80 research outputs found
HAPTIC AND VISUAL SIMULATION OF BONE DISSECTION
Marco AgusIn bone dissection virtual simulation, force restitution represents the key to realistically mimicking a patient– specific operating environment. The force is rendered using haptic devices controlled by parametrized mathematical models that represent the bone–burr contact. This dissertation presents and discusses a haptic simulation of a bone cutting burr, that it is being developed as a component of a training system for temporal bone surgery. A physically based model was used to describe the burr– bone interaction, including haptic forces evaluation, bone erosion process and resulting debris. The model was experimentally validated and calibrated by employing a custom experimental set–up consisting of a force–controlled robot arm holding a high–speed rotating tool and a contact force measuring apparatus. Psychophysical testing was also carried out to assess individual reaction to the haptic environment. The results suggest that the simulator is capable of rendering the basic material differences required for bone burring tasks. The current implementation, directly operating on a voxel discretization of patientspecific 3D CT and MR imaging data, is efficient enough to provide real–time haptic and visual feedback on a low–end multi–processing PC platform.
Fully Immersive Virtual Reality for Skull-base Surgery: Surgical Training and Beyond
Purpose: A virtual reality (VR) system, where surgeons can practice
procedures on virtual anatomies, is a scalable and cost-effective alternative
to cadaveric training. The fully digitized virtual surgeries can also be used
to assess the surgeon's skills using measurements that are otherwise hard to
collect in reality. Thus, we present the Fully Immersive Virtual Reality System
(FIVRS) for skull-base surgery, which combines surgical simulation software
with a high-fidelity hardware setup.
Methods: FIVRS allows surgeons to follow normal clinical workflows inside the
VR environment. FIVRS uses advanced rendering designs and drilling algorithms
for realistic bone ablation. A head-mounted display with ergonomics similar to
that of surgical microscopes is used to improve immersiveness. Extensive
multi-modal data is recorded for post-analysis, including eye gaze, motion,
force, and video of the surgery. A user-friendly interface is also designed to
ease the learning curve of using FIVRS.
Results: We present results from a user study involving surgeons with various
levels of expertise. The preliminary data recorded by FIVRS differentiates
between participants with different levels of expertise, promising future
research on automatic skill assessment. Furthermore, informal feedback from the
study participants about the system's intuitiveness and immersiveness was
positive.
Conclusion: We present FIVRS, a fully immersive VR system for skull-base
surgery. FIVRS features a realistic software simulation coupled with modern
hardware for improved realism. The system is completely open-source and
provides feature-rich data in an industry-standard format.Comment: IPCAI/IJCARS 202
A comprehensive evaluation of work and simulation based assessment in otolaryngology training
Introduction:
The otolaryngology curriculum requires trainees to show evidence of operative competence before completion of training. The General Medical Council recommended that structured assessment be used throughout training to monitor and guide trainee progression. Despite the reduction in operative exposure and the variation in trainee performance, a ‘one size fits all’ approach continues to be applied. The number of procedures performed remains the main indicator of competence.
Objectives:
To analyse the utilisation, reliability and validity of workplace-based assessments in otolaryngology training.
To identify, develop and validate a series of simulation platforms suitable for incorporation into the otolaryngology curriculum.
To develop a model of interchangeable workplace- and simulation-based assessment that reflects trainee’s trajectory, audit the delivery of training and set milestones for modular learning.
Methods:
A detailed review of the literature identified a list of procedure-specific assessment tools as well as simulators suitable to be used as assessment platforms. A simulation-integrated training programme was piloted and models were tested for feasibility, face, content and construct validity before being incorporated into the North London training programme. The outcomes of workplace- and simulation-based assessments of all core and specialty otolaryngology trainees were collated and analysed.
Results:
The outcomes of 6535 workplace-based assessments were analysed. The strengths and weaknesses of 4 different assessment tools are highlighted. Validated platforms utilising cadavers, animal tissue, synthetic material and virtual reality simulators were incorporated into the curriculum. 60 trainees and 40 consultants participated in the process and found it of great educational value.
