L'effet de serre lié à l'émission de CO2 a conduit à des projets de stockage de ce gaz dans des formations réservoirs. Ces formations peuvent être traversées de failles et l'examen de la sûreté du stockage nécessite alors l'étude du risque de réactivation et de propagation de ces failles. Cette étude passe par des investigations approfondies portant sur des conditions de propagation des fractures sous sollicitations hydromécaniques. Cette thèse a pour objectif l'étude théorique et numérique de ces conditions ainsi que la simulation numérique de la propagation. La modélisation numérique des processus thermo-hydro-mécaniques dans les milieux poreux fracturés par la méthode des éléments finis (MEF) permet de simuler des phénomènes complexes et non linéaires. Les difficultés liées à l'intégration des équations d'échanges de fluide entre la fracture et la matrice environnante avec la MEF ont été résolues dans des travaux récents et nos simulations numériques ont pu être basées sur cette méthode. Dans un premier temps, nous avons modélisé l'écoulement transitoire dans et au voisinage d'une fracture soumise à une injection de fluide et nous avons étudié le facteur d'intensité des contraintes (FIC) à l'extrémité de la fracture dans le cadre de la théorie de la poroélasticité linéaire. Si les conditions d'injection sont maintenues constantes et la fracture n'évolue pas, l'écoulement tend vers un état stationnaire. Le FIC évolue au cours de la phase transitoire pour atteindre une valeur limite dans l'état stationnaire. La modélisation de l'écoulement transitoire est très coûteuse en temps de calcul et il est intéressant de trouver un moyen d'exploiter au mieux les résultats d'un calcul en état stationnaire. L'analyse théorique et les résultats des simulations numériques montrent en effet que le FIC calculé à l'état stationnaire peut fournir certaines bornes pour la propagation des fractures sous l'écoulement transitoire. Dans le cadre de la poroélasticité linéaire et de l'écoulement de Poiseuille dans les fractures, des expressions semi-analytiques pour le FIC à l'état d'écoulement stationnaire ont pu être dérivées. Pour des géométries simples, ces formules approximatives se révèlent efficaces pour discuter des conditions de propagation des fractures pour des cas typiques et simples de géométrie de la fracture et des conditions d'injection de fluide. Dans un deuxième temps, un Modèle de Fracture Cohésive (MFC) a été utilisé pour modéliser la propagation de fracture sur la base de l'endommagent. Ce modèle, basé sur un critère de rupture de Mohr–Coulomb modifié, permet de simuler l'endommagement de l'interface à la fois sous sollicitations en mode I et II. Une relation d'équivalence entre les paramètres de ce modèle et du modèle de Mécanique Linéaire de la Rupture (MLR) a été établie sur la base de la longueur de propagation de fracture sous des charges similaires. Cette relation permet l'extension de l'équivalence théorique entre MLR et MFC établie pour les matériaux fragiles et sur la base de critères énergétiques, à des matériaux quasi-fragiles et ductiles. On a d'ailleurs montré que le MFC permet de simuler certains phénomènes spécifiques tels qu'instabilités de propagation en mode I et II et le branchement de la fracture en mode II. Enfin, la prise en compte de la pression de fluide dans la fracture a permis d'obtenir un modèle de MFC couplé avec l'hydraulique qui a été implémenté dans un code numérique aux éléments finis en vue d'étudier la propagation des fractures sous sollicitations hydromécaniques. Des simulations numériques ont été réalisées afin d'étudier le risque de réactivation et de propagation des failles dans le contexte de stockage du CO2 en particulier dans une configuration de formation réservoir du type Bassin de Paris / Global warming effect related to CO2 emission has led to sequestration projects of this gas in reservoir formations. These formations can be crossed by faults and safety issue of storage requires the study of fault reactivation and propagation risk. This study goes through in-depth investigations of fracture propagation conditions under hydromechanical solicitations. This thesis aims at theoretical and numerical studies of these conditions and the numerical simulation of fracture propagation. Numerical modelling of thermo-hydro-mechanical processes in fractured porous media using Finite Element Method (FEM) allows the simulation of complex and nonlinear phenomena. Difficulties in integrating fluid mass exchange between fracture and surrounding matrix in the equations with FEM have been solved in recent works and our numerical simulations have been based on this progress. In a first step, we modelled transient flow subjected to a fluid injection and we studied the Stress Intensity Factor (SIF) at fracture tip in the framework of linear poroelasticity theory. If injection conditions are kept constant and the fracture does not evolve, the flow tends to a steady state. The SIF develops during transient phase to reach a limit value in the steady state. Modelling of transient flow is very time consuming and it is interesting to find a method to exploit the results of a calculation in steady state. Theoretical analysis and results of numerical simulations show that the SIF calculated at steady state can provide some bounds for fracture propagation under transient flow. In the framework of linear poroelasticity and Poiseuille flow in fractures, some semi-analytical expressions of SIF at steady state could be derived. For simple geometries, these approximate formulations are efficient to discuss fracture propagation conditions for typical and simple cases of fracture geometry and fluid injection conditions. In a second step, a Cohesive Zone/Fracture Model (CFM) was used to model fracture propagation on the basis of damage. This model, based on a modified Mohr-Coulomb failure criterion, simulates interface damage under both mode I and II loads. An equivalence relation between parameters of CFM and Linear Elastic Fracture Mechanics model (LEFM) was established on the basis of fracture propagation length under similar loads. This relationship allows the extension of theoretical equivalence between LEFM and CFM established for brittle materials and on the basis of energy criteria, for quasi-brittle and ductile materials. It has also shown that CFM can simulate specific phenomena such as propagation instabilities for mode I and II and fracture kinking under mode II. Finally, taking into account the fluid pressure in the fracture permitted to obtain a CFM coupled with hydraulic processes which has been implemented in a numerical finite element code to study fracture propagation under hydromechanical solicitations. Numerical simulations were performed to study the risk of fault reactivation and propagation in the context of CO2 injection in Paris Basin reservoir formation

To compare the one-year postoperative outcomes of anti-gravity treadmill rehabilitation with those of standard rehabilitation in patients with ankle or tibial plateau fractures.

