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  • 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.
151

Finite Element Modeling of the Mitral Valve and Mitral Valve Repair

Baxter, Iain A. 28 May 2012 (has links)
As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.
152

Léčba arteriovenózních malformací mozku. / Treatment for Brain Arteriovenous Malformations

Bradáč, Ondřej January 2015 (has links)
Introduction: The surgical and endovascular results of the treatment of pial AVM provided at our Neurosurgical centre are presented. These results are supported by neuropsychological outcomes of subgroup of treated patients. Going by these results and by an overview of literary data on the efficacy and complications of each therapeutic modality, the optimal algorithm of indications is presented Cohort of patients: The main series comprises 222 patients aged 9 to 87 years treated in the years 1998 - 2013. The surgical group consists of 85 patients, 55 patients received solely endovascular treatment. Thirty-four patients were consulted and referred directly to the Radiosurgical unit. The remaining 48 were recommended to abide by the strategy of "watch and wait". A subgroup of 66 patients, who underwent treatment of AVM was neuro-psychologically tested at least two years after treatment using a battery of tests constructed specifically for this study. A control group consisted of 10 subjects without any neurological disease. Results: In the surgical group, serious complications were 3.5% at a 96.5% therapeutic efficacy. As for AVM treated with purely endovascular methods, serious procedural complications were seen in 5.5% of patients, with efficacy totalling 36.4%. One observed patient suffered...
153

Alterações dos níveis séricos do antígeno prostático específico encontradas no pós-operatório nos pacientes submetidos à ressecção transuretral da próstata / Changes on the serium levels of the prostate specifc antigen found on the post-operative submitted of the patients to the transuretral ressection of prostate

