A idade óssea é uma informação importante para o diagnóstico de anomalias ósseas e identificação dos estágios de desenvolvimento na pediatria, endocrinologia e ortodontia, assim como na estimação de idade na área forense. A idade óssea é obtida pela análise de qualquer osso ou conjunto de ossos por meio de radiografias da região de interesse. Este trabalho apresenta uma metodologia composta por duas fases. A primeira fase trata do processamento de imagem, responsável pela segmentação e extração de características de telerradiografias em norma lateral. A segunda fase é responsável pela estimação da idade óssea, que propõe um estudo para correlacionar o polinômio extraído da concavidade inferior da terceira vértebra com a idade óssea por meio de redes neurais artificiais. Para a média dos resultados da primeira fase, os valores encontrados foram 82,39% de precisão, 91,70% de exatidão e 8,30% de erro. Baseado nestes resultados concluiu-se que a metodologia é eficaz para a segmentação dos ossos das cervicais, entretanto como algumas estruturas não devem ser consideradas, a segmentação foi influenciada pela contribuição dos falsos positivos, que nas imagens analisadas são segmentos de ossos da parte posterior das cervicais. Em contrapartida, para a segunda fase os resultados validaram o uso do polinômio em métodos de estimação, que pode ser utilizado de forma direta (coeficientes do polinômio) ou indireta (área e máxima altura da concavidade), comprovando que ele contribui no aumento da correlação quando utilizado em conjunto com outras características. Para ambos os gêneros a correlação atingiu valores em torno de 0,97, com erro médio absoluto de 0,4 anos e sem diferenças estatisticamente significativas pelo T-Student com nível de significância de 5%. Portanto concluiu-se que a metodologia apresenta resultados expressivos, respeitando a tolerância dos métodos clássicos. / Bone age is important information for the diagnosis of bone anomalies and identification of developmental stages in pediatrics, endocrinology and orthodontics as well in the age estimation in the forensic field. Bone age is obtained by analysis of any bone or group of bones through of radiographs the region of interest. This paper presents a methodology that consists of two phases. The first phase deals with image processing, responsible for segmentation and feature extraction of lateral cephalograms. The second phase is responsible for bone age estimation, which proposes a study to correlate the polynomial extracted from bottom concavity of the third vertebra with bone age using artificial neural networks. The average of first phase results was 82.39% of precision, 91.70% of accuracy and 8.30% of error. Based on these results it was concluded that the method is effective for the segmentation of the cervical bone, however, since some structures should not be considered, the segmentation was influenced by the contribution of false positives, that in the images analyzed are bones segments from the back of the cervical. In contrast, for the second phase the results validated the use of polynomial in estimation methods that can be used directly (polynomial coefficients) or indirect (area and maximum height of concavity), proving that it contributes in increasing the correlation when used together with other features. For both genders the correlation reached values around 0.97, with a mean absolute error of 0.4 years and no statistically significant differences by T-Student with a significance level of 5%. Therefore it was concluded that the methodology shows significant results, respecting the tolerance of the classical methods.

Foi avaliada a participação dos corpos vertebrais e discos intervertebrais na lordose lombar e, a contribuição destes nas curvaturas lombares de diferentes magnitudes. Foram avaliadas as radiografias lombares em perfil de 350 adultos assintomáticos (143 homens e 207 mulheres, idade média 29 anos). Foram mensuradas a curvatura lombossacra (L1S1), a curvatura lombolombar (L1L5), a angulação de cada corpo vertebral e cada disco intervertebral por meio de uma variação do método de Cobb. A participação percentual dos corpos vertebrais e dos discos intervertebrais na curvatura lombossacra também foi determinada. Comparações entre os sexos e as faixas etárias foram realizadas. Os indivíduos foram divididos em três subgrupos populacionais, de acordo com a magnitude da lordose lombossacra, de modo a separar os indivíduos pertencentes aos extremos da curva de distribuição. Os componentes da curvatura lombar (corpos vertebrais e discos intervertebrais) foram comparados nestes três subgrupos. A medida da curvatura lombossacra no grupo inicial foi -60,9o (-33o a -89o). Os corpos vertebrais eram cifóticos em L1 (2,15o), tendiam ao neutro em L2 (-0,36o) e eram progressivamente lordóticos de L3 (-1,56o) a L5 (-9,23o). Os discos intervertebrais eram progressivamente lordóticos (variando de -4,99o em L1-L2 a -15,58o em L5-S1). Os corpos vertebrais e discos