Sze Pan Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 162-178). / Abstracts in English and Chinese. / ABSTRACT --- p.i / ABSTRACT (IN CHINESE) --- p.iv / ACKNOWLEGEMENT --- p.vi / TABLE OF CONTENTS --- p.viii / LIST OF FIGURES --- p.xv / LIST OF TABLES --- p.xviii / LIST OF APPENDIX --- p.xx / LIST OF ABBREVIATIONS --- p.xxi / LIST OF DEFINITIONS OF TERMS --- p.xxii / Chapter I. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Epidemiology of hip fracture among elderly worldwide --- p.1 / Chapter 1.2 --- Impact of hip fractures --- p.3 / Chapter 1.2.1 --- Mortality --- p.3 / Chapter 1.2.2 --- Hospitalization and institutionalization --- p.4 / Chapter 1.2.3 --- Morbidity --- p.4 / Chapter 1.2.4 --- Psychological impact and quality of life --- p.5 / Chapter 1.2.5 --- Financial burden --- p.6 / Chapter 1.3 --- Causes of hip fracture --- p.6 / Chapter 1.3.1 --- Mechanisms of hip fracture --- p.7 / Chapter 1.3.2 --- Degenerated protective mechanism --- p.8 / Chapter 1.3.3 --- Poor hip strength indices --- p.9 / Chapter 1.4 --- Prevention of hip fractures --- p.10 / Chapter 1.4.1 --- Reduction of the chance of lateral fall --- p.10 / Chapter 1.4.2 --- Increase hip strength indices --- p.11 / Chapter 1.4.3 --- Limitations of current strategies --- p.12 / Chapter 1.5 --- Hip protectors for prevention of hip fractures --- p.12 / Chapter 1.6 --- Effectiveness of hip protector --- p.14 / Chapter 1.6.1 --- Laboratory studies on effectiveness in force attenuation --- p.14 / Chapter 1.6.2 --- Clinical studies on prevention of hip fractures --- p.16 / Chapter 1.6.3 --- Cost-effectiveness study --- p.17 / Chapter 1.7 --- Problems on the use of hip protectors --- p.19 / Chapter 1.7.1 --- Discomfort --- p.19 / Chapter 1.7.2 --- Extra effort in wearing --- p.20 / Chapter 1.7.3 --- Appearance after wearing --- p.21 / Chapter 1.7.4 --- Urinary incontinence --- p.22 / Chapter 1.7.5 --- Oth er problems --- p.23 / Chapter 1.8 --- Acceptance and Compliance of hip protectors --- p.23 / Chapter 1.8.1 --- Acceptance --- p.23 / Chapter 1.8.2 --- Compliance --- p.24 / Chapter 1.9 --- Strategies to improve compliance of hip protector --- p.25 / Chapter 1.9.1 --- Better design of hip protector --- p.25 / Chapter 1.9.2 --- Encouragement/support to the user --- p.26 / Chapter 1.9.3 --- Support from nursing staff/carer --- p.27 / Chapter 1.10 --- Rationale and objectives of present study --- p.28 / Chapter II. --- METHODOLOGY --- p.36 / Chapter 2.1 --- Development of hip protector --- p.36 / Chapter 2.1.1 --- Design of the pads --- p.36 / Chapter 2.1.2 --- Design of the pants --- p.38 / Chapter 2.1.2.1 --- Fabric materials --- p.38 / Chapter 2.1.2.2 --- Anthropometric measurement --- p.42 / Chapter 2.1.2.3 --- Pattern design --- p.43 / Chapter 2.1.3 --- Trial use of hip protector --- p.43 / Chapter 2.1.4 --- Calculation and statistical method --- p.43 / Chapter 2.2 --- Mechanical test on force attenuation properties --- p.44 / Chapter 2.2.1 --- Testing system --- p.44 / Chapter 2.2.2 --- Simulation of impact force and identification of dropping height --- p.45 / Chapter 2.2.3 --- Testing method --- p.46 / Chapter 2.2.4 --- Calculation and statistical method --- p.47 / Chapter 2.3 --- Compliance study --- p.47 / Chapter 2.3.1 --- Setting --- p.47 / Chapter 2.3.2 --- Subjects --- p.48 / Chapter 2.3.3 --- Study design --- p.49 / Chapter 2.3.4 --- Implementation procedure and intervening Program --- p.49 / Chapter 2.3.4.1 --- Liaison with the heads and responsible staff in the elderly hostels --- p.49 / Chapter 2.3.4.2 --- Education program for hostel staff --- p.50 / Chapter 2.3.4.3 --- Education program for elderly subjects --- p.50 / Chapter 2.3.4.4 --- Fall and fracture risk counseling --- p.51 / Chapter 2.3.4.5 --- Consent and Ethical approval --- p.51 / Chapter 2.3.4.5 --- Provision of hip protector and training program on wearing hip protector --- p.51 / Chapter 2.3.4.6 --- Follow up and encouragement on the use of hip protector --- p.52 / Chapter 2.3.5 --- Outcome measures --- p.52 / Chapter 2.3.5.1 --- Primary outcome --- p.52 / Chapter 2.3.5.2 --- Secondary outcomes --- p.53 / Chapter 2.3.6 --- Measurement method --- p.55 / Chapter 2.3.6.1 --- Compliance --- p.55 / Chapter 2.3.6.2 --- Falls and fractures incidence --- p.56 / Chapter 2.3.6.3 --- Adverse effect and feedback after wearing hip protector --- p.56 / Chapter 2.3.6.4 --- Fear of fall --- p.57 / Chapter 2.3.6.5 --- Fall and fracture history --- p.57 / Chapter 2.3.6.6 --- Medical co-morbidities --- p.58 / Chapter 2.3.6.7 --- Presence of urinary incontinence --- p.58 / Chapter 2.3.6.8 --- Functional level --- p.58 / Chapter 2.3.6.9 --- Hand function --- p.58 / Chapter 2.3.6.10 --- Mobility --- p.59 / Chapter 2.3.6.11 --- Cognitive function --- p.59 / Chapter 2.3.7 --- Sample size calculation --- p.59 / Chapter 2.3.8 --- Calculation and Statistical method --- p.60 / Chapter III. --- RESULTS --- p.73 / Chapter 3.1 --- Design of hip protector --- p.73 / Chapter 3.1.1 --- The design of pants --- p.73 / Chapter 3.1.1.1 --- The fabric materials --- p.73 / Chapter 3.1.1.2 --- The size of the pants --- p.74 / Chapter 3.1.2 --- The design of pads --- p.75 / Chapter 3.1.2.1 --- Thickness of silicon padding --- p.75 / Chapter 3.1.1.2 --- Dimension of the hard shield --- p.75 / Chapter 3.2 --- Mechanical test on force attenuation properties of the pads --- p.76 / Chapter 3.2.1 --- Impact force --- p.76 / Chapter 3.2.2 --- Impact duration --- p.78 / Chapter 3.2.3 --- Selection of th e prototype --- p.78 / Chapter 3.3 --- Compliance study --- p.79 / Chapter 3.3.1 --- Demograph ics --- p.79 / Chapter 3.3.2 --- Primary outcome --- p.79 / Chapter 3.3.2.1 --- Initial acceptance rate --- p.79 / Chapter 3.3.2.2 --- Compliance rate --- p.79 / Chapter 3.3.2.3 --- Percentage of people wearing hip protector across the study period --- p.81 / Chapter 3.3.2.4 --- Percentage of protected fall --- p.81 / Chapter 3.3.3 --- Secondary outcomes --- p.81 / Chapter 3.3.3.1 --- Fall and related injury among the subjects in the study period --- p.81 / Chapter 3.3.3.2 --- Reasons for non-acceptance --- p.82 / Chapter 3.3.3.3 --- Feedback in using hip protector --- p.84 / Chapter 3.3.3.4 --- Factors associated with compliance and non-compliance (feedback in wearing hip protector) --- p.84 / Chapter 3.3.3.5 --- Factors associated with compliance and non-compliance (subject characteristics) --- p.85 / Chapter 3.3.3.6 --- Effect on mobility after wearing hip protector --- p.85 / Chapter 3.3.3.7 --- Fear of fall after wearing hip protector --- p.85 / Chapter IV. --- DISCUSSION --- p.123 / Chapter 4.1 --- Development of a hip protector for Chinese elderly --- p.124 / Chapter 4.1.1 --- Successful modifications made to the pads --- p.124 / Chapter 4.1.1.1 --- More comfort to wear with silicon cushioning materials added --- p.124 / Chapter 4.1.1.2 --- Better mechanical properties with semi-flexible plastic and silicon pad --- p.125 / Chapter 4.1.1.3 --- Smaller in dimension of the present model might improve appearance after wearing --- p.127 / Chapter 4.1.2 --- No significant improvement on compliance with modification of the pants --- p.128 / Chapter 4.2 --- Sufficient mechanical properties of hip protector demonstrated --- p.129 / Chapter 4.2.1 --- Mechanical test set up --- p.130 / Chapter 4.2.2 --- Mechanism of force attenuation --- p.132 / Chapter 4.3 --- No significant improvement on compliance shown --- p.134 / Chapter 4.4 --- Compliance at night time better than other studies --- p.136 / Chapter 4.5 --- Determinants of compliance mostly related to subjects' feedback of using hip protector rather than on their characteristics --- p.137 / Chapter 4.6 --- Better compliance observed in hostel with higher staff-to-subject ration and with occupational therapist as contact person --- p.138 / Chapter 4.7 --- Better acceptance rate of hip protector shown in the present study --- p.139 / Chapter 4.8 --- Identification of factors influencing acceptance --- p.139 / Chapter 4.9 --- Percentage of protected fall was higher than mean compliance --- p.141 / Chapter 4.10 --- No hip fracture occurred while subjects wearing hip protector --- p.141 / Chapter 4.11 --- Decreased fear of falling after wearing hip protector --- p.142 / Chapter 4.12 --- Limitation --- p.142 / Chapter 4.13 --- Recommendation --- p.143 / Chapter V. --- CONCLUSION --- p.146 / Chapter VI. --- APPENDIX --- p.148 / Chapter VII. --- BIBLIOGRAPHY --- p.162 / Chapter VIII. --- PUBLICATIONS --- p.179

The mevalonate pathway is an important biosynthetic pathway, found in all cells of virtually all known pro- as well as eukaryotic organisms. This thesis is an investigation into the use of two drugs, originally developed for different applications, but both affecting the mevalonate pathway, in to models of fracture repair. Using two different rodent models of fracture repair, a commonly used cholesterol lowering drug (statin) and two drugs used to treat osteoporosis (bisphosphonate) were applied both systemically as well as locally in order to enhance fracture repair. Papers I and II investigate the potential of simvastatin to improve the healing of femoral fractures in mice. Papers III and IV explore the use of two bisphosphonates to improve early fixation of stainless steel screws into rat bone. The statin simvastatin lead to an increased strength of the healing cellus. The application of bisphosphonates increased early screw fixation. It seems clear that both drugs have uses in orthopaedic applications. One interesting avenue of further research would be to combine the two classes of drugs and see if we can get the benefits while at the same time diminishing the drawbacks.

