Prof. Dr. med. Ralph Peterli

Research Project  | 1 Project Members

1.1. Background Obesity is reaching epidemic proportions in the developed world. In morbidly obese patients only surgical treatment (bariatric operations) leads to a sustained weight loss and cure of co-morbidities in the majority of patients. There exist a number of different operations resulting in either a restrictive and/or malabsorptive effect, accompanied by a humoral effect which is caused by changes of the different gastrointestinal peptides. It is still unknown which patients needs which operation. 1.2. Working Hypothesis The laparoscopic sleeve-gastrectomy (LSG) is as successful as laparoscopic proximal Roux-Y-gastric bypass (LRYGB) in the treatment of morbid obesity in the majority of patients. In case of insufficient weight loss malabsorption can be added by performing laparoscopic bilio-pancreatic diversion duodenal switch (BPD). The resection of the gastric fundus (LSG) leads to changes in gastrointestinal peptides that are possibly different to bypassing the fundus (LRYGB). 1.3. Specific Aims We plan to compare the LSG and LRYGB in a prospective randomized Swiss multicentre study. The primary outcome measure is effectiveness in terms of weight loss, reduction in co-morbidity, and quality of life; secondary outcome measures are postoperative changes in gastrointestinal peptides, early morbidity, duration and cost of the operation, late morbidity, and re-operations (for complications, for insufficient weight loss). 1.4. Experimental Design/Methods Each of the 4 Swiss bariatric centers evaluates with an interdisciplinary team morbidly obese patients for bariatric surgery. After informed consent, eligible patients will be randomly selected for LSG or LRYGB, a total number of 100 per group. Preoperative examination consists of: quantification of comorbidity, eating behavior, indirect calorimetry, body composition by DEXA*, routine blood chemistry, gastrointestinal peptides before and after test meal*, gastroscopy, manometry of the esophagus, upper GI series*, abdominal ultrasound, quality of life. Perioperative investigations: operative time, fat tissue samples* (omental and subcutaneous), early morbidity, gastrointestinal peptides before and after test meal*, duration of hospital stay, costs*; Follow-up data will be obtained once a year until 5 years postop: weight, reduction in comorbidities, quality of life, complications, re-operations, (gastrointestinal peptides before and after test meal*, DEXA*). (* only at one center) 1.5. Expected Value of the Proposed Project With this study we intend to show that LSG has the potential to be a dependable bariatric operation in a staged therapy concept, with equivalent effectiveness in the majority of patients compared to LRYGB. In case of failure of LSG, it can be turned into the more invasive but more effective BPD only in patients who fail restriction alone, thus avoiding over-treatment in a number of patients. This study will add important information regarding which operation technique or which therapy concept has to be applied to morbidly obese patients. In the near future, more operations will have to be performed to treat the growing number of morbidly obese patients; thus, more surgeons will have to be trained. It will add to the safety of bariatric surgery if an operation that is easier to learn, such as the LSG, can be proven to be as effective compared to the more difficult and more expensive LRYGB. Bariatric surgery adds to the basic understanding of the pathophysiology of obesity. In this study we expect to determine whether bypass of the fundus and its resection are equivalent in changes of gastrointestinal peptides and whether a specific preoperative peptide profile or postoperative changes of the peptides may help determining which patient will sufficiently lose weight by restriction alone or will need a malabsorptive procedure.