intervertebrais apresentaram participação progressivamente maior na curvatura lombossacra no sentido crânio-caudal. Os discos intervertebrais participaram com cerca de 80% da curvatura lombossacra, sendo que os elementos mais caudais (corpos vertebrais L4 e L5 e discos intervertebrais L4-L5 e L5-S1) corresponderam a mais de 65% da curvatura lombossacra. Os indivíduos mais velhos apresentaram medidas das curvaturas lombares maiores cerca de 4º em comparação aos indivíduos mais jovens, havendo diferença significante para as medidas dos corpos vertebrais L2 e L5 e o disco intervertebral L3-L4, sendo maiores as medidas nos indivíduos mais velhos. As medidas das curvaturas lombares e dos corpos vertebrais L2 e L4 apresentaram diferença estatisticamente significante entre os sexos, sendo as medidas maiores nos indivíduos do sexo feminino. A curvatura lombossacra apresentou média de -46,9° no subgrupo lordose menor; -61,59° no subgrupo lordose intermediária e; -74,13° no subgrupo lordose maior. A curvatura lombolombar apresentou média de -33,28° no subgrupo lordose menor; -45,34° no subgrupo lordose intermediária e; -56,96° no subgrupo lordose maior. Os corpos vertebrais e os discos intervertebrais apresentaram medidas absolutas menores no subgrupo lordose menor do que as dos subgrupos lordose intermediária e lordose maior, mas a participação dos discos intervertebrais na curvatura lombossacra no subgrupo lordose menor (88%) foi maior que nos subgrupos lordose intermediária (81%) e no subgrupo lordose maior (75%). Complementarmente, os corpos intervertebrais apresentaram maior participação nos subgrupos lordose maior e lordose intermediária. Individualmente, os corpos vertebrais apresentaram maior participação no subgrupo lordose maior, exceto pelo corpo vertebral L5 que apresentou maior participação no subgrupo lordose menor. A maior participação percentual dos discos intervertebrais no subgrupo lordose menor era devida à inclinação cifótica dos corpos vertebrais mais cefálicos (especialmente L1 e L2) no subgrupo lordose menor do que nos demais subgrupos, que, por um efeito compensatório, causava uma maior participação discal nas curvaturas menores. Os demais subgrupos apresentavam os corpos vertebrais cefálicos com inclinação muito mais lordótica do que o observado no subgrupo lordose menor. Concluímos que os discos intervertebrais são os principais responsáveis pela curvatura lombar e que a contribuição dos corpos vertebrais e discos intervertebrais na lordose lombar difere entre indivíduos com curvaturas de diferentes magnitudes. Apesar de ocorrer um aumento gradual do acunhamento lordótico do corpo e disco a cada nível vertebral conforme aumenta a medida da lordose, as vértebras mais cefálicas provocam uma diferença na contribuição percentual entre discos intervertebrais e corpos vertebrais nas curvaturas de tamanhos diferentes. / The vertebral bodies and intervertebral discs participation in lumbar lordosis and their contribution between lumbar curves of different size were studied. 350 lumbar spine radiographs of asymptomatic adults (143 men and 207 women, average age 29 years) were evaluated. Lumbosacral (L1S1) and lumbolumbar (L1L5) curves and the angular inclination of each vertebral boby and intervertebral disc were measured using a Cobb method variant. The percentile participation of each vertebral body and intervertebral disc in the lumbossacal curve was calculated. Sex and age were compared. The subjects were separated in tree subgroups, in acording to lumbosacral curve size. The compounds of lumbar curve (discs and vertebrae) were compared in these tree subgroups. The mean lumbosacral curve was ?60,9º (-33º to ?89º). L1 vertebral body was kyphotic (2,15º), L2 was neutral (-0,36º), and the other ones were progressively lordotic from L3 (-1,56º) to L5 (-9,23º). The intervertebral discs were progressively lordotic from L1-L2 (?4,99º) to L5-S1 (?15,58º). Both vertebrae and discs showed a progressive participation in cephalic-caudal direction. The participation of discs was about 80% of lumbosacral curve, and the caudal elements (L4, L5 vertebrae and L4-L5, L5-S1 discs) contributed far 65% of the curve. The older subjects presented lumbar curves larger than younger 4º average, with significant statistical difference to L2, L5 and L3-L4 measures, with older subjects presenting bigger angular values. There were statistical differences of lumbar curves, L2 and L4 measures between sexes, with females presenting bigger values. The lumbosacral curve presented average -46,9º in minor lordosis subgroup, -64,59º in intermediate lordosis sugbroup, and ?74,13º in major lordosis subgroup. The lumbolumbar curve presented average ?33,28º in minor lordosis subgroup, -45,34º in intermediate lordosis subgroup, and ?56,96º in major lordosis subgroup. The absolut values of vertebrae and discs angles were smaller in minor lordosis subgroup than in major lordosis subgroup, but the intervertebral discs participation of was bigger in minor lordosis subgroup (88%) than intermediate lordosis (81%) and major lordosis (75%) subgroups. Complementarely, the vertebrae had a bigger participation in intermediate and major lordosis subgroups. Individually, the vertebrae presented a larger participation in major lordosis subgroup, excepting L5 that presented bigger participation in minor lordosis subgroup. The discs presented larger participation in minor lordosis subgroup. That is consequence of a more kyphotic inclination of the cephalic vertebrae in minor lordosis subgroup than the other ones, causing a compensating effect, with a larger disc participation in the small curves. The intermediate and major lordosis subgroups had the cephalic vertebrae more lordotic than that of the minor lordosis subgroup. We concluded that the intervertebral discs are the main responsible for the lumbar curve angulation and that the contribution of vertebrae and discs in lumbar curves of different sizes is not equal. In spite of a gradual increase of lordotic wedging while lumbar curve increase, the cephalic vertebrae make the disc and vertebrae participation different between different magnitude lumbar curves.

The association between age-related vertebral fractures (VFx) and disc degeneration (DD) is not clear, despite the high prevalence of both conditions. Load is transferred to the vertebra by the adjacent intervertebral discs, and degenerative changes within the disc alter how the net force is distributed over the interface between vertebra and disc, known as the vertebral endplate (EP). The ability of the vertebra to resist fracture depends not only on the magnitude of the net force, but also on the distribution. Multiple lines of evidence suggest that the ability of the vertebra to withstand the distribution of applied force depends on the spatial distribution of bone mineral density (BMD) within the vertebra. First, the strength and stiffness of a region of bone in the vertebra are highly correlated with the BMD of that region. Second, changes in the spatial distribution of regional BMD have been associated with aging and DD. Thirdly, some of these observed changes have been replicated in computer models bone adaption with in the presence of progressive DD, suggesting that bone adaption is occurring in response to the altered force distribution associated with DD, and that maladaptation could elevate the risk of fracture. Notably, the current clinical method of identifying patients at risk of fracture is to use an average measure of BMD for the entire vertebra. The lack of consideration of the spatial distribution of BMD may explain why the clinical method used at present does not adequately identify those at risk of fracture. The possible relationship among spatial distribution of BMD, DD, force distribution across the endplate, and vertebral strength suggests that characterizing the spatial distribution of BMD within a vertebra could add to the understanding of why some vertebra are more likely to fracture. This project sought to determine if an association exists between the spatial distribution of vertebral BMD and disc health in order to provide an improved perspective of the clinical sequelae of DD and to improve the ability of clinicians to identify those who would benefit most from intervention. This study found evidence that the distribution of bone in the vertebral body and EP depend on the health of the adjacent disc. The distribution of pressure in discs favors the anterior most portion of the disc in anteriorly flexed postures and the density in the anterior most portion of the EP appears to respond to this shift, suggesting that bone is adapting to loading patterns associated with certain postures more than others. This study also found association between reduced regional disc height and altered distribution of trabecular density which was positive in the nuclear region and negative in the annular region. In some cases there was a lack of association between disc height and density distribution that may indicate maladaptation and thus increased risk of fracture. This study, being cross-sectional could not identify whether the observed alterations in density and degeneration initiated in the vertebra or the disc. However, this study contributes to the understanding of the relationship between the distribution of vertebral density and the functional properties of the adjacent disc that may ultimately improve the clinician's ability to predict VFx. / 2017-06-21T00:00:00Z

