• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 330
  • 136
  • 65
  • 33
  • 25
  • 22
  • 20
  • 19
  • 12
  • 7
  • 6
  • 4
  • 3
  • 3
  • 3
  • Tagged with
  • 797
  • 146
  • 129
  • 116
  • 114
  • 107
  • 94
  • 90
  • 79
  • 71
  • 63
  • 59
  • 56
  • 53
  • 53
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
631

The relative effectiveness of three treatment protocols in the management of temporomandibular disorder

Poacher, Elizabeth January 2011 (has links)
Dissertation submitted in partial compliance with the requirements for a Masters Degree in Technology: Chiropractic, Durban University of Technology, 2011. / The relationship between TMD and dysfunction in the cervical spine has been reported in the literature and there are many case studies which have shown favourable results when treatment was aimed at the TMJ, cervical spine relationship. However, the numerous TMD treatment protocols described in the literature concerning this relationship, and the effectiveness of these treatments have not been well established. In spite of this many chiropractors treat TMD. TMD is a multifactoral condition and conservative treatment options need to be further investigated in order to determine if manual interventions directed at the cercival spine in the treatment of TMD are beneficial. Objectives: The purpose of this study was to compare myofascial trigger point therapy and manipulative therapy of either the TMJ, cervical spine or a combination of the two in order to determine their effectiveness for the TMD. Method: Thirty participants with TMD were randomly assigned to one of three treatment groups. Participants in each group received two treatments per week for two weeks with a follow up consultation in the third week. Data were collected before the commencement of the first, second, and fourth treatments and at the follow up consultation. Outcome measures included algometer readings, CROM, Mouth opening readings, NRS and a disability questionnaire. SPSS version 15.0 was used for analysis of the data. A p value <0.05 was considered as statistically significant. Multivariate testing was used for intra- and inter-group comparisons. Profile plots were generated to assess the direction and trend of the effect and to visually compare the trends in the different treatment groups. Results: Inter-group comparisons did not reveal any statistically significant different improvements between the three treatment groups. Conclusion: All groups responded favourably to treatment and showed trends towards improvement. However, statistically analysis revealed that no one treatment protocol was superior to the other. Although no definitive inferences may be drawn regarding the effectiveness of each treatment approach, within group trends indicated that the combination of the two treatment approaches may be preferred. / M
632

Rôles des protéines Staufen 1 et 2 dans la plasticité synaptique des cellules pyramidales hippocampiques

