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At least 343 records · Page 19Linked to original sources

PubMed2006

A simulation-based training system for surgical wound debridement.

A simulation-based training system for surgical wound debridement was developed and comprises a multimedia introduction, a surgical simulator (tutorial component), and an assessment component. The simulator includes two PCs, a haptic device, and mirrored display. Debridement is performed on a virtual leg model with a shallow laceration wound superimposed. Trainees are instructed to remove debris with forceps, scrub with a brush, and rinse with saline solution to maintain sterility. Research and development issues currently under investigation include tissue deformation models using mass-spring system and finite element methods; tissue cutting using a high-resolution volumetric mesh and dynamic topology; and accurate collision detection, cutting, and soft-body haptic rendering for two devices within the same haptic space.

Computer Simulation↗

PubMed2004

Patient-specific bronchoscope simulation with pq-space-based 2D/3D registration.

OBJECTIVE: The use of patient-specific models for surgical simulation requires photorealistic rendering of 3D structure and surface properties. For bronchoscope simulation, this requires augmenting virtual bronchoscope views generated from 3D tomographic data with patient-specific bronchoscope videos. To facilitate matching of video images to the geometry extracted from 3D tomographic data, this paper presents a new pq-space-based 2D/3D registration method for camera pose estimation in bronchoscope tracking. METHODS: The proposed technique involves the extraction of surface normals for each pixel of the video images by using a linear local shape-from-shading algorithm derived from the unique camera/lighting constraints of the endoscopes. The resultant pq-vectors are then matched to those of the 3D model by differentiation of the z-buffer. A similarity measure based on angular deviations of the pq-vectors is used to provide a robust 2D/3D registration framework. Localization of tissue deformation is considered by assessing the temporal variation of the pq-vectors between subsequent frames. RESULTS: The accuracy of the proposed method was assessed by using an electromagnetic tracker and a specially constructed airway phantom. Preliminary in vivo validation of the proposed method was performed on a matched patient bronchoscope video sequence and 3D CT data. Comparison to existing intensity-based techniques was also made. CONCLUSION: The proposed method does not involve explicit feature extraction and is relatively immune to illumination changes. The temporal variation of the pq distribution also permits the identification of localized deformation, which offers an effective way of excluding such areas from the registration process.

Algorithms↗

PubMed2002

Quantitative methodology of evaluating surgeon performance in laparoscopic surgery.

Quantitative performance and skill assessments are critical for evaluating the progress of surgical residents and the efficacy of different training programs. Current evaluation methods are subjective and potentially unreliable, so there is a need for objective methods to evaluate surgical performance. We identify a feasible method to measure kinematic data in the live operating room setting and to assess the repeatability of an analysis method based on a hierarchical decomposition of surgical tasks. We used an optoelectronic motion analysis system to acquire postural data and tool tip trajectories of one expert surgeon over a period of four months. To assess repeatability of performance measures, we created a hierarchical decomposition diagram describing the procedure in terms of surgical tasks, tool sequences and fundamental tool actions. From the kinematic data, we extracted characteristic measures of individual tool actions and compared these measured distributions using the Kolmogorov-Smirnov statistic. The comparisons of distributions show consistent performance over time by a trained surgeon and little effect from patient variability, and so are likely reliable measures of performance. An expanded set of reliable kinematic measures will form the basis for quantifying surgical skill and should be useful in validating surgical simulations for use in training, certifying surgeons and designing and evaluating new surgical tools.

Biomechanical Phenomena↗

PubMed1998

[Telemedicine applied to surgery].

The transmission of images, audio, video and computed data allows new possibilities in initial or continuing education/training of surgeons and new interactivities between medical or surgical specialties. In the field of surgery, telemedicine is used for teaching, diagnostic or therapeutic assistance, and even consultation of remote patients. This article reviews telemedicine technologies, national legislation current, surgical telemedicine practices and the future applications (telementoring, surgical simulator, telesurgery...).

France↗

PubMed2005

Simulated hand-assisted laparoscopic surgery (HALS) in microgravity.

