T signature. RESULTS: The magnitude of F/T applied by NS and ES were significantly different (p < 0.05) and varied based on the task being performed. Higher F/T magnitudes were applied by NS than by ES when performing tissue manipulation, whereas lower F/T magnitudes were applied by NS than by ES during tissue dissection. Furthermore, the time to complete the surgical procedure was longer for NS by a factor of 1.5-4.8 when compared to the time for ES. State analysis suggests that most of this time is consumed in an [idle] state, in which movements of the surgeon make no tissue contact. CONCLUSIONS: Preliminary data suggest that F/T magnitudes associated with the tool/tissue interactions provide an objective means of distinguishing novices from skilled surgeons. Clinical F/T analysis using the proposed technology and methodology may be helpful in training, developing surgical simulators, and measuring technical proficiency during laparoscopic surgery.

Cholecystectomy, Laparoscopic↗

PubMed2005

Use of ultra-high-resolution data for temporal bone dissection simulation.

OBJECTIVES: For the past 5 years, our group has been developing a virtual temporal bone dissection environment for training otologic surgeons. Throughout the course of our development, a recurring challenge is the acquisition of high-resolution, multimodal, and multi-scale data sets that are used for the visual as well as haptic (sense of touch) display. This study presents several new techniques in temporal bone imaging and their use as data for surgical simulation. METHODS: At our institution (OSU), we are fortunate to have a high-field (8 Tesla) magnetic resonance imaging (MRI) research magnet that provides an order of magnitude higher resolution compared to clinical 1.5T MRI scanners. Magnetic resonance imaging has traditionally been superb at delineating soft tissue structure, and certainly, the 8T unit does indeed do this at a resolution of 100-200 microm(3). To delineate the bony structure of the mastoid and middle ear, computed tomography (CT) has traditionally been used because of the high signal-to-noise ratio delineating bone signal from air and soft tissue. We have partnered with researchers at other institutions (CCF) to make use of a "microCT" that provides a resolution of 214 x 214 x 390 micrometers of bony structure. RESULTS: This report provides a description of the 2 methodologies and presentation of the striking image data capable of being generated. See images presented. CONCLUSIONS: Using these 2 new and innovative imaging modalities, we provide an order of magnitude greater resolution to the visual and haptic display in our temporal bone dissection simulation environment.

Cadaver↗

PubMed2004

Sphere-filled organ model for virtual surgery system.

We have been developing a virtual surgery system that is capable of simulating surgical maneuvers on elastic organs. In order to perform such maneuvers, we have created a deformable organ model using a sphere-filled method instead of the finite element method. This model is suited for real-time simulation and quantitative deformation. Furthermore, we have equipped this model with a sense of touch and a sense of force by connecting it to a force feedback device. However, in the initial stage the model became problematic when faced with complicated incisions. Therefore, we modified this model by developing an algorithm for organ deformation that performs various, complicated incisions while taking into account the effect of gravity. As a result, the sphere-filled model allowed our system to respond to various incisions that deform the organ. Thus, various physical manipulations that involve pressing, pinching, or incising an organ's surface can be performed. Furthermore, the deformation of the internal organ structures and changes in organ vasculature can be observed via the internal spheres' behavior.

Animals↗

PubMed2001

Issues in validation of a dermatologic surgery simulator.

At the University of Washington, we have been developing a suturing simulator using novel finite element model techniques which allow real-time haptic feedback. The issues involved in measuring validity in a suturing model have not been examined in a systematic way. Very few studies exist on the surgical factors that lead to good sutures. We have examined published data on these factors as well as previously studied metrics in suture training. This information has been combined with a review of types of validity (e.g., face, construct, predictive and concurrent) and reliability that must be considered in assessing any surgical simulator.

Computer Simulation↗

PubMed1995

Surgical correction of skeletal Class III malocclusions using cranial base length (corrected and uncorrected) as a reference.

This study was an attempt to show how a variation in the anteroposterior position of nasion, or length of the anterior cranial base, when used as a reference line, affects the esthetic outcome of surgically repositioned bony bases. Five white female subjects exhibiting a short anterior cranial base and characterized by maxillary retrusion were included in this study. Lateral cephalograms and 35-mm photographs of each subject were digitized into a computer imaging system, and computer-simulated surgical procedures were performed. Soft tissue profiles were then generated to reflect the skeletal changes that took place. When three groups of respondents were asked to choose the most pleasing profile, the majority (65%) chose the maxillary (Le Fort I) surgical procedure, in which the cranial base was extended to a range of corrected "normals." These results indicate that when cephalometrics are used to formulate a diagnosis and treatment plan, the most esthetic result may be obtained if the landmarks that are important to the analysis, in this case, the anterior cranial base length, are normalized.

Cephalometry↗

PubMed2000

Intuitive operation planning based on force feedback.

In the craniofacial surgery image-slices obtained from tomographies are used for planning and simulation of surgical interventions. Using these image-slices three-dimensional geometric models can be reconstructed, representing bones and soft tissue. However, for planning complex surgical interventions simulation methods are needed additionally to the pure visualisation. Exemplary, planning a Frontal Orbital Advancement (FOA) operation the cutting trajectories, their depth and orientation in each point, the drill hole, the position, orientation and deformation of bones, etc. are the point of interest. Especially for intraoperative execution supported by navigation systems or robots. In order to be able to plan such complex interventions with the help of computers, geometrical and haptical models must be generated from the image-slices. On the one hand these models represent the anatomical structures exactly, on the other hand they are needed for the simulation of the different activities, which have to be performed during the surgical intervention like drilling, milling, deforming, positioning, etc. Beside the geometrical and haptical models methods for interactions must be supplied to the physician for an accurate and intuitive planning of the surgical intervention. We developed such an operation planning system which is already used in clinical practise in Heidelberg.

Artificial Intelligence↗