Comparison of Roux-en-Y Gastric Bypass (RYGB) and One Anastomosis Gastric Bypass (OAGB)

Feature Roux-en-Y Gastric Bypass (RYGB) One Anastomosis Gastric Bypass (OAGB) Notes
Image Roux-en-Y Gastric Bypass Diagram

Roux-en-Y Gastric Bypass (RYGB)

One Anastomosis Gastric Bypass Diagram

One Anastomosis Gastric Bypass (OAGB)

Mechanism of Action Restricts food intake and reroutes small bowel to bypass absorption sites. Restricts food intake with a single connection bypassing absorption sites. Both induce hormonal changes (e.g., increased GLP-1, reduced ghrelin), improving satiety and glucose metabolism.
Stomach Modification Small and narrow gastric pouch created (~30 mL). Long narrow gastric pouch created (~150 mL). OAGB pouch is longer compared to RYGB.
Number of Anastomoses Two (gastrojejunal and jejunojejunal). One (gastrointestinal). The single anastomosis in OAGB simplifies the procedure and reduces operative time.
Bile Reflux Rare. Possible due to single anastomosis. Bile reflux is a significant consideration in OAGB and may require revision surgery in symptomatic cases.
Risk of Marginal Ulcers Small. Small but likely higher than RYGB due to bile and acid exposure at the single anastomosis. In both operations, the risk of marginal ulcers is higher in smokers or with use of NSAIDs (anti-inflammatory drugs).
Weight Loss Outcomes 70–80% excess weight loss (EWL) or 30–40% of total body weight. 70–80% excess weight loss (EWL) or 30–40% of total body weight. Comparable weight loss outcomes in the first 2 years; durability varies depending on individual factors and compliance with lifestyle changes.
Improvement in Metabolic Conditions Significant improvement in type II diabetes, insulin resistance, and metabolic syndrome. Significant improvement in type II diabetes, insulin resistance, and metabolic syndrome. Both procedures improve glucose homeostasis through hormonal changes and weight loss, often leading to remission of type II diabetes.
Risk of Internal Hernias Higher due to two mesenteric defects. Lower due to one mesenteric defect. RYGB has a higher risk of hernias requiring surgical intervention.
Risk of Gastroesophageal Reflux Disease (GERD) Reduced in most patients. Bile reflux may mimic or worsen GERD symptoms. Both can improve GERD, but OAGB's bile reflux risk can be problematic for some patients.
Suitability for NSAIDs Contraindicated. Contraindicated. NSAID use is not advised in either procedure due to the increased risk of marginal ulcers.
Revisional Surgery Risk Moderate. Moderate. Both procedures can require revisions for complications such as reflux, malnutrition, or inadequate weight loss.

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