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Results for “Surgical simulation”

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At least 127 records · Page 7Linked to original sources
PubMed1981

Simulated surgical wound infection in mice: effect of stimulation on nonspecific host defense mechanisms.

Experiments were conducted to ascertain whether nonspecific host defenses could be enhanced in a reliable animal model simulating the local bacterial infection that frequently complicates surgical wounds. The test lesion was studied in detail and exemplifies the concept that the ultimate expression of the host-pathogen interaction is the capacity of that pathogen to persist or grow in a given host. Mice were challenged by intramuscular insertion of cotton suture impregnated with 10(7) to 10(8) Escherichia coli K-12. The mice were subsequently killed at intervals, and the suture and muscle mass were retrieved, homogenized, and quantitatively cultured. Numbers of viable organisms in tissue from control animals were compared with those from experimental animals that received BCG (Bacillus Calmette-Guérin) vaccine, a nonspecific immunostimulant, prior to bacterial challenge. Improved tissue antibacterial activity appeared in animals that had received BCG vaccine 13 days prior to bacterial challenge. Differing doses and intervals were not protective. Enhancement of nonspecific host defense mechanisms may be helpful in combination with current measures for improved control of surgical wound infection.

Animals↗
PubMed2001

The representation of blood flow in endourologic surgical simulations.

An image-based approach has been developed to represent bleeding in a simulator for transurethral resection of prostate (TURP). While previous attempts have simulated bleeding over tissue surfaces or in blood vessels, our approach focused on the macroscopic visualization of bleeding in a fluid environment. TURP is an ideal procedure for simulation-based training because of the dynamic environment and the variety of flow patterns it presents. The first step in the development of the simulator was the generation of blood flow movies which consisted of capturing videos of bleeding vessels in vitro, processing them to separate the actual blood from the background anatomy and organizing the movies into a parametric database. During the running of the simulation, resection of prostate tissue systematically triggers bleeding events and the playback of a blood flow movie. The blood flow movie is texture mapped onto a virtual surface that is positioned oriented, morphed, composited and looped into the virtual scene.

Blood Loss, Surgical↗
PubMed2001

Intracorporeal suturing and knot tying in surgical simulation.

Intracorporeal suturing and knot tying is one of the most difficult tasks to perform during minimally invasive surgery. To master these tasks the student requires extensive training in a real or simulated environment. Realistic simulation of suturing and knot tying is a challenging task, the dynamic behaviors of the needle and thread are complicated to calculate efficiently in real time. We present our approach to simulated training of intracorporeal suturing and knot tying as well as our method for performance assessment. Different algorithms for physical modeling of suture thread dynamics are examined and evaluated.

Computer Simulation↗
PubMed2002

[Usefulness of three-dimensional MR images of brain tumors for surgical simulation].

The purpose of this study was to determine the usefulness of three-dimensional (3D) MR imaging of brain tumors for surgical planning. Sixty-nine patients with various tumors of the brain were included in the present study. Using a volume-rendering (VR) method on an independent workstation, 3D-MR images were obtained with the fast-SPGR sequence after Gd-DTPA administration. VR images could show an exact relationship between the surface of the brain and major vessels. However, in patients with deeply located tumors, VR images did not necessarily provide sufficient information as to the relationship between the tumor and vessels. In combination with a surface-rendering method, 3D-MR imaging could demonstrate the exact relationships among the tumors, major vessels, and surface of the brain. In tumors without contrast enhancement, this method was able to show 3D images of tumors with surrounding structures. For neurosurgeons, 3D-MR images were useful for understanding the surface anatomy and surrounding structures of the tumors prior to surgery. These images were also helpful in explaining the condition of the disease to patients and their families.

Adolescent↗
PubMed2006

Measurement of the mechanical response of intra-abdominal organs of fresh human cadavers for use in surgical simulation.

Determination of soft tissue properties is essential for the realism of the virtual scenarios. The major challenge is that soft tissues exhibit complicated mechanical properties including viscoelastic, nonlinear, inhomogeneous, and rate dependent behaviors. Measurements on live human patients present significant risks, thus making the use of cadavers a logical alternative. Cadavers are widely used in present day surgical training, are relatively easy to procure through excellent donor programs and have the right anatomy, which makes them better candidates for training than the porcine model. To investigate the static and dynamic properties of soft tissue, we have developed a high precision tactile stimulator by modifying an existing haptic interface device, the Phantom, and used it to record the force-displacement behavior of intra-abdominal organs of fresh human cadavers at the US Surgical facility in Connecticut and Albany Medical College.

Abdomen↗
PubMed2005

Quantifying risky behavior in surgical simulation.

Evaluating a trainee's performance on a simulated procedure involves determining whether a specified objective was met while avoiding certain "injurious" actions that damage vulnerable structures. However, it is also important to teach the stylistic behaviors that minimize overall risk to the patient, even though these criteria may be more difficult to explicitly specify and detect. In this paper, we address the development of metrics that evaluate the risk in a trainee's behavior while performing a simulated mastoidectomy. Specifically, we measure the trainee's ability to maintain an appropriate field of view so as to avoid drilling bone that is hidden from view, as well as to consistently apply appropriate forces and velocities. Models of the maximum safe force and velocity magnitudes as functions of distances from key vulnerable structures are learned from model procedures performed by an expert surgeon on the simulator. In addition to quantitatively scoring the trainee's performance, these metrics allow for interactive 3D visualization of the performance by distinctive coloring of regions in which excessive forces or velocities were applied or insufficient visibility was maintained, enabling the trainee to pinpoint his/her mistakes and how to correct them. Although these risky behaviors relate to a mastoidectomy simulator, the objectives of maintaining visibility and applying safe forces and velocities are common in surgery, so it may be possible to extend much of this methodology to other procedures.

