Selecting biliopancreatic limb length in laparoscopic mini-gastric bypass

The therapeutic effect of mini-gastric bypass (one-anastomosis gastric bypass) is primarily mediated by malabsorption. The length of the small intestine section excluded from nutrient and micronutrient absorption has a direct impact on both the efficacy of surgery and the risk of postoperative complications; however, the optimal length is still debated. This review examines the anatomic and functional changes in the gastrointestinal tract following one-anastomosis gastric bypass, as well as the pathogenesis and association between postoperative nutritional deficiencies and biliopancreatic limb length. In current bariatric surgery, 150–175 cm biliopancreatic limbs are preferred over 200 cm biliopancreatic limbs in routine practice. However, given the variability in total small intestine length in patients with morbid obesity (250–1300 cm), this approach cannot be considered totally safe or effective. Experimental and clinical studies have shown comparable rates of comorbidity remission with different biliopancreatic limb lengths, regardless of overall weight loss. The feasibility of determining biliopancreatic limb length individually, based on a patient’s total small intestine length, has yet to be established, as evidenced by national and international consensus reports. In patients with obesity, small intestine length correlates with height, male sex, and neck, chest, and waist circumference. The proposed minimal functional length of the small intestine (common channel) for mini-gastric bypass is either 300 or 400 cm; however, even the latter does not completely prevent postoperative nutritional complications. Preoperative personalized markers that correlate with total small intestine length, as well as other pathogenic factors of morbid obesity and associated complications, are being investigated in order to optimize the degree of malabsorption during one-anastomosis gastric bypass.