Lebeau, Geneviève 01 1900 (has links)
La mémoire et l’apprentissage sont des phénomènes complexes qui demeurent encore incertains quant aux origines cellulaire et moléculaire. Il est maintenant connu que des changements au niveau des synapses, comme la plasticité synaptique, pourraient déterminer la base cellulaire de la formation de la mémoire. Alors que la potentialisation à long-terme (LTP) représente un renforcement de l’efficacité de transmission synaptique, la dépression à long-terme (LTD) constitue une diminution de l’efficacité des connexions synaptiques. Des études ont mis à jour certains mécanismes qui participent à ce phénomène de plasticité synaptique, notamment, les mécanismes d’induction et d’expression, ainsi que les changements morphologiques des épines dendritiques. La grande majorité des synapses excitatrices glutamatergiques se situe au niveau des épines dendritiques et la présence de la machinerie traductionnelle près de ces protubérances suggère fortement l’existence d’une traduction locale d’ARNm. Ces ARNm seraient d’ailleurs acheminés dans les dendrites par des protéines pouvant lier les ARNm et assurer leur transport jusqu’aux synapses activées. Le rôle des protéines Staufen (Stau1 et Stau2) dans le transport, la localisation et dans la régulation de la traduction de certains ARNm est bien établi. Toutefois, leur rôle précis dans la plasticité synaptique demeure encore inconnu. Ainsi, cette thèse de doctorat évalue l’importance des protéines Staufen pour le transport et la régulation d’ARNm dans la plasticité synaptique. Nous avons identifié des fonctions spécifiques à chaque isoforme; Stau1 et Stau2 étant respectivement impliquées dans la late-LTP et la LTD dépendante des récepteurs mGluR. Cette spécificité s’applique également au rôle que chaque isoforme joue dans la morphogenèse des épines dendritiques, puisque Stau1 semble nécessaire au maintien des épines dendritiques matures, alors que Stau2 serait davantage impliquée dans le développement des épines. D’autre part, nos travaux ont permis de déterminer que la morphogenèse des épines dendritiques dépendante de Stau1 était régulée par une plasticité synaptique endogène dépendante des récepteurs NMDA. Finalement, nous avons précisé les mécanismes de régulation de l’ARNm de la Map1b par Stau2 et démontré l’importance de Stau2 pour la production et l’assemblage des granules contenant les transcrits de la Map1b nécessaires pour la LTD dépendante des mGluR. Les travaux de cette thèse démontrent les rôles spécifiques des protéines Stau1 et Stau2 dans la régulation de la plasticité synaptique par les protéines Stau1 et Stau2. Nos travaux ont permis d’approfondir les connaissances actuelles sur les mécanismes de régulation des ARNm par les protéines Staufen dans la plasticité synaptique. MOTS-CLÉS EN FRANÇAIS: Staufen, hippocampe, plasticité synaptique, granules d’ARN, traduction, épines dendritiques. / Learning and memory are complex processes that are not completly understood at the cellular and molecular levels. It is however accepted that persistent modifications of synaptic connections, like synaptic plasticity, could be responsible for the encoding of new memories. Whereas long-term potentiation (LTP) is classically defined as a persistent and stable enhancement of synaptic connections, long-term depression (LTD) is a reduction in the efficacy of neuronal synapses. Numerous studies have identified some of the mechanisms of this phenomenon, in particular, the induction and expression mechanisms, as well as the changes in dendritic spine morphology. The most abundant type of synapse in the hippocampus is the excitatory glutamatergic synapse made on dendritic spines; the presence of the translational machinery in dendrites near spines strongly supports the concept of local mRNA translation. Moreover, those mRNA are transported in dendrites to activated synapses by RNA binding-proteins (RBP). Staufen proteins (Stau1 and Stau2) function in transport, localization and translational regulation of mRNA are now established. However, their precise roles in synaptic plasticity are still unknown. Thus, this Ph.D. thesis evaluates the importance of Staufen proteins in mRNA transport and regulation in synaptic plasticity. We have identified specific functions for each isoform; while Stau1 is implicated in late-LTP, Stau2 is required for mGluR-LTD. This specificity is also relevant for dendritic spine morphogenesis since Stau1 is involved in mature dendritic spine maintenance while Stau2 participates in dendritic spine morphogenesis at a developmental stage. Moreover, our studies have indicated that Stau1 involvement in spine morphogenesis is dependent on ongoing NMDA receptor-mediated plasticity. Finally, our results suggest that Stau2 is implicated in a particular form of synaptic plasticity through transport and regulation of specific mRNA granules required for mGluR-LTD such as Map1b. Our work uncovers specific roles of Stau1 and Stau2 in regulation of synaptic plasticity. These studies help to better understand mechanisms involving mRNA regulation by Staufen in long-term synaptic plasticity and memory. ENGLISH KEY WORDS: Staufen, hippocampus, synaptic plasticity, RNA granules, translation, dendritic spines
633

Stanovení nových referenčních hodnot maximálních inspiračních a expiračních tlaků a hodnot PO.1 u normální populace ve věkovém rozmezí 16 až 17 let / Definition of new referential values of maximum inspiratory and expiratory pressures and P0.1 values in normal population of the 16 - to - 17 age range

Kálalová, Tereza January 2014 (has links)
The purpose of this thesis is to define norms for inspiratory (Pimax) and expiratory (Pemax) pressures and mouth occlusion pressure (P0.1) in healthy white population of the 16-17 age group in the Czech Republic, specifically the capital city of Prague and its close vicinity. Furthermore, this work aspires to ascertain whether there is a correlation between the respiratory pressures, P0.1 and selected anthropometric and pulmonary values. In order to define the norms, 79 children were tested, including 41 boys and 38 girls 16 to 17 years old. After establishing the subjects' case histories, anthropometric, spirometric inspiratory, expiratory and forced vital capacity measurements were made. The study defined the norms of respiratory pressures and P0.1 in 16 to 17-year-old boys and girls, thus achieving its main goal. Furthermore, a difference was found between the average measured Pimax and Pemax values for boys and girls, with the boys showing higher values comparing with the girls. The study did not ascertain a correlation between respiratory pressures, P0.1 and selected anthropometric values (age, height, weight, BMI, BSA). No correlation was found between respiratory pressures and static pulmonary volumes. Powered by TCPDF (www.tcpdf.org)
634

