Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-18T12:19:11Z No. of bitstreams: 1 anapaulatellespiresdias.pdf: 1519258 bytes, checksum: 115fa6d893019191b30393d181c96383 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-10-25T12:07:25Z (GMT) No. of bitstreams: 1 anapaulatellespiresdias.pdf: 1519258 bytes, checksum: 115fa6d893019191b30393d181c96383 (MD5) / Made available in DSpace on 2016-10-25T12:07:26Z (GMT). No. of bitstreams: 1 anapaulatellespiresdias.pdf: 1519258 bytes, checksum: 115fa6d893019191b30393d181c96383 (MD5) Previous issue date: 2008-02-29 / O carcinoma colorretal (CCR) é a segunda neoplasia mais freqüente na população mundial. A alta incidência do CCR e a diferença nos resultados do tratamento desta neoplasia, de acordo com o estádio da doença, justificam os esforços para o rastreamento, prevenção e detecção precoce. Objetiva-se neste estudo descrever os aspectos: epidemiológicos, endoscópicos e anatomopatológicos das neoplasias colorretais em uma série de casos e avaliar o papel da colonoscopia na prevenção do CCR. Trata-se de estudo descritivo de série de casos atendida em centro especializado em endoscopia digestiva, no período de janeiro de 2002 a dezembro de 2006. Foram coletados dados sobre 1.962 colonoscopias realizadas em 1.491 indivíduos e, em 492 (33%) foram identificadas lesões polipóides. 408 indivíduos foram considerados para fins de análise. Na série de casos 70% dos indivíduos eram assintomáticos. A prevalência de neoplasias colorretais foi de 50% (60/120) em homens e de 42,4% em mulheres (122/288). As neoplasias foram detectadas em 138 dos 287 indivíduos (48%), com 50 anos ou mais, e a sua prevalência foi significantemente maior do que naqueles com menos de 50 anos (44/121) 36,3% (p=0,01). Verificou-se que 58,9% dos indivíduos com neoplasia e neoplasia avançada apresentavam história familiar positiva para câncer de mama, útero, ovário e/ou colorretal. Nos 408 indivíduos, foram realizadas 679 colonoscopias, com retirada de 959 lesões polipóides; destas, 463 (48,3%) eram neoplásicas, incluindo 13(1,35%) adenocarcinomas. Nas lesões menores que 5 mm, foi evidenciado displasia em 36% (346/959). No colon proximal, 21% (85/408) dos indivíduos apresentavam lesões neoplásicas e 2% (8/408), neoplasias avançadas, incluindo seis casos de adenocarcinoma sem qualquer evidência de lesão em colon distal. Dentre os 232 indivíduos que apresentavam lesões neoplásicas (benignas e ou avançadas), 130 (56%) apresentavam apenas lesões em colon proximal. Se o rastreamento fosse realizado apenas com a retossigmoidoscopia, a perda diagnóstica de lesões neoplásicas benignas seria de 76(62,3%) nas mulheres e 29(48,3%) nos homens. Em relação ao adenocarcinoma, a perda diagnóstica seria de 50% para ambos os sexos. Neoplasias colorretais são comuns em indivíduos assintomáticos. Sexo masculino, idade avançada e história familiar para câncer são fatores de risco para a detecção de lesões. A colonoscopia consiste em método eficaz de rastreamento para o CCR, a remoção de lesões neoplásicas colorretais interfere diretamente na história natural desta forma de câncer. / The colorectal carcinoma (CRC) is the second most frequent cancer in the world population. The high incidence of CRC and the difference in the results of the treatment of cancer, according to the stage of disease justify the efforts for screening, prevention and early detection. The objective of this study was to describe the epidemiological, endoscopic and pathological of polypoid lesions and colorectal cancers and assess the role of colonoscopy in preventing the CRC. This is a descriptive study of number of cases addressed in centre specializing in gastrointestinal endoscopy. In the period January 2002 to December 2006, colonoscopies were performed in 1962 and 1,491 individuals in 492 (33%) of these have been identified polypoid lesions; 408 individuals were considered for analysis. The data were included and analyzed in the Epi Info-2000. In a series of cases studied, 60% of the subjects were asymptomatic. The prevalence of colorectal cancers was 50% (60/120) in men and 42.4% in women (122/288). The cancers were detected on 138 of the 287 individuals (48%) with 50 years or more, and their prevalence was significantly higher than those with less than 50 years (44/121) 36.3% (p = 0.01). It was found that 58.9% of individuals with advanced cancer and cancer had positive family history for cancer of the breast, uterus, ovary, or colorectal. In 408 individuals, 679 colonoscopies were performed, with withdrawal of 959 polypoid lesions; these, 463 (48.3%) were neoplasms, included 13 adenocarcinomas. In lesions smaller than 5 mm, was shown dysplasia in 36% (346/959). In the proximal colon, 21% (85/408) of the subjects had neoplastic lesions in 2% (8 / 408), advanced malignancies, including six cases of adenocarcinoma without any evidence of damage in distal colon. The indication of colonoscopy only by the presence of lesions in the distal colon is controversial. Among the 232 individuals who had neoplastic lesions (benign, or advanced), 130 (56%) had only injuries in proximal colon. If the screening was done only with the retossigmoidoscopy, loss diagnosis of benign neoplastic lesions would be 76 (62.3%) in women and 29 (48.3%) in men. Regarding adenocarcinoma, the loss would be diagnostic of 50% for both sexes. Colorectal neoplasms are common even in asymptomatic subjects. Male, age and family history for cancer are risk factors for the detection of lesions. A colonoscopy is the most effective method of screening for the CRC, indicated for all individuals over 50 years old because, by identifying and removing neoplastic lesions, the colonoscopist have the ability to interfere directly in the natural history of this form of cancer.

Colonoscopy provides a minimally invasive tool for examining and treating the colon without surgery, but current endoscope designs still cause a degree of pain and injury to the colon wall. The most common colonoscopies are long tubes inserted through the rectum, with locomotion actuators, fiber optic lights, cameras, and biopsy tools on the distal end. The stiffness required to support these tools makes it difficult for the scopes to navigate the twisted path of the colon without damaging the inside wall of the colon or distorting its shape. In addition, little is known about how sharp and forceful endoscopes can be without accidentally cutting into tissue during navigation. In order to solve the requirements of stiffness (to support tools) and flexibility (to navigate turns), we expanded on a design by Zehel et al. [49], who proposed surrounding a flexible endoscope with an external exoskeleton structure, with controllable stiffness. The exoskeleton structure is comprised of rigid, articulating tubular units, which are stiffened or relaxed by four control cables. The stiffened or locked exoskeleton structure aids navigation and provides stability for the endoscope when it protrudes beyond the exoskeleton structure for examination and procedures. This research determined the design requirements of such an exoskeleton structure and simulated its behavior in a sigmoid colon model. To predict just how pointed an endoscope can be without damaging tissue under a given force, we extrapolated a strength model of the descending colon from published stress-strain curves of human colon tissue. Next we analyzed how friction, cable forces, and unit angles interact to hold the exoskeleton structure in a locked position. By creating two- and three-dimensional models of the exoskeleton structure, we optimized the dimensions of the units of an exoskeleton structure (diameter, thickness, and leg angle) and cable holders ( cable attachment location) to achieve the turns of the sigmoid colon, while still remaining lockable. Models also predicted the loss of force over the exoskeleton structure due to curving, further determining the required cable angles and friction between units. Finally we determined how the stiffness of the endoscope stem affected locking ability and wear inside the exoskeleton structure. / Ph. D.