Optimal efferent limb length in Single Anastomosis Sleeve Ileal Bypass: a balance between efficacy and safety

Abstract Background: Bariatric and metabolic surgery is considered to be the most effective long-term treatment of morbid obesity and related comorbidities, for instance, diabetes mellitus, hypertension and dyslipidemia. Classic bariatric surgery techniques usually result in restriction and/or malabsorption. Some procedures create obstacles to ingestion of food and may cause dysphagia, vomiting, esophagitis, etc. Other types of bariatric surgery may impair the absorption of vitamins, macro- and microelements, and cause hypoproteinemia. Some procedures involve partial exclusion of digestive system segments, which may trouble endoscopic access. Potential complications are forcing bariatric surgeons to look for less risky alternative, which could be easy to perform, require no exclusion of any segment, prevent endoscopic blind areas and guarantee predictable weight loss and metabolic result without development of excessive malabsorption. Hypothetically, bariatric procedure should change the neuroendocrine control of hunger and satiety without making any harm to digestive functions such as gastrointestinal motility, peristalsis, and enzyme secretion. Aim: This study was conducted to evaluate the effects of novel type of bariatric procedure, the single anastomosis sleeve ileal (SASI) bypass, on weight loss, metabolic effect of this type of surgery, and development of possible complications. Methods: We performed a retrospective study of patients with obesity who underwent SASI bypass between February 2017 and March 2022. Patients who completed one-year follow up were included in the study. Postoperative BMI changes, percent excess weight loss (% EWL), and complications were analyzed, as well as glucose, cholesterol, and protein levels before and after surgery. Additionally, the effects of efferent limb length on weight loss and protein levels were studied. Results: During the study period, 66 patients underwent laparoscopic SASI bypass, and 59 patients (89.4%) with completed follow-up were included in the study. The length of the common channel, counted from the ileocecal valve, was 250 cm in 30 patients and 350 cm in 29 patients. The mean age was 44.8 ± 9.53 years and the mean BMI was 47.6 ± 8.9 kg/m2; 27 of them (45.8%) had diabetes mellitus. The %EWL reached 79.8%, and all patients with diabetes mellitus had normal blood glucose levels one year after surgery. There were 3 early postoperative complications: 2 cases of postoperative bleeding and one case of rhabdomyolysis. One patient died 8 months after surgery, and alcoholic cirrhosis was diagnosed postmortem. We compared the results of SASI bypass in patients with different length of efferent limb (250 cm and 350 cm); BMI after surgery was 29.4±5.3 and 30.8±5.52 (p=0.317) in short and long efferent limbs, respectively. The rate of hypoproteinemia was 10.16% (6 cases) and occurred only in patients with 250 cm efferent limb. Revisional surgery was performed in 3 of them, the length of the common limb was changed from 250 cm to 350 cm in 2 patients, and in one patient with refractory hypoproteinemia, the bypass was restored to normal anatomy. Conclusion: SASI bypass is a novel operation with promising bariatric and metabolic effects. It is based on digestive adaptation principles and combines moderate restriction with early nutritive stimulation of the distal gut, modulating the neuroendocrine control of hunger and satiety. The lengthening of efferent limb up to 350 cm can prevent hypoproteinemia without compromising weight loss. To estimate the sustainability of the short-term outcome of SASI bypass longer follow-up is needed.