INTRODUCTION: Previous simulation and porcine experiments aboard the reduced gravity program KC-135 turbojet have demonstrated that microgravity surgery is feasible. Ideally, surgical care in spaceflight will incorporate recent advances in care while remaining easy enough for a crew medical officer (CMO) lacking surgical proficiency or extensive surgical experience to perform. As a minimally invasive surgical technique, hand-assisted laparoscopic surgery (HALS) benefits the patient via smaller incisions, less pain, and faster recovery than traditional open surgery. HALS also helps less experienced laparoscopic surgeons perform laparoscopic surgery. METHODS: An inexpensive inanimate surgical simulator was constructed to evaluate the usefulness of HALS in microgravity. This simulator was utilized during brief periods of microgravity provided by parabolic flight on the KC-135. The simulator was successfully used by both a physician-astronaut and an experienced laparoscopic surgeon. Task completion included simulated surgery with exploration of the intestines and ligation of the appendix. RESULTS: Simulated HALS was successfully performed in microgravity. HALS effectively contained operative equipment and small amounts of introduced fluids within the simulated abdominal cavity. Astronaut and surgeon experience suggest that HALS could facilitate minimally invasive surgery (MIS) in microgravity. DISCUSSION: HALS holds promise as a surgical approach in microgravity, particularly as space travel extends beyond low earth orbit. HALS provides the benefits of MIS, facilitates MIS surgery by less surgically proficient or experienced CMOs, and contains equipment and fluid within the operative field. Simulation provides an easy, cost-effective platform to evaluate medical technology for space flight as well as a method to train CMOs on-orbit.

Appendix↗

PubMed1977

A simplified model for teaching minor oral surgery.

A teaching model, specially constructed for the purpose of training senior dental students in the use of surgical instruments, is described. The advantages of this model are inexpensiveness and reproducible simulated surgical situations securing a uniform teaching objective.

Education, Dental↗

PubMed2002

Multimodal simulation of laparoscopic Heller myotomy using a meshless technique.

In this work we focus our attention on developing a surgical simulator for performing laparoscopic Heller myotomy using force feedback. A meshless numerical technique, the method of finite spheres, is used for the purpose of physically based, real time haptic and graphical rendering of soft tissues. Localized discretization allows display of deformations in the vicinity of the tool tip as well as interaction forces at high update rates (kHz). Novel cutting algorithms are implemented using point-based representation of anatomical models. Graphical rendering is accomplished by using a recently developed volumetric rendering technique known as splatting.

Computer Graphics↗

PubMed2005

Validation framework of the finite element modeling of liver tissue.

In this work, we aim at validating some soft tissue deformation models using high resolution Micro Computed Tomography (Micro-CT) and medium resolution Cone-Beam CT (CBCT) images. These imaging techniques play a key role in detecting the tissue deformation details in the contact region between the tissue and the surgical tool (probe) even for small force loads, and provide good capabilities for creating accurate 3D models of tissues. Surgical simulations rely on accurate representation of the mechanical response of soft tissues subjected to surgical manipulations. Several finite element (F.E.) models have been suggested to characterize soft tissues. However, validating these models for specific tissues still remains a challenge. For our validation, ex vivo lamb liver is chosen to validate the linear elastic model (LEM), the linear viscoelastic model (LVEM), and the neo-Hooke hyperelastic model (NHM). We found that the LEM is more applicable to lamb liver than the LVEM for small force loads (< 40 g) and that the NHM is closer to reality than the LVEM for this same range of force loads.

Algorithms↗

PubMed2001

Virtual reality: current urologic applications and future developments.

The concept of virtual reality (VR) involves the computer generation of environments with which a user can interact directly. Virtual reality is now being used for medical applications, especially in the area of surgical simulation. As technology advances, VR simulation will play an important training role for both residents and urologists already in practice. This paper examines the history of VR, current developments, and its future implications for the field of urology.

Computer Simulation↗

PubMed2004

Remeshed smoothed particle hydrodynamics simulation of the mechanical behavior of human organs.

