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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.
11

Positional accuracy in a natural resource database: comparison of a single-photo resection versus affine registration

Combs, Russell G. 10 January 2009 (has links)
Positional and area accuracies were calculated for digitized data taken from 1:20,000 scale aerial photographs and United States Geological Survey (USGS) 1:24,000 scale topographic maps. Positional accuracy was determined as the Euclidian distance between the digitized coordinate and the reference ground coordinate collected with global positioning systems (GPS). Area accuracy was the acreage difference between the digitized area and GPS calculated area. Three methods were employed to collect the digitized data: manual digitizing from topographic maps and aerial photographs followed by an affine transformation, and manual digitizing from aerial photographs while applying a single-photo space resection. Two study sites, one in low terrain relief and one in high terrain relief, were used to examine the effects of terrain on positional accuracies. The single-photo space resection technique provided the most accurate positional data on both study sites. The single-photo space resection produced mean positional accuracies of 5.0 to 6.0 meters. In comparison, the uncorrected digitized photo data produced mean positional accuracies of 7.0 to 26.0 meters. The effects of terrain displacement were evident in these data sets, as the mean positional accuracy at the low-relief study site was 18.96 meters less than the corresponding accuracy at the high-relief study site. The uncorrected digitized photo data set from the high-relief study site provided the highest mean positional accuracy, 25.86 meters. The topographic map digitized data from both study sites provided mean positional accuracies below 12.0 meters, but failed to meet National Map Accuracy Standards (NMAS) for 1:20,000 scale or smaller maps. The average area accuracy from both study sites proved to be not significantly different, regardless of the digitizing technique or terrain conditions. The average area accuracy between the two study sites differed by at most 0.05 hectares. Average percent area errors ranged from 9.96% to 11.74% on the low-relief study site and from 11.84% to 12.65% on the high-relief study site. / Master of Science
12

Functional outcomes of pharyngeal stimulation in patients with dysphagia after surgical treatment for head and neck cancer

Harris, Jennifer Unknown Date
No description available.
13

Unresolved issues and controversies surrounding the management of colorectal cancer liver metastasis

Kassahun, Woubet T. 25 February 2015 (has links) (PDF)
Ideally, tumors that might cause morbidity and mortality should be treated, preferably early, with proven, convincing, and effective therapy to prevent tumor progression or recurrence, while maintaining a favorable risk-benefit profile for the individual patient. For patients with colorectal cancer (CRC), this diagnostic, prognostic, and therapeutic precision is currently impossible. Despite significant improvements in diagnostic procedures, a sizable number of patients with CRC have liver metastases either at presentation or will subsequently develop it. And in many parts of the world, most cancer-related deaths are still due to metastases that are resistant to conventional therapy. Metastases to the liver occur in more than 50% of patients with CRC and represent the major determinant of outcome following curative treatment of the primary tumor. Liver resection offers the best chance of cure for metastases confined to the liver. However, due to a paucity of randomized controlled trials, its timing is controversial and a hotly debated topic. This article reviews some of the main controversies surrounding the surgical management of colorectal cancer liver metastases (CRLM).
14

Functional outcomes of pharyngeal stimulation in patients with dysphagia after surgical treatment for head and neck cancer

Harris, Jennifer 11 1900 (has links)
Head and neck cancer patients often experience swallowing disorders placing them at risk for aspiration and malnutrition. This study examined the effects of electrical stimulation to the pharyngeal wall on swallowing function in post-surgical head and neck cancer patients. Swallowing of liquid, pudding, and cookie consistencies was examined using videofluoroscopy before, and 30 minutes after, a ten minute application of electrical stimulation the pharyngeal wall in 5 male patients experiencing moderate-severe dysphagia. A total of ten measures of swallowing function were obtained from pre- and post-videofluoroscopy studies. Changes were observed post-stimulation in duration of posterior pharyngeal wall to base of tongue contact, total number of swallows, cricopharyngeal opening durations, and pharyngeal transit time. Preliminary findings indicate that electrical stimulation of the pharynx may impact certain features of swallowing in head and neck cancer patients who experience dysphagia. However, further studies are required to confirm the present findings, explore the mechanisms responsible for these changes, and investigate the effect on swallowing function as a result of manipulating stimulus frequencies, intensities and durations. / Speech-Language Pathology
15