Um dos possíveis mecanismos de desenvolvimento da fissura palatina é representado pelas anomalias congênitas da coluna vertebral. Se faz necessária a correlação dos diferentes tipos de anomalias com as fissuras de lábio e/ou palato para um melhor entendimento do fenômeno embriológico e do processo de malformação. Embora alguns achados indiquem que as anomalias de vértebras cervicais estão presentes mais freqüentemente em fissuras palatinas que em outras categorias de fissura, ou que no grupo controle, a distribuição das anomalias em relação aos tipos de fissura é pouco analisada. Desta maneira o objetivo do trabalho foi determinar a prevalência das anomalias de vértebras cervicais superiores em indivíduos com e sem fissura e comparar a prevalência destas anomalias entre as amostras, bem como comparar a incidência das anomalias vertebrais entre os tipos de fissura. Foram utilizados 300 pacientes com fissura e 300 sem fissura. O presente estudo confirma a provável associação entre fissuras labiopalatinas e as anomalias cervicais. Houve diferença estatisticamente significante na incidência das anomalias cervicais no grupo com fissura (38,67%) quando comparada com o grupo controle (31,00%). Concordando com os achados da literatura, a hipótese de a presença da anomalia cervical estar relacionada com a etiologia da fissura labiopalatina é provável, mas são necessários mais estudos na área. Não houve diferença significante quando foram comparados os tipos de fissura,nem quando foram comparados os sexos tanto do grupo controle e do grupo fissurado. / One of the possible mechanisms for cleft palate development is represented by the congenital anomalies of the vertebral spine. Correlation of cleft different types with associated anomalies may enhance the understanding on the embryonic phenomena and processes of malformation The studies have observed a relationship between cleft palate and vertebral anomalies. Vertebral anomalies are more often seen in cleft patients than in the control group, although the distribution of the anomalies between the cleft types is scarcely studied. The aim of this study was to investigate the prevalence of upper cervical vertebrae anomalies in patients with isolated cleft lip, isolated cleft palate, complete cleft lip and palate and in non cleft patients, and compare the prevalence of these anomalies between groups and between genders. The sample was composed of 300 lateral cephalograms of patients with clefts and 300 lateral cephalograms of patients without clefts of both genders. There was statistical significant difference in the prevalence of cervical anomalies in the cleft group (38,67%) when compared with the noncleft sample (31,00%). In this way, the study confirms the probable association between clefts and cervical anomalies, but further research is needed. There were no statistical significant difference neither when the types of cleft were compared with each other nor when both sexes were compared in the two samples, control group and cleft group.

Foi avaliada a participação dos corpos vertebrais e discos intervertebrais na lordose lombar e, a contribuição destes nas curvaturas lombares de diferentes magnitudes. Foram avaliadas as radiografias lombares em perfil de 350 adultos assintomáticos (143 homens e 207 mulheres, idade média 29 anos). Foram mensuradas a curvatura lombossacra (L1S1), a curvatura lombolombar (L1L5), a angulação de cada corpo vertebral e cada disco intervertebral por meio de uma variação do método de Cobb. A participação percentual dos corpos vertebrais e dos discos intervertebrais na curvatura lombossacra também foi determinada. Comparações entre os sexos e as faixas etárias foram realizadas. Os indivíduos foram divididos em três subgrupos populacionais, de acordo com a magnitude da lordose lombossacra, de modo a separar os indivíduos pertencentes aos extremos da curva de distribuição. Os componentes da curvatura lombar (corpos vertebrais e discos intervertebrais) foram comparados nestes três subgrupos. A medida da curvatura lombossacra no grupo inicial foi -60,9o (-33o a -89o). Os corpos vertebrais eram cifóticos em L1 (2,15o), tendiam ao neutro em L2 (-0,36o) e eram progressivamente lordóticos de L3 (-1,56o) a L5 (-9,23o). Os discos intervertebrais eram progressivamente lordóticos (variando de -4,99o em L1-L2 a -15,58o em L5-S1). Os corpos vertebrais e discos intervertebrais apresentaram participação progressivamente maior na curvatura lombossacra no sentido crânio-caudal. Os discos intervertebrais participaram com cerca de 80% da curvatura lombossacra, sendo que os elementos mais caudais (corpos vertebrais L4 e L5 e discos intervertebrais L4-L5 e L5-S1) corresponderam a mais de 65% da curvatura lombossacra. Os indivíduos mais velhos apresentaram medidas das curvaturas lombares maiores cerca de 4º em comparação aos indivíduos mais jovens, havendo diferença significante para as medidas dos corpos vertebrais L2 e L5 e o disco intervertebral L3-L4, sendo maiores as medidas nos indivíduos mais velhos. As medidas das curvaturas lombares e dos corpos vertebrais L2 e L4 apresentaram diferença estatisticamente significante entre os sexos, sendo as medidas maiores nos indivíduos do sexo feminino. A curvatura lombossacra apresentou média de -46,9° no subgrupo lordose menor; -61,59° no subgrupo lordose intermediária e; -74,13° no subgrupo lordose maior. A curvatura lombolombar apresentou média de -33,28° no subgrupo lordose menor; -45,34° no subgrupo lordose intermediária e; -56,96° no subgrupo lordose