No description available.

Os anti-hipertensivos bloqueadores de canais de cálcio, por interferirem no transporte de cálcio através das membranas celulares, podem afetar muitos processos metabólicos, incluindo o metabolismo ósseo. O objetivo deste estudo foi avaliar, de forma radiográfica, histológica e bioquímica, os efeitos do bloqueador de canais de cálcio amlodipina no processo de reparo de um defeito ósseo, simulando fratura, no ramo mandibular de ratos. Foram utilizados 50 ratos machos Wistar, que foram submetidos ao mesmo procedimento cirúrgico unilateral simulando fratura mandibular, e distribuídos em dois grupos de 25 animais: grupo experimental, que receberam amlodipina, via oral, na dosagem de 0,04 mg / rato / dia, iniciando 12 dias antes do procedimento e continuando até o sacrifício; grupo controle, que permaneceu não tratado. Os animais foram sacrificados nos períodos de 1, 7, 14, 30 e 90 dias pós-operatórios. Foram realizados testes bioquímicos de fosfatase alcalina e cálcio séricos. Exame radiográfico foi obtido para mensuração da área radiolúcida do defeito ósseo. O estudo histológico compreendeu a análise descritiva do processo de reparo ósseo e a avaliação histomorfométrica da quantidade de osso neoformado. Os valores numéricos foram submetidos a análises estatísticas. A análise radiográfica demonstrou maior área radiolúcida no interior do defeito ósseo para o grupo experimental, nos períodos de 14 (p=0,016), 30 (p=0,009) e 90 (p=0,028) dias. Na análise histológica não se observaram atrasos no processo de reparo ósseo para ambos os grupos. Porém, na análise histomorfométrica, o grupo da amlodipina apresentou redução significante do volume de osso neoformado nos períodos de 7 e 14 dias (p=0,049), não havendo diferenças significativas no período de 30 dias. Houve redução significante nos níveis de fosfatase alcalina para o grupo da amlodipina nos períodos iniciais (p=0,049). Não houve alterações para os níveis de cálcio sérico. Concluiu-se que o uso crônico da amlodipina prejudicou a neoformação óssea no processo de reparo do defeito cirúrgico no ramo mandibular de ratos, porém não impediu a consolidação da fratura. / Antihypertensive, calcium channel blockers, which interfere on calcium transport across the cell membrane, may affect many metabolic processes, including bone metabolism. The aim of this study was to evaluate by radiographic, histologic and biochemical analyses the effects of calcium channel blocker amlodipine on bone healing of a defect simulating a fracture in mandibular ramus of rats. Fifty male Wistar rats were used, and submitted to the same unilateral surgical procedure simulating a mandibular fracture, distributed into two groups of 25 animals: experimental group, which received oral doses of 0.04 mg / rat / day starting 12 days before of procedure and continuing until sacrifice; control group, which remained untreated. Animals were sacrificed at 1, 7, 14, 30 and 90 days postoperatively. Blood biochemical tests of alkaline phosphatase and serum calcium were made. Radiographic examination was obtained in order to mensurate the radiolucent area of bone defect. Histological study comprised descriptive analysis of bone healing and histomorphometric analysis of the amount of newly formed bone. Numerical values were submitted to statistical analyses. Radiographic analysis showed larger radiolucent area into bone defect to the experimental group at the periods of 14 (p=0.016), 30 (p=0.009) and 90 (p=0.028) days. In the histological analysis there was no delay in the bone repair stages in both groups. However, in the histomorphometric analysis, the experimental group presented significative lowering of newly formed bone volume at 7 and 14 days periods (p=0.049), with no significant differences at 30 days period. There was significative decrease of alkaline phosphatase levels in experimental group in the initial periods (p=0.049). There was no change in the serum calcium levels. It was concluded that chronic use of amlodipine compromised bone neoformation in the repairing process of surgical defect in the mandibular ramus of rats, but no precluded occurrence of fracture consolidation.