Kvantifikace axiálního systému člověka metodou TVS / Quantification of the axial system of humans by the TVS method

Benyovszky, Adam January 2015 (has links)
Title: Quantification of the axial system of humans by the TVS method Objective: The aim of this thesis is to introduce the TVS method as an adequate method for determining the biomechanical properties of the human axial system (AS). Method: This thesis presents data analysis from a series of case studies, which were obtained during the development of the TVS method. The data for the analysis were selected by the TVS measurements two times during the pregnancy of six women. On two sections of AS (Th2-Th9 and T11-L2), we examined the ability to soften vibrations of AS with regard to the stage of pregnancy. The results are quantified and provide information about the resonant frequencies, stiffness and damping of selected parts of AS. Results: The TVS method seemed to be adequate to provide information about the change of mechanical properties in depending on the selected parameter and allows the quantification of the biomechanical properties of AS. The results showed the improvement of damping parameter in case of four respondents, whereas the deterioration in case of two respondents. Keywords: IVD, Transfer Vibration through Spine, transmitting mechanical vibrations by the axial system, damping and throughput AS
635

Vliv hlubokého stabilizačního systému na pohybový aparát / Effect of deep stabilization system on the musculoskeletal system

Burianová, Zuzana January 2012 (has links)
6 Abstract Title: Effect of deep stabilization system on the musculoskeletal system Objectives: The aim of the study is to demonstrate the influence of therapeutic interventions on the deep stabilization system using investigative techniques and principles used used in practice in physiotherapy. Methods: This thesis has been characterized as a case study. It is based on an experimental basis in the form of qualitative research. For the research five clients were chosen with problems in the cervical, thoracic and lumbar spine. Applying exercise procedures was to show a positive effect on the deep stabilizing system. Following investigative methods were used: anamnesis, examination of static orientation, trigonometric spine examination, assessment of posture, postural stability testing, palpation, flexion of the neck stereotype by Lewit and "S" reflex. Testing was performed twice, at intervals of 3-4 months. Results: The results showed significant improvement in four out of five clients. Pain, stiffness or paraesthesia cervical, thoracic or lumbar spine alleviated or even disappeared. Postural muscle activation possession and corset improved. Exercises also positively influenced the stereotype of breathing and it was confirmed that an active cooperation of clients is necessary for the most efficient effect of...
636

Tvarové změny v axiálním systému při respiraci / Shape changes in the axial system during respiration

Slawiková, Eliška January 2012 (has links)
The name of the work: Shape changes in the axial system during respiration Goal of the work: the main objective is to perform a case study of brass parameters and changes the shape of the trunk during the ventilation maneuver, prepare the correct methodology of research and to conduct separate measurements. The thesis will be divided into two parts, the first will contain the theoretical background to the subject, in the second part will then be described by the research, where I measured the change in the volume of the lungs in relation to time, assess the impact of implemented ventilation maneuver on the individual probands and examine the respiratory dynamics in selected ventilation maneuver. Methods: in the framework of the fulfilment of the tasks of this work have been carried out experiments with the use of 3D kinematic record with Qualisys and spirometric measurement. The experiment involved three probands aged 20 to 40 specific common features. Each of the proband performed during the measurement of quiet breathing, maximum inhalation and exhalation and ventilation maneuver. Measurements were carried out in one day under standard conditions, measurements made on the day of probands quiet breathing, maximum inhalation and exhalation and ventilation maneuver (5 min total). Data records were...
637

Effets biomécaniques des implants interépineux lombaires / Biomecanical effects of interspinous lumbar devices