maior. Os corpos vertebrais e os discos intervertebrais apresentaram medidas absolutas menores no subgrupo lordose menor do que as dos subgrupos lordose intermediária e lordose maior, mas a participação dos discos intervertebrais na curvatura lombossacra no subgrupo lordose menor (88%) foi maior que nos subgrupos lordose intermediária (81%) e no subgrupo lordose maior (75%). Complementarmente, os corpos intervertebrais apresentaram maior participação nos subgrupos lordose maior e lordose intermediária. Individualmente, os corpos vertebrais apresentaram maior participação no subgrupo lordose maior, exceto pelo corpo vertebral L5 que apresentou maior participação no subgrupo lordose menor. A maior participação percentual dos discos intervertebrais no subgrupo lordose menor era devida à inclinação cifótica dos corpos vertebrais mais cefálicos (especialmente L1 e L2) no subgrupo lordose menor do que nos demais subgrupos, que, por um efeito compensatório, causava uma maior participação discal nas curvaturas menores. Os demais subgrupos apresentavam os corpos vertebrais cefálicos com inclinação muito mais lordótica do que o observado no subgrupo lordose menor. Concluímos que os discos intervertebrais são os principais responsáveis pela curvatura lombar e que a contribuição dos corpos vertebrais e discos intervertebrais na lordose lombar difere entre indivíduos com curvaturas de diferentes magnitudes. Apesar de ocorrer um aumento gradual do acunhamento lordótico do corpo e disco a cada nível vertebral conforme aumenta a medida da lordose, as vértebras mais cefálicas provocam uma diferença na contribuição percentual entre discos intervertebrais e corpos vertebrais nas curvaturas de tamanhos diferentes. / The vertebral bodies and intervertebral discs participation in lumbar lordosis and their contribution between lumbar curves of different size were studied. 350 lumbar spine radiographs of asymptomatic adults (143 men and 207 women, average age 29 years) were evaluated. Lumbosacral (L1S1) and lumbolumbar (L1L5) curves and the angular inclination of each vertebral boby and intervertebral disc were measured using a Cobb method variant. The percentile participation of each vertebral body and intervertebral disc in the lumbossacal curve was calculated. Sex and age were compared. The subjects were separated in tree subgroups, in acording to lumbosacral curve size. The compounds of lumbar curve (discs and vertebrae) were compared in these tree subgroups. The mean lumbosacral curve was ?60,9º (-33º to ?89º). L1 vertebral body was kyphotic (2,15º), L2 was neutral (-0,36º), and the other ones were progressively lordotic from L3 (-1,56º) to L5 (-9,23º). The intervertebral discs were progressively lordotic from L1-L2 (?4,99º) to L5-S1 (?15,58º). Both vertebrae and discs showed a progressive participation in cephalic-caudal direction. The participation of discs was about 80% of lumbosacral curve, and the caudal elements (L4, L5 vertebrae and L4-L5, L5-S1 discs) contributed far 65% of the curve. The older subjects presented lumbar curves larger than younger 4º average, with significant statistical difference to L2, L5 and L3-L4 measures, with older subjects presenting bigger angular values. There were statistical differences of lumbar curves, L2 and L4 measures between sexes, with females presenting bigger values. The lumbosacral curve presented average -46,9º in minor lordosis subgroup, -64,59º in intermediate lordosis sugbroup, and ?74,13º in major lordosis subgroup. The lumbolumbar curve presented average ?33,28º in minor lordosis subgroup, -45,34º in intermediate lordosis subgroup, and ?56,96º in major lordosis subgroup. The absolut values of vertebrae and discs angles were smaller in minor lordosis subgroup than in major lordosis subgroup, but the intervertebral discs participation of was bigger in minor lordosis subgroup (88%) than intermediate lordosis (81%) and major lordosis (75%) subgroups. Complementarely, the vertebrae had a bigger participation in intermediate and major lordosis subgroups. Individually, the vertebrae presented a larger participation in major lordosis subgroup, excepting L5 that presented bigger participation in minor lordosis subgroup. The discs presented larger participation in minor lordosis subgroup. That is consequence of a more kyphotic inclination of the cephalic vertebrae in minor lordosis subgroup than the other ones, causing a compensating effect, with a larger disc participation in the small curves. The intermediate and major lordosis subgroups had the cephalic vertebrae more lordotic than that of the minor lordosis subgroup. We concluded that the intervertebral discs are the main responsible for the lumbar curve angulation and that the contribution of vertebrae and discs in lumbar curves of different sizes is not equal. In spite of a gradual increase of lordotic wedging while lumbar curve increase, the cephalic vertebrae make the disc and vertebrae participation different between different magnitude lumbar curves.

