Papers by Greg Ruthenbeck
4th International Conference on Computational and Mathematical Biomedical Engineering Proceedings: CMBE15, Jul 1, 2015
Knowledge of the whole-bone mechanics at micro-structural level can improve our understanding of ... more Knowledge of the whole-bone mechanics at micro-structural level can improve our understanding of age-related bone changes and related fractures. Finite-element (FE) models based on micro-CT images are able to estimate the contribution of the cortical and trabecular compartments to the mechanical behavior of entire bones at high resolution. However, generating, solving and analyzing FE models of hundreds of million elements, such as micro-FE models of entire proximal femurs, is computationally challenging and requires ad-hoc software and hardware solutions. We developed a novel software pipeline for generating, solving and analyzing micro-FE models of the proximal femur
Virtual reality surgical simulations provide a unique opportunity to evaluate surgical skills. H... more Virtual reality surgical simulations provide a unique opportunity to evaluate surgical skills. Here we describe a simple new method for visualizing simulator interactions to simplify performance evaluation and facilitate the development of new and improved performance metrics, especially those based on motion analyses. The new Summary Graphics are discussed in the context of a haptic virtual reality volumetric tissue removal task. The motions used during the task, together with the rate of volumetric tissue removal are clearly depicted in these graphics, thus providing a strong basis for the development of more informative and robust performance metrics.
Haptics: Perception, Devices, Control, and Applications, 2016
In the literature, haptic training has long been regarded as an effective means of acquiring skil... more In the literature, haptic training has long been regarded as an effective means of acquiring skills that involve force feedback. This is relevant in the context of haptic virtual reality applications that argue that the addition of haptics increases the effectiveness of the training system. Here we describe an experimental investigation which examines whether haptic feedback increases people's spatial knowledge of a simulation. In particular, we address the following question: Is visuo-haptic interaction a more effective way of learning spatial information than purely visual interaction? A comparison of two groups of participants visual versus visuo-haptic revealed no significant differences in their spatial knowledge of the simulation. The findings are discussed with reference to potential variables which may affect spatial learning such as cognitive load.
Journal of Simulation, 2014
Virtual reality (VR) medical simulations deliver a tailored learning experience that can be stand... more Virtual reality (VR) medical simulations deliver a tailored learning experience that can be standardized, and can cater to different learning styles in ways that cannot be matched by traditional teaching. These simulations also facilitate self-directed learning, allow trainees to develop skills at their own pace and allow unlimited repetition of specific scenarios that enable them to remedy skills deficiencies in a safe environment. A number of simulators have been validated and have shown clear benefits to medical training. However, while graphical realism is high, realistic haptic feedback and interactive tissues are limited for many simulators. This paper reviews the current status and benefits of haptic VR simulation-based medical training for bone and dental surgery, intubation procedures, eye surgery, and minimally invasive and endoscopic surgery.
Journal of Simulation, 2012
Virtual reality (VR) surgical simulations are among the most difficult software applications to d... more Virtual reality (VR) surgical simulations are among the most difficult software applications to develop mainly because of the type of user interactions that they must support. Surgery typically includes precise cutting of often intricate structures. Modelling these structures and accurately simulating their response to user interaction requires many software components to effectively work in unison. Some of these components are readily available but are tailored to more common applications such as computer games or open-world simulations such as flight-simulators. This article explores the software libraries that are currently available to developers of VR surgical simulation software. Like computer games and other VR simulations, VR surgical simulations require real-time lighting and rendering systems and physics-based interactions. However, in addition they require haptic interaction with cut-able and deformable soft-tissue, a key requirement that is not supported by the majority of the available tools. In this article, we introduce currently available software development tools and the specific benefits and limitations that can be encountered when using them to develop VR surgical simulations. We also provide a detailed review of collision detection libraries that are central to achieving reliable haptic rendering.