A quantidade de trabalhos específicos sobre os traumatismos alvéolo-dentários de maior extensão encontrados na literatura é pequena. Este estudo mostra o resultado de 127 casos de traumatismos alvéolo-dentários diagnosticados no Hospital Municipal Arthur Ribeiro de Saboya, em São Paulo, entre junho de 2001 e dezembro de 2002. A análise dos dados permitiu identificar o grupo etário de 0 a 10 anos e o sexo masculino como os mais atingidos, a queda como o fator etiológico mais comum e a fratura alveolar como o principal tipo de lesão encontrada. A maioria dos pacientes apresentou lesões extra e intra orais e 73,2% tardaram até 05 horas para procurar atendimento após o acontecimento do trauma. / There are few specific reports in the literature bearing information on dento-alveolar injuries. A survey was done considering 127 patients recorded from June 2001 to December 2002 showing dento-alveolar injuries treated at the Arthur Ribeiro Saboya Municipal Hospital, Sao Paulo, Brazil. The analysis of data revealed that male patients and the age group 0–10 yr were most prevalently involved in this kind of trauma, the main cause was accidental fall and alveolar fractures were the most frequent type of injury. The majority of the patients suffered some kind of soft tissues injuries and 73,2% of the patients received the first dental assistance during the first 5 hours following the incident.

As fraturas benignas osteoporóticas e malignas da coluna vertebral representam um desafio diagnóstico para os médicos especialistas. As fraturas benignas osteoporóticas ocorrem em virtude da fragilidade óssea da osteoporose e as fraturas malignas são secundárias a infiltração neoplásica. Estes dois grupos tem em comum o fato de acometerem predominantemente a população idosa. Alguns sinais radiológicos favorecem o diagnóstico de fraturas benignas osteoporóticas enquanto outros sinais de imagem favorecem o diagnóstico de fraturas malignas, no entanto nenhum sinal identificado nas imagens é específico. O propósito de realizar esse estudo foi identificar se o nível de formação médica dos radiologistas e ortopedistas (cirurgiões da coluna vertebral) exerce influência para o diagnóstico etiológico dessas fraturas nos exames de RM da coluna lombar, assim como avaliar o grau de concordância intra e interobservador para o diagnóstico de fraturas benignas por osteoporose e fraturas malignas. Foram incluídos no estudo de forma retrospectiva os exames de 63 pacientes consecutivos da rotina clínica do HCRP, realizados previamente por indicação clínica e com diagnóstico de fratura não traumática de corpo vertebral. Para avaliar a influência do nível de formação médica, quatro radiologistas e dois cirurgiões da coluna vertebral com diferentes níveis de formação realizaram avaliações de forma independente e as cegas em relação as demais leituras e em relação às informações do prontuário clínico. As imagens de RM anonimizadas e no formato DICOM foram avaliadas em workstation OsiriX. Os médicos observadores fizeram as leituras classificando cada vértebra da região lombar da seguinte forma: sem fratura, com fratura de características benignas ou com fratura de características malignas. Cada observador realizou duas leituras, com intervalo de 15 dias entre as leituras. O padrão de referência foi obtido a partir da avaliação pormenorizada do prontuário eletrônico de cada paciente realizada por médico radiologista sênior, a partir do Sistema de Informações do Hospital (HIS) e do Sistema Informatizado da radiologia (RIS), incluindo a biópsia com confirmação histopatológica nos casos de neoplasia e o seguimento clinico e laboratorial por pelo menos dois anos nos casos em que não houve indicação clínica de biópsia. Utilizando este padrão de referência foram calculadas para cada leitura, a sensibilidade, a especificidade, acurácia, valor preditivo positivo e negativo com intervalo de confiança (IC) 95%. Os resultados demonstram uma excelente concordância intraobservador e uma boa concordância interobservador, porém sem relevância estatística. Além disso, de uma forma geral a sensibilidade dos observadores