Dec. 06, 2025
Metabolic bariatric surgery (MBS) remains the most effective treatment for morbid obesity and related comorbidities. While restrictive procedures such as gastric banding and intragastric balloons have largely fallen out of favor, metabolic operations — particularly sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) — are now the mainstay of surgical management in the United States.
However, for patients with a BMI over 50 kg/m² (grade 4 obesity) or those with slightly lower BMI but with severe diabetes, the traditional two-anastomosis duodenal switch (DS) has historically offered the most powerful metabolic effect, especially on diabetes remission. This operation combines a sleeve gastrectomy with a proximal duodenoileostomy and a distal ileoileostomy, creating a short common channel of approximately 125 to 150 cm. While highly effective for weight loss and diabetes resolution, it is technically complex and associated with higher risks of nutritional deficiencies requiring proper long-term patient follow-up.
A simplified modification of the DS, the single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S), has gained increasing acceptance and is endorsed by both the American Society for Metabolic and Bariatric Surgery and International Federation for the Surgery of Obesity and Metabolic Disorders. SADI-S preserves the pylorus and replaces the two-anastomosis reconstruction with a single loop duodeno-ileal anastomosis, significantly reducing the likelihood of internal hernias and marginal ulcers seen with RYGB. By maintaining a longer common channel of 250 to 300 cm compared with traditional DS, SADI-S lowers the risk of malnutrition while retaining strong metabolic benefits.
SADI-S achieves substantial and durable weight loss and sustained improvements in type 2 diabetes, hypertension, dyslipidemia and sleep apnea. At five years, multicenter prospective data shows total weight loss (%TWL) of 42% for DS and 36% for SADI-S. Although its use continues to increase, SADI-S remains less common than other MBS procedures in the United States. Long-term outcome data beyond five years is still evolving. More recently, Omar M. Ghanem, M.D., a metabolic surgeon and chair of Metabolic and Abdominal Wall Reconstructive Surgery at Mayo Clinic in Rochester, Minnesota, reported 10-year outcomes in a retrospective study of 101 patients undergoing DS or SADI-S. This showed sustained long-term weight loss with maximum %TWL of 46% for DS versus 47% for SADI-S. More nutritional complications were seen after DS compared with SADI, 53 versus 16%, respectively. Study results were published in Surgical Endoscopy in 2025.
Omar M. Ghanem, M.D., reported diabetes outcomes of SADI-S with a multicenter retrospective review of 419 patients showing an average diabetes remission rate of 60% with mean follow-up of two years. Study results were published in Surgery for Obesity and Related Diseases in 2025. Simon J. Laplante, M.D., a metabolic surgeon at Mayo Clinic in Minnesota and co-author of the study says: "SADI-S can be performed as a primary procedure or as a revisional option following sleeve gastrectomy in cases of inadequate weight loss or weight regain. It can also be staged with a sleeve gastrectomy first in cases of super-super obese patients with technical restrictions and later second-stage duodeno-ileostomy."
In summary, when comparing the two duodenal switch procedures for patients with severe obesity or diabetes, SADI-S provides weight-loss and metabolic outcomes comparable to DS, with lower nutritional risks. It also tends to produce fewer bowel movements and gastrointestinal symptoms, contributing to improved quality of life. For these reasons, SADI-S is increasingly viewed as a balanced option for grade 4 obesity or severe diabetes, offering robust efficacy with a more favorable safety and nutritional profile.
For more information
El Ghazal N, et al. Long-term 10-year outcomes of biliopancreatic diversion with duodenal switch (BPD/DS) and single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S): A comparative multicenter cohort study. Surgical Endoscopy. In press.
Sample JW, et al. Single-anastomosis duodenal-ileal bypass with sleeve gastrectomy for diabetes: Predictors of remission and metabolic outcomes in a multicenter study. Surgery for Obesity and Related Diseases. 2025;21:883.
Refer a patient to Mayo Clinic.