Laparoscopic sleeve gastrectomy (LSG) gained popularity and has become one of the most performed weight loss procedures worldwide. In the long-term follow-up, the literature states that the incidence of gastroesophageal reflux disease (GERD) accounts for 16%, and weight regains accounting for 70% after LSG. These are the two most common complications which can necessitate further surgical intervention.~The hypotheses are that laparoscopic conversion from LSG to Single anastomosis duodeno-ileal bypass (SADI-S), Roux-en-Y gastric bypass (RYGB), or one anastomosis gastric bypass (OAGB) will provide a new significant weight loss, improvement in obesity-related health problems and provide no nutritional deficiency in all cases.~Since the three types of procedures have other anatomical presentations, whereby these is not well tested next to each other in a blinded, controlled setting for the patient, this study is designed to discover if the procedures are superior to each other or not and what the best outcome is for the patient.~A sample size is calculated and with a medium effect size of 0.5 corresponds to a mean difference in %EBMIL between SADI-S, RYGB, and OAGB of at least 10%. Using a power of 0.8 with an alpha of 0.05 resulted in a sample size of 64 patients per group.~Considering a possible loss of patients to follow-up, an additional 20% increase in sample size was included per group, resulting in a minimum of 78 patients per group.~(Total of 3 groups together of 234 patients).
Assess what revisional surgery is superior and provides the best weight loss after primary LSG. What is the occurrence of complications and the nutritional laboratory status? And if the resolution and /or improvement of associated medical problems after the weight loss will occur.