para a detecção de fraturas malignas foi boa. A especificidade, acurácia e valor preditivo negativo foram elevados para todos os observadores. O valor preditivo positivo variou de moderado a substancial. Portanto, não houve influência do nível de formação médica para o desempenho diagnóstico na detecção de fraturas benignas osteoporóticas e fraturas malignas nas imagens de ressonância magnética. / Benign osteoporotic and malignant spinal fractures represent a diagnostic challenge for medical specialists. Osteoporotic benign fractures occur because of the bone fragility of osteoporosis and malignant fractures are secondary to neoplastic infiltration. These two groups have in common the fact that they affect predominantly the elderly population. Some radiological signs favor the diagnosis of benign osteoporotic fractures while other imaging signs favor the diagnosis of malignant fractures, however no signs identified in the images are specific. The purpose of this study was to identify whether the level of medical training of radiologists and orthopedists (spine surgeons) influences the etiological diagnosis of these fractures in lumbar spinal MRI (magnetic resonance imaging), as well as to evaluate the degree of intra and interobserver agreement for the diagnosis of benign fractures due to osteoporosis and malignant fractures. We retrospectively included the exams of 63 consecutive patients from the clinical routine of the HCRP, performed previously by clinical indication and with diagnosis of non-traumatic vertebral body fracture. To evaluate the influence of the level of medical training, four radiologists and two spine surgeons with different levels of training performed evaluations independently, without knowing the other readings and without the information in the medical record. The anonymized MRI in the DICOM format were evaluated in OsiriX workstation. Observer doctors did the readings by classifying each vertebra in the lumbar region as follows: no fracture, with fracture of benign features or with fracture of malignant characteristics. Each observer performed two readings, with a 15-day interval between readings. The reference standard was obtained from the detailed evaluation of each patient\'s electronic medical record by a senior radiologist, with the Hospital Information System (HIS) and the Computerized Radiology System, including biopsy with histopathological confirmation in cases of neoplasia and clinical and laboratory follow-up for at least two years in cases in which there was no clinical indication of biopsy. Using this reference standard, sensitivity, specificity, accuracy, positive and negative predictive value with 95% confidence interval (CI) were calculated for each reading. The results demonstrate excellent intraobserver agreement and good interobserver agreement, but without statistical relevance. In addition, the sensitivity of the observers for the detection of malignant fractures was generally good. The specificity, accuracy and negative predictive value were high for all observers. The positive predictive value ranged from moderate to substantial. Therefore, there was no influence of the level of medical training for diagnostic performance in the detection of benign osteoporotic fractures and malignant fractures in magnetic resonance imaging.

Leung Ping-chung. / Thesis (D.Sc.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references.

Or Pui Ching. / Thesis submitted in: December 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 174-201). / Abstracts in English and Chinese. / acknowledgement --- p.i / abstract (english version) --- p.ii / abstract (chinese version) --- p.vii / table of contents --- p.xi / abbreviations --- p.xvi / list of tables --- p.xviii / list of figures --- p.xxii / Chapter chapter 1. --- introduction --- p.1 / Chapter chapter 2. --- literature review --- p.3 / Chapter 2.1. --- Bone structure --- p.3 / Chapter 2.1.1. --- Composition --- p.3 / Chapter 2.1.2. --- Cortical and Trabecular bone --- p.3 / Chapter 2.2. --- Bone Remodeling --- p.4 / Chapter 2.3. --- Bone Mass --- p.5 / Chapter 