Khiami, Frédéric 19 December 2013 (has links)
En pathologie lombaire dégénérative, [des] procédures chirurgicales peuvent être employées pour répondre aux situations clinicoradiologiques rencontrées. Ces procédures sont efficaces mais invasives et grevées d'un taux de complications non négligeables. Les dispositifs interépineux (DIE) [diminuent] ainsi la morbidité. Cependant leur efficacité est controversée. Les effets des DIE peuvent être appréciés sur la modification cinématique de l'étage implanté et sur la modification de la taille des foramens. A travers une série d'études biomécaniques cadavériques, les auteurs tentent de vérifier s'il existe bien ces effets attendus avec 4 dispositifs différents. Concernant L4, DIAM® et In-Space® n'avaient aucun effet contrairement à Wallis qui avait un effet significatif en flexion et en extension. Concernant L5, aucun implant n'avait d'effet en flexion, alors que tous avaient un effet amortissant en extension. Il n'y avait pas d'implant supérieur aux autres. Concernant les variations de mobilité, Wallis® est l'implant qui diminue le plus les amplitudes globales de L4 et L5, de l'ordre de 50% et 42.7%, respectivement. […] Une étude cadavérique de la surface latérale du foramen intervertébrale par méthode photographique et binarisation des images a permis de montrer qu'avec le YODA, la longueur moyenne du foramen était de 15.7±2.8mm et la largeur moyenne de 9.4±1.2mm. Après implantation des DIE, ces dimensions variaient respectivement à 16.8±2.5mm et 10.1±1.3mm. La surface foraminale moyenne était de 150.4±35.8 mm2 à vide et de 165.1±28.3mm2, après implantation. Le gain moyen était de 14.7mm2 (5.3-26.9). Cependant, cet implant n'avait aucun effet sur la cinématique de l'étage implanté, même en extension, justifiant de discuter une modification de sa structure. La mesure stéréoscopique 3D des variations de surface foraminale L4-L5 et des foramens adjacents a permis de montrer que tous les implants ouvrent le foramen L4-L5 en extension. Deux catégories d'implants : 1 qui ouvrent le foramen en position neutre, en flexion et en extension ; 2 qui ferment le foramen en flexion mais l'ouvrent en extension. La mise en place des implants en L4-L5 n'avait aucune conséquence sur la taille du foramen à l'étage L3-L4. En revanche, XSTOP et DIAM entraînaient une fermeture minime du foramen L5-S1 vers l'extension. La mesure de surface nous a semblé insuffisante pour évaluer la globalité de la sténose. Nous avons développé une nouvelle mesure de la taille du foramen en appréciant son volume au scanner. Avec cette technique de mesure, le volume moyen de 60 foramens et de 20 foramens L4-L5 étaient respectivement de 1.17±0.23 et de 1.25±0.27 mm3 pour l'observateur 1 et de 1.21±0.21 et 1.29±0.23 mm3 pour l'observateur 2. Les CIC intra observateurs pour l'observateur 1 pour la mesure de l'ensemble des foramens et pour L4-L5 étaient de 0.98 et 0.99. Pour l'observateur 2, les CIC étaient de 0.90 et 0.92, respectivement. Les CIC inter observateurs pour l'observateur 1 pour la mesure de l'ensemble des foramens et pour L4-L5 étaient de 0.78 et 0.83. Pour l'observateur 2, les CIC étaient de 77 et 0.8. La moyenne des différences de mesures entre les observateurs étaient de moins de 0.2 mm3 (0.05 and 0.15). […] L'excellente reproductibilité de cette mesure simple complète les outils de mesure de la taille du foramen. La validation de cette mesure du volume a permis de vérifier s'il y avait ou pas, une variation du volume foraminal après implantation comparative des quatre dispositifs inter épineux. Les volumes des foramens L4-L5 étaient significativement augmentés après implantation de INSPACE®, XSTOP® et WALLIS®. Le volume foraminal moyen de l'étage sus jacent n'était pas modifié et seul le WALLIS® diminuait le volume en L5-S1. XSTOP® : l’implant qui ouvrait le plus les foramens. Les dispositifs interépineux ont bien des effets biomécaniques sur l'étage implanté, aussi bien en