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- Axer, Stephan, 1971-
(författare)
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Revisional bariatric surgery : more than a moral obligation
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Growing awareness of biological, genetic, environmental, and behavioural factors contributed to the recognition of obesity as a chronic disease. Nowadays, obesity and its medical/surgical treatment is widely acknowledgedin the medical curriculum. Bariatric surgery has long been shown to provide superior induction and maintenance of weight loss, together with improvement or resolution of obesity-related diseases. The role of revisional bariatric surgery for treatment of procedure-related complications is accepted. However, its role as second-line treatment of patients with primary or secondary non-response is still a matter of debate. This prompted Dr Henry Buchwald in 2015 to publish his article “Revisional Metabolic/Bariatric Surgery: A Moral Obligation”. Studies I and II in this doctoral thesis covered issues that fuel the ongoing controversy, namely effects and risks of revisional surgery. Conversion to gastric bypass is the most common revisional procedure in Sweden. In Studies I and II, we found revisional gastric bypass to give inferior weight loss with a higher risk for perioperative complications compared to primary gastric bypass. However, the beneficial effects on obesity-related disease were similar (Papers I and II). In Study III, the theoretical need for revisional bariatric surgery in patients with primary or secondary weight non-response was evaluated. When applying four different indication criteria, more than 13% of patients met the criteria for second-line treatment, with a significant higher probability after sleeve gastrectomy compared to gastric bypass (Paper III). To gain a clearer picture, a systematic review of the literature on revisional bariatric surgery after sleeve gastrectomy was inevitable. However, an evidence-based treatment strategy for patients with primary or secondary weight non-response could not be deduced from the current literature (Paper IV).
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| 2. |
- Raoof, Mustafa, 1966-
(författare)
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Long term effects of gastric bypass on quality of life and bone mineral density
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is a worldwide disease. Surgery is currently the only available management option which offers an adequate long-term effect on comorbidity, quality-of-life and weight loss. It is evident that overweight and obesity are associated with low health-related quality-of life (HRQoL) and multiple comorbidities. The aim of this thesis has been to explore the long-term effect of gastric bypass surgery on HRQoL and bone mineral density.In study 1: 486 patients (average age 50.7±10.0 years, 84 % female) operated with gastric bypass (GBP) from 1993 to 2003 at the University Hospitals of Örebro and Uppsala. Mean follow-up after GBP was 11.5±2.7 years (range 7–17). The study group was compared with two control groups. The study group scored better in the SF-36 domains and OP scale compared to obese controls, but their HRQoL scores were lower than those of the general population. HRQoL was better among younger patients and in the following subgroups: men; patients with satisfactory weight loss; those satisfied with the procedure; those free from comorbidity and gastrointestinal symptoms; employed; good oral status; and those not hospitalised or regularly followed up for non-bariatric reasons.In study 3: Patients operated with a primary GBP between January 2008 and December 2012 were identified in the Scandinavian Obesity Surgery Register (SOReg). Patients with HRQoL data available at both baseline and 5 years after surgery were included. The study sample comprised 6998 patients (21% men). Gender differences in change in HRQoL were minor. Younger patients showed greater improvements in physical health scales. In general linear regression model analyses, age and weight loss correlated significantly with improvement in HRQoL after 5 years. Patients treated medically for depression preoperatively (13%) experienced less improvement in HRQoL than patients without such treatment. Patients with a postoperative complications (26%) had significantly less improvement in all aspects of HRQoL compared to those without any form of postoperative complication.This study confirmed the importance of weight loss for improvement in HRQoL after bariatric surgery. Preoperative medication for depression and suffering a complication during the five-year follow-up period were associated with less improvement in HRQoL.Studies 2 and 4: Included patients operated with laparoscopic gastric bypass at the department of surgery at the Örebro University Hospital between January 2004 and December 2005. Thirty-two females were prospectively recruited for this longitudinal study. In both studies, the following were measured at baseline, 2, 5 and 10 years postoperatively: bone mineral density (BMD); weight; height; S-calcium; S-albumin; S-creatinine; S-25(OH)-vitamin D; and fP-PTH. In study 4: Nine of the patients declined follow-up. BMD showed a statistically significant decline over the study period. The fall in BMD of the spine and femoral neck between baseline and 5 years after surgery was 19% and 25%,respectively. During the next five years period BMD continued to decline but at a lower rate. At 5 years 58 % had elevated PTH, this number declined at the next 5 years.
