Introdução: A microdiscectomia para tratamento de hérnia de disco lombar, mesmo apresentando ótimos resultados, pode resultar em danos consequentes à lesão tecidual local. As cirurgias endoscópicas já são consideradas padrão ouro em outras áreas da medicina devido ao mínimo dano colateral causado e consequente melhora dos resultados. Autores internacionais demonstraram a eficácia e segurança da técnica, mas ainda não existem estudos na América Latina que validem esses estudos. Objetivo: Comparar os resultados cirúrgicos da abordagem endoscópica e convencional para tratamento da hérnia de disco lombar quanto à melhora da dor, da incapacidade e suas complicações. Métodos: Estudo prospectivo randomizado envolvendo pacientes com hérnia de disco lombar, submetidos a tratamento cirúrgico. Quarenta e sete pacientes foram randomizados prospectivamente em dois grupos, discectomia endoscópica e microdiscectomia, e foram acompanhados ao longo de 12 meses. Questionário de incapacidade de Oswestry validado para o português e escala analógica de dor foram aplicados durante o seguimento. Os eventos adversos também foram recordados. Resultados: Após a cirurgia os pacientes tiveram melhoras significativas da dor irradiada (68%), mas sem diferença entre os grupos estudados e apresentaram significativa melhora da incapacidade. Quanto a dor lombar, a discectomia endoscópica resultou em menor dor lombar pós-operatória nas avaliações de uma semana, um e três meses quando comparada a microdiscectomia. Entretanto não se observou diferença entre os grupos no sexto e décimo segundo mês de seguimento. Não foram evidenciadas diferenças estatísticas quanto a recidiva, infecções e cirurgias subsequentes. Conclusão: Os resultados clínicos da discectomia endoscópica são semelhantes aos da microdiscectomia quanto à melhora da dor irradiada e da incapacidade, mas oferecem uma vantagem quanto à dor lombar pós-operatória até o terceiro mês. A discectomia endoscópica consiste em uma técnica segura e eficaz representando uma alternativa ao tratamento padrão ouro representado pela microdiscectomia / Introduction: Microdiscectomy, despite the good results, may result in damages to the local tissue. In other fields, endoscopic surgeries are considered the gold standard due to the minimal collateral damage. There aren\'t studies comparing both methods performed in Latin America. Objective: Compare the traditional microdiscectomy and percutaneous endoscopic lumbar discectomy for the treatment of disc herniation regarding pain, disability and complications. Methods: Prospective randomized trial with patients with sciatica due to lumbar disc herniation comparing two different surgical techniques. Forty-seven patients were divided in two groups and monitored for twelve months. Oswestry disability index and visual analog scale for pain were recorded. Results: After surgery the leg pain and disability improved significantly, but without significant difference between the groups. There was significantly less back pain after surgery until the third month. After that the groups were statistically the same. There were no statistical differences regarding recurrence, infection and subsequent surgeries. Conclusion: Endoscopic discectomy results are similar than conventional microdiscectomy according to pain and disability improvement, however, lumbar pain are less during the first three months. Endoscopic discectomy consists in a safe and efficient alternative to microdiscectomy

Intervertebral disc (IVD) degeneration is strongly associated with back pain, and affects approximately 60% of the population by age 70. Furthermore, it has been suggested that this degeneration may play an important role in the initiation or perpetuation of vertebral fractures. Given that the IVD is a primary load-bearing structure in the spine, the change of intradiscal pressure (IDP) over time that accompanies disc degeneration provides a functional measure of the disease pathology. Studies show that both an overall decrease in IDP magnitude and changes in the spatial distribution of IDP are found with increasing levels of degeneration. Thus, the overall goal of this study was to determine the correlation between the spatial distributions of IDP, as measured along both mid-sagittal and mid-coronal paths, and a clinically feasible assessment of disc health. Disc degeneration was assessed non-invasively using quantitative computed tomography (QCT). A custom, electro-mechanical device was designed, manufactured and assembled to measure IDP distributions. The results indicated that the spatial distribution of IDP was most homogenous for the nucleus pulposus (NP) region regardless of load type and disc health grade. Mean IDP tended to be lowest in severely degenerated discs, consistent with earlier findings that axial loads in spinal columns with degenerated IVDs shift from the disc to the neural arch in both flexural and erect postures.