The Journal of laryngology and otology, 2012
Objectives:To develop a virtual-reality subtotal tonsillectomy simulation for surgical training.M... more Objectives:To develop a virtual-reality subtotal tonsillectomy simulation for surgical training.Materials and Methods:Computer models of a male patient's head and throat, and the surgical instrument, were created. These models were combined with custom-built simulation software. Recently developed tissue simulation technology that exploits recent developments in programmable graphics processing units was used to model tonsillar tissue in a way that allows surgical interaction whilst providing accurate tactile feedback. Current real-time rendering techniques were used to provide realistic visuals. Iterative refinements were made to the simulation, and in particular the tissue simulation, in consultation with relevantly experienced surgeons.Results:We have used newly developed tissue simulation technology to developed a novel virtual-reality subtotal tonsillectomy simulation for surgical training, the first of its kind.Conclusion:Early feedback suggests that this simulator can he...
SIMULATION, 2014
This article describes a new approach for producing highly realistic visualizations that are inte... more This article describes a new approach for producing highly realistic visualizations that are interactively cuttable by utilizing the programmability of the graphics rendering pipeline. It combines interactively changing scalar-field derived mesh geometry with static mesh geometry that contains additional lighting terms created offline using three-dimensional modeling software packages. This improves visual realism of surgical simulations whilst enabling more efficient surface representations for interactive areas of the same model, in this case the newly formed surface created when interactively cutting a model. The boundary between the interactively cut surface (generated from the scalar field), and the remaining surface triangles of the static model, is jagged and unrealistic when un-enhanced. Here we describe a method for blending the two models using a simple bleeding effect along the cut edge. This allows the cut edge and the internal cut surface to blend and thereby conceals unrealistic and distracting jagged cut edges. The bloodied edge is more realistic than an unmodified hard edge, which improves the quality of the simulation overall. Moreover, as the available processing power increases the resolution that can be achieved will increase and should allow this method to be extended for slice cutting simulation.
Veterinary and comparative orthopaedics and traumatology : V.C.O.T, 2018
The formulation of appropriate postoperative strategies, following fracture repair, currently inv... more The formulation of appropriate postoperative strategies, following fracture repair, currently involves an understanding of radiological and clinical outcome measures. This study has evaluated several modalities used to assess the progression of bone healing in a sheep tibial segmental defect model. Measures of defect optical density and volumetric data including bone density (BD), bone volume (BV) and bone mass (BM) were compared with qualitative data involving visual appraisal of radiographs [% bridging callus and modified radiographic union score tibia (mRUST)] and a clinical outcome measure (locomotory function). Percent bridging callus and mRUST measures displayed strong correlation ( = 0.999), while locomotory function was weakly correlated with bridging callus ( = 0.029) and mRUST ( = 0.046). There was moderate to strong correlation between the qualitative and quantitative data. Bone density, BV and BM showed strong correlations within this dataset (BD-BV, = 0.814; BD-BM, = ...
American Journal of Rhinology & Allergy, 2013
Background: Endoscopic sinus surgery (ESS) is the surgical standard treatment for chronic rhiniti... more Background: Endoscopic sinus surgery (ESS) is the surgical standard treatment for chronic rhinitis/rhinosinusitis and nasal polyposis. There is a reported complication rate of 5-10% associated with this type of surgery. Simulation has been advocated as a means to improve surgical training and minimize the rates of complication and medical error. This study aimed to show how a virtual reality ESS simulator was developed, with particular emphasis on achieving satisfactory photorealism and surgical verisimilitude. Methods: Sinus computed tomography scans were processed to create a triangle-based three-dimensional mesh model; this was incorporated into a spring-damper model of thousands of interconnected nodes, which is allowed to deform in response to user interactions. Dual haptic handpiece devices were programmed to simulate an endoscope and various surgical instruments. Textures and lighting effects were added to the mesh model to provide an accurate representation of the surgical field. Effects such as vasoconstriction in response to "virtual" decongestant were added. Results: The final simulated endoscopic view of the sinuses accurately simulates the moist and glossy appearance of the sinuses. The interactive tissue simulation system enables the user to interactively cut and remove tissue while receiving accurate haptic feedback. A working prototype of the simulator has been developed that leverages recent advances in computer hardware to deliver a realistic user experience, both visually and haptically. Conclusion: This new computer-based training tool for practicing ESS provides a risk-free environment for surgical trainees to practice and develop core skills. The novel use of customized precision force feedback (haptic) devices enables trainees to use movements during training that closely mimic those used during the actual procedure, which we anticipate will improve learning, retention, and recall.