Roberto Cepêda Fonseca 08 April 2005 (has links)
Introdução - A ressecção transuretral da próstata continua sendo uma das cirurgias mais realizadas em homens com idade acima de 50 anos e é considerada o padrão-ouro no tratamento cirúrgico de pacientes com sintomas de hiperplasia prostática benigna (HPB). Embora sua eficácia no alívio dos sintomas de pacientes com HPB já tenha sido extensamente documentada, seu impacto sobre os níveis séricos de antígeno prostático específico não é bem conhecido. O objetivo do presente estudo foi avaliar o comportamento dos níveis séricos do antígeno prostático específico (PSA) em pacientes submetidos à ressecção transuretral da próstata. Métodos - No período de abril de 2003 a julho de 2004, 30 pacientes portadores de hiperplasia prostática benigna, selecionados para tratamento cirúrgico por meio de ressecção transuretral da próstata foram avaliados prospectivamente. A idade dos pacientes variou de 46 a 84 anos (mediana de 68,5 anos). A avaliação pré-operatória incluiu quantificação dos sintomas do trato urinário inferior através do escore internacional de sintomas prostáticos (IPSS), dosagem sérica do PSA total, relação de PSA livre sobre total (PSAl/t) e avaliação do peso prostático por ultrassonografia transretal. Os fragmentos ressecados na cirurgia foram pesados e submetidos a exame histopatológico com coloração pela hematoxilina-eosina. Os pacientes foram avaliados após 30, 60 e 180 dias da cirurgia com IPSS, dosagem sérica do PSA total e relação de PSAl/t. Para estudar o impacto da presença de prostatite crônica sobre os níveis de PSA, os pacientes foram divididos em dois grupos com base na presença ou ausência de prostatite e foram comparados em relação às variáveis clínicas e níveis de PSA préoperatórios bem como evolução pós-operatória dos níveis de PSA. Resultados - Na avaliação pré-operatória, o I-PSS variou de 18 a 29, com média de 22,5 ± 2,9. O PSA total variou de 0,79 ng/ml a 33,46 ng/ml com média de 6,19 ng/ml e mediana de 3,79. A relação de PSAl/t foi de 18,18% ± 3,36. O peso prostático variou de 29,0 a 130,0g com média de 71,8g. O peso dos fragmentos prostáticos ressecados variou de 11g a 102g, com média de 29,87g ± 19,58g. O I-PSS reduziu-se significantemente em todos os momentos avaliados após a cirurgia, sendo 12,6 ± 2,0 no 30º dia pósoperatório (PO); 11,6 ± 1,6 no 60º PO; e 11,3 ± 1,8 no 180º PO (p< 0,01 para todas as comparações com o IPSS pré-operatório). O PSA total reduziu-se significantemente em todos os momentos avaliados após a cirurgia em comparação com o PSA pré-operatório, sendo 2,27ng/ml ± 2,20 no 30° PO; 1,75ng/ml ± 1,66 no 60° PO e 1,79 ng/ml ± 1,26 no 180° PO (p<0,001 para todas as comparações). Houve diferença estatisticamente significante quando se comparou o PSA total do 30° PO com o 60° e 180° PO (p<0,05) mas não na comparação entre o 60° e 180° PO. A relação de PSAl/t não variou de forma significante após a cirurgia em comparação com o pré-operatório, sendo 17,78% ± 8,59 no 30° PO; 18,69% ± 9,89 no 60°, e 21 ± 7,49 % no 180° (p =0,91). No exame histopatológico, foram identificados 12 (40%) pacientes com hiperplasia prostática benigna e prostatite crônica e 18 (60%) com diagnóstico somente de hiperplasia prostática benigna. Não houve diferenças estatisticamente significantes entre os pacientes com e sem prostatite em relação aos parâmetros préoperatórios idade, I-PSS, PSAt, relação do PSAl/t e peso ressecado da próstata. Os níveis de PSA total pós-operatório variaram de 8,1ng/ml ± 10,2 para 2,4ng/ml ± 2,3; 1,6ng/ml ± 1,0 e 1,9ng/ml ± 0,9, respectivamente nos 30, 60 e 180 dias pós-operatórios, entre os pacientes com prostatite. Entre os pacientes sem prostatite, o PSA total reduziu-se de 4,9ng/ml ± 3,7 para 2,2ng/ml ± 2,2; 1,8ng/ml ± 2,0 e 1,7ng/ml ± 1,5, respectivamente nos 30, 60 e 180 dias pós-operatórios. Não houve diferença estatisticamente significante na comparação dos pacientes com e sem prostatite em nenhum dos momentos avaliados. Conclusões - Os níveis séricos de PSA total dos pacientes com hiperplasia prostática reduzem-se significantemente após a cirurgia de ressecção transuretral da próstata, atingindo o valor mínimo de estabilização após 60 dias da cirurgia. A relação de PSAl/t não é afetada pela cirurgia. A presença de prostatite crônica não tem influencia