No description available.

This thesis first describes theory of range of methods of textural and shape analysis. In several published articles some of the mentioned methods are used for automatic detection of lesion in spine in CT images. Some of these articles are shortly presented (in this thesis). Next part of the thesis includes description of various classifiers which are used for classification of feature vectors. Practical part of the thesis is a design and implementation of image data segmentation solution (metastatic lesions in vertebrae) with use of classification of feature vectors formed by texture and shape symptoms. The thesis also deals with the selection of significant features for segmentation. Segmentation algorithm is tested on medical data.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-04T15:04:20Z No. of bitstreams: 1 joanadedornellascysneirosgomesdeamorim.pdf: 1811388 bytes, checksum: 09763f5f5602a497decd667655eb0c68 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:56:58Z (GMT) No. of bitstreams: 1 joanadedornellascysneirosgomesdeamorim.pdf: 1811388 bytes, checksum: 09763f5f5602a497decd667655eb0c68 (MD5) / Made available in DSpace on 2016-04-24T03:56:58Z (GMT). No. of bitstreams: 1 joanadedornellascysneirosgomesdeamorim.pdf: 1811388 bytes, checksum: 09763f5f5602a497decd667655eb0c68 (MD5) Previous issue date: 2013-02-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A autotomia caudal é uma resposta anti-predação voluntária amplamente empregada por lagartos. Suas consequências estão bem descritas na literatura, mas os fatores envolvidos na sua ocorrência carecem de aprofundamento. Pretendeu-se então averiguar se há diferença tanto na propensão à autotomia quanto no padrão de crescimento corporal e caudal de indivíduos com tamanho corporal diferente durante as estações quente/chuvosa (verão tropical) e fria/seca (inverno tropical). Para tanto foram mantidos em terrários externos três grupos experimentais (n = 19) de massas corpóreas diferentes (P1, P2 e P3), cujas caudas foram autotomizadas por constrição mecânica, medindo-se a pressão exercida e o tempo até a soltura da cauda. Dados morfométricos foram aferidos semanalmente e avaliados usando o test T bicaudal para amostras não pareadas, comparando-se as variáveis em função do peso corporal. As porções caudais liberadas foram conservadas em álcool e dissecadas, assim como quatro lagartos que morreram ao longo dos experimentos. A anatomia caudal foi analisada e comparada com descrições existentes. Elaborou-se um modelo tridimensional passível de ser usado como ferramenta didática e analítica. Foram encontradas em média 32 vértebras caudais em T. itambere. A maioria dos parâmetros avaliados não apresentou significância estatística, devido ao pequeno número amostral, mas tendências e possibilidades são apresentadas e discutidas em vista da literatura atual. Foi significativa a relação inversa entre temperatura cloacal e tempo até a autotomia. / Autotomy is an anti-predator behavior widely employed by lizards. The energetic consequences of this process are vastly describe in literature, yet the details involved in it’s occurrence lack thoroughness. This study intent to evaluate if there are differences related to body weight in propensity to realize autotomy, in body and caudal growth, both during the hot/wet season (tropical summer) and the cold/dry season (tropical winter). To accomplish that three groups of lizards (n = 19) with different body mass (P1, P2 and P3) were kept in out-doors cages during cold (July to September 2012) and hot seasons (November 2012 to January 2013). Autotomy was induced by constriction of the tail, while measuring the pression applie to it’s surface as well as the time until it’s release. Morphometric data was assessed weekly and processed using two-tailed t-test for unpaired samples, comparing variables according to body weight. The released portion of the tail was preserved in alcohol and dissected, as were the four lizards that happened to die during the experimental process. Caudal anatomy was analyzed and compare with preexisting descriptions. A three-dimensional model with didactic and analytic potential was elaborated. We found an average of 32 caudal vertebraes in T. itambere. Most of the analyzed parameters did not present statistical significance, due to the small sample size. However we present and discuss every tendency and possibility in face of the current literature. We did found a significant inverse relation between cloacal temperature and the time subjects took to undergo autotomy.

