722 research outputs found

    Métrica Vertebral: Alterações biomecânicas da coluna vertebral em indivíduos com Espondilite Anquilosante

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    A análise das alterações biomecânicas da coluna vertebral na posição ortostática é extremamente relevante para delinear estratégias de intervenção direccionadas para a problemática de cada pessoa. Porém, esta análise tem sido travada pela inexistência de metodologias não invasivas que façam a análise global da coluna vertebral. Neste contexto, foi desenvolvido o Métrica Vertebral, um instrumento, de carácter não invasivo, que permite a análise global da coluna vertebral, na posição ortostática, através da identificação automática da posição tridimensional do vértice de cada apófise espinhosa, aferindo sobre as alterações biomecânicas da coluna vertebral. A Espondilite Anquilosante é uma doença reumática crónica, de etiologia desconhecida, que afecta a vida pessoal e profissional do indivíduo, diminuindo, significativamente, a sua qualidade de vida. É caracterizada, principalmente, por raquialgias e alterações da biomecânica da coluna vertebral. Recorrendo ao Métrica Vertebral, este projecto teve como objectivos principais: identificar e analisar os factores relacionados com as alterações da biomecânica da coluna vertebral em doentes com Espondilite Anquilosante; desenvolver uma interface clínica adaptada à patologia e com uma forte componente de visualização da coluna vertebral; criar uma base de dados para registo dos parâmetros analisados através da interface clínica, incluindo os dados obtidos pelo Métrica Vertebral. Esta dissertação esteve integrada num projecto mais abrangente, aceite pela comissão de ética do Centro Hospitalar de Lisboa Ocidental e contou com uma amostra de catorze indivíduos. De maneira a analisar e relacionar informação, foram preenchidos questionários e adquiridas nove aquisições, com o Métrica Vertebral, por indivíduo. A análise dos dados obtidos, demonstrou a existência de uma oscilação ântero-posterior da posição de equilíbrio e uma rectificação da cifose dorsal e da lordose lombar. Os dados demonstraram ainda, que os indivíduos possuíam uma boa capacidade funcional e mobilidade axial, não tendo sinais de uma doença muito activa

    Medical Robotics

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    The first generation of surgical robots are already being installed in a number of operating rooms around the world. Robotics is being introduced to medicine because it allows for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, robots have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. The use of robotics in surgery will expand over the next decades without any doubt. Minimally Invasive Surgery (MIS) is a revolutionary approach in surgery. In MIS, the operation is performed with instruments and viewing equipment inserted into the body through small incisions created by the surgeon, in contrast to open surgery with large incisions. This minimizes surgical trauma and damage to healthy tissue, resulting in shorter patient recovery time. The aim of this book is to provide an overview of the state-of-art, to present new ideas, original results and practical experiences in this expanding area. Nevertheless, many chapters in the book concern advanced research on this growing area. The book provides critical analysis of clinical trials, assessment of the benefits and risks of the application of these technologies. This book is certainly a small sample of the research activity on Medical Robotics going on around the globe as you read it, but it surely covers a good deal of what has been done in the field recently, and as such it works as a valuable source for researchers interested in the involved subjects, whether they are currently “medical roboticists” or not

    Desenvolvimento e validação do instrumento Métrica Vertebral: avaliação da biomecânica da face posterior do tronco

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    A avaliação da biomecânica da coluna vertebral é extremamente relevante no sentido de prevenir, monitorizar e delinear estratégias de intervenção direccionadas a cada indivíduo. No entanto, tem sido condicionada pela inexistência de instrumentos não-invasivos capazes de proporcionar uma análise completa da coluna vertebral. Para colmatar as lacunas referidas, desenvolveu-se o terceiro protótipo do Métrica Vertebral. Este instrumento não-invasivo avalia a coluna vertebral de forma global e quantitativa, ao determinar a posição 3D da projecção cutânea do vértice dos processos espinhosos. Para cumprir esse objectivo, utiliza um sistema de visão estéreo e algoritmos de processamento de imagem optimizados para reconhecer marcas específicas na pele. O trabalho realizado compreendeu a implementação de hardware, definição de software e aferição do sistema, bem como o desenvolvimento e validação de um modelo matemático único para facultar a representação 3D da coluna vertebral além de estimar a amplitude da cifose dorsal, da lordose lombar e dos ângulos intervertebrais. O novo instrumento efectua aquisições de dados em cerca de 45 s. A sua resolução espacial é de 0.6 mm em X e Z e de 1.5 mm em Y, enquanto o erro máximo é 0.7 mm, 1.1 mm e 0.8 mm em X, Y e Z, respectivamente. Este conjunto de características sugere a sua viabilidade para futuras aplicações clínicas. A aplicabilidade do sistema integrado (terceiro protótipo e modelo matemático) foi demonstrada, pela primeira vez, em duas populações. Concluiu-se que: a alteração na posição de um processo espinhoso leva os restantes a adaptar-se em conformidade para garantir a estabilidade fisiológica; a variabilidade dos ângulos intervertebrais aparece como resposta aos pequenos ajustes posturais; a cifose dorsal aparenta ter uma rectificação; o comportamento da lordose lombar corresponde ao esperado para cada população. O Métrica Vertebral não se esgota nas amostras analisadas, pode ser aplicado repetidamente sem representar um perigo para o indivíduo e revela um forte potencial para se adaptar a outras necessidades clínicas, como a análise da cintura escapular