sobre a evolução dos níveis séricos de PSA. Estes achados deverão ajudar no seguimento de pacientes submetidos à ressecção transuretral da próstata / Introduction - Transurethral resection of the prostate (TURP) remains as one of the most common surgeries in men over 50 years old and is considered the gold standard in the surgical treatment of patients with benign prostatic hyperplasia (BPH). Although its efficacy in the relief of lower urinary symptoms in patients with BPH have been extensively demonstrated, it is not clear how it affects the serum levels of prostate-specific antigen (PSA). The objective of this study was to evaluate the progression of the serum levels of PSA after TURP in patients with BPH. Materials - From April 2003 to July 2004, 30 patients with BPH were selected for TURP and were prospectively evaluated. The age of the patients varied from 46 to 84 years (median 68,5 years). Preoperative evaluation included quantification of the lower urinary tract symptoms with the international prostatic symptom score (IPSS), assessment of the serum levels of total and free PSA and evaluation of the prostate weight bytransrectal ultrasound. Prostate fragments resected in the surgery were weighed and histologically evaluated. Postoperatively, patients were evaluated after 30, 60 and 180 days of the surgery, with IPSS, free-tototal PSA ratio (PSAf/t). To evaluate the influence of the presence of chronic prostatitis on the PSA levels, patients were divided in two groups based on the presence or absence of prostatitis and compared in terms of preoperative clinical variables and PSA levels as well as the postoperative progression of the PSA levels. Results - In the preoperative evaluation, I-PSS varied from 18 to 29, with a mean of 22,5 ± 2,9. Total PSA levels varied from 0,79 ng/ml to 33,46 ng/ml with a mean of 6,19 ng/ml and median of 3,79. The mean PSAf/t ration was 18,18% ± 3,36. Prostate weight varied from 29,0 to 130,0g with a mean of 71,8g. Resected prostate weight varied from 11g to 102g, mean 29,87g ± 19,58g. A significant decrease of the IPSS was observed in all moments of postoperative evaluation, with a mean of 12,6 ± 2,0 on the 30th postoperative day (PO); 11,6 ± 1,6 on the 60 PO and 11,3 ± 1,8 on the 180 PO (p< 0,01 for all comparisons with the preoperative IPSS). Total PSA was significantly reduced in all moments of postoperative evaluation in comparison with the preoperative levels, with a mean of 2,27ng/ml ± 2,20 on the 30 PO; 1,75ng/ml ± 1,66 on the 60 PO and 1,79 ng/ml ± 1,26 on the 180 PO (p<0,001 for all comparisons). A significant difference was observed in the PSA levels of the 30 PO in comparison with the 60 and 180 PO (p<0,05) but not in the comparison of the 60 PO with 180 PO. The PSAf/t ration did not significantly varied in comparison with the preoperative values, with a mean of 17,78% ± 8,59 on the 30 PO; 18,69% ± 9,89 on the 60 PO and 21 ± 7,49 % on the 180 PO (p =0,91). On the histopathological studies, 12 (40%) patients were diagnosed with chronic prostatitis and BPH and e 18 (60%) with isolated BPH. There was no statisticaly significant differences between patients with and without prostatitis in terms of the preoperative parameters age, I-PSS, total PSA, PSAf/t ration and resected prostate weight. Among the patients with prostatitis, serum levels of total PSA varied from 8,1ng/ml ± 10,2 preoperatively, to 2,4ng/ml ± 2,3; 1,6ng/ml ± 1,0 e 1,9ng/ml ± 0,9, respectively after 30, 60 and 180 days postoperatively. Among the patients without prostatitis, serum levels of total PSA varied from 4,9ng/ml ± 3,7 preoperatively, to 2,2ng/ml ± 2,2; 1,8ng/ml ± 2,0 e 1,7ng/ml ± 1,5, respectively after 30, 60 and 180 days postoperatively. There was no significant differences between the groups in any of the evaluations. Conclusions - Serum levels of total PSA in patients with benign prostatic hyperplasia reduce significantly after transurethral resection of the prostate, reaching the lowest stabilization value 60 days after the surgery. The PSAf/t ration is not altered by the surgery. The presence of chronic prostatitis has no influence on the progression of the serum levels of total PSA. These findings should help the clinician in the management of patients submitted to transurethral resection of the prostate
154