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| 3. |
- Rubensdotter, Lena, 1972-
(författare)
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Alpine lake sediment archives and catchment geomorphology : causal relationships and implications for paleoenvironmental reconstructions
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lake sediments are frequently used as archives of climate and environmental change. Minerogenic sediment variability in alpine lakes is often used to reconstruct past glacier and slope process activity. Alpine lake sediments can however have many different origins, which may induce errors in paleoenvironmental reconstructions. The aim of this project was to enhance the understanding of minerogenic lake sedimentation in alpine lakes and improve their use as environmental archives.Catchment geomorphology and Holocene sediment sequences were analysed for five alpine lakes. Several minerogenic sediment sources were detected in catchments and sediment sequences. Slope-, fluvial-, periglacial-, nival- and aeolian sediment transportation processes contribute to create complex lake sediment patterns. Large variations in sedimentation rates were discovered within and between lakes, which has implications for sampling strategies and age-model constructions. Similar fine-grained minerogenic laminations were found in four of the investigated lakes, despite large differences in setting. The demonstrated similarity between glacial and non-glacial lakes may complicate interpretations of glaciolacustrine sediment signals.The main conclusion is that lake sedimentation in alpine environments is highly dependent on several geomorphological factors. All lakes should therefore be viewed as unique and the geomorphology should be thoroughly investigated before environmental reconstructions are based on lake sediment proxies. This study has confirmed the multi-source origin of alpine lake sediment, which also opens possibilities of more multi-faceted paleoenvironmental studies. Different process-proxies could potentially be used to separate different climate signals, e.g. precipitation, temperature and wind, in lake sediments. Analysis of grain-size distribution, detailed mineralogy and magnetic mineralogy in combination with X-ray radiography are suggested methods for such reconstructions.
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| 4. |
- Stenberg, Erik, 1979-
(författare)
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Preventing complications in bariatric surgery
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is a major public health problem. Bariatric surgery is currently the only available treatment that offers sufficient weight-loss and metabolic benefits over time. Although bariatric surgery is considered safe now, serious complications still occur. The aim of this thesis was to identify factors associated with an increased risk for postoperative complication after laparoscopic gastric bypass surgery.Study I included patients operated with laparoscopic gastric bypass surgery in Sweden from May 2007 until September 2012. The risk for serious complication was low (3.4%). Suffering an intraoperative adverse event or conversion of the operation to open surgery were the strongest risk factors for postoperative complication. The annual operative volume and experience of the procedure at the institution were also important risk factors. Patient-specific risk factors appeared to be less important although age was associated with an increased risk. In Study II, a raised glycated haemoglobin A1c (HbA1c) was evaluated as a risk factor for serious postoperative complications in non-diabetics. A higher incidence of serious postoperative complications was seen with elevated HbA1c values, even at levels classified as ‘‘pre-diabetic’’.Study III was a multicentre, randomised clinical trial (RCT). 2507 patients planned for laparoscopic gastric bypass surgery were randomised to either mesenteric defects closure or non-closure. Closure of the mesenteric defects reduced the rate of reoperation for small bowel obstruction from 10.2% to 5.5% at 3 years after surgery. A small increase in the rate of serious postoperative complication within the first 30 days was seen with mesenteric defects closure. This relatively small increase in risk was however outweighed by the marked reduction of later reoperations for small bowel obstruction.Study IV was a comparison between study III and an observational study on the same population under the same period of time. Although the observational study reached the same conlusion as the RCT, the efficacy of mesenteric defects closure was less pronounced. Observational studies may thus be an alternative to RCTs under situations when RCTs are not feasible. The efficacy may however be underestimated.
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