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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.
1

Same-day vs. next-day reconstruction following Mohs micrographic surgery: a comparative study

Zingas, Louis P. 07 December 2020 (has links)
BACKGROUND: Skin cancer is the most common malignant neoplasm, with more than 5.4 million cases diagnosed annually in the United States. Treatment varies based on the type of neoplasm, its location, as well as primary vs. recurrent lesions. Nonetheless, surgical treatment remains the gold standard. Mohs micrographic surgery (MMS) is a commonly used surgical technique in the excision of such neoplasms. The technique of MMS allows for the precise removal of skin cancers while offering the highest cure rates with maximal preservation of surrounding tissue. Repairs of MMS defects are often done the same day if performed by the resecting Mohs surgeon. However, for more complicated reconstructive procedures, repairs are often performed by a separate reconstructive surgeon. When this occurs, MMS repairs may be delayed and performed on a different day due to a variety of factors such as surgical scheduling conflicts and patient tolerance. Researchers are urgently trying to explore the implications and postoperative complications of delayed MMS as compared to same day MMS. OBJECTIVE: This study compares same-day vs. next day eyelid reconstruction following MMS with attention to postoperative complications. Our aim is to investigate whether or not a delay in closure is associated with an increase in postoperative complications. METHODS: We performed a retrospective chart review of patients who underwent eyelid reconstruction following MMS from January 2008 to December 2018, by a single private practice oculoplastic surgeon. The timing of each patient’s reconstruction along with age, sex, comorbidities, such as diabetes, current smoking status, previous radiation therapy, anticoagulation treatment, and occurrence of postoperative complications were recorded. The specific location of the defect was recorded as well. The timing of reconstruction was classified as same-day or next-day reconstruction. No reconstructions took place more than 48 hours after tumor excision. The complications included in our analysis were: hematoma, wound infection, flap necrosis, dehiscence, and ectropion. Statistical significance was determined by Pearson’s chi-squared analysis. RESULTS: A total of 485 procedures were performed on 390 patients. 334 (69%) of those procedures were same-day reconstructions, while 151 (31%) of those procedures were next-day reconstructions. 19 (5.7%) of the 334 same-day reconstructions and 9 (5.9%) of the 151 next-day reconstructions were associated with complications (p=0.905). Therefore, a total of 28 (5.8%) procedures were associated with complications. More women (54%) than men (46%) underwent reconstruction. Multivariate logistic regression showed that males had a 1.274-fold higher risk of developing complication post reconstruction. Current smokers had a 1.054-fold higher risk of developing complications post reconstruction. CONCLUSIONS: There is no statistically significant difference in the postoperative complication rate when comparing same-day vs. next-day eyelid reconstruction following Mohs micrographic surgery.
2

A comparative retrospective study of Mohs micrographic surgery and vismodegib chemotherapy for the treatment of advanced basal cell carcinoma

Bunnell, Charles F. 03 November 2023 (has links)
Basal cell carcinoma is the most common form of human malignancy, and as such there are varied methods for treating its various forms. Its more advanced and aggressive forms have required both the use of and advent of therapies which offer differing safety profiles, cost, and efficacy. Two therapies which differ substantially in these respects but have overlap in their recommended use are Mohs micrographic surgery and the pharmaceutical drug vismodegib. Few studies have sought to compare the two methods using these criteria, and as vismodegib has only received FDA approval in the past ten years, it is worthwhile to explore the limitations and advantages of each therapy. In exploring previous clinical trials and retrospective studies, the two therapies are put side by side to contrast their results with their shared intended use. The general findings were that Mohs micrographic surgery remains the gold standard for the treatment of locally advanced basal cell carcinoma, and there are few demonstrable instances in which vismodegib could be deemed a more appropriate therapy. The future of vismodegib appears to be in its use as a neoadjuvant therapy for locally advanced basal cell carcinomas for which a decrease in size by vismodegib would allow for better treatment outcomes.
3