Ressecção lateral do conduto auditivo externo: Avaliação no tratamento da otite externa crônica e proposta do uso de adesivos / Resection lateral of the external ear canal: Evolution on the treatment of chronic external otitis and use the adhesives

Wilhelm, Graziela 30 April 2010 (has links)
Made available in DSpace on 2014-08-20T14:37:59Z (GMT). No. of bitstreams: 1 dissertacao_graziela_wilhelm.pdf: 1275443 bytes, checksum: 5ac7d92c65d4c9206a6a7f09cb6abe47 (MD5) Previous issue date: 2010-04-30 / The external otitis corresponds to all inflammatory process, acute or chronic, that reaching the external auditory epithelium, may also affect the pinna. In chronic or recurrent cases of canine otitis, not responsive to therapy with drugs, the surgical treatment is indicating, thus, lateral resection to external auditory canal one of the techniques applied. The objective of this work was evaluated the clinical, microbiological and histopathological aspects of the resection of the lateral external auditory canal in the treatment of chronic external otitis in dogs and compared the surgical wounds healing process of the external auditory and the lumbar region skin of rabbits using in the suture tissue adhesives and nylon yarn. In the first experiment was studying seven canines with chronic recurrent, with time course of a year or more, not responsive to drug treatment, presenting vertical conduit stenosis, ceruminous secretion (moderate to abundant) or purulent secretion and presence of erythema (moderate to intense). In the 0 day the dogs were evaluated clinically and collected samples of ear secretion for microbiological analysis and, after, submitted to lateral resection of external auditory canal procedure. In the 45, 60, 90 days postoperative, the dogs were reassessed clinically and micorbiologically as the evolution of otitis. The auditory pinna was evaluated as the purid and erythema presence. The external auditory canal was evaluated considering the presence of erythema, secretion, stenosis, tumor and growth offungi and bacteria. In the second experiment 12 rabbits was used (n=24 ears) submitted to lateral resection of external auditory canal and to two cutaneous incision in the dorsal region. The surgical wounds suture were realized with monofilament nylon and tissue adhesives. The clinical aspects of the surgical wounds healing process in the 1º, 3º, 7º, 14º and 21º postoperative day (pod) were evaluated. At the end of the experiment (21º postoperative day) were collected surgical wounds samples for hystopathology analysis. The results of the experiment with dogs demonstrated that the lateral resection technical of external auditory was effective in the chronic external otitis treatment, it shown a significant reduce (p<0,000) of the erythema, pruritus and secretion when compared the 0 day with 45, 60 and 90 postoperative day. In the experiment realized with rabbits, the surgical wounds of the ears and the skin clinical evaluations indicating no significant difference (p >0,05) between the treatments, with a tendency towards outcome in the healing process, of etyl-cyanocrylate. When compared the surgical wounds healing of the ears and the skin, was evidenced that in the skin the three treatments were greatest than in the ear. The results demonstrated that the lateral resection of the external auditory conduit was effective in the chronic external otitis treatment and that both the monofilament nylon 5-0 and the n-butyl cyanoacrylate adhesives (Vetbond®) and