cinématique que sur les variations de la taille du foramen intervertébral. / In lumbar degenerative disease, many surgical procedures can be used to respond to different radiological clinical situations. These invasive procedures are effective, but with a significant complication rate. Interspinous devices (DIE) are positioned with more limited approaches, thereby reducing morbidity. However, their effectiveness is controversial. The effects of EIS can be evaluated on the kinematic changes of the implanted level and changing in the foramina size. Through a series of cadaveric biomechanical studies, the authors try to check if these are good effects expected with 4 devices. Concerning L4, DIAM® and In-Space® had no effect on either flexion or extension, contrary to Wallis®, which had a significant effect on flexion and extension. Concerning L5, no implant had an effect in flexion, while all presented a significant amortisation effect on extension.No significant difference was revealed between implants on flexion, in extension or on a global cycle. Concerning the mobility variations, Wallis® is the implant which decreases the global average movement of L4 and L5 the most, by 50% and 42.7%, respectively.The analysis of variations in the size of foramina is still confidential. Few authors are concerned. A cadaver study of the lateral surface of the intervertebral foramen by photographic method and binarization images has shown that with YODA, the average length of foramen was 15.7 ± 2.8mm and the average width of 9.4 ± 1.2mm. After implantation of DIE, these dimensions ranged respectively 16.8 ± 2.5mm and 10.1 ± 1.3mm. The mean foraminal area was 150.4 ± 35.8 mm2 vacuum and 165.1 ± 28.3mm2 after implantation. The average gain was 14.7mm2 (5.3-26.9). However, this implant has no effect on the kinematics of the implanted level even in extension justifying discuss a modification of the implant. Stereoscopic 3D measuring foraminal area variations on L4-L5 level and adjacent foramina has shown that all implants open the L4-L5 foramen in extension. There seems to be two types of implants: those who open the foramen in neutral, flexion and extension, and those who close the foramen bending but open to extension. There were no effects on the size of the foramen L3 -L4. However, Xstop and DIAM resulted minimal closure L5-S1 foramen to the extension. Surface measurement seemed insufficient to assess the totality of the stenosis. We developed a new measure of the foramen size enjoying its volume scanner. With this measurement technic, the mean volume of 60 foramen and 20 L4-L5 foramen were respectively 1.17 ± 0.23 and 1.25 mm 3 ± 0.27 for the observer 1 and 1.21 ± 0.21 and 1.29 ± 0.23 mm 3 for the observer 2. The intra observer CIC 1 for the observer for all measuring foramina and L4 - L5 were 0.98 and 0.99, respectively. For observer 2, ICC were 0.90 and 0.92, respectively. The inter-observer CIC for the observer 1 for measuring all foramina and L4 - L5 were 0.78 and 0.83, respectively. For observer 2, the CIC were 77 and 0.8, respectively.The average differences in measurements between observers were less than 0.2 mm3 (0.05 et 0.15). This is the first study to measure the volume of the foraminal scanner. The excellent reproducibility of this simple measure complements the tools to measure the size of the foramen. The validation of this volume measurement was used to check whether or not there was a change in the foraminal volume after comparative implementation of four interspinous devices. L4-L5 foramina volumes were significantly increased after implantation of InSpace ®, Xstop ® and WALLIS ®. The average volume of the underlying foraminal volume was not changed and only WALLIS ® decreased the volume L5 -S1. Interspinous devices have many biomechanical effects on the implanted level, as well as kinematic changes in the size (area and volume) of the intervertebral foramen. They have no impact on adjacent
638