2.3.1. --- Peak Bone Mass --- p.5 / Chapter 2.3.1.1. --- Racial and Genetic Factors --- p.5 / Chapter 2.3.1.2. --- Gonadal Factors --- p.6 / Chapter 2.3.1.3. --- Nutrition Factors --- p.6 / Chapter 2.3.1.4. --- Exercise and Physical Activity --- p.7 / Chapter 2.3.2. --- Bone Loss --- p.7 / Chapter 2.3.2.1. --- Determinants of Osteoporotic Bone Loss --- p.7 / Chapter 2.3.2.2. --- Estrogen Deficiency --- p.8 / Chapter 2.3.2.3. --- Dietary Calcium deficiency and Vitamin D deficiency --- p.8 / Chapter 2.3.2.4. --- Physical Activity --- p.9 / Chapter 2.3.2.5. --- Alcoholism and Smoking --- p.9 / Chapter 2.3.2.6. --- Disease-specific Osteoporosis --- p.9 / Chapter 2.3.2.7. --- Drug-induced Osteoporosis --- p.10 / Chapter 2.3.3. --- Bone Mass and Fracture Risk --- p.11 / Chapter 2.4. --- Clinical Presentation of Osteoporosis --- p.12 / Chapter 2.4.1. --- Vertebral Fractures --- p.12 / Chapter 2.4.1.1. --- Radiological Aspects of Vertebral Fracture --- p.13 / Chapter 2.4.1.1.1. --- Changes in Trabecular Pattern --- p.13 / Chapter 2.4.1.1.2. --- Changes in Shape of the Vertebral bodies --- p.13 / Chapter 2.4.1.1.3. --- Changes of Intervertebral Discs --- p.14 / Chapter 2.4.1.2. --- Back Pain --- p.15 / Chapter 2.4.2. --- Hip Fractures --- p.15 / Chapter 2.4.3. --- Quality of Life --- p.16 / Chapter 2.5. --- Treatment of Established Osteoporosis --- p.18 / Chapter 2.5.1. --- Pain Relief --- p.18 / Chapter 2.5.2. --- Drug Therapy --- p.19 / Chapter 2.5.2.1. --- Calcium Supplement --- p.19 / Chapter 2.5.2.2. --- Vitamin D --- p.20 / Chapter 2.5.2.3. --- Estrogen --- p.21 / Chapter 2.5.2.4. --- Fluorides --- p.22 / Chapter 2.5.2.5. --- Calcitonin --- p.23 / Chapter 2.5.2.6. --- Bisphosphonates --- p.24 / Chapter 2.5.2.6.1. --- Physicochemical effects --- p.27 / Chapter 2.5.2.6.2. --- Mechanisms --- p.27 / Chapter 2.5.2.6.3. --- Therapeutic Use --- p.27 / Chapter 2.5.2.6.4. --- Side effects --- p.29 / Chapter 2.5.2.6.5. --- Alendronate --- p.30 / Chapter 2.5.2.7. --- Summary of drug treatment --- p.33 / Chapter 2.6. --- Diagnostic Methods of Osteoporosis --- p.40 / Chapter 2.6.1. --- Biochemical Markers of Bone Metabolism in Osteoporosis --- p.40 / Chapter 2.6.1.1. --- Bone Formation Markers --- p.41 / Chapter 2.6.1.1.1. --- Bone-specific Alkaline Phosphatase (bALP) --- p.41 / Chapter 2.6.1.2. --- Bone Resorption Markers --- p.42 / Chapter 2.6.1.2.1. --- Deoxypyridinoline (Dpd) --- p.43 / Chapter 2.6.2. --- Bone Densitometry --- p.45 / Chapter 2.6.2.1. --- Dual Energy X-ray Absorptiometry (DEXA) --- p.45 / Chapter 2.6.2.2. --- Peripheral Quatitative Computed Tomography (pQCT) --- p.47 / Chapter 2.6.2.3. --- Quantitative Ultrasound (QUS) --- p.48 / Chapter 2.6.3. --- Summary of Diagnostic Methods --- p.49 / Chapter chapter 3. --- methodology --- p.50 / Chapter 3.1. --- Study on Vertebral Structures --- p.51 / Chapter 3.1.1. --- Procedures --- p.51 / Chapter 3.1.2. --- Data analysis --- p.53 / Chapter 3.2. --- Alendronate Treatment --- p.54 / Chapter 3.2.1. --- Subject Selection --- p.54 / Chapter 3.2.2. --- Study design and drug administration --- p.55 / Chapter 3.2.3. --- Bone Densitometry --- p.56 / Chapter 3.2.3.1. --- Dual Energy X-ray absorptiometry --- p.56 / Chapter 3.2.3.2. --- Peripheral Quantitative Computed Tomography (pQCT) --- p.58 / Chapter 3.2.4. --- Biochemical Markers --- p.63 / Chapter 3.2.4.1. --- Bone formation marker --- p.63 / Chapter 3.2.4.2. --- Bone resorption marker --- p.64 / Chapter 3.2.5. --- Quality of Life --- p.65 / Chapter 3.2.6. --- New fracture assessment --- p.66 / Chapter 3.2.7. --- Statistical analysis --- p.67 / Chapter 3.3. --- Proximal femur fracture study --- p.68 / Chapter 3.3.1. --- Subject and study design --- p.69 / Chapter 3.3.2. --- Statistical analysis --- p.70 / Chapter chapter 4. --- results of study on vertebral structures --- p.71 / Chapter 4.1. --- Results of morphological change of vertebral bodes in osteoporotic patients --- p.71 / Chapter 4.2. --- Morphological changes of intervertebral discs --- p.71 / Chapter 4.3. --- Correlation between morphological changes of vertebrae and bulging ratio --- p.72 / Chapter chapter 