Ensaios mecânicos e caracterização microestrutural de tubos soldados por fricção

Haupt, William January 2013 (has links)
O presente trabalho avalia a evolução das microestruturas e das propriedades mecânicas em tubos API 5L X65 soldados por fricção com auxílio de um anel centralizador na posição de topo. A soldagem foi realizada em tubos de 114,3 mm (4,5’’) de diâmetro nominal e 8 mm de espessura. A avaliação mecânica foi realizada segundo normas ASTM para os ensaios de tração, dobramento de raiz, dobramento de face, ensaio de impacto Charpy V e perfis de microdurezas. Os ensaios de fadiga foram realizados para análise da vida em fadiga das juntas soldadas. Os ensaios mecânicos realizados comprovam que houve a união metalúrgica dos materiais, sendo registradas regiões com defeitos de falta de adesão o que prejudicou as propriedades mecânicas ocasionando rupturas com baixa ductilidade nas interfaces de soldagem nestes locais. Nos resultados dos ensaios de microdurezas houve um pequeno aumento das microdurezas registradas próximo às interfaces de soldagem e uma redução nas microdurezas registradas nas regiões de ZACs. Os resultados do ensaio de impacto Charpy -20 °C foi aceitável segundo a norma API 5L. As microestruturas formadas nas interfaces de soldagem são compostas por ferrita de Widmanstätten e ferrita poligonal com crescimento de grão quando comparado com o tamanho de grão do material de base. Nas regiões de ZACs houve um reordenamento de carbonetos aliado a refino de grão sendo registrada uma redução nas microdurezas destas regiões. / This paper assesses the evolution of microstructures and mechanical properties in pipes API 5L X65 welded by friction with the aid of centering ring on top position. The welding was performed in tubes of 114.3 mm (4.5'') nominal diameter and 8 mm in thickness. The mechanical evaluation was performed according to ASTM standards for tensile, root bending, face folding, Charpy V impact test and microhardness profile. Fatigue tests were performed to analyze the fatigue life of the welded joints. The mechanical tests prove that there was a metallurgical union of the materials, regions with lack of adhesion defects being recorded which affected the mechanical properties causing fractures with low ductility in the weld interfaces in these places. Microhardness test results registered a small increase in the microhardness near the weld interfaces and a reduction in the microhardness recorded in the HAZ regions. The results of the Charpy impact test at -20°C was acceptable according to API 5L. The microstructures formed at the weld interfaces are composed of Widmanstatten ferrite and polygonal ferrite with grain growth when compared to the grain size in the base material. In HAZ regions there was a reorganization of carbides combined with grain refinement, with a reduction in microhardness of these regions being registered.
4

Ensaios mecânicos e caracterização microestrutural de tubos soldados por fricção

Haupt, William January 2013 (has links)
O presente trabalho avalia a evolução das microestruturas e das propriedades mecânicas em tubos API 5L X65 soldados por fricção com auxílio de um anel centralizador na posição de topo. A soldagem foi realizada em tubos de 114,3 mm (4,5’’) de diâmetro nominal e 8 mm de espessura. A avaliação mecânica foi realizada segundo normas ASTM para os ensaios de tração, dobramento de raiz, dobramento de face, ensaio de impacto Charpy V e perfis de microdurezas. Os ensaios de fadiga foram realizados para análise da vida em fadiga das juntas soldadas. Os ensaios mecânicos realizados comprovam que houve a união metalúrgica dos materiais, sendo registradas regiões com defeitos de falta de adesão o que prejudicou as propriedades mecânicas ocasionando rupturas com baixa ductilidade nas interfaces de soldagem nestes locais. Nos resultados dos ensaios de microdurezas houve um pequeno aumento das microdurezas registradas próximo às interfaces de soldagem e uma redução nas microdurezas registradas nas regiões de ZACs. Os resultados do ensaio de impacto Charpy -20 °C foi aceitável segundo a norma API 5L. As microestruturas formadas nas interfaces de soldagem são compostas por ferrita de Widmanstätten e ferrita poligonal com crescimento de grão quando comparado com o tamanho de grão do material de base. Nas regiões de ZACs houve um reordenamento de carbonetos aliado a refino de grão sendo registrada uma redução nas microdurezas destas regiões. / This paper assesses the evolution of microstructures and mechanical properties in pipes API 5L X65 welded by friction with the aid of centering ring on top position. The welding was performed in tubes of 114.3 mm (4.5'') nominal diameter and 8 mm in thickness. The mechanical evaluation was performed according to ASTM standards for tensile, root bending, face folding, Charpy V impact test and microhardness profile. Fatigue tests were performed to analyze the fatigue life of the welded joints. The mechanical tests prove that there was a metallurgical union of the materials, regions with lack of adhesion defects being recorded which affected the mechanical properties causing fractures with low ductility in the weld interfaces in these places. Microhardness test results registered a small increase in the microhardness near the weld interfaces and a reduction in the microhardness recorded in the HAZ regions. The results of the Charpy impact test at -20°C was acceptable according to API 5L. The microstructures formed at the weld interfaces are composed of Widmanstatten ferrite and polygonal ferrite with grain growth when compared to the grain size in the base material. In HAZ regions there was a reorganization of carbides combined with grain refinement, with a reduction in microhardness of these regions being registered.
5