Experimentelle und klinische Untersuchung des Einflusses von Prä- und Probiotika auf bakterielle Translokation und postoperative Infektionen nach abdominalchirurgischen Eingriffen

Rayes, Nada 28 May 2004 (has links)
In der vorliegenden Arbeit wurde der Einfluss von Prä- und Probiotika auf bakterielle Translokation (BT) und postoperative Infektionen nach großen viszeralchirurgischen Eingriffen untersucht. Dabei wurde aus methodischen Gründen zunächst BT nach Leber- (LR) und Colonresektion (CR) allein oder in Kombination experimentell im Rattenmodell quantifiziert und deren potentielle Pathomechanismen untersucht. Anschließend wurde der Einfluss von einzelnen Probiotika und einer Kombination verschiedener Probiotika und Präbiotika auf die Inzidenz bakterieller Infektionen nach Lebertransplantation (LTX) und pyloruserhaltender Pankreaskopfresektion (PPPD) in zwei prospektiv randomisierten klinischen Studien analysiert. Im experimentellen Teil der Untersuchungen wurde BT nach LR vor allem in Leber und Milz, nach CR hauptsächlich in mesenterialen Lymphknoten (MLK) und Milz nachgewiesen. Kombination von LR und CR führte zu einer Potenzierung der BT, parallel zum Ausmaß der LR. Durch Gabe von Probiotika wurde die Konzentration von Bakterien in den MLK signifikant gesenkt. Tiere mit einer hohen coecalen Laktobazillenkonzentration hatten eine signifikant niedrigere bakterielle Konzentration in allen untersuchten Organen als Tiere mit weniger Laktobazillen. CR führten zu einer Zunahme der coecalen gramnegativen Bakterienkonzentration und zu einer Abnahme der Laktobazillen. Histologische Veränderungen der Darmmukosa wurden nicht beobachtet. Die parazelluläre Permeabilität für Ionen, nicht aber für die höhermolekulare Laktulose war im Colon in allen Gruppen im Vergleich zur Kontrollgruppe erhöht. Probiotika beeinflussten die Zusammensetzung der coecalen Flora und damit auch die BT. In der ersten klinischen Studie verminderte postoperative orale Gabe von Laktobazillus plantarum und einer ballaststoffhaltigen Ernährungslösung die Inzidenz von bakteriellen Infektionen nach LTX im Vergleich zu selektiver Darmdekontamination und ballaststofffreier Ernährung signifikant. Die Gabe von Ballaststoffen und hitzeinaktivierten Laktobazillen führte zwar auch zu einer geringen Reduktion der Infektionen; diese war jedoch nicht signifikant. In der Mehrzahl wurden enteropathogene Bakterien isoliert. Die zweite klinische Studie untersuchte den Einfluss einer Kombination von vier verschiedenen Milchsäurebakterien und vier Präbiotika auf die Inzidenz bakterieller Infektionen nach LTX und PPPD. Im Vergleich zu Präbiotika und Placebo kam es zu einer deutlichen Verminderung der Infekte, die nach LTX auch signifikant war. In beiden Studien wurde die enterale Ernährung gut vertragen mit relativ wenig Nebenwirkungen. BT tritt somit sehr häufig auch nach kleineren viszeralchirurgischen Eingriffen auf und hat organspezifisch verschiedene Ursachen. Probiotika konnten sowohl tierexperimentell die BT vermindern als auch klinisch die Inzidenz bakterieller Infektionen nach großen viszeralchirurgischen Eingriffen senken. Da sie leicht zu verabreichen sind und wenig Nebenwirkungen verursachen, könnten sie breit eingesetzt werden. / In the present study, the impact of pre- and probiotics on bacterial translocation (BT) and postoperative bacterial infection rates was assessed. Due to methodological reasons, we first quantified BT following single liver (LR) and colon resection (CR) or a combination of both and analysed potential pathogenic mechanisms for BT. Then, we performed two prospective randomised clinical studies to analyse the influence of a single probiotic strain and a combination of different pre- and probiotics on the incidence of bacterial infections in patients with liver transplantation (OLT) or pylorus preserving partial pancreatoduodenectomy (PPPD). In the rat model, BT after LR mainly occurred in the liver and spleen, after CR mainly in the mesenteric lymph nodes (MLN) and spleen. BT was increased in the animals with combined operation, in parallel to the extent of liver resection. Probiotics significantly decreased the bacterial concentration in the MLN. Animals with a high cecal concentration of lactobacilli had significantly less BT than the others. CR led to an increase of cecal gramnegative bacterial concentrations and to a decrease of lactobacilli. No histological changes were observed in the intestine. Paracellular permeability for ions, but not for the larger molecule lactulose, was increased in the colon in all groups compared to the sham group. Probiotics had an influence on cecal bacterial concentration. In the first clinical study, postoperative oral administration of Lactobacillus plantarum and a fibre-enriched enteral diet significantly decreased bacterial infection rates after OLT compared to selective bowel decontamination and a fibre-free diet. Fibre and heat-inactivated Lactobacillus also led to a slight, but not significant decrease of infections. Mainly gut-derived bacteria were isolated. The second clinical study analysed the influence of a combination of four different lactic acid bacteria and fibres on bacterial infection rates after OLT and PPPD. Compared to fibres and placebo, infection rates were significantly lower after OLT and markedly lower after PPPD. In both studies, the study substances were well tolerated without serious side effects. BT even occurs following minor abdominal surgery and is caused by different mechanisms related to the kind of operation. Probiotics were able to diminish BT in the rat model as well as to decrease bacterial infection rates following major abdominal surgery in the clinical studies. As they are easy to administer and do not cause severe side effects, they could be useful in clinical practice.
16