In computer aided surgery the accurate simulation of the mechanical behavior of human organs is essential for the development of surgical simulators. In this paper we introduce particle based simulations of two different human organ materials modeled as linear viscoelastic solids. The constitutive equations for the material behavior are discretized using a particle approach based on the Smoothed Particle Hydrodynamics (SPH) method while the body surface is tracked using level sets. A key aspect of this approach is its flexibility which allows the simulation of complex time varying topologies with large deformations. The accuracy of the original formulation is significantly enhanced by using a particle reinitialization technique resulting in remeshed Smoothed Particle Hydrodynamics (rSPH). The mechanical parameters of the systems used in the simulations are derived from experimental measurements on human cadaver organs. We compare the mechanical behavior of liver- and kidney-like materials based on the dynamic simulations of a tensile test case. Moreover, we present a particle based reconstruction of the liver topology and its strain distribution under a small local load. Finally, we demonstrate a unified formulation of fluid structure interaction based on particle methods.

Biomechanical Phenomena↗

PubMed1986

Biomechanical analysis and simulation of scoliosis surgical correction.

In scoliosis, presurgical determination of each patient's segmental spinal stiffness will permit model simulation of the surgical correction. It also permits calculation of the optimal combination of corrective forces applied to the spine by the internal fixation system. This information can help to optimize the surgical procedure, especially if calculated forces and corrections can be monitored during surgery. To this end, a finite-element model of the spine has been developed that determines segmental stiffness from data of spinal geometries, derived from the radiographs of the patient, taken with incremental distraction applied to the head. On this model, custom-tailored combinations of corrective forces are applied incrementally until optimal correction is obtained, for safe levels of distraction and lateral forces. With variations in the computer software, any desired surgical instrumentation system can be simulated. Instrumented distractor and compression forceps have been fabricated to monitor surgical forces and displacements, and to permit eventual implementation of the model recommendations. Comparison of surgically acquired correction with that predicted by the model is then carried out. Data on complete analysis of two cases of idiopathic scoliosis are presented. They show significant variations in segmental and interpatient stiffness values, and how spinal stiffness governs the amount of correction gained by the nature and magnitude of corrective forces.

Adult↗

PubMed2000

G2H--graphics-to-haptic virtual environment development tool for PC's.

For surgical training and preparations, the existing surgical virtual environments have shown great improvement. However, these improvements are more in the visual aspect. The incorporation of haptics into virtual reality base surgical simulations would enhance the sense of realism greatly. To aid in the development of the haptic surgical virtual environment we have created a graphics to haptic, G2H, virtual environment developer tool. G2H transforms graphical virtual environments (created or imported) to haptic virtual environments without programming. The G2H capability has been demonstrated using the complex 3D pelvic model of Lucy 2.0, the Stanford Visible Female. The pelvis was made haptic using G2H without any further programming effort.

Computer Graphics↗

PubMed2006

An evaluation of image-guided technologies in the placement of percutaneous iliosacral screws.

STUDY DESIGN: A surgical simulation study in human cadaver spine specimens was conducted to evaluate the accuracy of 3 different surgical navigation systems compared to standard fluoroscopy in the percutaneous placement of iliosacral screws. OBJECTIVES: To compare the accuracy of percutaneous iliosacral screw placement using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance (Medtronic Surgical Navigation Technologies, Louisville, CO), and electromagnetic fluoroscopic image guidance. SUMMARY OF BACKGROUND DATA: Conventional percutaneous sacroiliac screw placement has a malposition rate as high as 15%, as reported in the English-speaking literature (Hinsche et al [Clin Orthop Relat Res 2002;395:135-44] and Templeman et al [Clin Orthop Relat Res 1996;329:194-8]). Iso-C3D and computer-assisted image guidance technologies have been proposed to increase this accuracy rate. METHODS: Two iliosacral screws were placed bilaterally (4 screws) in each of 4 cadavers using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance, and electromagnetic fluoroscopic image guidance. Screw positions were analyzed by computerized tomography after instrumentation and assigned a score based on deviation from ideal screw position. RESULTS: The StealthStation with FluoroNav (Medtronic Surgical Navigation Technologies) appeared to provide the highest accuracy of all guidance techniques. This result was more accurate than standard fluoroscopy. CONCLUSIONS: Computer-assisted fluoroscopy based image navigation appears to be more accurate than standard fluoroscopy in placing these screws. However, errors may occur with all techniques. Further refinement in registration procedures may highly improve the accuracy of percutaneous screw placement in a variety of spinopelvic procedures.

Aged↗

PubMed1999

Computer-generated microsurgical anatomy of the basilar artery bifurcation. Technical note.

