Anatomical Models (anatomical + models)

Distribution by Scientific Domains

Selected Abstracts

Improving realism of a surgery simulator: linear anisotropic elasticity, complex interactions and force extrapolation

Guillaume Picinbono
Abstract In this article, we describe the latest developments of the minimally invasive hepatic surgery simulator prototype developed at INRIA. The goal of this simulator is to provide a realistic training test bed to perform laparoscopic procedures. Therefore, its main functionality is to simulate the action of virtual laparoscopic surgical instruments for deforming and cutting tridimensional anatomical models. Throughout this paper, we present the general features of this simulator including the implementation of several biomechanical models and the integration of two force-feedback devices in the simulation platform. More precisely, we describe three new important developments that improve the overall realism of our simulator. First, we have developed biomechanical models, based on linear elasticity and finite element theory, that include the notion of anisotropic deformation. Indeed, we have generalized the linear elastic behaviour of anatomical models to ,transversally isotropic' materials, i.e. materials having a different behaviour in a given direction. We have also added to the volumetric model an external elastic membrane representing the ,liver capsule', a rather stiff skin surrounding the liver, which creates a kind of ,surface anisotropy'. Second, we have developed new contact models between surgical instruments and soft tissue models. For instance, after detecting a contact with an instrument, we define specific boundary constraints on deformable models to represent various forms of interactions with a surgical tool, such as sliding, gripping, cutting or burning. In addition, we compute the reaction forces that should be felt by the user manipulating the force-feedback devices. The last improvement is related to the problem of haptic rendering. Currently, we are able to achieve a simulation frequency of 25,Hz (visual real time) with anatomical models of complex geometry and behaviour. But to achieve a good haptic feedback requires a frequency update of applied forces typically above 300,Hz (haptic real time). Thus, we propose a force extrapolation algorithm in order to reach haptic real time. Copyright 2002 John Wiley & Sons, Ltd. [source]

Effectiveness of simulation on health profession students' knowledge, skills, confidence and satisfaction

Susan Laschinger
Abstract Background, Despite the recent wave of interest being shown in high-fidelity simulators, they do not represent a new concept in healthcare education. Simulators have been a part of clinical education since the 1950s. The growth of patient simulation as a core educational tool has been driven by a number of factors. Declining inpatient populations, concerns for patient safety and advances in learning theory are forcing healthcare educators to look for alternatives to the traditional clinical encounter for skill acquisition for students. Objective, The aim of this review was to identify the best available evidence on the effectiveness of using simulated learning experiences in pre-licensure health profession education. Inclusion criteria,Types of studies: This review considered any experimental or quasi-experimental studies that addressed the effectiveness of using simulated learning experiences in pre-licensure health profession practice. In the absence of randomised controlled trials, other research designs were considered for inclusion, such as, but not limited to: non-randomised controlled trials and before-and-after studies. Types of participants: This review included participants who were pre-licensure practitioners in nursing, medicine, and rehabilitation therapy. Types of intervention(s)/phenomena of interest: Studies that evaluated the use of human physical anatomical models with or without computer support, including whole-body or part-body simulators were included. Types of outcome measures, Student outcomes included knowledge acquisition, skill performance, learner satisfaction, critical thinking, self-confidence and role identity. Search strategy, Using a defined search and retrieval method, the following databases were accessed for the period 1995,2006: Medline, CINAHL, Embase, PsycINFO, HealthSTAR, Cochrane Database of Systematic Reviews and ERIC. Methodological quality, Each paper was assessed by two independent reviewers for methodological quality prior to inclusion in the review using the standardised critical appraisal instruments for evidence of effectiveness, developed by the Joanna Briggs Institute. Disagreements were dealt with by consultations with a third reviewer. Data collection, Information was extracted from each paper independently by two reviewers using the standardised data extraction tool from the Joanna Briggs Institute. Disagreements were dealt with by consultation with a third reviewer. Data synthesis, Due to the type of designs and quality of available studies, it was not possible to pool quantitative research study results in statistical meta-analysis. As statistical pooling was not possible, the findings are presented in descriptive narrative form. Results, Twenty-three studies were selected for inclusion in this review including partial task trainers and high-fidelity human patient simulators. The results indicate that there is high learner satisfaction with using simulators to learn clinical skills. The studies demonstrated that human patient simulators which are used for teaching higher level skills, such as airway management, and physiological concepts are useful. While there are short-term gains in knowledge and skill performance, it is evident that performance of skills over time after initial training decline. Conclusion, At best, simulation can be used as an adjunct for clinical practice, not a replacement for everyday practice. Students enjoyed the sessions and using the models purportedly makes learning easier. However, it remains unclear whether the skills learned through a simulation experience transfer into real-world settings. More research is needed to evaluate whether the skills acquired with this teaching methodology transfer to the practice setting such as the impact of simulation training on team function. [source]