Computer Simulation↗
PubMed2006

Construct validity of the LapSim laparoscopic surgical simulator.

BACKGROUND: Computer-aided simulators may increase the safety and efficiency of training in laparoscopic surgery. Before implementation of the Immersion LapSim (Gaithersburg, MD) simulator in our training curriculum, we wished to determine its construct validity (ie, whether the simulator could differentiate laparoscopic novices from trainees with greater experience). METHODS: Subjects were medical students (MS), residents (RES), and laparoscopic faculty (FAC). Subjects performed 10 repetitions of 6 LapSim tasks. The LapSim measured performance in 6 to 10 parameters per task, and performance was compared between groups. Post hoc t tests were used to make pair-wise comparisons among the 3 groups using the Bonferroni technique. Statistical significance was set at P < .05. RESULTS: The degree of prior laparoscopic experience was reflected in performance on at least 1 parameter for each task. Several patterns of performance between MS, RES, and FAC were observed. CONCLUSIONS: The LapSim has performance parameters that reliably differentiate between subjects with varying laparoscopic experience. However, some performance parameters do not differentiate between groups. To accurately measure a trainee's skill level, only parameters that sensitively measure the true level of performance should be used.

Computer Simulation↗
PubMed1997

[Role of the pulsatile organ perfusion surgical simulator in surgery education].

The operation simulator with pulsatile organ perfusion ("POP trainer") simulates the blood supply of organs or organ complexes and was developed for the training in both minimally invasive and conventional surgery. With the redesigned new POP-trainer, even complex operations, such as colorectal and antireflux procedures can be practised. Due to perfect quality of simulation, simple handling and economic aspects, the POP trainer serves to intensify the training of surgeons, simultaneously decreasing the number of animal experiments.

Animal Testing Alternatives↗
PubMed1998

Telepresence interface with applications to microsurgery and surgical simulation.

To address the needs for performing microsurgical procedures, the SRI telepresence surgery workstation has been combined with a pair of micromanipulator arms. The prototype microsurgery system has been tested with ex-vivo tasks similar to those required for surgical procedures, such as cutting, grasping, suturing, and knot tying. Initial animal testing has been done on a rat model in which end-to-end anastomosis of the femoral artery (approximately 1 millimeter in diameter) was completed with ten rats, and 100% patency was obtained. To address the needs of surgical training, SRI has begun to develop a system that uses a 6-DOF telepresence workstation. A computer-generated stereo image is reflected in a mirror and appears to be superimposed on the surgeon's hands, creating an immersive and realistic environment. Tools held in the surgeon's hands are connected to left- and right-hand manipulators that both continuously measure tool position/orientation and apply force/torque to the tools. Furthermore, the visual image and tool locations are registered, so that the user perceives that he or she is looking at and moving the simulated tools in the visual image.

Animals↗
PubMed1999

Computer-generated surgical simulation of morphological changes in microstructures: concepts of "virtual retractor." Technical note.

The authors' goal was to develop a computer graphics model to simulate the displacement and morphological changes that are caused by the retraction of fine intracranial structures. The authors developed an application program to interpolate the contour of models of an artery and a retractor. The center of the displacement was determined by spatial coordinates, and the shape of the displacement of the arterial model was calculated using a cosine-based formula with representation of a brain retractor. This computer graphics model was applied to the simulation of the displacement and morphological changes that occur when retraction is performed in the optic nerve. An illustrative case is presented, in which the optic nerve was displaced by a retractor to simulate the surgery performed in a carotid cave aneurysm of the internal carotid artery. The authors have named this methodological tool a "virtual retractor." This new navigational system for open microneurosurgery would be useful in teaching surgical microanatomy and in presurgical operative planning.

Algorithms↗
PubMed2002

Virtual temporal bone dissection: an interactive surgical simulator.

OBJECTIVE: Our goal was to integrate current and emerging technology in virtual systems to provide a temporal bone dissection simulator that allows the user interactivity and realism similar to the cadaver laboratory. STUDY DESIGN: Iterative design and validation of a virtual environment for simulating temporal bone dissection. SETTING: University otolaryngology training program with interdisciplinary interaction in a high-performance computer facility. RESULTS: The system provides visual, force feedback (haptic), and aural interfaces. Unlike previous "fly through" virtual systems, this environment provides a richer emulation of surgical experience. CONCLUSION: The system provides a high level of functional utility and, through initial evaluations, demonstrates promise in adding to traditional training methods. SIGNIFICANCE: The system provides an environment to learn temporal bone surgery in a way similar to the experience with cadaver material where the subject is able to interact with the data without constraints (nondeterministic). Eventually, it may provide the "front end" to a large repository of various temporal bone pathologies that can be accessed through the Internet.

Algorithms↗