Third International Conference on Innovative Computing Technology (INTECH 2013), 2013
ABSTRACT Nasendoscopy is commonly used to examine the sinus cavity. The anatomy of the sinuses is... more ABSTRACT Nasendoscopy is commonly used to examine the sinus cavity. The anatomy of the sinuses is highly varied and complex. It consists of intricate, interconnected structures and anatomical landmarks that can be difficult to identify; firstly because of the complexity, and secondly because of the diversity across patients. Consequently, teaching medical trainees to recognize these anatomical landmarks requires a way of highlighting landmarks without concealing important, and often subtle, details. Further, when using virtual reality simulations to assess a trainee's knowledge of the anatomy, it is important to annotate 3-dimensional models in a manner that does not reveal a target location prematurely. Here we describe a simple new method that uses recent advances in the programmability of the graphics processing unit, to efficiently, clearly and accurately display visual markers. Moreover, our method allows markers to be positioned simply and intuitively using a pair of haptic devices without requiring complex modifications to surface textures.
ANZ journal of surgery, Jan 21, 2015
This study evaluates whether surgical experience influences technical competence using the Flinde... more This study evaluates whether surgical experience influences technical competence using the Flinders sinus surgery simulator, a virtual environment designed to teach nasal endoscopic surgical skills. Ten experienced sinus surgeons (five consultants and five registrars) and 14 novices (seven resident medical officers and seven interns/medical students) completed three simulation tasks using haptic controllers. Task 1 required navigation of the sinuses and identification of six anatomical landmarks, Task 2 required removal of unhealthy tissue while preserving healthy tissue and Task 3 entailed backbiting within pre-set lines on the uncinate process and microdebriding tissue between the cuts. Novices were compared with experts on a range of measures, using Mann-Whitney U-tests. Novices took longer on all tasks (Task 1: 278%, P < 0.005; Task 2: 112%, P < 0.005; Task 3: 72%, P < 0.005). In Task 1, novices' instruments travelled further than experts' (379%, P < 0.005), ...
Proceedings of the second international conference on Human-agent interaction - HAI '14, 2014
Lecture Notes in Computer Science, 2014
Clinical Otolaryngology, 2015
Virtual reality (VR) simulators provide an alternative to real patients for practicing surgical s... more Virtual reality (VR) simulators provide an alternative to real patients for practicing surgical skills but require validation to ensure accuracy. Here we validate the use of a virtual reality sinus surgery simulator with haptic feedback for training in Otorhinolaryngology - Head &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Neck Surgery (OHNS). Participants were recruited from final year Medical Students, Interns, Resident Medical Officers (RMOs), OHNS Registrars and Consultants. All participants completed an online questionnaire after performing four separate simulation tasks. These were then used to assess face, content and construct validity. ANOVA with post-hoc correlation was used for statistical analysis. The following groups were compared: a) Medical Students / Interns, b) RMOs, c) Registrars and d) Consultants. Face validity results had a statistically significant (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) difference between the Consultant group and others while there was no significant difference between medical student/intern and RMOs. Variability within groups was not significant. Content validity results based on Consultant scoring and comments indicated that the simulations need further development in several areas in order to be effective for Registrar-level teaching. However students, interns and RMOs indicated that the simulations provide a useful tool for learning OHNS related anatomy and as an introduction to ENT specific procedures. The VR simulations have been validated for teaching sinus anatomy and nasendoscopy to Medical Students, Interns and RMOs. However, they require further development before they can be regarded as a valid tool for more advanced surgical training. This article is protected by copyright. All rights reserved.
