Bariatric surgery has become one of the preferred options in treatment of severe obesity and its comorbidities in the Western world. In Switzerland, the approximate 5000 annual bariatric operations are performed exclusively in centres certified by the "Swiss Society of Study of Morbid Obesity and Metabolic Disorders (SMOB)". Among the different bariatric surgical procedures, the laparoscopic gastric bypass remains one of the most frequently performed operations. A critical step of this operation is the creation of the gastrojejunal anastomosis. This can be done using either a linear or a circular stapler. The optimal method continues to be discussed in current academic research. The linear anastomosis technique seems to be more feasible, uses smaller incisions and is therefore faster performed. The circular anastomosis technique benefits from a standardised diameter of the anastomosis with consecutive higher reproducibility. No difference in long-term weight loss have been described for these two techniques until today. The linear technique has been linked to marginal ulcers, while the circular technique has been associated with higher rates of stenosis and incisional hernia. The associations with other long-term adverse events such as internal hernias remain under discussion. However, according to several international analyses, the linear technique seems to have favourable short-term outcomes with shorter operation time and lower rates of wound complications and postoperative bleeding. Both techniques are used in Switzerland but Swiss national data on this topic is scarce. Given the high annual case volume of bariatric surgery in Switzerland and the inconsistent international evidence, a systematic comparison of these two techniques is of relevance.

This retrospective registry study provides Swiss national data on short-term postoperative outcomes after elective laparoscopic Roux-en-Y gastric bypass from 2015 to 2022. It aims to compare the linear vs. circular gastrojejunal anastomosis in terms of postoperative short-term postoperative, reoperation rate, and length of hospital stay.

Inclusion Criteria:

• Elective laparoscopic Roux-en-Y gastric bypass

Exclusion Criteria:

• Incomplete documentation
• Age under 20 years
• Other hospitals than general or surgical hospitals
• Omega-loop gastric bypass
• Emergency admission
• No stapler coded
• Open access

All patients with gastric bypass surgery in Switzerland between 2015 and 2022