etyl-cyanoacrylate (Super Bonder®) were acted in similar form in the surgical wounds healing, with a tendency to better the healing evolution when using the etyl-cyanocrylate. / A otite externa corresponde a todo processo inflamatório, agudo ou crônico, que atinge o epitélio do conduto auditivo externo, podendo também acometer o pavilhão auricular. Em casos crônicos ou recidivantes de otite canina, não responsivos a terapia com medicamentos, o tratamento cirúrgico é indicado, sendo, a ressecção lateral do conduto auditivo externo uma das técnicas aplicadas. Neste trabalho objetivou-se avaliar os aspectos clínicos, microbiológicos e histopatológicos da ressecção lateral do conduto auditivo externo no tratamento da otite externa crônica em cães e comparar o processo de cicatrização de feridas cirúrgicas do conduto auditivo externo e da pele da região lombar de coelhos utilizando na síntese adesivos teciduais e o fio de náilon. No primeiro experimento foram estudados sete caninos com otite externa crônica recidivante, com tempo de evolução de um ano ou mais, não responsiva a tratamento medicamentoso, apresentando estenose do conduto vertical, secreção ceruminosa (moderada a abundante) ou purulenta e presença de eritema (moderado a intenso). No dia 0 os cães foram avaliados clinicamente e coletadas amostras de secreção auricular para análise microbiológica e, posteriormente, submetidos ao procedimento de ressecção lateral do conduto auditivo externo. Nos dias 45, 60 e 90 pós-operatório foram reavaliados clinicamente e microbiologicamente quanto à evolução da otite. O pavilhão auricular foi avaliado quanto à presença de prurido e eritema. O conduto auditivo externo foi avaliado considerando a presença de eritema, secreção, estenose, tumorações e crescimento de fungos e bactérias. A técnica foi efetiva no tratamento da otite externa crônica canina. No segundo experimento, foram utilizados 12 coelhos (n=24 orelhas) submetidos à ressecção lateral do conduto auditivo externo e a duas incisões cutâneas na região dorsal. A síntese das feridas cirúrgicas foram realizadas com náilon monofilamentar e adesivos teciduais. Foram avaliados os aspectos clínicos do processo cicatricial das feridas cirúrgicas no 1º, 3º, 7º, 14º e 21º dia pós-operatório. No final do experimento (21º dia pós-operatório) foram coletadas amostras das feridas cirúrgicas para análise histopatológica. Os resultados do experimento com cães demonstraram que a técnica de ressecção lateral do conduto auditivo externo foi efetiva no tratamento da otite externa crônica demonstrando redução significativa (p<0,000) do eritema, prurido e secreção quando comparado o dia 0 com os dias 45, 60 e 90 dias pós-operatório, bem como redução no crescimento de fungos e bactérias. No experimento realizado com coelhos, as avaliações clínicas das feridas cirúrgicas das orelhas e da pele indicaram não haver diferenças significativas (p >0,05) entre os tratamentos, apesar de apresentar tendência de melhor evolução no processo cicatricial do etil-cianoacrilato. Quando comparado à cicatrização das feridas cirúrgicas da orelha e da pele, foi evidenciando que na pele os três tratamentos foram melhores do que na orelha. Os resultados demonstraram que tanto o náilon monofilamentar 5-0 quanto os adesivos n-butil cianoacrilato (Vetbond®) e etil-cianoacrilato (Super Bonder®) atuaram de forma semelhante na cicatrização das feridas cirúrgicas, com tendência para melhor evolução cicatricial quando utilizado o etil-cianoacrilato.
155