2014 IEEE Haptics Symposium (HAPTICS), 2014
2014 IEEE International Symposium on Multimedia, 2014
Computer Methods in Biomechanics and Biomedical Engineering, 2013
Efficient rendering of a changing volumetric data-set is central to the development of effective ... more Efficient rendering of a changing volumetric data-set is central to the development of effective medical simulations that incorporate haptic feedback. A new method referred to as real-time interactive isosurfacing (RTII) is described in this paper. RTII is an algorithm that can be applied to output from Marching Cubes-like algorithms to improve performance for real-time applications. The approach minimises processing by re-evaluating the isosurface around changing sub-volumes resulting from user interactions. It includes innovations that significantly reduce mesh complexity and improve mesh quality as triangles are created from the Marching Tetrahedra isosurfacing algorithm. Rendering efficiency is further improved over other marching isosurfacing algorithm outputs by maintaining an indexed triangle representation of the mesh. The effectiveness of RTII is discussed within the context of an endoscopic sinus surgery simulation currently being developed by the authors.
American Journal of Rhinology and Allergy, 2013
Background -Endoscopic sinus surgery is the surgical standard treatment for chronic rhinitis/rhin... more Background -Endoscopic sinus surgery is the surgical standard treatment for chronic rhinitis/rhinosinusitis, and nasal polyposis. There is a reported complication rate of 5-10% associated with this type of surgery. Simulation has been advocated as a means to improve surgical training and minimise the rates of complication and medical error.
Objectives: To develop a virtual-reality subtotal tonsillectomy simulation for surgical training.... more Objectives: To develop a virtual-reality subtotal tonsillectomy simulation for surgical training.
Materials and Methods: Computer models of a male patient’s head and throat, and the surgical instrument, were
created. These models were combined with custom-built simulation software. Recently developed tissue simulation
technology that exploits recent developments in programmable graphics processing units was used to model
tonsillar tissue in a way that allows surgical interaction whilst providing accurate tactile feedback. Current realtime rendering techniques were used to provide realistic visuals. Iterative refinements were made to the
simulation, and in particular the tissue simulation, in consultation with relevantly experienced surgeons.
Results: We have used newly developed tissue simulation technology to developed a novel virtual-reality subtotal
tonsillectomy simulation for surgical training, the first of its kind.
Conclusion: Early feedback suggests that this simulator can help surgeo
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Papers by Greg Ruthenbeck
Materials and Methods: Computer models of a male patient’s head and throat, and the surgical instrument, were
created. These models were combined with custom-built simulation software. Recently developed tissue simulation
technology that exploits recent developments in programmable graphics processing units was used to model
tonsillar tissue in a way that allows surgical interaction whilst providing accurate tactile feedback. Current realtime rendering techniques were used to provide realistic visuals. Iterative refinements were made to the
simulation, and in particular the tissue simulation, in consultation with relevantly experienced surgeons.
Results: We have used newly developed tissue simulation technology to developed a novel virtual-reality subtotal
tonsillectomy simulation for surgical training, the first of its kind.
Conclusion: Early feedback suggests that this simulator can help surgeo
Materials and Methods: Computer models of a male patient’s head and throat, and the surgical instrument, were
created. These models were combined with custom-built simulation software. Recently developed tissue simulation
technology that exploits recent developments in programmable graphics processing units was used to model
tonsillar tissue in a way that allows surgical interaction whilst providing accurate tactile feedback. Current realtime rendering techniques were used to provide realistic visuals. Iterative refinements were made to the
simulation, and in particular the tissue simulation, in consultation with relevantly experienced surgeons.
Results: We have used newly developed tissue simulation technology to developed a novel virtual-reality subtotal
tonsillectomy simulation for surgical training, the first of its kind.
Conclusion: Early feedback suggests that this simulator can help surgeo