Top screw pullout is a significant problem in anterior scoliosis correction, with rates of 5-15% reported in the literature. The Mater Misericordiae Hospital in Brisbane currently has a series of 125 patients with scoliosis treated by thoracoscopic anterior fusion, instrumentation and correction between April 2000 and August 2007. In this series 11 top screws are known to have pulled out (a rate of 8.8%), with six occurring in the first week, and all within 6 weeks, suggesting that the problem is one of excessive static force rather than fatigue. This thesis describes a biomechanical investigation into the mechanics of vertebral body screw pullout in anterior scoliosis surgical constructs. Previous biomechanical studies of vertebral body screws have evaluated their resistance to either straight pullout or cephalo-caudad compression forces, however the aim of this study was to assess screw resistance to more realistic loading conditions, namely pullout of initially angled screws, and pullout where the motion path is an arc rather than a straight axial pullout, as would be expected in a single rod anterior construct. The first series of experiments involved straight and angled pullout tests using synthetic bone. In the angled tests, both locked and free-to-pivot configurations were tested. The second series of experiments tested the effect of cephalo-caudad pre-compression (the actual deformity correction step performed during surgery) on subsequent axial pullout strength. A third series of experiments performed arc pullouts using synthetic bone, and the final series of experiments tested the pullout resistance of a newly proposed screw position configuration against the standard screw positioning using ovine lumbar vertebrae. Synthetic bone testing revealed that for initially angled pullout, resistance is greatest as the screw angle approaches 0 (ie a direct axial pullout). Cephalo-caudad pre-compression reduced subsequent pullout strength for cases where a staple was not used under the screw head, but if a staple was used the pre-compression did not decrease pullout force significantly. Arc pullout resistance was greatest when the screw was angled at 10 cephalad, and the mean pullout strength for the proposed screw configuration using ovine lumbar vertebrae (1864N) was almost double that of the standard screw positioning (993N). The clinical implication of this study is that top screw pullout resistance can be maximised by placing the top screw as close as possible to the top endplate and the bottom screw as close as possible to the bottom endplate, although this will have detrimental effects on the pullout of the second screw should the top screw pull out. Screw angulation is a less important factor but any angulation should be in a cephalad direction and around 10º in magnitude. The experimental results also suggest that the use of a staple may play a role in preventing cephalo-caudad pre-compression forces from reducing screw resistance to subsequent pullout forces.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Current technology enables researchers to identify a broad spectrum of opportunities in the biomedical industry to develop new and innovative products. Imaging technology, such as Computerised Tomography (CT) scanners or Magnetic Resonance Imaging (MRI) scanners, allow doctors to visualise a patient’s internal organs and bone structure in high quality three-dimensional images. Rapid Prototyping Technology (RPT) can already produce high quality complex parts, such as concept parts for the automobile industry and medical models for preoperative planning. These parts are divided into thin layers and manufactured layer by layer. At the same time the layers are joined together to produce the desired part. Generic artificial intervertebral disc implants already exist. However, these discs are only available in standard geometrical dimensions. The possibility of using imaging technology and RPT to design and manufacture a customized, patient specific implant will be investigated. A simple design (ball and socket) is used to illustrate the design process of a customized disc. It should be noted that this project does not attempt to design a new artificial intervertebral disc implant, but rather describes the design process. The research question is: How accurate can the customised disc implant’s inverse geometry represent the geometry of the vertebrae’s endplates? A preliminary research was done and the results were used to calculate the sample size for this study. A cadaver, provided by Stellenbosch University’s Faculty of Health Sciences’ Anatomy and Histology Department, was CT scanned. The L4- and L5-vertebrae were dissected, cleaned and measured using a photogrammetry measuring machine. Meanwhile, the data gathered