Retrospektiver Vergleich der Behandlungsergebnisse konventioneller Resektionstechniken des NSCLC im Stadium Ia/Ib mit Lasersegmentresektionen unter Anwendung eines neu entwickelten 1318nm Nd:YAG-Lasers

Huscher, Stefan 20 June 2008 (has links) (PDF)
Unter den bösartigen Tumoren hat das Bronchialkarzinom wohl die dramatischste Entwicklung genommen. Die Inzidenz und Mortalität ist in den letzten 15-20 Jahren bei Männern zwar leicht rückläufig, für Frauen ist jedoch ein entgegen gesetzter Trend zu erkennen. Dies wird in erster Linie auf die veränderten Lebensgewohnheiten, wie steigender Zigarettengenuss unter den Frauen, zurückgeführt. Derzeit gibt es in Deutschland circa 20 Millionen Raucher, von denen etwa 140˙000 jährlich an den Folgen ihres Inhalationsrauchens versterben...
17

Unresolved issues and controversies surrounding the management of colorectal cancer liver metastasis

Kassahun, Woubet T. January 2015 (has links)
Ideally, tumors that might cause morbidity and mortality should be treated, preferably early, with proven, convincing, and effective therapy to prevent tumor progression or recurrence, while maintaining a favorable risk-benefit profile for the individual patient. For patients with colorectal cancer (CRC), this diagnostic, prognostic, and therapeutic precision is currently impossible. Despite significant improvements in diagnostic procedures, a sizable number of patients with CRC have liver metastases either at presentation or will subsequently develop it. And in many parts of the world, most cancer-related deaths are still due to metastases that are resistant to conventional therapy. Metastases to the liver occur in more than 50% of patients with CRC and represent the major determinant of outcome following curative treatment of the primary tumor. Liver resection offers the best chance of cure for metastases confined to the liver. However, due to a paucity of randomized controlled trials, its timing is controversial and a hotly debated topic. This article reviews some of the main controversies surrounding the surgical management of colorectal cancer liver metastases (CRLM).
18