The HUDSEN Atlas: a three-dimensional (3D) spatial framework for studying gene expression in the developing human brain

Janet Kerwin
Abstract We are developing a three-dimensional (3D) atlas of the human embryonic brain using anatomical landmarks and gene expression data to define major subdivisions through 12 stages of development [Carnegie Stages (CS) 12,23; approximately 26,56 days post conception (dpc)]. Virtual 3D anatomical models are generated from intact specimens using optical projection tomography (OPT). Using mapaint software, selected gene expression data, gathered using standard methods of in situ hybridization and immunohistochemistry, are mapped to a representative 3D model for each chosen Carnegie stage. In these models, anatomical domains, defined on the basis of morphological landmarks and comparative knowledge of expression patterns in vertebrates, are linked to a developmental neuroanatomic ontology. Human gene expression patterns for genes with characteristic expression in different vertebrates (e.g. PAX6, GAD65 and OLIG2) are being used to confirm and/or refine the human anatomical domain boundaries. We have also developed interpolation software that digitally generates a full domain from partial data. Currently, the 3D models and a preliminary set of anatomical domains and ontology are available on the atlas pages along with gene expression data from approximately 100 genes in the HUDSEN Human Spatial Gene Expression Database ( The aim is that full 3D data will be generated from expression data used to define a more detailed set of anatomical domains linked to a more advanced anatomy ontology and all of these will be available online, contributing to the long-term goal of the atlas, which is to help maximize the effective use and dissemination of data wherever it is generated. [source]

Predicted SAR in sprague-dawley rat as a function of permittivity values,,

P. Gaj
Abstract Specific absorption rate (SAR) value is dependent on permittivity value. However, variability in the published permittivity values for human and animal tissue and the development of sophisticated 3-dimensional digital anatomical models to predict SAR values has resulted in the need to understand how model parameters (permittivity value) affect the predicted whole body and localized SAR values. In this paper, we establish the partial derivative of whole body SARs and localized SAR values (defined as SAR for individual organs with respect to a change in the permittivity values of all tissue types, as well as for those tissues with the most variable permittivity values. Variations in the published permittivity values may substantially influence whole body and localized SAR values, but only under special conditions. Orientation of the exposed object to the incident electromagnetic wave is one of the most crucial factors. Bioelectromagnetics 22:384,400, 2001. Published 2001 Wiley-Liss, Inc. [source]

The multidimensionality of cell behaviors underlying morphogenesis: a case study in ascidians

BIOESSAYS, Issue 9 2006
Anna Di Gregorio
Databases where different types of information from different sources can be integrated, cross-referenced and interactively accessed are necessary for building a quantitative understanding of the molecular and cell biology intrinsic to the morphogenesis of an embryo. Tassy and colleagues1 recently reported the development of software tailor-made to perform such a task, along with the generation and integration of three-dimensional anatomical models of embryos. They convincingly illustrated the utility of their approach by applying it to the early ascidian embryo. BioEssays 28: 874,879, 2006. 2006 Wiley periodicals, Inc. [source]

Effects of an alternate dissection schedule on gross anatomy laboratory practical performance

David L. McWhorter
Abstract The current medical curricula reform that is taking place in many medical schools throughout the world has resulted in less time for gross anatomy laboratory instruction. In response, anatomists are using a variety of approaches (e.g., peer teaching, prosections, plastinated anatomical models, etc.) to adapt to these changes. To accommodate recent curricular reform at the University of Health Sciences College of Osteopathic Medicine, an alternating dissection schedule was implemented. The purpose of this study is to examine the effects of the alternating schedule on gross anatomy laboratory practical performance. Using a Mann-Whitney Rank Sum test, back and upper limb (back-upper limb), and lower extremity laboratory practical performance for students who dissected in every laboratory (EL group; n = 227) is compared to students who dissected in every other laboratory (EOL group; n = 254). For the back-upper limb part of the anatomy laboratory practical, the mean percentage scores for the EL and EOL groups were 74.5% and 68.1%, respectively (P < 0.001). The mean percentage scores for the EL and EOL groups on the lower limb portion of the anatomy lab practical were 75.9% and 75.6%, respectively (P = 0.994). These data suggest that the use of an alternating dissection schedule had an equivocal effect on the students' gross anatomy laboratory practical performance for these two sections. The reasons for these conflicting results may have been related to regional complexity or volume of information, and the sequence in which the regions were taught. Clin. Anat. 17:144,148, 2004. 2004 Wiley-Liss, Inc. [source]