74 research outputs found

    The Use of Stereoscopy in a Neurosurgery Training Virtual Environment

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    Published in Presence: Teleoperators and Virtual EnvironmentsWe have previously investigated the effectiveness of a custom built virtual environment in assisting training of a ventriculostomy procedure, which is a commonly performed procedure by a neurosurgeon and a core task for trainee surgeons. The training tool (called VCath) was initially developed as a low fidelity app for a tablet platform to provide easy access and availability to trainees. Subsequently we have developed a high fidelity version of VCath that uses a stereoscopic display to immerse the trainee in the virtual environment. This paper reports on two studies that have been carried out to compare the low and high fidelity versions of VCath, particularly to assess the value of stereoscopy. Study 1 was conducted at the second annual boot camp organized for all year one trainees in neurosurgery in the UK. Study 2 was performed on lay people, with no surgical experience. Our hypothesis was that using stereoscopy in the training task would be beneficial. Results from Study 1 demonstrated that performance improved for both the control group and the group trained with the tablet version of VCath. The group trained on the high fidelity version of VCath with a stereoscopic display showed no performance improvement. The indication is that our hypothesis is false. In Study 2, six different conditions were investigated that covered the use of training with VCath on a tablet, a mono display at two different sizes, a stereo display at two different sizes, and a control group who received no training. Results from this study with lay people show that stereoscopy can make a significant improvement to the accuracy of needle placement. The possible reasons for these results and the apparent contradiction between the two studies are discussed

    Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

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    One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

    Creation of a Virtual Atlas of Neuroanatomy and Neurosurgical Techniques Using 3D Scanning Techniques