Analysis of open and laparoscopic liver resections in a german high-volume liver tumor center

Guice, Hanna 04 August 2022 (has links)
In recent years laparoscopic liver surgery established itself into today’s standard of care regarding surgical liver treatment. It was a long way for minimally invasive liver resection to develop and popularize as it was accompanied by initial reservations and concerns. Some of these already had been clarified while other questions still remain and require further investigation in the complex field of laparoscopic liver surgery. Initial concerns with respect to oncological inferiority and technical inapplicability in contrast to open surgery treatment could have been disproved within the framework of retrospective studies. In contribution to that, the aim of the study was to compare the surgical results and postoperative outcomes of consecutive laparoscopic liver resections (LLR) and open liver resections (OLR) at the high-volume liver tumor center of Leipzig university hospital. Since common classification systems for open liver surgery cannot be applied for LLR, the introduction of specific difficulty scoring systems for LLR helps to assess and classify the complexity of minimal invasive liver resection. With an increase in experience, modification of hybrid surgery and the application of novel visualization techniques such as indocyanine green (ICG) staining or hyperspectral imaging (HSI), more challenging procedures were accomplished, that initially would have been contraindicated for the laparoscopic approach (e.g. perihilar cholangiocarcinoma (pCCA) requiring biliary reconstruction). During the years 2018 and 2019 42% of all liver resections were approached laparoscopically at the Leipzig University hospital. A retrospective data analysis of n=231 patients undergoing LLR or OLR for the years 2018 and 2019 was performed and previously determined variables were collected. As a primary outcome measure, the short-term surgical and postoperative outcome of patients receiving LLR (=LLR group) compared to the patient cohort being treated by open resection (=OLR group) was evaluated. All liver resections were executed or assisted by the same two surgeons. Prior to surgery, every case was reviewed in a multidisciplinary tumor-board meeting and primarily assessed for possible minimal invasive approach. Analysis for patient demographics, pathologic diagnosis, radiologic findings and peri- and intraoperative surgical data was carried out. For LLRs intraoperatively, ICG counter perfusion staining was used in anatomic liver resection and direct ICG tumor staining was employed for tumor demarcation. With respect to classification, the extent of OLR was graded according to the Brisbane 2000 terminology in minor and major resections, whereas LLRs were categorized by means of difficulty (in accordance with Ban et al. and Di Fabio et al.). For measurement of surgical complication and assessment of morbidity, the Clavien-Dindo classification was applied. OLR was performed in n=124 (57%) and LLR in n=93 (43%). From all minimally invasive treated patients, 79% were operated totally laparoscopic and 16% were laparoscopic-hand-assisted due to infeasible lesions in the posterosuperior segments 7, 8 and 4a. In 5 cases a conversion to open surgery was necessary because of inaccessibility, tumor infiltration or morbid obesity. 28% of patients had previous upper abdominal surgery, whereof 36% in the OLR group and 19% in the LLR group. Regarding patient demographics, the mean age was significantly higher in OLR and the sex ratio was in favor of men for both groups. Malignant tumor lesions comprised 77%, while 24% were benign lesions. In both groups this larger number of malignant oncologic operation remained valid. The most common benign indications comprised focal nodular hyperplasia (FNH) and liver adenomas. It was shown that patients with CCA and Colorectal liver metastases (CRLM) were predominantly treated by open surgery, while patients with HCC diagnosis received LLR to a greater extent. Concerning the type of liver resection, non-anatomical resections were the most frequent in the cohort with 47%, thereof 55% LLR and 40% OLR. Followed second most by anatomic right and left hemihepatectomies and third most by left