Are There Ideal Small Bowel Limb Lengths for One-Anastomosis Gastric Bypass (OAGB) to Obtain Optimal Weight Loss and Remission of Comorbidities with Minimal Nutritional Deficiencies?

Abstract

Ideal jejunal and ileal lengths in bariatric/metabolic procedures to be left in alimentary continuity still remain unclear. We aimed to evaluate different lengths of biliopancreatic limb (BPL) and common limb (CL) performed in a series of patients submitted to OAGB, and correlate them with weight loss and nutritional deficits. A prospective observational study of 350 consecutive morbidly obese patients undergoing OAGB was performed. BPL and CL lengths were determined intraoperatively; BPL/TBL and CL/TBL ratios were then calculated. Anthropometric variables, remission of comorbidities and specific supplementation needs were recorded at 1, 2 and 5 years after surgery. Three hundred patients were included for final analysis. BPL length and BPL/TBL ratio directly correlated with Units of BMI lost (UBMIL). Conversely, CL length and CL/TBL ratio showed an inverse correlation with UBMIL. Establishing a BMI ≤ 25 kg/m² as ideal, the most accurate AUC, to predict achieving an ideal BMI at 1, 2 and 5 years after surgery, was obtained for the CL/TBL ratio, followed by the CL length at 1, 2 and 5 years. An ideal range was established between 0.40 and 0.43 for the CL/TBL ratio, and 200 to 220 cm for the CL length. Among these ranges, there were no cases of protein or calorie malnutrition. TBL measurement is essential to obtain optimal outcomes after OAGB, both in terms of excellent weight loss and remission/improvement of comorbidities, as well as with a low risk of nutritional deficiencies. The CL/TBL ratio, followed by CL length, are the most accurate parameters to predict a 5-year postoperative BMI ≤ 25 kg/m².