5. --- results of alendronate study --- p.76 / Chapter 5.1. --- Baseline measurement --- p.76 / Chapter 5.1.1. --- Demographic characteristics --- p.76 / Chapter 5.1.2. --- Reasons for admission --- p.77 / Chapter 5.1.3. --- Social support --- p.77 / Chapter 5.1.4. --- Number of vertebral fracture(s) --- p.78 / Chapter 5.1.5. --- BMD measurement (Baseline) --- p.79 / Chapter 5.1.5.1. --- BMD of Lumbar spine and Hip (measured by DEXA) --- p.79 / Chapter 5.1.5.2. --- BMD of distal tibia and radius measured by pQCT --- p.80 / Chapter 5.1.6. --- Biochemical Markers (Bone formation and resorption) --- p.86 / Chapter 5.2. --- After treatment --- p.88 / Chapter 5.2.1. --- Bone mineral density measurement (measured by DEXA) --- p.90 / Chapter 5.2.1.1. --- Lumbar spine --- p.90 / Chapter 5.2.1.2. --- Femoral Neck --- p.93 / Chapter 5.2.1.3. --- Trochanter --- p.95 / Chapter 5.2.1.4. --- Ward's Triangle --- p.98 / Chapter 5.2.1.5. --- Summary --- p.101 / Chapter 5.2.2. --- Bone Mineral Density measured by pQCT --- p.103 / Chapter 5.2.2.1. --- Distal Radius (Program 1) --- p.103 / Chapter 5.2.2.1.1. --- BMD change of D50 --- p.103 / Chapter 5.2.2.1.2. --- BMD changes of D100 --- p.106 / Chapter 5.2.2.1.3. --- BMD change of P100 --- p.108 / Chapter 5.2.2.2. --- Distal Radius (Program 2) --- p.111 / Chapter 5.2.2.2.1. --- BMD change of pure trabecular bone --- p.112 / Chapter 5.2.2.2.2. --- BMD changes of pure cortical bone --- p.114 / Chapter 5.2.2.3. --- Distal Tibia (Program 1) --- p.118 / Chapter 5.2.2.3.1. --- BMD changes of D50 --- p.118 / Chapter 5.2.2.3.2. --- BMD changes of D100 --- p.121 / Chapter 5.2.2.3.3. --- BMD changes of P100 --- p.124 / Chapter 5.2.2.4. --- Distal Tibia (Program 2) --- p.128 / Chapter 5.2.2.4.1. --- BMD changes of pure trabecular bone --- p.128 / Chapter 5.2.2.4.2. --- BMD changes of pure cortical bone --- p.131 / Chapter 5.2.3. --- Bone turnover --- p.135 / Chapter 5.2.3.1. --- Bone Resorption Marker (urinary Deoxypyridinoline) --- p.135 / Chapter 5.2.3.2. --- Bone Formation Marker (Bone Specific Alkaline Phosphatase) --- p.137 / Chapter 5.2.4. --- Quality of Life (QOL) --- p.139 / Chapter 5.2.5. --- Oswestry Disability Index (ODI) --- p.139 / Chapter 5.2.6. --- Pain --- p.141 / Chapter 5.2.6.1. --- Pain frequency --- p.141 / Chapter 5.2.6.2. --- Night Pain --- p.142 / Chapter 5.2.6.3. --- Administration of pain relief drugs --- p.143 / Chapter 5.2.7. --- Activity of daily living --- p.144 / Chapter 5.2.8. --- Prevention of new vertebral fracture(s) --- p.146 / Chapter 5.2.9. --- Safety and Tolerability --- p.147 / Chapter chapter 6. --- results on proximal femoral fractures study --- p.149 / Chapter 6.1. --- Epidemiological study on proximal femoral fractures --- p.149 / Chapter 6.2. --- The role of ultrasound equipment in the assessment osteoporosis in patients with proximal femoral fractures --- p.154 / Chapter 6.3. --- Summary --- p.155 / Chapter chapter 7. --- discussion --- p.156 / Chapter 7.1. --- The study on vertebral structures --- p.156 / Chapter 7.1.1. --- Changes in Shape of Vertebral Bodies --- p.156 / Chapter 7.1.2. --- Changes of Interevertbral Discs --- p.157 / Chapter 7.2. --- Alendronate treatment on Chinese elderly women with Osteoporotic vertebral fracture --- p.158 / Chapter 7.2.1. --- The Effect of Alendronate on BMD of Lumbar Spine --- p.159 / Chapter 7.2.2. --- The Effects of Alendronate on BMD of Proximal Femur --- p.159 / Chapter 7.2.3. --- The Effects of Alendronate on the BMD of Trabecular and Cortical Bone in the Distal Radius and Distal Tibia --- p.160 / Chapter 7.2.4. --- The Effects of Calcium Supplementation in the study --- p.162 / Chapter 7.2.5. --- The Effect of alendronate on Biochemical Turnover --- p.162 / Chapter 7.2.6. --- The Efficacy of Alendronate on Prevention of New Fractures --- p.163 / Chapter 7.2.7. --- The Effect of Alendronate on Quality of Life --- p.164 / Chapter 7.2.8. --- Adverse Effects of Alendronate --- p.165 / Chapter 7.3. --- Proximal Femur Fracture Study --- p.165 / Chapter chapter 8. --- conclusion --- p.168 / bibliography --- p.174 / epilogue --- p.202 / appendix --- p.xxv