Optimisation de la technique de dissection sous muqueuse à l’aide d’un bistouri à jet d’eau haute-pression pulsée pour le traitement endoscopique des tumeurs superficielles du tube digestif / Endoscopic submucosal dissection optimizations using a water jet system with high pulsed pressure for the endoscopic treatment of superficial tumors in the digestive tract

Pioche, Mathieu 24 September 2015 (has links)
Dans cette thèse, nous avons travaillé sur les différents versants de la technique de dissection sous-muqueuse et les problèmes que pose ce geste quasi chirurgical dans des unités d'endoscopie initialement médicales. Tout d'abord, nous avons travaillé sur la formation à la technique en développant un modèle d'apprentissage sur colon de bovin plus adapté à la situation européenne où les lésions colo-rectales sont les plus fréquentes. Ce modèle de rectum de bovin, simple à trouver et à préparer permet une formation dans des conditions plus proches de la paroi colique humaine que celles offertes par l'estomac de cochon. Un travail à plus grande échelle évaluant les bénéfices d'une aide à l'apprentissage par un logiciel interactif dédié mené sur ce modèle avec 37 étudiants français et japonais est en cours d'analyse et sera publié prochainement. Ensuite, nous avons réfléchi à la stratégie de la procédure pour la rendre plus simple en évaluant précocement la technique du tunnel pour la dissection des lésions œsophagiennes. Cette stratégie permet de maintenir une traction sur les bords lésionnels et nous offrent une sorte de triangulation en élargissant physiquement la zone de travail. Cette stratégie est devenue un standard pour les résections œsophagiennes dans de nombreuses équipes. Enfin, nous avons travaillé conjointement avec la société Nestis® au développement d'un outil permettant d'optimiser la procédure de dissection sous-muqueuse en associant les bénéfices des bistouris bi fonction (injectant et coupant avec le même outil}, de la haute pression pulsée et des solutions macromoléculaires visqueuses. Le système Nestis® permet pour la première fois cette association et a démontré son intérêt en termes de sécurité et de performance par rapport à la méthode classique utilisant l'aiguille et un bistouri électrique conventionnel. Avec cet outil bi fonction, il n'est plus nécessaire de changer d'instrument puisque toutes les étapes de la procédure sont désormais réalisées avec un seul et même outil. D'autres projets sont déjà prévus avec ce matériel pour étudier ses bénéfices et sa sécurité en dissection colique humaine qui est réputée comme la plus difficile compte tenu de la finesse de la paroi. Enfin, ce matériel offre la possibilité d'injecter sous pression des principes actifs qui pourrait dans le futur permettre de prévenir la survenue de sténoses œsophagiennes ou diriger la cicatrisation. Nous avons ainsi travailler avec la pharmacie de l'hôpital Edouard Herriot pour stabiliser la solution macromoléculaires de mélange de glycérol pour permettre son utilisation en pratique quotidienne / First of all, we worked on the training for unexperienced operators by developing a bovine colon model more adapted to the European situation where colo-rectal lesions are the most common. This model of rectum from bovine, easy to find and to prepare allows training in conditions most close to the human colonic wall than those offered by the pig stomach. Furthermore, such models allows to teach the initial skills but avoiding the risk of adverse events for the first procedures in humans. A future work evaluating the benefits of a learning support by a dedicated interactive software on this model with 37 french and Japanese students is now being analyzed and will be reported soon. Then we thought about the strategy of the procedure in order to make it more simple using the tunnel technique to perform ESD for the esophageal lesions. This strategy helps to maintain traction on the edges and offers a sort of triangulation physically expanding the working space. This strategy has become a standard for esophageal resections in many teams and we still work to improve its efficacy. Finally, we worked jointly with Nestis® Company to develop a tool to optimize the submucosal dissection procedure by combining the benefits of the catheters bi function (injecting and cutting with the same tool), but adding high pulsed pressure and capability to inject viscous macromolecular solutions. The Nestis® system allows for the first time this association and demonstrated his interest in terms of security and performance compared with the conventional method using the needle and a conventional electrocautery device. With this bi function tool, it is not necessary to change instrument frequently since all stages of the procedure are now done with a single device. Other projects are already included with this material to explore its benefits and its safety in human colonic dissection that is deemed as the most difficult due to the thinner wall. Finally, this material offers the possibility to inject pressurized active drugs which could be used in the future to prevent the occurrence of esophageal strictures or to direct healing. We also worked with the hospital Edouard Herriot pharmacy to stabilize the solution glycerol mix to allow its use in daily practice in our unit
156

Finite Element Modeling of the Mitral Valve and Mitral Valve Repair

Baxter, Iain A. January 2012 (has links)
As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.
157

Model-Based Evaluation of Spontaneous Tumor Regression in Pilocytic Astrocytoma

Buder, Thomas, Deutsch, Andreas, Klink, Barbara, Voss-Böhme, Anja 08 June 2016 (has links)
Pilocytic astrocytoma (PA) is the most common brain tumor in children. This tumor is usually benign and has a good prognosis. Total resection is the treatment of choice and will cure the majority of patients. However, often only partial resection is possible due to the location of the tumor. In that case, spontaneous regression, regrowth, or progression to a more aggressive form have been observed. The dependency between the residual tumor size and spontaneous regression is not understood yet. Therefore, the prognosis is largely unpredictable and there is controversy regarding the management of patients for whom complete resection cannot be achieved. Strategies span from pure observation (wait and see) to combinations of surgery, adjuvant chemotherapy, and radiotherapy. Here, we introduce a mathematical model to investigate the growth and progression behavior of PA. In particular, we propose a Markov chain model incorporating cell proliferation and death as well as mutations. Our model analysis shows that the tumor behavior after partial resection is essentially determined by a risk coefficient γ, which can be deduced from epidemiological data about PA. Our results quantitatively predict the regression probability of a partially resected benign PA given the residual tumor size and lead to the hypothesis that this dependency is linear, implying that removing any amount of tumor mass will improve prognosis. This finding stands in contrast to diffuse malignant glioma where an extent of resection threshold has been experimentally shown, below which no benefit for survival is expected. These results have important implications for future therapeutic studies in PA that should include residual tumor volume as a prognostic factor.
158