Ensaios mecânicos e caracterização microestrutural de tubos soldados por fricção

Haupt, William January 2013 (has links)
O presente trabalho avalia a evolução das microestruturas e das propriedades mecânicas em tubos API 5L X65 soldados por fricção com auxílio de um anel centralizador na posição de topo. A soldagem foi realizada em tubos de 114,3 mm (4,5’’) de diâmetro nominal e 8 mm de espessura. A avaliação mecânica foi realizada segundo normas ASTM para os ensaios de tração, dobramento de raiz, dobramento de face, ensaio de impacto Charpy V e perfis de microdurezas. Os ensaios de fadiga foram realizados para análise da vida em fadiga das juntas soldadas. Os ensaios mecânicos realizados comprovam que houve a união metalúrgica dos materiais, sendo registradas regiões com defeitos de falta de adesão o que prejudicou as propriedades mecânicas ocasionando rupturas com baixa ductilidade nas interfaces de soldagem nestes locais. Nos resultados dos ensaios de microdurezas houve um pequeno aumento das microdurezas registradas próximo às interfaces de soldagem e uma redução nas microdurezas registradas nas regiões de ZACs. Os resultados do ensaio de impacto Charpy -20 °C foi aceitável segundo a norma API 5L. As microestruturas formadas nas interfaces de soldagem são compostas por ferrita de Widmanstätten e ferrita poligonal com crescimento de grão quando comparado com o tamanho de grão do material de base. Nas regiões de ZACs houve um reordenamento de carbonetos aliado a refino de grão sendo registrada uma redução nas microdurezas destas regiões. / This paper assesses the evolution of microstructures and mechanical properties in pipes API 5L X65 welded by friction with the aid of centering ring on top position. The welding was performed in tubes of 114.3 mm (4.5'') nominal diameter and 8 mm in thickness. The mechanical evaluation was performed according to ASTM standards for tensile, root bending, face folding, Charpy V impact test and microhardness profile. Fatigue tests were performed to analyze the fatigue life of the welded joints. The mechanical tests prove that there was a metallurgical union of the materials, regions with lack of adhesion defects being recorded which affected the mechanical properties causing fractures with low ductility in the weld interfaces in these places. Microhardness test results registered a small increase in the microhardness near the weld interfaces and a reduction in the microhardness recorded in the HAZ regions. The results of the Charpy impact test at -20°C was acceptable according to API 5L. The microstructures formed at the weld interfaces are composed of Widmanstatten ferrite and polygonal ferrite with grain growth when compared to the grain size in the base material. In HAZ regions there was a reorganization of carbides combined with grain refinement, with a reduction in microhardness of these regions being registered.
6

Leitliniengerechte operative Versorgung von Primärmelanomen und Evaluation individueller Abweichungen