Orientador: José Elias Tomazini / Banca: José Geraldo Trani Brandão / Banca: Marcelo Sampaio Martins / Banca: Paulo José Oliveira Cortez / Banca: Everaldo de Barros / Resumo: A degenerescência em função da idade, de posturas e de movimentos não ergonômicos acarreta perdas das funções mecânicas e patologias nas colunas, principalmente nos discos intervertebrais. Ultimamente têm sido desenvolvidos muitos modelos matemáticos e feitas muitas experiências para avaliação desses discos. Neste trabalho foi desenvolvido e fabricado um dispositivo para testar partes de coluna vertebral objetivando obter dados de características mecânicas dos discos intervertebrais, fornecendo informações para desenvolvimento de próteses. Concomitantemente foi desenvolvido um programa matemático para tratamento dos dados dos sensores do dispositivo em informações cinemáticas, além do desenvolvimento de um programa de simulação para comparação com os dados dos testes. O modelo matemático para simulação baseou-se no corpo de teste utilizado nos testes e os dados experimentais foram compatíveis com os resultados obtidos na simulação / Abstract: The degeneration in function of age, postures and movements not ergonomic causes loss of mechanical functions and pathologies in spinal column, mainly in intervertebral discs. Lately it has been developed many mathematical models and made many experiments for evaluation of these discs. In this work it was developed and manufactured a device to test parts of the spinal column aiming to obtain data of mechanical characteristics of intervertebral discs, providing information for the development of prosthesis. At the same time it was developed a program to turn the data of the sensors of the device into kinematical information, besides the development of a program of simulation for comparison with the data of the tests. The mathematical model for simulation was based on a body of test used in the tests and the experimental data were compatible with the results obtained in the simulation / Doutor

Physical activity impacts health and disease in multiple body tissues including the intervertebral discs. Fluid flow within the disc is an indicator of disc health that can be observed using diffusion weighted magnetic resonance imaging. We monitored activity levels of 26 participants, age 35 to 55 yrs, using Actigraph accelerometers for four days to evaluate vigorous-intensity activity, moderate to vigorous-intensity activity, and sedentary time. Participants underwent structural and diffusion weighted magnetic resonance imaging to evaluate intervertebral disc health and fluid flow. They also underwent bone density scans, carotid artery ultrasounds, a treadmill test, and a physical exam for pain, range of motion, and instability. These measures were used to correlate MRI indicators of intervertebral disc health with participant activity. Participants with any vigorous-intensity physical activity compared with no vigorous-intensity activity had significantly greater L5/S1 apparent diffusion coefficient values (p = 0.002), corresponding to higher freedom of diffusive movement for cellular nutrients and metabolic waste. Sagittal T2 values in the L5/S1 were also higher (p = 0.004), corresponding to higher water content in the discs. Higher apparent diffusion coefficients were also found in participants with more than 30 minutes compared with less than 30 minutes of daily moderate to vigorous physical activity (p = 0.03), and in participants with less than 67% awake time as sedentary time compared with more than 67% sedentary time (p = 0.03). Increased dynamic loading through physical activity and decreased static loading from sedentary time benefit intervertebral disc health. Physical activity, particularly vigorous activity, is beneficial in helping maintain intervertebral disc health.