from the CT scan is used to design the customised disc implant. The disc is manufactured from Ti6Al4V using a RPT technique called Direct Metal Laser Sintering. After the part is manufactured it is also measured using a photogrammetry measuring machine. The photogrammetry data from the vertebrae and the manufactured customised disc implant are compared, analysed and a hypothesis is formed. It can now be determined, with a certain degree of confidence, how accurate the customised disc implant’s geometry can represent the geometry of the vertebrae’s endplates. The design of a customised disc implant demands many work hours from a qualified engineer or designer, which in turn increases the production costs. This study describes a user-friendly program which will semi-automate the design process. Only limited input from the physician will be required. This program will decrease design time, which will have a direct effect on the production costs. The manufacturing costs are investigated as well. The results from this study indicates that it is possible to design a customized prosthetic, with the help of a custom disc generator, within 27 minutes. The customized disc can then be manufactured with an accuracy of 0.37 mm using rapid prototyping. / AFRIKAANSE OPSOMMING: Huidige tegnologie maak dit vir navorsers moontlik om ʼn breë spektrum geleenthede in die biomediese bedryf te identifiseer en nuwe produkte te ontwikkel. ʼn Pasiënt kan met ʼn Gerekenariseerde Tomografie (GT) -flikkergram of ʼn Magnetiese Resonansiebeelding (MRB) - masjien geskandeer word om sodoende ʼn drie-dimensionele beeld van sy of haar interne organe en beenstrukture te verkry. Deur gebruik te maak van snelle prototiperingstegnologie (SPT) kan daar alreeds enige komplekse geometriese vorm vervaardig word. Hierdie tegnologie word ingespan om parte, ontwerp met die hulp van RGO (Rekenaargesteunde Ontwerp), te vervaardig. Die spesifieke part word in dun lae opgedeel en daarna laag vir laag vervaardig. Terselfdertyd word die lae aan mekaar geheg, totdat die gewenste vorm gegenereer is. Die moontlikheid om ʼn GT-flikkergram én SPT te gebruik, met die doel om ʼn pasklaar-vervaardigde, persoon-spesifieke implantaat te ontwerp en te vervaardig, word in hierdie projek ondersoek. Daar bestaan alreeds generiese kunsmatige intervertebrale skyf-implantate (KISI’s). Hierdie skywe word egter beperk deurdat dit slegs in standaard geometriese dimensies vervaardig word. Met dié projek word die moontlikheid van ʼn pasklaar-vervaardigde intervertebrale skyf-implantate (PVKISI) vir ʼn bepaalde pasiënt, ondersoek. ʼn Eenvoudige meganiese ontwerp (bal-en-pootjie) word gebruik om die ontwerpproses van ʼn pasklaar-skyf in hierdie projek te beskryf. Let daarop dat die projek nie poog om ʼn nuwe kunsmatige intervertebrale skyf te ontwerp nie, maar om die ontwerpproses te beskryf. Die vraag wat ondersoek word, is: Hoe akkuraat kan ʼn PVKISI die inverse geometrie van die pasiënt se intervertebrale kontakoppervlaktes voorstel? ʼn Voorafgaande ondersoek is gedoen en die resultate is gebruik om die steekproef-grootte vir hierdie studie te bepaal. ʼn Kadawer, voorsien deur die Universiteit van Stellenbosch se Fakulteit Gesondheidwetenskappe se Departement Anatomie en Histologie, is met ʼn GT-flikkergram geskandeer. Die L4- en L5-werwels is gedissekteer, skoon gemaak en met ʼn fotogrammetriemeetmasjien gemeet. Intussen is die data, verkry van die GT-flikkergram, gebruik om die PVKISI te ontwerp. Die PVKISI is van Ti6Al4V vervaardig deur Direkte Metaal Laser-Sintering (DMLS). Die part is ook met ʼn fotogrammetrie-meetmasjien gemeet. Die fotogrammetrie-data van die werwels en die PVKISI is vergelyk, geanaliseer en ʼn hipotese is daar gestel. Daar kan dus met statistiese sekerheid bepaal word hoe akkuraat die PVKISI die inverse geometrie van die intervertebrale kontakoppervlaktes kan voorstel. Die ontwerp van ʼn PVKISI vereis baie werksure van ʼn gekwalifiseerde ingenieur of ontwerper, wat veroorsaak dat die vervaardigingskoste van so ʼn implantaat kan verhoog. In dié projek word ʼn gebruikersvriendelike koppelprogram beskryf wat die ontwerpproses semi-outomatiseer. Daar sal slegs beperkte bystand van die betrokke medici vereis word. Dié koppelprogram behoort heelwat te bespaar aan die hoeveelheid werksure bestee aan die ontwerp van die PVKISI, wat direk die koste van ʼn implantaat sal verlaag. Die kostes vir die vervaardiging van die PVKISI met DMLS is ook ondersoek om te bepaal hoe kostes bespaar kan word. Daar is getoon dat ʼn pasklaar-prostese se kontakoppervlaktes met ʼn akkuraatheid van 0.37 mm, deur snelle prototipering, vervaardig kan word. Deur van die koppelprogram, wat in die studie beskryf word, gebruik te maak, sal dit moontlik wees om ʼn pasklaar-protese binne 27 minute te ontwerp.