lateral resections, which were predominantly performed in laparoscopic technique. On the other hand, extended resections and trisectionectomies were predominantly operated by OLR. Radical lymphadenectomy was performed to a greater extent during OLR. Results showed that the mean operative time was longer for OLR (341 minutes in median) compared to LLR (273 minutes in median). Also the mean length of hospital stay was shorter for LLR patients, as well as abdominal drains were placed to lesser extent in LLR compared to OLR. In regard to R0-resection, R0-rates were higher in LLR with 98% vs. 86% in OLR. Thereby being highest for CRLM resections, followed by HCC and CCA. Putting all liver resections into classification systems, it was found that of all open procedures, 52% had major and 48% underwent minor resection according to Brisbane 2000. From the LLR group, in accordance with Di Fabio et al. 39% were classified as laparoscopic major hepatectomies, comprising 44% laparoscopic traditional major hepatectomies (LTMH) and 56% laparoscopic posterosuperior major hepatectomies (LPMH), which were technically challenging. The difficulty index stated by Ban et al. was classified as low for 8% of all performed LLRs, intermediate for 45% and of high difficulty in even 47%. Relating to morbidity (=Clavien-Dindo 3b or greater), patients with LLR had significantly lower morbidity compared to OLR. The same applies for in-hospital mortality. Our data show that despite the high number of complex and high-difficulty-classified liver resections that were performed, morbidity and mortality rates were low. As mentioned before, R0 resection rate in the LLR group was better than in the OLR group, however, this was not a case matched study, so a direct comparison is not valid. But still the study could demonstrate that the high number of LLRs being performed at the Leipzig University hospital, did not impair R0-resection rates. With an overall hospital mortality rate of 5.9% in the cohort, good results were achieved. Particularly the low rate of 1% in the LLR group speaks for itself and confirms that the development of a minimal invasive liver resection program should be on the right track. The majority of patients in the LLR and OLR group received an oncologic resection, what also resembles the global attitude that minimally invasive techniques are not reserved for selected tumor entities. Still it should be emphasized, the indication for a liver resection should not be loosened just due to minimal invasive accessibility, especially in benign liver lesions. Nevertheless, in the study the majority of benign lesions was operated by LLR. A few patients diagnosed with CCA received LLR. Thereof predominantly iCCA cases were indicated for a minimal invasive approach without biliary duct reconstruction and satisfying short-term outcomes over OLR could be obtained. However, only one case of pCCA which required Roux-Y bile duct reconstruction was treated with LLR in the study group, so if laparoscopic surgery is capable to replace the open approach in terms of treatment strategies for pCCA remains questionable. Patients with CRLM represent the centerpiece of our study population, still only 13% received LLR. The main reason of applying OLR was the high tumor load requiring future liver remnant augmentation strategies. As liver resection is confirmed to be the approach of choice for patients with HCC in cirrhosis, it is not surprising that HCC diagnosis accounted for the major part of LLRS in our collective.:Vorbemerkung und Bibliographie, 3 Abkürzungsverzeichnis, 4 Einführung, 5 - 1. Development of minimal invasive liver surgery, 5 - 2. Prior concerns of LLR, 6 - 3. Benefits of laparoscopic surgery, 6 3.1 General advantages of minimal invasive surgery, 6 3.2 Specific benefits of applying LLR, 7 - 4. Indications for LLR, 7 4.1 Benign liver lesions, 8 4.2 Malignant liver lesions, 8 4.3 Liver transplantation, 9 - 5. Technical supplement, 9 5.1 Hybrid and hand-assisted techniques, 10 - 6. Classification systems, 11 6.1 Difficulty scoring, 11 6.2 Clavien-Dindo Classification ,12 - 7. Limitations of LLR, 12 - 8. Aim of the study, 13 Publikation, 14 Zusammenfassung, 26 Literaturverzeichnis, 30 Darstellung des eignen Beitrags, 34 Selbstständigkeitserklärung, 35
19