El presente estudio tuvo como objetivos describir los hallazgos radiológicos de la radiografía simple en animales con sospecha de hernia discal y establecer su coincidencia con los del examen tomográfico. Se estudiaron 16 pacientes caninos, que llegaron a la Clínica de Animales Menores de la Facultad de Medicina Veterinaria – U.N.M.S.M. entre julio del 2007 y diciembre del 2009, cuya evaluación neurológica reveló una disfunción neurológica compatible a una compresión medular a nivel toracolumbar y una magnitud de lesión a partir del grado III. Dos pacientes fueron retirados del estudio por no presentar sospecha de diagnóstico de hernia discal en el examen radiográfico simple ni en la evaluación tomográfica. La radiografía simple identificó 14 animales con signos radiográficos compatibles a una hernia discal. Al realizar la comparación de resultados entre los exámenes radiográfico y tomográfico se observó que 71.4% (10/14) de los casos coincidieron en diagnosticar la presencia de la enfermedad y la localización del espacio intervertebral afectado. Los signos radiográficos más frecuentes en los animales sospechosos a hernia discal tipo 1 por radiografía simple fueron la disminución del espacio intervertebral 92.9% (13/14), disminución del foramen intervertebral 57.1% (8/14) y opacidad del foramen intervertebral 28.6% (4/14). Los hallazgos tomográficos de mayor presentación en los animales con hernia discal tipo 1 fueron la presencia de material discal en el canal medular y la estenosis del mismo presentes ambos en el 100% (12/12) y la estenosis del espacio foraminal en el 66.7% (8/12). El espacio intervertebral más afectado del segmento toracolumbar (T3-L3) fue el L1-L2 con 33.3% (4/12). Los resultados obtenidos permiten concluir que la radiografía simple no puede ser considerada como indicativo absoluto en el diagnóstico de hernia discal tipo 1; ya que aparentemente las alteraciones radiográficas encontradas no son suficientemente determinantes y; por lo tanto, es necesario realizar un protocolo diagnóstico que se inicie con la obtención de una placa simple complementada siempre por un examen tomográfico. Palabras clave: Hernia discal tipo 1, radiografía simple, tomografía computarizada, toracolumbar. / -- The objectives of this study were to describe the radiologic findings of plain radiography in animals with suspected herniated disc and to establish its coincidence with the computed tomography (CT) examination. Sixteen dogs were studied who came to the Small Animal Clinic of Faculty of Veterinary Medicine - UNMSM between July 2007 and December 2009, whose neurological evaluation revealed a neurological dysfunction compatible with thoracolumbar spinal cord compression and a magnitude of injury from grade III. Two patients were withdrawn of study for failure to submit suspected diagnosis of disc herniation in both plain radiographic and CT examination. Plain radiographs identified 14 animals with radiographic abnormalities consistent with a herniated disc. The comparison of the results between radiographic and CT examinations showed that 71.4% (10/14) of cases agreed on the diagnosis of the presence of the disease and location of the affected intervertebral space. The radiographic findings most common in animals suspected to herniated disc type 1 were narrowed intervertebral space 92.9% (13/14), decreased size intervertebral foramen 57.1% (8/14) and opacity of the intervertebral foramen 28.6% (4/14). The most common CT findings in animals with herniated disc type 1 were the presence of disc material in the spinal canal and spinal canal stenosis both at 100% (12/12), and the foraminal space stenosis in the 66.7% (8/12). The intervertebral space most affected of segment thoracolumbar (T3-L3) was the L1-L2 with 33.3% (4/12). The results show that the plain radiography can’t be regarded as an absolute indicator in the diagnosis of herniated disc type 1, as apparently found radiographic changes are not decisive enough and; therefore, is necessary to perform a diagnostic protocol starting with obtaining a plain radiography always complemented by a CT examination. Key words: Herniated disc type 1, plain radiography, computed tomography, thoracolumbar. / Tesis

No description available.

Bibliography: leaves 107-109.

Back pain is one of the most common physical conditions in the United States, for which approximately 15% of the population will visit a doctor every year. The most common type of back pain is low back pain (LBP) and millions of dollars are spent every year healthcare are a due to LBP. Although poorly understood, low back pain has been associated to interveterbral disc (IVD) degeneration. The IVD is an important structure that helps maintaining normal skeletal support. It is composed of three different tissues called the annulus fibrosus (AF), and the nucleus pulposus (NP), attached to a cartilage endplate (CEP) at its top and bottom surfaces. The AF tissue is composed of chondrocyte-like cells, while the NP tissue is composed of notochordal cells at a young age, which are replaced by mature NP cells later in life. Common signs of degeneration are the inability to maintain extracellular matrix integrity and calcification of the cartilage endplate. Extracellular matrix synthesis and cartilage endplate calcification are closely related to production of adenosine triphosphate (ATP) or energy metabolism of the cells. AF and NP tissues are known to be structurally and compositionally different; therefore it is believed that their metabolic pathways are also distinct. The objective of this study was to determine the differences between AF and NP cells, specifically in their energy metabolism with and without dynamic loading.

