Conventional Versus Distal Laparoscopic One-Anastomosis Gastric Bypass: a Randomized Controlled Trial with 1-Year Follow-up.

Background: There is no consensus on the ideal small bowel length that should be bypassed in laparoscopic one-anastomosis gastric bypass (OAGB). This study aimed to compare the safety and efficacy of conventional versus distal techniques of laparoscopic OAGB.

Methods: This randomized controlled trial involved 60 adults with morbid obesity scheduled for laparoscopic OAGB randomly assigned to one of the two techniques; conventional technique (fixed anastomosis 200 cm from the ligament of Treitz) and distal technique (anastomosis 400 cm from the ileocecal valve). Total small bowel length (TSBL) was measured in all cases. Quality of life was assessed using the Gastrointestinal Quality of Life Index (GIQLI). Outcome measures were excess body weight loss percentage (EBWL%), resolution of associated comorbidities, frequency of nutritional deficiencies, and quality of life.

Results: No patients were lost to follow-up. The two groups were comparable in TSBL, EBWL%, and complete resolution of comorbidities up to 12 months. The percentage of afferent loop length to TSBL was significantly higher in the distal group (p < 0.001) but was not correlated with EBWL%. The levels of hemoglobin, cholesterol, triglycerides, iron, and albumin were significantly lower and parathormone hormone was higher in the distal group. The GIQLI score was significantly higher in the conventional group during follow-up.

Conclusion: OAGB achieves optimum results when the afferent loop length is 200 cm; bypassing more than 200 cm does not improve weight loss or comorbidity resolution. Measuring TSBL is recommended to avoid excessive small bowel shortening that increases the risk of nutritional consequences.