The value of hepatic resection in metastasic renal cancer in the era of Tyrosinkinase Inhibitor Therapy

Hau, Hans Michael, Thalmann, Florian, Lübbert, Christoph, Morgul, Mehmet Haluk, Schmelzle, Moritz, Atanasov, Georgi, Benzing, Christian, Lange, Undine, Ascherl, Rudolf, Ganzer, Roman, Uhlmann, Dirk, Tautenhahn, Hans-Michael, Wiltberger, Georg, Bartels, Michael 22 July 2016 (has links) (PDF)
Background: The value of liver-directed therapy (LDT) in patients with metastasic renal cell carcinoma (MRCC) is still an active field of research, particularly in the era of tyrosinkinase inhibitor (TKI) therapy. Methods: The records of 35 patients with MRCC undergoing LDT of metastasic liver lesions between 1992 and 2015 were retrospectively analyzed. Immediate postoperative TKI was given in a subgroup of patients after LDT for metastasic lesions. Uni- and multivariate models were applied to assess overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS). Results: Following primary tumor (renal cell cancer) resection and LDT, respectively, median OS was better for a total of 16 patients (41 %) receiving immediate postoperative TKI with 151 and 98 months, when compared to patients without TKI therapy with 61 (p = 0.003) and 40 months (p = 0.032). Immediate postoperative TKI was associated with better median PFS (47 months versus 19 months; p = 0.023), whereas in DFS only a trend was observed (51 months versus 19 months; p = 0.110). Conclusions: LDT should be considered as a suitable additive tool in the era of TKI therapy of MRCC to the liver. In this context, postoperative TKI therapy seems to be associated with better OS and PFS, but not DFS.
20

Extended resection in pancreatic metastases

Wiltberger, Georg, Bucher, Julian Nikolaus, Krenzien, Felix, Benzing, Christian, Atanasov, Georgi, Schmelzle, Moritz, Hau, Hans-Michael, Bartels, Michael 29 June 2016 (has links) (PDF)
Background: Metastases to the pancreas are rare, accounting for less then 2 % of all pancreatic malignancies. However, both the benefit of extended tumor resection and the ideal oncological approach have not been established for such cases; therefore, we evaluated patients with metastasis to the pancreas who underwent pancreatic resection. Methods: Between 1994 and 2012, 676 patients underwent pancreatic surgery in our institution. We retrospectively reviewed patients’ medical records according to survival, and surgical and non-surgical complications. Student’s t-test and the log-rank test were used for statistical analysis. Results: Eighteen patients (2.7 %) received resection for pancreatic metastases (12 multivisceral resections and 6 standard resections). The pancreatic metastases originated from renal cell carcinoma (n = 10), malignant melanoma (n = 2), neuroendocrine tumor of the ileum (n = 1), sarcoma (n = 1), colon cancer (n = 1), gallbladder cancer (n = 1), gastrointestinal stromal tumor (n = 1), and non-small cell lung cancer (n = 1). The median time between primary malignancy resection to metastasectomy was 83 months (range, 0–228 months). Minor surgical complications (Grade I-IIIa) occurred in six patients (33.3 %) whereas major surgical complications (Grade IIIb-V) occurred in three patients (16.6 %). No patients died during hospitalization. The median follow-up was 76 months (range, 10–165 months). One-year, 3-year and 5-year survival for standard resection versus multivisceral resection was 83, 50, and 56 % versus 83, 66, and 50, respectively. Twelve patients died after a median of 26 months (range, 5–55 months). Conclusions: A surgical approach with curative intent is justified in select patients suffering from metastases to the pancreas and offers good long-term survival. The resection of pancreatic metastases of different tumor types was associated with favorable morbidity and mortality when compared with resection of the primary pancreatic malignancies. Our findings also demonstrated that multivisceral resection was feasible, with acceptable long term outcomes, even though morbidity rates tended to be higher after multivisceral resection than after standard resection.

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