Ocorrência de traumatismo raquidiano em doentes em coma decorrente de traumatismo cranioencefálico / Spine injuries in patents presenting coma due to head injury

Rosi Junior, Jefferson 05 April 2012 (has links)
Foi realizado estudo prospectivo com o objetivo de se determinar a ocorrência de traumatismo raquidiano (TR) em 355 doentes em coma decorrente de traumatismo cranioencefálico (TCE) resultante de acidente de tráfego atendidos no Pronto Socorro de Neurocirurgia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (PSNCHCFMUSP) de 1° de setembro de 2003 a 31 de dezembro de 2009. Todos os doentes foram submetidos ao exame físico e neurológico e à tomografia computadorizada (TC) do corpo inteiro para diagnosticar-se e avaliar-se a gravidade das lesões traumáticas encefálicas, vertebrais ou de outras regiões no momento da admissão ao PSNCHCFMUSP. Em 69 (19,4%) doentes, foi(ram) diagnosticada(s) lesão(ões) na coluna vertebral com o exame de TC da coluna vertebral. As idades dos doentes variaram de 12 a 55 anos (média de 29,0 anos). Eram do sexo masculino 57 (82,6%) doentes. As causas do(s) traumatismo(s) foi(ram) acidente(s) envolvendo motocicleta em 28 (40,6%) casos, atropelamento em 21 (30,5%), colisão de automóvel, caminhão ou caminhonete, em 18 (26,1%) ou acidente com bicicleta em dois (2,9%). Hemorragia subaracnóidea traumática foi a anormalidade intracraniana traumática mais evidenciada no exame de TC do crânio; ocorreu em 57 (82,6%). O(s) processo(s) transverso(s) foi(ram) o(s) segmento(s) vertebral(is) mais acometido(s) pela(s) fratura(s). A sétima vértebra cervical foi a mais lesada; nela identificaram-se fraturas em 24 (34,8%) doentes. Evidenciou-se que a distribuição das fraturas foi similar ao longo das demais vértebras da coluna cervical, quatro primeiras vértebras torácicas e vértebras lombares. Em oito (11,6%) doentes a(s) lesão(ões) neurológica(s) foi(ram) classificada(s) como Frankel A, e nos demais 61(88,4%), como Frankel não-A. Houve necessidade de cirurgia espinal em 24 (34,8%) doentes e de neurocirurgia craniana em 18 (26,0%) doentes. A Escala de Recuperação de Glasgow foi aplicada para avaliar-se as condições neurológicas do doente no momento da alta hospitalar e revelou ocorrência de óbito em dois (2,9%) doentes. Concluiuse que é recomendada a avaliação clínica e também com métodos de imagem da coluna vertebral nos doentes em coma decorrente de TCE / The author presents a prospective study aiming the evaluation of coexistence of spinal injury (SI) in 355 patients presenting coma due to craniocerebral trauma assisted at the Emergency Room of the Hospital das Clínicas of the University of São Paulo Medical School, from September, 1st, 2003 to december, 31th,2009. All patients underwent physical and neurological examination and had computed tomography (CT) scanning of the entire body to diagnose and evaluate the severity of brain and spinal injury at the time of admission. Traumatic lesions of the spine were diagnosed in 69 (19.4%) patients. The ages of patients ranged from 12 to 55 years (mean = 29,0 years).The SI predominated in males, corresponding to 57 (82.6%) patients. The causes of the trauma were motorcycle accident in 28 (40.6%) cases, running over in 21(30.5%), car collision 18 (26.1%) cases and bicycle accident in two (2.9%). Traumatic subarachnoid hemorrhage was the most common traumatic intracranial abnormality in the CT images; it was identified in 57 (82.6%) patients. The transverse process was the most common vertebral part presenting fracture(s). The 7th cervical vertebra was individually the most commonly affected; traumatic lesion of this vertebra presented in 24 (34.8%) patients. The diagnosis of fracture(s) was similar in the other cervical vertebrae and occurred also in the first four thoracic and in the lumbar vertebrae. Severe neurological deficit secondary to spine fracture was diagnosed in eight (11.6%) patients, classified as Frankel A. The others 61(88.4%) patients did not present complete spinal cord or spinal roots neurological deficits were classified as Frankel non A. The Recovery Scale of Glasgow was used to evaluate the neurological status at discharge from hospital. Two (2.9%) patients died. Spinal surgery was necessary in 24 (34.8%) patients and cranial surgery in 18 (26.0%). It was concluded that in addition to clinical evaluation, the CT imaging of the spine is recommended in patients in coma due to mechanical traumatic head injury
639

Avaliação da utilização de um programa computadorizado para aplicação da escala de Basso, Beattie e Bresnahan (BBB) em ratos Wistar / Evaluation of the use of a computer software for the application of the Basso, Beattie e Bresnahan (BBB) scale in Wistar rats

