The IFSO Worldwide One Anastomosis Gastric Bypass Survey: Techniques and Outcomes?



One anastomosis gastric bypass (OAGB) has become one of the most commonly performed gastric bypass procedures in some countries.


To assess how surgeons viewed the OAGB, perceptions, indications, techniques, and outcomes, as well as the incidence of short- and long-term complications and how they were managed worldwide.


A questionnaire was sent to all IFSO members in all 5 chapters to study the pattern of practice and outcomes of OAGB.


Seven hundred and forty-two surgeons responded. The most commonly performed procedures were sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and OAGB. Preoperatively, 70% of the surgeons performed endoscopy routinely. In regards to weight loss, 83% (570 surgeons) responded that OAGB produces better weight loss than SG, and 49% (342 surgeons) responded that OAGB produces better weight loss than RYGB. The most common length of the biliopancreatic limb (BPL) utilized was 200 cm. Sixty-seven percent of surgeons did not measure the total length of the small bowel. In patients with reflux disease and history of smoking, 53% and 22% of surgeons respectively still offered OAGB as a treatment option. Postoperatively, leak was documented in 963 patients, and it was the leading cause for mortality. Leak management was conservative in 35%. Conversion to RYGB was performed in 31%. In 16% the anastomosis was reinforced, 6% of the patients were reversed, and other procedures were performed in 12%. Revision of OAGB for malnutrition/steatorrhea or severe bile reflux was reported at least once by 37% and 45% of surgeons, respectively (200 cm was the most commonly encountered biliopancreatic limb BPL in those revised for malnutrition). Most common strategy for revision was conversion to RYGB (43%), reversal to normal anatomy (32%), shortening of the BPL (20%), and conversion to SG (5%). Nevertheless, 5 out of 98 mortalities (5%) were due to liver failure/malnutrition.


There are infrequent but potentially severe specific complications including malnutrition, liver failure, and bile reflux that may require surgical correction after OAGB.

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Correspondence to Ashraf Haddad.

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Conflict of Interest

Ashraf Haddad, Ahmad Bashir, Kelvin Higa, Miguel Herrera, Almino Ramos, Antonio Torres, and Lilian Kow do not have any conflict of interests.

Mathias Fobi is the founding President of Bariatric Corporation, Maker of Rings for Bariatric operations.

Jacques Himpens reports personal fees from J&J and Medtronic, outside the submitted work.

Scott Shikora is the Editor-in-Chief of Obesity Surgery Journal.

Abdelrahman Nimeri reports personal fees from Medtronic, outside the submitted work.

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Haddad, A., Bashir, A., Fobi, M. et al. The IFSO Worldwide One Anastomosis Gastric Bypass Survey: Techniques and Outcomes?. OBES SURG (2021).

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  • One anastomosis gastric bypass
  • Gastric bypass
  • Mini gastric bypass
  • Biliopancreatic limb length
  • Postoperative leak
  • Bile reflux
  • Malnutrition
  • Liver failure
  • Postoperative complications
  • Revision of one anastomosis gastric bypass