Single-Anastomosis Duodeno-Ileal Bypass

Worldwide, approximately 650 million adults and 340 million children are designated as obese. Environmental and genetic factors influence obesity, which is associated with comorbidities including diabetes, dyslipidemia, obstructive sleep apnea, nonalcoholic fatty liver disease, and coronary artery disease. Truncal obesity is associated with an increased risk of hypertension, heart disease, diabetes, and metabolic syndrome, which is defined by triglyceride levels greater than 150 mg/dL, fasting glucose levels of 100 to 125 mg/dL, or an elevated hemoglobin A1c level. Recently, the World Health Organization noted that over 60% of people in Europe are overweight or obese, which represents a tripling of obesity in the last 50 years, mainly due to decreased activity and diet. In the United States, obesity, morbid, and super morbid obesity continue to increase in both children and adults, predominantly impacting those with the highest genetic predisposition. Genetic influences include single genes associated with hyperphagia. Obesity has the most significant impact on Black women, Hispanic adults, and indigenous peoples. Treating obesity, its physiological and psychological sequelae, and comorbidities is costly and requires a comprehensive interdisciplinary approach for the most effective management. A recent surge in medications targeting energy expenditure and appetite-regulating mechanisms has occurred; these are most effective when implemented in conjunction with behavioral changes. National and global increases in obesity place a sizeable burden on health systems and economies and necessitate a multidisciplinary approach to management. Conventional weight management often fails in severe obesity, and surgery is the most effective intervention in such cases by offering persistent weight loss and improving obesity-related comorbidities. A body mass index (BMI) of 40 kg/m² or higher, or a BMI of 35 kg/m² or higher with severe comorbidities, is most effectively treated with surgical intervention to achieve a BMI between 18.5 and 24.9. The primary mechanism by which obesity surgery impacts weight loss is through restriction and malabsorption. Still, multiple complex hormonal and neuroregulatory factors influence the regulation of metabolism and food intake, which can aid in weight loss. Sustained weight loss following bariatric surgery also depends on patient compliance with diet and exercise. Bariatric surgery can resolve comorbid conditions such as hypertension, diabetes, and sleep apnea. The American Society of Metabolic and Bariatric Surgery in conjunction with the International Federation for the Surgery of Obesity and Metabolic Disorders has updated their indications for bariatric surgery to include persons with a BMI of 35 kg/m² or higher with or without comorbidities, and persons with a BMI between 30 to 34.9 kg/m² with related conditions. Additionally, the recent implementation of obesity surgery-specific quality improvement and enhanced recovery after surgery programs has standardized and improved the quality of care for these patients. According to the ASMBS, the most commonly performed bariatric surgery procedure in the United States is sleeve gastrectomy, followed by Roux-en-Y gastric bypass. Additional bariatric surgery options include biliopancreatic diversion with or without duodenal switch, 1 anastomosis gastric bypass, and SADI, all of which are typically performed laparoscopically or robotically. The SADI bypass, in conjunction with sleeve gastrectomy, is a relatively recent modification that exhibits physiology comparable to that of the duodenal switch and biliopancreatic diversion, with similar weight loss and improvements in comorbidities. In early studies, patients who had undergone SADI experienced resolution of diabetes and hypertension within months of surgery. The restrictive component of SADI with sleeve gastrectomy is created through resection of the stomach, and the malabsorptive aspect is generated through bypassing the small bowel. The distal small bowel becomes the common channel that receives ingested items from the esophagus and stomach, as well as secretions from the biliopancreatic limb, thereby reducing the absorption of nutrients. SADI has become more common due to its relative simplicity, with comparable efficacy compared to more complex surgeries like gastric bypass. First described by Sánchez-Pernaute and colleagues, this intervention offers the combined benefits of restriction and malabsorption, aiming to optimize weight loss and metabolic outcomes with fewer complications. The metabolic outcomes of SADI eliminate diabetes, hypertension, dyslipidemia, and obstructive sleep apnea. The single anastomosis technique reduces the number of potential failure points, thereby lowering the incidence of internal hernias and anastomotic leaks, which are more common in multianastomosis procedures. Additionally, the incidence of dumping syndrome is reduced with SADI compared to gastric bypass through preservation of the pylorus, which maintains a more natural gastric emptying process. However, SADI is not without potential complications. Nutritional deficiencies are common and require lifelong monitoring. Furthermore, while fewer steps reduce operative time and immediate postoperative risks, long-term data are still emerging, necessitating ongoing research to understand durability and long-term safety.