    Statistical Shape Analysis for the Human Back

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    A thesis submitted to the department of Engineering and Technology in partial fulfilment of the requirements for the degree of Master of Philosophy in Production and Manufacturing Engineering at the University of WolverhamptonIn this research, Procrustes and Euclidean distance matrix analysis (EDMA) have been investigated for analysing the three-dimensional shape and form of the human back. Procrustes analysis is used to distinguish deformed backs from normal backs. EDMA is used to locate the changes occurring on the back surface due to spinal deformity (scoliosis, kyphosis and lordosis) for back deformity patients. A surface topography system, ISIS2 (Integrated Shape Imaging System 2), is available to measure the three-dimensional back surface. The system presents clinical parameters, which are based on distances and angles relative to certain anatomical landmarks on the back surface. Location, rotation and scale definitely influence these parameters. Although the anatomical landmarks are used in the present system to take some account of patient stance, it is still felt that variability in the clinical parameters is increased by the use of length and angle data. Patients also grow and so their back size, shape and form change between appointments with the doctor. Instead of distances and angles, geometric shape that is independent of location, rotation and scale effects could be measured. This research is mainly focusing on the geometric shape and form change in the back surface, thus removing the unwanted effects. Landmarks are used for describing back information and an analysis of the variability in positioning the landmarks has been carried out for repeated measurements. Generalized Procrustes analysis has been applied to all normal backs to calculate a mean Procrustes shape, which is named the standard normal shape (SNS). Each back (normal and deformed) is then translated, rotated and scaled to give a best fit with the SNS using ordinary Procrustes analysis. Riemannian distances are then estimated between the SNS and all individual backs. The highest Riemannian distance value between the normal backs and the SNS is lower than the lowest Riemannian distance value between the deformed backs and the SNS. The results shows that deformed backs can be differentiated from normal backs. EDMA has been used to estimate a mean form, variance-covariance matrix and mean form difference from all the normal backs. This mean form is named the standard normal form (SNF). The influence of individual landmarks for form difference between each deformed back and the SNF is estimated. A high value indicates high deformity on the location of that landmark and a low value close to 1 indicates less deformity. The result is displayed in a graph that provides information regarding the degree and location of the deformity. The novel aspects of this research lie in the development of an effective method for assessing the three-dimensional back shape; extracting automatic landmarks; visualizing back shape and back form differences

    A multi-factorial evaluation of lower back injury risk factors in fast bowlers.