Low back pain is one of the major health concerns in the US. It affects up to 80% of the population at some time during their lives. It not only causes discomfort to patients and affects their physical ability but also has a huge economic impact on society. Although the cause of low back pain is still poorly understood, it is implicated that degeneration of the intervertebral disc is the primary factor. Currently, researchers are trying to use tissue engineering approaches to develop new treatments capable of removing the degenerated disk and replacing it with a biological substitute. However, to create such a biological substitute, we need to first understand the structure-function relationship of the tissue. Only when we understand the function of the tissue, can we begin creating biological substitutes. While culturing a biological substitute, we also need methods to determine how the substitute responds to its environment. At present, there are many different types of bioreactors developed for cartilaginous tissues. However, there is a lack of a system that can detect the chemical, electrical and mechanical response noninvasively with control feedback in real-time. It is hard to provide the optimal culture environment to the substitute without knowing its response in real-time. The objective of this dissertation is to develop new methods to investigate the transport property, oxygen consumption rate and mechano-electrochemical and mechanical properties of the tissue. Because cells are responsible for the tissue health, it is necessary to understand how they can obtain nutrients under different environments, e.g. under different loading condition. In addition, with the use of a bioreactor with the capability of detecting the real-time response combined with a feedback control system, we can provide the most favorable conditions for tissue or biological substitutes to grow. The new measurement methods developed in this dissertation can contribute to further understanding the function of the tissue. The methods outlined in this dissertation can also provide new tools for future tissue engineering applications. Moreover, the findings in this dissertation can provide information for developing a more comprehensive theoretical model to elucidate the etiology of disc degeneration.