Reißig, Franziska 04 March 2019 (has links)
In der vorliegenden Arbeit werden operative Vorgehensweisen bei Melanompatienten der Hautklinik des Universitätsklinikums Leipzig analysiert, die Adhärenz der aktuellen Melanom-Leitlinienempfehlung geprüft und Auswirkungen bei Abweichungen von dieser untersucht. Dabei konnte gezeigt werden, dass die „mikrografisch kontrollierte Chirurgie' (MKC) eine gute und gewebeschonende Alternative zur konventionellen Nachexzision mit 1cm oder 2cm Sicherheitsabstand darstellt. Der Sentinel-Lymphknoten-Entfernung (SLNE) konnte lediglich eine diagnostische Relevanz nachgewiesen werden. Die Durchführung einer Lymphknoten-Dissektion (LAD) zeigte keinen Vorteil hinsichtlich der 5-Jahres-Überlebenszeit. Zudem wurden hier mehr Rezidive als bei Ablehnung des Eingriffs beobachtet.:1. Einleitung 1 1.1 Geschichte und Epidemiologie 1 1.2 Ätiopathogenese und Risikofaktoren 2 1.3 Klinik und Subtypen 3 1.4 Diagnostik 6 1.5 Stadieneinteilung und Prognose 6 1.6 Therapie 11 1.6.1 Chirurgische Therapie 11 1.6.2 Medikamentöse Therapie 12 1.6.3 Weitere Therapieoptionen 14 1.7 Nachsorge 14 2. Ziel der Arbeit 16 3. Patienten und Methoden 17 3.1 Patientenauswahl 17 3.1.1 Einschlusskriterien 17 3.1.2 Ausschlusskriterien 18 3.2 Methoden 18 3.3 Statistische Auswertung 19 4. Ergebnisse 20 4.1 Analyse der Patienten und der Tumoreigenschaften 20 4.2 Metastasierungsverhalten des Melanoms 27 4.3 Todesfälle 30 4.4 Operative Versorgung der Melanome 32 4.4.1 Primärexzision extern und in der Universitätshautklinik Leipzig 32 4.4.2 Primäroperationen in der Hautklinik 32 4.4.3 Mikrografisch kontrollierte Chirurgie 34 4.4.4 Sicherheitsabstand 35 4.4.5 Sentinel-Lymphknoten-Entnahme 37 4.4.5.1 Sentinel-Lymphknoten-Entnahme und histologischer Befund 37 4.4.5.2 Lymphabfluss und Entnahmestelle des Sentinel-Lymphknotens 38 4.4.5.3 Einflussfaktoren für Sentinel-Lymphknoten-Entnahme und histologischer Befund 41 4.4.6 Lymphknoten-Dissektion 41 4.4.6.1 Lymphknoten-Dissektion und histologischer Befund 41 4.4.6.2 Entnahmestelle des Lymphknoten-Dissektats 43 4.5. Analyse der Leitlinienadhärenz 44 4.5.1 Sentinel-Lymphknoten-Entnahme (SLNE) 44 4.5.1.1 Indikation zur SLNE durch Ulzeration und/ oder Alter < 40 Jahren 46 4.5.1.2 Indikation zur SLNE durch Breslow- Index ≥ 1 mm 48 4.5.1.3 Leitliniengerechte vs. nicht leitliniengerechte Sentinel-Lymphknoten- Entnahme 52 4.5.2 Lymphknoten-Dissektion 53 4.5.2.1 Beurteilung der indizierten Dissektion nach Durchführung 54 4.5.2.2 Beurteilung der durchgeführten Dissektion nach Indikation 55 4.6 Überlebenszeitanalyse 56 4.6.1 5-Jahres-Rezidivfreiheit 56 4.6.1.1 Parameter mit Einfluss auf 5-Jahres-Rezidivfreiheit 57 4.6.1.2 Parameter ohne Einfluss auf 5-Jahres-Rezidivfreiheit 61 4.6.2 5-Jahres-Überlebenszeit 63 4.6.2.1 Parameter mit Einfluss auf 5-Jahres-Überlebenszeit 64 4.6.2.2 Parameter ohne Einfluss auf die 5-Jahres-Überlebenszeit 68 5. Diskussion 70 5.1 Charakterisierung der Patienten und Tumoreigenschaften 70 5.2 Charakterisierung von operativen Therapien 71 5.3 Identifizierung von Prognoseparametern der 5-Jahres- Rezidivfreiheit und 5-Jahres-Überlebenszeit 73 5.4 Abweichungen von der Leitlinie und potentielle Auswirkungen auf das rezidivfreie Überleben 76 6. Zusammenfassung der Arbeit 80 7. Literaturverzeichnis 83 8. Anlagen 97
7

Predictors of wound healing in lower extremity wounds

Honaker, Jeremy Seth 02 June 2017 (has links)
No description available.

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