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    Fast bowlers have consistently been reported to suffer with the greatest frequency of injury, with the lower back being the most common site. The biomechanics of technique, musculoskeletal fitness and workload parameters have all been implicated in the risk of injury. Conversely, aspects of spinal morphology (spinal shrinkage and lumbar curvature) have received little attention, and thus this thesis aimed to investigate whether these should be considered as part of the multifactorial risk of injury to elite fast bowlers. The Spinal Mouse demonstrated good to high within and between day inter- and intra-rater reliability for measuring sagittal lumbar lordosis, although no acute changes were found after bowling in club standard fast bowlers. Stature measured before, during and after bowling, using a custom-built laboratory stadiometer, resulted in 5-6 mm of spinal shrinkage in club standard fast bowlers. However, this stadiometer did not provide adequate reliability for between-day intra-rater measurements and an alternative device for measuring stature changes in the field was required. The Seca 287 ultrasound stadiometer demonstrated excellent within- and between-day reliability alongside excellent concurrent validity for measuring large stature changes associated with exercise such as fast bowling. Using the Seca 287 and Spinal Mouse, spinal morphology measurements before and after bowling, were included as injury risk factors alongside three-dimensional kinematics of the bowling action, fitness measures and musculoskeletal function of 14 First-Class county cricket elite fast bowlers. A retrospective analysis of injuries over the 2019 season supported previous research demonstrating that elite fast bowlers experienced a high injury incidence. Bowlers who suffered lower back injuries experienced significantly more spinal shrinkage after five overs of bowling than those who remained injury free (8 ± 1 mm vs 4 ± 3 mm), indicating that this may be of clinical significance. Lumbar lordosis of the injured bowlers (31 ± 2°) was not significantly greater than the non-injured bowlers (25 ± 6°), although the effect size was large (r = 0.5), indicating its potential importance as an injury risk factor. Biomechanical parameters of the action, fitness measures and musculoskeletal function were not found to be related to lower back injury. Bowling and physical workload were measured across 4-day, 50 over and T20 cricket formats during the 2019 season in 10 elite bowlers, using GPS units, as additional risk factors. More deliveries were bowled in 4-day and 50 over matches when compared to T20, although adjusting for deliveries per hour resulted in no difference between formats. Intensity of bowling in T20 cricket was perceived to be lower than other game formats, although GPS metrics that calculated changes in acceleration indicated that the T20 format placed an increased intensity on the body when bowling. A lack of high intensity running and sprinting during bowling training sessions was associated with a high injury rate, although bowling workload was not associated with injury to fast bowlers. This thesis has shown that measures of spinal shrinkage and lumbar lordosis should be added to other injury risk factors measured during pre-season screening. These new risk factors should not be viewed in isolation, but as part of an approach that examines the interrelationships between the factors that could potentially lead to injury. Utilizing big data, machine learning, and a new injury model for fast bowlers may aid future research

    Combined numerical and morphological study of the lumbar spine: parametric finite element model and evaluation of dynamic implants

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    Low back pain is a major cause of disability and requires the development of new devices to treat pathologies and improve prognosis following surgery. Finite Element (FE) Methods represent an appealing solution to provide mechanical evaluations of new devices speeding up the design process, as well as evaluating several anatomical scenarios. The aim of this thesis was to develop an accurate FE of the lumbar spine and the evaluation of the variability introduced by morphological and material parameters. The generation of the geometrical model were implemented in a toolbox, the LMG (Lumbar Model Generator), with dimensions based on correlation analyses or subject-specific measurements. It allows the automatic preparation of the FE model, performing the mesh generation and evaluation, assigning material properties, boundary conditions and analysing the results. The FE model of a functional unit (L1-L2) was evaluated and the FE results were in agreement with studies available in literature. Sensitivity analyses on the material properties and morphological parameters were performed and the most influential parameters identified. Moreover, the mechanical behaviour of two devices, the BDyn (S14 Implants (Pessac, France)) and the GsDyn (a device for the paediatric scoliosis developed as part of the Spinal Implant Design project) were evaluated

    Designing a robotic port system for laparo-endoscopic single-site surgery

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    Current research and development in the field of surgical interventions aim to reduce the invasiveness by using few incisions or natural orifices in the body to access the surgical site. Considering surgeries in the abdominal cavity, the Laparo-Endoscopic Single-site Surgery (LESS) can be performed through a single incision in the navel, reducing blood loss, post-operative trauma, and improving the cosmetic outcome. However, LESS results in less intuitive instrument control, impaired ergonomic, loss of depth and haptic perception, and restriction of instrument positioning by a single incision. Robot-assisted surgery addresses these shortcomings, by introducing highly articulated, flexible robotic instruments, ergonomic control consoles with 3D visualization, and intuitive instrument control algorithms. The flexible robotic instruments are usually introduced into the abdomen via a rigid straight port, such that the positioning of the tools and therefore the accessibility of anatomical structures is still constrained by the incision location. To address this limitation, articulated ports for LESS are proposed by recent research works. However, they focus on only a few aspects, which are relevant to the surgery, such that a design considering all requirements for LESS has not been proposed yet. This partially originates in the lack of anatomical data of specific applications. Further, no general design guidelines exist and only a few evaluation metrics are proposed. To target these challenges, this thesis focuses on the design of an articulated robotic port for LESS partial nephrectomy. A novel approach is introduced, acquiring the available abdominal workspace, integrated into the surgical workflow. Based on several generated patient datasets and developed metrics, design parameter optimization is conducted. Analyzing the surgical procedure, a comprehensive requirement list is established and applied to design a robotic system, proposing a tendon-driven continuum robot as the articulated port structure. Especially, the aspects of stiffening and sterile design are addressed. In various experimental evaluations, the reachability, the stiffness, and the overall design are evaluated. The findings identify layer jamming as the superior stiffening method. Further, the articulated port is proven to enhance the accessibility of anatomical structures and offer a patient and incision location independent design
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