Molina, Alessandra Eira Iague Sleiman 31 October 2012 (has links)
A escala de Basso, Beattie e Brenahan (BBB) serve para avaliação da recuperação locomotora em ratos com lesão medular nos níveis torácicos. É baseada em critérios observacionais da movimentação do animal durante a marcha e atribui uma pontuação de 0 a 21 segundo a gravidade da lesão neurológica. Menor pontuação, maior gravidade. Tal escala pode ser aplicada de modo livre, em que o pesquisador observa o rato e emite uma nota; pode ser aplicada de modo dirigido, em que o pesquisador segue uma sequência de perguntas pré-estabelecidas e atribui uma nota; ou de modo automatizado, em que as respostas à mesma sequência de perguntas são fornecidas a um programa de computador, que emitirá uma nota com o grau de lesão. Trabalhos já publicados mostram que existe variação interobservadores na aplicação desta escala. O objetivo do trabalho foi avaliar a utilização de um programa de computador para auxiliar os pesquisadores na atribuição de notas na aplicação da escala BBB e comparar as notas obtidas por esses pesquisadores quando o fazem de modo livre, dirigido e utilizando um programa automatizado. Para testar o programa, foi realizada lesão medular padronizada em 12 ratos Wistar utilizando-se metodologia da New York University - Impactor System. Na sequência, filmou-se a movimentação dos ratos para aplicação da escala BBB no 28o dia. Foram convocados oito pesquisadores do laboratório de estudos de trauma raquimedular da Universidade de São Paulo. As avaliações de dois chefes do laboratório, com 15 anos de experiência na aplicação da escala, foram consideradas o padrão ouro na avaliação. Seis pesquisadores receberam as filmagens dos ratos com o objetivo de aplicar a escala BBB nas três metologias: livre, dirigida e automatizada, com 15 dias de intervalo entre as avaliações. A ordem da aplicação da escala foi randomizada entre os pesquisadores e a ordem dos ratos, nas análises das filmagens, também foi variada para evitar a memorização por parte dos pesquisadores. Os resultados interavaliadores e entre os métodos mostraram-se similares. A comparação dos resultados entre os seis pesquisadores e os dois considerados padrão ouro mostrou diferença para dois pesquisadores nos métodos livre e dirigido. Concluiu-se que a aplicação da escala BBB pelo modo automatizado não apresentou diferença em relação ao padrão ouro para todos os avaliadores, e que, quando feita pelo modo livre, dirigido e automatizado, não apresentou diferença em relação ao padrão ouro, considerando a média dos avaliadores em cada método / The BBB is an evaluation scale in the locomotor recovery in rats presenting thoracic medullar injury. It is based on observation criteria of animal movement while walking, and a provides a score ranging from 0 to 21 according to the severity of the neurological injury. The lower the score, the higher the severity. Such scale can be applied by using a free system of analysis, that is, when the researcher observes the rat and gives a score. The evaluation can also be made in an assisted way, where the researcher follows a series of pre-established questions and then gives a score,or in an automated manner, where the answers to the same sequence of questions are provided to a computer program, which provides a score with the degree of injury. Published research shows that there is a interobserver variation in the scale application The objective of the present study was to evaluate the use of a computer program for helping researchers in the scoring by the BBB scale, and comparing these grades obtained when they are making a free evaluation, in an assisted evaluation and while using a computer program. In order to test the program, a standardized spinal cord injury was performed in 12 Wistar rats in accordance with the methodology proposed by the New York University - Impactor System. Then, the rat movements were filmed on the 28th day, so that the Basso, Bettie and Bresnahan scale could be applied. Eight researchers working in the spinal cord injury laboratory in the University of São Paulo were invited for the study. Two heads of the laboratory, with a fifteen year-experience in the usage and application of the scale, were considered to be gold standard in the evaluation. Six researchers were shown the films and asked to apply the BBB scale by the three methodologies: free, assisted and computerized, with a fifteen-day interval between evaluations. The scale application order was randomized among the researchers as well as the order of the rats in the film analysis so as to avoid memorization on the part of the researchers. Results proved to be similar between researchers and methods. The comparison of results among the six researchers and the gold standard ones showed discrepancies in two of the researchers in the free and assisted methods of analysis. It was concluded that the BBB scale evaluated through the computer method was no different than the gold standard for all the researchers. When the analysis was performed using the free, assisted and computer-assisted methods, no difference was observed in relation to the gold standard considering the mean values in each method
640

Uso do método de elementos finitos na análise biomecânica de parafusos do sistema de fixação vertebral / Use of finite element analysis in the biomechanical analysis of screws used for spine fixation system.