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    Neuroanatomy is one of the most challenging and fascinating topics within the human anatomy, due to the complexity and interconnection of the entire nervous system. The gold standard for learning neurosurgical anatomy is cadaveric dissections. Nevertheless, it has a high cost (needs of a laboratory, acquisition of cadavers, and fixation), is time-consuming, and is limited by sociocultural restrictions. Due to these disadvantages, other tools have been investigated to improve neuroanatomy learning. Three-dimensional modalities have gradually begun to supplement traditional 2-dimensional representations of dissections and illustrations. Volumetric models (VM) are the new frontier for neurosurgical education and training. Different workflows have been described to create these VMs -photogrammetry (PGM) and structured light scanning (SLS). In this study, we aimed to describe and use the currently available 3D scanning techniques to create a virtual atlas of neurosurgical anatomy. Dissections on post-mortem human heads and brains were performed at the skull base laboratories of Stanford University - NeuroTraIn Center and the University of California, San Francisco - SBCVL (skull base and cerebrovascular laboratory). Then VMs were created following either SLS or PGM workflow. Fiber tract reconstructions were also generated from DICOM using DSI-studio and incorporated into VMs from dissections. Moreover, common creative license materials models were used to simplify the understanding of the specific anatomical region. Both methods yielded VMs with suitable clarity and structural integrity for anatomical education, surgical illustration, and procedural simulation. We described the roadmap of SLS and PGM for creating volumetric models, including the required equipment and software. We have also provided step-by-step procedures on how users can post-processing and refine these images according to their specifications. The VMs generated were used for several publications, to describe the step-by-step of a specific neurosurgical approach and to enhance the understanding of an anatomical region and its function. These models were used in neuroanatomical education and research (workshops and publications). VMs offer a new, immersive, and innovative way to accurately visualize neuroanatomy. Given the straightforward workflow, the presently described techniques may serve as a reference point for an entirely new way of capturing and depicting neuroanatomy and offer new opportunities for the application of VMs in education, simulation, and surgical planning. The virtual atlas, divided into specific areas concerning different neurosurgical approaches (such as skull base, cortex and fiber tracts, and spine operative anatomy), will increase the viewer's understanding of neurosurgical anatomy. The described atlas is the first surgical collection of VMs from cadaveric dissections available in the medical field and could be a used as reference for future creation of analogous collection in the different medical subspeciality.La neuroanatomia è, grazie alle intricate connessioni che caratterizzano il sistema nervoso e alla sua affascinante complessità, una delle discipline più stimolanti della anatomia umana. Nonostante il gold standard per l’apprendimento dell’anatomia neurochirurgica sia ancora rappresentato dalle dissezioni cadaveriche, l’accessibilità a queste ultime rimane limitata, a causa della loro dispendiosità in termini di tempo e costi (necessità di un laboratorio, acquisizione di cadaveri e fissazione), e alle restrizioni socioculturali per la donazione di cadaveri. Al fine di far fronte a questi impedimenti, e con lo scopo di garantire su larga scala l’apprendimento tridimensionale della neuroanatomia, nel corso degli anni sono stati sviluppati nuovi strumenti e tecnologie. Le tradizionali rappresentazioni anatomiche bidimensionali sono state gradualmente sostituite dalle modalità 3-dimensionali (3D) – foto e video. Tra questi ultimi, i modelli volumetrici (VM) rappresentano la nuova frontiera per l'istruzione e la formazione neurochirurgica. Diversi metodi per creare questi VM sono stati descritti, tra cui la fotogrammetria (PGM) e la scansione a luce strutturata (SLS). Questo studio descrive l’utilizzo delle diverse tecniche di scansione 3D grazie alle quali è stato creato un atlante virtuale di anatomia neurochirurgica. Le dissezioni su teste e cervelli post-mortem sono state eseguite presso i laboratori di base cranica di Stanford University -NeuroTraIn Center e dell'Università della California, San Francisco - SBCVL. I VM dalle dissezioni sono stati creati seguendo i metodi di SLS e/o PGM. Modelli di fibra bianca sono stati generate utilizzando DICOM con il software DSI-studio e incorporati ai VM di dissezioni anatomiche. Inoltre, sono stati utilizzati VM tratti da common creative license material (materiale con licenze creative comuni) al fine di semplificare la comprensione di alcune regioni anatomiche. I VM generati con entrambi i metodi sono risultati adeguati, sia in termini di chiarezza che di integrità strutturale, per l’educazione anatomica, l’illustrazione medica e la simulazione chirurgica. Nel nostro lavoro sono stati esaustivamente descritti tutti gli step necessari, di entrambe le tecniche (SLS e PGM), per la creazione di VM, compresi le apparecchiature e i software utilizzati. Sono state inoltre descritte le tecniche di post-elaborazione e perfezionamento dei VM da poter utilizzare in base alle necessità richieste. I VM generati durante la realizzazione del nostro lavoro sono stati utilizzati per molteplici pubblicazioni, nella descrizione step-by-step di uno specifico approccio neurochirurgico o per migliorare la comprensione di una regione anatomica e della sua funzione. Questi modelli sono stati utilizzati a scopo didattico per la formazione neuroanatomica di studenti di medicina, specializzandi e giovani neurochirurghi. I VM offrono un modo nuovo, coinvolgente e innovativo con cui poter raggiungere un’accurata conoscenza tridimensionale della neuroanatomia. La metodologia delle due tecniche descritte può servire come punto di riferimento per un nuovo modo di acquisizione e rappresentazione della neuroanatomia, ed offrire nuove opportunità di utilizzo dei VM nella formazione didattica, nella simulazione e nella pianificazione chirurgica. L'atlante virtuale qui descritto, suddiviso in aree specifiche relative a diversi approcci neurochirurgici, aumenterà la comprensione dell'anatomia neurochirurgica da parte dello spettatore. Questa è la prima raccolta chirurgica di VM da dissezioni anatomiche disponibile in ambito medico e potrebbe essere utilizzato come riferimento per la futura creazione di analoga raccolta nelle diverse sotto specialità mediche

    Performance Factors in Neurosurgical Simulation and Augmented Reality Image Guidance