Rechnergestützte Planung und Rekonstruktion für individuelle Langzeit-Knochenimplantate am Beispiel des Unterkiefers

Sembdner, Philipp 25 January 2017 (has links)
Die vorliegende Arbeit befasst sich mit der Entwicklung und Umsetzung von Methoden und Werkzeugen zur Bereitstellung von Modellen und Randbedingungen für die Konstruktion individueller Langzeit-Knochenimplantate (Konstruktionsvorbereitung). Grundlage dabei ist, dass die Planung aus medizinischer Sicht z.B. durch einen Chirurgen und die Konstruktion unter technischen Aspekten z.B. durch einen Konstrukteur getrennt erfolgt. Hierfür wird ein erarbeitetes Planungskonzept vorgestellt, welches sowohl die geplanten geometrischen Merkmale, als auch weiterführende Metadaten beinhaltet (Randbedingungen). Die Übergabe dieser Planungsdaten an die Konstruktion erfolgt über eine dafür entworfene Formatbeschreibung im Kontext der Schnittstelle zwischen Mediziner und Ingenieur. Weiterführend wird die Notwendigkeit von speziellen Funktionen für die Konstruktion von individuellen Implantaten in der Arbeitsumgebung des Konstrukteurs (z.B. Modelliersystem – CAD) am Beispiel der konturlinienbasierten Modellrekonstruktion erörtert. Die gesamtheitliche Basis bildet eine durchgängig digitale Prozesskette zur Datenaufbereitung, Konstruktion und Fertigung. Die Anwendbarkeit der Methoden und zweier umgesetzter Demonstratoren wurde innerhalb eines interdisziplinär angelegten Projektes am realen Patientenfall bestätigt.
159

Pooperační projevy po resekci vestibulárního schwannomu a jejich dopad na kvalitu života / Postoperative symptoms after vestibular schwannoma surgery and their impact on quality of life

Koutná, Sára January 2019 (has links)
Vestibular schwannoma is one of the most common tumors found in a cerebellopontine angle. Despite tumor's benignity, there are many cases that are indicated for a surgical resection. Frequently postoperative symptoms described by patients and also by literature are hearing loss, vertigo, tinnitus and weakness or numbness of face. Our work wants to show also other factors which can be damaging for patient life. We talk about postoperative headache and anxiety or depression disorders. The aim of the study will be describe these symptoms, try to find the corelations between them and determine the impact on quality of life. In our survey, patients one year after vestibular schwannoma resection recieve convenient questionnaires to fill. The questionnaires will be focused on headache disability, anxiety and depression, vestibular dysfunction and perception of quality of life.
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Léčba arteriovenózních malformací mozku. / Treatment for Brain Arteriovenous Malformations

Bradáč, Ondřej January 2015 (has links)
Introduction: The surgical and endovascular results of the treatment of pial AVM provided at our Neurosurgical centre are presented. These results are supported by neuropsychological outcomes of subgroup of treated patients. Going by these results and by an overview of literary data on the efficacy and complications of each therapeutic modality, the optimal algorithm of indications is presented Cohort of patients: The main series comprises 222 patients aged 9 to 87 years treated in the years 1998 - 2013. The surgical group consists of 85 patients, 55 patients received solely endovascular treatment. Thirty-four patients were consulted and referred directly to the Radiosurgical unit. The remaining 48 were recommended to abide by the strategy of "watch and wait". A subgroup of 66 patients, who underwent treatment of AVM was neuro-psychologically tested at least two years after treatment using a battery of tests constructed specifically for this study. A control group consisted of 10 subjects without any neurological disease. Results: In the surgical group, serious complications were 3.5% at a 96.5% therapeutic efficacy. As for AVM treated with purely endovascular methods, serious procedural complications were seen in 5.5% of patients, with efficacy totalling 36.4%. One observed patient suffered...

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