The authors' goal was to develop a computer graphics model to represent the microsurgical anatomy of the basilar artery (BA) bifurcation and surrounding structures to simulate surgery of a BA bifurcation aneurysm performed via the transsylvian approach. The source of the input data was a variety of publications that showed detailed anatomy of the area. A computer graphics model of the area near the BA bifurcation including relevant structures, such as perforating branches or cranial nerves, was depicted in detail. A BA bifurcation aneurysm was added to the computer graphics model and it was rotated to simulate the transsylvian approach. After the internal carotid artery was displaced using a virtual retractor, the aneurysm was exposed, thus providing an understanding of the three-dimensional surgical orientation of the area. Designing a standard anatomical model on the basis of data culled from a variety of publications and adding morphological changes by using a virtual retractor to displace structures that obstruct the view along a critical path at the base of the brain are useful strategies of computer manipulation for surgical simulation in open microneurosurgery. This methodological tool would be useful in teaching surgical microanatomy and in introducing a new navigational system for virtual reality. Both concept and technical details are discussed.

Basilar Artery↗

PubMed2001

Computer-guided surgery utilizing a computer-milled surgical template.

The primary objective of implant placement is to support prosthetic restorations that return patients to proper oral form, function, and aesthetics. Since correct implant placement can be a technique-sensitive process, it is performed in conjunction with various diagnostic and guidance procedures. For accurate diagnosis, radiographic templates, computed tomography scans, and surgical simulation software are unparalleled. This article demonstrates the manner by which computer-guided surgery and computer-milled surgical templates can enable precise implant placement for the entire implant team.

Alveolar Process↗

PubMed2005

Digital technologies and quality improvement in cancer surgery.

Telecommunications, multimedia and computer technologies will introduce marked changes in the management of cancer. New modalities in the representation of patient's medical records using computer technology products and services allow unlimited cross-sharing of information. Education taught through multimedia methods, and through the Internet, is available anywhere and any time just like surgical simulation, robotics and virtual reality. Thanks to computer and IT technologies, surgeons will be able to acquire, assess and validate new surgical procedures or concepts from any geographical location. Live demonstrations shared via videoconferencing facilitate mental development through the acquisition of the cognitive aspects of surgical procedures. Virtual reality is a major improvement in the processing of medical imaging. As a result, the interpretation and the simulation of therapeutic approaches to patients with cancer are facilitated through transparency, navigation and manipulation. The Internet eventually offers uninterrupted communication links between healthcare providers (teaching, training or multidisciplinary telementoring included). Computer and IT technologies will undoubtedly contribute to standardized cancer treatment modalities and determined guidelines for good clinical practice worldwide.

Computer-Assisted Instruction↗

PubMed2002

A methodology for objective assessment of errors: an example using an endoscopic sinus surgery simulator.

A well-proven methodology (the modified Delphi method) was used to generate a first-order approximation of errors that should be measured in a virtual reality surgical simulator (the ES3). The methodology and the errors derived were crafted in such a way as to be generalizable. Although some of the error measures are specific for sinus surgery, the same type of methodology can be used for other otolaryngologic, general, and [table: see text] subspecialty surgical procedures. The value of this process is that it can provide a uniform framework for investigators in surgical education and training to establish error measurements in their particular procedures or disciplines and to generate data and outcomes that are comparable, interoperable, and sharable with other investigators. Admittedly, the process is time consuming and rigorous, but it does provide a solid scientific basis to generate evidence-based data for the validation of training methods and for outcomes analysis.

Clinical Competence↗

PubMed2001

Cubby: a unified interaction space for precision manipulation.

Precision manipulation in surgical simulation poses special requirements on a VR system. One such requirement is unification, i.e. that the user manipulates a virtual object where it appears. We have designed Cubby, a system of which the visualization part was presented at MMVR97 [3], for precision manipulation and unification. In an experiment Cubby was compared with a single screen head-tracked display, both in a unified and a non-unified version. The results show that subjects could manipulate virtual objects in Cubby with significantly higher accuracy and preferred it to the single screen head-tracked display. Though no significant difference in accuracy between the unified and non-unified conditions could be shown, subjects did prefer the unified over the non-unified condition within both setups.

Computer Simulation↗