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    Virtual reality surgical simulators have seen widespread adoption in an effort to provide safe, cost-effective and realistic practice of surgical skills. However, the majority of these simulators focus on training low-level technical skills, providing only prototypical surgical cases. For many complex procedures, this approach is deficient in representing anatomical variations that present clinically, failing to challenge users’ higher-level cognitive skills important for navigation and targeting. Surgical simulators offer the means to not only simulate any case conceivable, but to test novel approaches and examine factors that influence performance. Unfortunately, there is a void in the literature surrounding these questions. This thesis was motivated by the need to expand the role of surgical simulators to provide users with clinically relevant scenarios and evaluate human performance in relation to image guidance technologies, patient-specific anatomy, and cognitive abilities. To this end, various tools and methodologies were developed to examine cognitive abilities and knowledge, simulate procedures, and guide complex interventions all within a neurosurgical context. The first chapter provides an introduction to the material. The second chapter describes the development and evaluation of a virtual anatomical training and examination tool. The results suggest that learning occurs and that spatial reasoning ability is an important performance predictor, but subordinate to anatomical knowledge. The third chapter outlines development of automation tools to enable efficient simulation studies and data management. In the fourth chapter, subjects perform abstract targeting tasks on ellipsoid targets with and without augmented reality guidance. While the guidance tool improved accuracy, performance with the tool was strongly tied to target depth estimation – an important consideration for implementation and training with similar guidance tools. In the fifth chapter, neurosurgically experienced subjects were recruited to perform simulated ventriculostomies. Results showed anatomical variations influence performance and could impact outcome. Augmented reality guidance showed no marked improvement in performance, but exhibited a mild learning curve, indicating that additional training may be warranted. The final chapter summarizes the work presented. Our results and novel evaluative methodologies lay the groundwork for further investigation into simulators as versatile research tools to explore performance factors in simulated surgical procedures

    Los juegos en entornos virtuales como herramientas de aprendizaje : estudio de la respuesta emocional de los participantes

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    El artículo analiza las posibilidades de la realidad virtual como herramienta de aprendizaje a través del juego y presenta los resultados de un trabajo experimental que analizó la respuesta emocional de los participantes durante la experiencia de juego en un ambiente virtual compartido. El estudio se realizó con 56 voluntarios que participaron en un juego interactivo en el que debían aprender a colaborar para lograr el objetivo. Los resultados muestran que los participantes se sintieron positivos y activados durante la experiencia. La utilización del juego en ambientes virtuales con fines educativos podría dar resultados altamente positivos.The article analyses the possibilities of virtual reality as learning tool through game playing and it presents the results of an experimental study that analyzed participants' emotional response during the experience of playing in a shared virtual environment. A study was carried out with 56 volunteers. Participants played an interactive game where they needed to learn to collaborate to achieve the goal. Participants felt positive and activated during the experience. Using games in virtual environments with educational purposes could be a highly positive experience

    Computerized Evaluatution of Microsurgery Skills Training

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    The style of imparting medical training has evolved, over the years. The traditional methods of teaching and practicing basic surgical skills under apprenticeship model, no longer occupy the first place in modern technically demanding advanced surgical disciplines like neurosurgery. Furthermore, the legal and ethical concerns for patient safety as well as cost-effectiveness have forced neurosurgeons to master the necessary microsurgical techniques to accomplish desired results. This has lead to increased emphasis on assessment of clinical and surgical techniques of the neurosurgeons. However, the subjective assessment of microsurgical techniques like micro-suturing under the apprenticeship model cannot be completely unbiased. A few initiatives using computer-based techniques, have been made to introduce objective evaluation of surgical skills. This thesis presents a novel approach involving computerized evaluation of different components of micro-suturing techniques, to eliminate the bias of subjective assessment. The work involved acquisition of cine clips of micro-suturing activity on synthetic material. Image processing and computer vision based techniques were then applied to these videos to assess different characteristics of micro-suturing viz. speed, dexterity and effectualness. In parallel subjective grading on these was done by a senior neurosurgeon. Further correlation and comparative study of both the assessments was done to analyze the efficacy of objective and subjective evaluation

    Los juegos en entornos virtuales como herramientas de aprendizaje : estudio de la respuesta emocional de los participantes

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    El artículo analiza las posibilidades de la realidad virtual como herramienta de aprendizaje a través del juego y presenta los resultados de un trabajo experimental que analizó la respuesta emocional de los participantes durante la experiencia de juego en un ambiente virtual compartido. El estudio se realizó con 56 voluntarios que participaron en un juego interactivo en el que debían aprender a colaborar para lograr el objetivo. Los resultados muestran que los participantes se sintieron positivos y activados durante la experiencia. La utilización del juego en ambientes virtuales con fines educativos podría dar resultados altamente positivos.The article analyses the possibilities of virtual reality as learning tool through game playing and it presents the results of an experimental study that analyzed participants' emotional response during the experience of playing in a shared virtual environment. A study was carried out with 56 volunteers. Participants played an interactive game where they needed to learn to collaborate to achieve the goal. Participants felt positive and activated during the experience. Using games in virtual environments with educational purposes could be a highly positive experience