Degeneration and age affect the biomechanics of the intervertebral disc, by reducing its stiffness, flexibility and shock absorption capacities against daily movement and spinal load. The biomechanical characterization of intervertebral discs is achieved by conducting mechanical testing to vertebra-disc-vertebra segments and applying axial, shear, bend and torsion loads, statically or dynamically, with load magnitudes corresponding to the physiological range. However, traditional testing does not give a view of the load and deformation states of the disc components: nucleus pulposus, annulus fibrosus and endplate. Thus, the internal state of stress and strains of the disc can only be predicted by numerical methods, one of which is the finite element method. The objective of this thesis was, to study the biomechanics of degenerated intervertebral discs to load conditions in compression, bending and torsion, by using mechanical testing and a finite element model of disc degeneration, based on magnetic resonance imaging (MRI). Therefore, lumbar discs obtained from cadavers corresponding to spinal levels L2-L3 and L4-L5 with mild to severe degeneration were used. Intervertebral osteochondrosis and spondylosis deformans were identified, being the disc space collapse, the most striking feature. Next, all discs were tested to static and dynamic load conditions, the results gained corresponded to the disc stiffness (in compression, bending and torsion), stress relaxation and dynamic response. Of these, the stiffness response was used to validate the disc model. The testing results suggest that discs with advanced degeneration over discs with mild degeneration are, less rigid in compression, less stiffer under bending and torsion, showed less radial bulge, and reduce their viscoelastic and damping properties. This study shows that degeneration has an impact on the disc biomechanical properties which can jeopardize normal functionality. Development of one finite element model of disc degeneration started by choosing a MRI of a L2-L3 disc. Segmentation of vertebra bone and disc materials followed, and were based on pixel brightness and radiology fundamentals, then a finite element mesh was created to account for the disc irregular shape. The disc materials were modeled as hyperelastic and the bone materials were modeled as orthotropic and isotropic. Adjustment of material properties was based on integrity of the annulus fibrosus, giving a stiffness value matching that of a mild degeneration disc. Then, validation of the model was performed, and included a study of the distributions of stress and strain under loads of compression, bending and torsion. The results from all load simulations show that the disc undergoes large deformations. In contrast, the vertebrae are subjected to higher stress but with negligible deformations. In compression, the model predicted formation of symmetrical disc bulge which agree with the testing behavior. The nucleus pulposus showed to be the principal load carrier with negative principal stresses and strains. In bending and torsion, the annulus fibrosus showed to be the principal load carrier with large symmetrical principal strains and stresses for the former loading and large shearing for the latter. The study showed the importance of soft tissue deformation, mostly noticed in advanced degeneration. In contrast, the higher stresses in the vertebra over those of the intervertebral disc showed the relevance of bone predisposition to fracture. Such kind of studies, should contribute to the understanding of the biomechanics of the intervertebral disc. / La degeneración y edad afectan la biomecánica del disco intervertebral, reduciendo la capacidad de rigidez, flexibilidad y atenuación de impactos, contra el movimiento y carga del raquis. La caracterización biomecánica del disco se realiza con ensayos mecánicos a segmentos de vértebra-disco-vértebra y aplicando cargas axiales, cortantes, flexión y torsión, estáticas ó dinámicas, con magnitudes de carga según el intervalo fisiológico. Sin embargo, las pruebas tradicionales no dan una visión de los estados de carga y deformación de los componentes del disco: núcleo pulposo, anillo fibroso y placa terminal. Por lo tanto, el estado interno de esfuerzos y deformaciones del disco, solo puede ser predicho con métodos numéricos, uno de los cuales es el método de elemento finito. El objetivo de esta tesis fue, estudiar la biomecánica de discos intervertebrales degenerados a las condiciones de carga en compresión, flexión y torsión, mediante el uso de ensayos mecánicos y de un modelo de elementos finitos de la degeneración de disco, basado en imágenes con resonancia magnética (MRI). Por lo tanto, se usaron discos lumbares L2-L3 y L4-L5 obtenidos de cadáveres, con degeneración leve a severa. Se identificó osteocondrosis intervertebral y espondilosis deformante, siendo el colapso del espacio intervertebral el aspecto más relevante. Luego, todos los discos fueron ensayados a condiciones de carga estática y dinámica, y los resultados correspondieron a la rigidez del disco (a compresión, flexión y torsión), a la relajación de tensiones y a la respuesta dinámica. De éstos, la rigidez fue usada para validar el modelo de disco. Los resultados de los ensayos sugieren que los discos con degeneración avanzada sobre aquellos con degeneración leve son, menos rigidos a compresión, menos rigidos a flexión y torsión, presentan menor protuberancia radial, y reducen sus propiedades viscoelásticas y de amortiguamiento. El estudio muestra que la degeneración impacta las propiedades biomecánicas del disco, poniendo en riesgo la funcionalidad normal. El desarollo de un modelo de elementos finitos de la degeneración de disco inició eligiendo una secuencia de resonancia magnética de un disco L2-L3. La segmentación de los materiales del disco y de las vértebras se realizó basado en intensidad de brillo del pixel y en fundamentos de radiología, y se creó una malla de elementos finitos correspondiente a la forma irregular del disco. Los materiales del disco se modelaron como hiperelásticos y los tejidos óseos se modelaron como materiales ortotrópicos e isotrópicos. El ajuste de propiedades de los materiales fue basado en la integridad del anillo fibroso, y dio una rigidez correspondiente a la de un disco con degeneración leve. Luego, se realizó la validación del modelo, e incluyó un estudio de las distribuciones de esfuerzo y deformación a las condiciones de carga en compresión, flexión y torsión. Los resultados de todas las simulaciones de carga mostraron que el disco es sometido a grandes deformaciones. En contraste, las vértebras fueron sometidas a mayores esfuerzos pero con deformaciones insignificantes. En compresión, el modelo predijo la formación de una protuberancia radial simétrica, en concordancia con la experimentación. El núcleo pulposo mostró ser el portador principal de carga, con tensiones y deformaciones principales negativas. En flexión y torsión, el anillo fibroso mostró ser el portador principal de carga, con grandes deformaciones y tensiones principales simétricas para la primera carga, y con grandes tensiones cortantes para la segunda carga. El estudio mostró la importancia de las deformaciones de los tejidos blandos, principalmente notados en la degeneración avanzada. Por el contrario, las tensiones mayores en los cuerpos vertebrales sobre aquellas del disco intervertebral mostraron la relevancia de la predisposición a las fracturas óseas. Este tipo de estudio debe contribuir a la comprensión de la biomecánica del disco intervertebral.