Conclusion:
Assessment with structured feedback is integral to surgical training. Assessment using validated simulation modules can complement that undertaken in the workplace. The outcomes of structures assessments can be used to monitor and guide trainee trajectory at individual and regional level. The derived learning curves can shape and audit future otolaryngological training.Open Acces
Metrics for Evaluating Surgical Microscope Usage During Myringotomy
Abstract
Although teaching and learning surgical microscope manoeuvring is a fundamental step in middle ear surgical training, currently there is no objective method to teach or assess this skill. This thesis presents an experimental study designed to implement and test sets of metrics capable of numerically evaluating microscope manoeuvrability and qualitatively assessing surgical expertise of a subject during a middle ear surgery called myringotomy. The experiment involved performing a myringotomy on a fixed cadaveric ear. As participants, experienced ear-nose-throat (ENT) surgeons and ENT surgical residents were invited. While performing the procedure, their microscope manoeuvring motions were captured as translational and angular coordinates using an optical tracker. These data were analyzed in terms of motion path length, velocity, acceleration, jitter, manoeuvring volume, smoothness, rotation and time. Participants’ hand motion, body posture and microscopic view were also video recorded to qualitatively assess their surgical expertise. Several metrics were statistically identified as discriminatory. These metrics will be incorporated into a myringotomy surgical simulator to train ENT residents
Automated Segmentation of Temporal Bone Structures
Mastoidectomy is a challenging surgical procedure that is difficult to perform and practice. As supplementation to current training techniques, surgical simulators have been developed with the ability to visualize and operate on temporal bone anatomy. Medical image segmentation is done to create three-dimensional models of anatomical structures for simulation. Manual segmentation is an accurate but time-consuming process that requires an expert to label each structure on images. An automatic method for segmentation would allow for more practical model creation. The objective of this work was to create an automated segmentation algorithm for structures of the temporal bone relevant to mastoidectomy. The first method explored was multi-atlas based segmentation of the sigmoid sinus which produced accurate and consistent results. In order to segment other structures and improve robustness and accuracy, two convolutional neural networks were compared. The convolutional neural network implementation produced results that were more accurate than previously published work
Developing a virtual reality environment for petrous bone surgery: a state-of-the-art review
The increasing power of computers has led to the development of sophisticated systems that aim to immerse the user in a virtual environment. The benefits of this type of approach to the training of physicians and surgeons are immediately apparent. Unfortunately the implementation of “virtual reality” (VR) surgical simulators has been restricted by both cost and technical limitations. The few successful systems use standardized scenarios, often derived from typical clinical data, to allow the rehearsal of procedures. In reality we would choose a system that allows us not only to practice typical cases but also to enter our own patient data and use it to define the virtual environment. In effect we want to re-write the scenario every time we use the
environment and to ensure that its behavior exactly duplicates the behavior of the real tissue. If this can be achieved then VR systems can be used not only to train surgeons but also to rehearse individual procedures where variations in anatomy or pathology present specific surgical problems. The European Union has recently funded a multinational 3-year project (IERAPSI, Integrated
Environment for Rehearsal and Planning of Surgical Interventions) to produce a virtual reality
system for surgical training and for rehearsing individual procedures. Building the IERAPSI system will bring together a wide range of experts and combine the latest technologies to produce a true, patient specific virtual reality surgical simulator for petrous/temporal bone
procedures. This article presents a review of the “state of the art” technologies currently available to construct a system of this type and an overview of the functionality and specifications such a system requires
Haptic and visual simulation of bone dissection
Tesi di dottorato: Università degli Studi di Cagliari, Facoltà di Ingegneria, Dipartiemnto di Ingegneria Meccanica, XV Ciclo di Dottorato in Progettazione Meccanica.In bone dissection virtual simulation, force restitution represents the key to realistically mimicking a patient--specific operating environment. The force is rendered using haptic devices controlled by parametrized mathematical models that represent the bone--burr contact. This dissertation presents and discusses a haptic simulation of a bone cutting burr, that it is being developed as a component of a training system for temporal bone surgery. A physically based model was used to describe the burr--bone interaction, including haptic forces evaluation, bone erosion process and resulting debris. The model was experimentally validated and calibrated by employing a custom experimental set--up consisting of a force--controlled robot arm holding a high--speed rotating tool and a contact force measuring apparatus. Psychophysical testing was also carried out to assess individual reaction to the haptic environment. The results suggest that the simulator is capable of rendering the basic material differences required for bone burring tasks. The current implementation, directly operating on a voxel discretization of patient-specific 3D CT and MR imaging data, is efficient enough to provide real--time haptic and visual feedback on a low--end multi--processing PC platformInedit
Towards a psychophysical evaluation of a surgical simulator for bone-burring
The CRS4 experimental bone-burr simulator implements visual and haptic effects through the incorporation of a physics-based contact model and patient-specific data. Psychophysical tests demonstrate that, despite its simplified model and its inherent technological constraints, the simulator can articulate material differences, and that its users can learn to associate virtual bone with real bone material. Tests addressed both surface probing and interior drilling task. We also explore a haptic contrast sensitivity function based on the model s two main parameters: an elastic constant and an erosion factor. Both parameters manifest power-law-like sensitivity with respective exponents of around two and three. Further tests may reveal how well simulator users perceive fine differences in bone material, like those encountered while drilling through real volume boundaries.139-14
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