    History of virtual reality and its use in medicine

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    Virtual Reality can be defined as an advanced interface between man and machine, that simulates a realistic environment and allows participants to interact with such ambience. This Science has its origins in the military academies and in the entertainment industry, and experienced great impulse in the second half of twentieth century. Using techniques like stereoscopy, it is possible to use human senses and to emulate experiences with much fidelity. Models of Virtual Reality became more and more important for medicine. Today, we can find many applications in this field, such as preoperative planning, assistance, surgical training and teaching. For the study of neuroanatomy and neurosurgery in particular, the technology of Virtual Reality has shown great effectiveness and utility, despite of high costs and low quality of visual information. Virtual Reality is now definitively included in the context of medical education.Realidade Virtual pode ser definida como uma avançada interface homem-máquina que simula um ambiente realístico e permite que participantes interajam com ele. Essa ciência tem suas origens nas academias militares e na indústria do entretenimento, com grande impulso na segunda metade do século XX. Através de técnicas como a estereoscopia, é possível usar os sentidos humanos e emular experiências com grande fidelidade. Modelos de Realidade Virtual ganham importância cada vez maior para a medicina. Hoje é possível encontrar diversas aplicações nessa área, como planejamento pré-operatório, assistência, treinamento cirúrgico e ensino. Para o estudo da neuroanatomia e da neurocirurgia especificamente, embora os custos proibitivos e a experiência visual limitada ainda sejam realidade, a tecnologia da Realidade Virtual tem demonstrado grande eficiência e utilidade, assumindo definitivamente seu papel no contexto da educação médica

    Contributions to the Development of Objective Techniques for Presence Measurement in Virtual Environments by means of Brain Activity Analysis

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    En esta tesis, se propone el uso de la técnica de Doppler transcraneal (DTC) para monitorizar la actividad cerebral durante la exposición a entornos virtuales (EV) y así poder analizar los correlatos cerebrales del sentido de presencia. Las hipótesis de partida son las siguientes: 1) DTC se podrá utilizar fácilmente en combinación con sistemas de realidad virtual. 2) Los datos de velocidad de flujo sanguíneo medidos por DTC se podrán utilizar para analizar cambios de actividad cerebral durante la exposición a EV. 3) Habrá diferencias en la velocidad del flujo sanguíneo asociadas a distintos niveles de presencia. 4) Habrá correlación entre el grado de presencia medido por cuestionarios y parámetros de la velocidad de flujo sanguíneo. 5) Cada componente de la experiencia virtual tendrá una influencia en las variaciones de velocidad observadas. Para analizar las hipótesis planteadas, se realizaron cuatro experimentos distintos, en los que se analizó la velocidad del flujo sanguíneo durante: 1) distintas condiciones de navegación, 2) distintas condiciones de inmersión, 3) una tarea de percepción visual y 4) tareas motoras para manejo de un joystick. Durante la tesis, se han propuesto distintas técnicas de procesado de señal basadas en análisis espectral y en la obtención parámetros no lineales de la señal, que no habían sido utilizadas previamente en experimentos psicofisiológicos con DTC. Se ha observado que existe un incremento en la velocidad del flujo sanguíneo durante la exposición a un EV, el cual puede deberse a distintos factores que intervienen en la experiencia: tareas de interacción visuoespacial, tareas de atención, la creación y ejecución de un plan motor, cambios emocionales Los análisis han mostrado que existen correlaciones significativas entre la velocidad media de flujo sanguíneo en las arterias cerebrales medias durante la exposición al EV y respuestas a los cuestionarios de presencia utilizados.Rey Solaz, B. (2010). Contributions to the Development of Objective Techniques for Presence Measurement in Virtual Environments by means of Brain Activity Analysis [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8505Palanci
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