Macedo, Ana Paula 09 November 2009 (has links)
O parafuso como elemento de ancoragem de sistemas de fixação vertebral já é há muito utilizado. Porém a forma de distribuição da tensão gerada por ele na região de ancoragem não está ainda bem clara. O método de elementos finitos (MEF) é um método matemático desenvolvido no século passado e permite, quando em um estudo estático, avaliar reações internas de estruturas ao se aplicar uma força. Este estudo teve por objetivo analisar as tensões e deformações internas geradas por parafusos do sistema de fixação vertebral por meio do MEF. Os Parafusos USS1 de 5, 6 e 7 mm de diâmetro e 45 mm de comprimento (Grupo 1 G1, Grupo 2 G2 e Grupo 3 - G3) e os parafusos USS2 anterior, USS2 posterior de 6,2mm de diâmetro e USS1 de 6 mm de diâmetro e 30 mm de comprimento (Grupo 4 G4, Grupo 5 G5 e Grupo 6 - G6) foram utilizados neste estudo. Para validação dos modelos foram utilizados: ensaio mecânico de arrancamento do parafuso em corpos de prova de poliuretana com densidade de 0,16 g/cm3 e resultados de ensaios de arrancamento encontrados na literatura. Foi confeccionado um modelo tridimensional para cada conjunto parafuso e poliuretana estudado no programa SolidWorks®2006. Foram confeccionados 30 corpos de prova em poliuretana para validação de G1, G2 e G3, sendo 10 corpos de prova para cada grupo. O orifício piloto foi realizado por broca de 3,8 mm para G1 e 4,8 mm para G2 e G3. Os modelos dos grupos G4, G5 e G6 foram validados por resultados encontrados na literatura de ensaios em poliuretana de mesma densidade e orifício piloto realizados por sonda de 3,8 mm para G4 e G5 e 4,8mm para G6. A análise pelo método de elementos finitos, foi realizada no programa ANSYS®Workbench 10.0. A validação foi obtida pela comparação da rigidez relativa obtida no ensaio mecânico e o resultado da simulação pelo MEF. Foram encontradas divergências de 8,3% para G1, 3,1% para G2, 0,5% para G3, 14,4% para G4, 9,5% para G5 e 10,3% para G6, sendo todas consideradas aceitáveis. Validados os modelos, os grupos G4 e G6, utilizados na fixação anterior, foram submetidos à força de compressão, tração e dobramento lateral. Os grupos G5 e G6, empregados na fixação posterior, foram submetidos à força de compressão, tração, flexão e extensão. Na fixação anterior as menores tensões foram encontradas para G4 e as maiores para G6 para todas as forças aplicadas. Na fixação posterior as menores tensões foram encontradas para G5 e as maiores para G6 para todas as forças aplicadas. As maiores tensões foram geradas ao se realizar o dobramento lateral na fixação anterior e a extensão na fixação posterior. / Screws have been used to stabilize spine fixation systems. However, stress distribution around them is not clear yet. The finite element method (FEM) is a mathematic model developed in the last century and allows evaluating internal reactions of the structure submitted to a load in a static analysis. The present study aimed to evaluate stress and internal deformation caused by screws of the spine fixation system using FEM. USS1 screws measuring 5, 6 and 7 mm in diameter and 45 mm in length (Group 1 G1, Group 2 G2 and Group 3 G3) and the screws USS2 anterior, USS2 posterior measuring 6.2 mm in diameter and USS1 measuring 6 mm in diameter and 30 mm in length (Group 4 G4, Group 5 G5 and Group 6 G6) were used in the present study. For validation models, mechanical tests evaluating pull-out strength in polyurethane samples presenting density of 0.16 g/cm3, and results of pull-out tests related in the literature were used. Threedimensional (3D) models were built for each screw-polyurethane sample set using SolidWorks® 2006 software. Thirty polyurethane samples were made for G1, G2 and G3 validation, 10 for each group. The pilot hole was made using a 3.8 mm drew for G1, and 4.8 mm for G2 and G3. The G4, G5 and G6 models were validated based on literature results that used polyurethane of same density and pilot hole made using 3.8 mm probe for G4 and G5, and 4.8 mm for G6. The FEM analysis was performed using ANSYS®Workbench 10.0 software. Validation was reached by comparing relative stiffness obtained in mechanical tests and results of FEM simulation. Differences of 8.3% for G1, 3.1% for G2, 0.5% for G3, 14.4% for G4, 9.5% for G5, and 10.3% for G6 were found, but all values were considered acceptable. Validated the models, G4 and G6 groups, used for anterior fixation, were submitted to compression, traction and lateral bending load. The G5 and G6 groups, used for posterior fixation, were submitted to compression, traction, flexion and extension force. In the anterior fixation, lower stress were found for G4, and greater for G6 at all applied forces. In the posterior fixation, lower stress were found for G5 and greater for G6 at all applied forces. Greater stress were caused simulating lateral bending in the anterior fixation, and extension in the posterior fixation.

Page generated in 0.064 seconds