Sleeve Gastrectomy

Abstract

Sleeve gastrectomy (SG) is a vertical left gastrectomy of the body and fundus to create a long, narrow tubular gastric sleeve along the lesser curvature that reduces the size of gastric reservoir to 80–120 ml (Fig. 7.1). SG was originally intended as a bridge procedure for high-risk super obese patients preceding the definitive bariatric procedure such as biliopancreatic diversion with duodenal switch (BPD/DS) or Roux-en-Y gastric bypass (RYGB). However, the initial promising results of SG in terms of weight loss and resolution of comorbidities have rendered it popular not only as a first-stage procedure but also as a primary bariatric surgery. Laparoscopic sleeve gastrectomy (LSG) is now considered as a newer stand-alone operation being performed with increasing frequency, which is approved by both the American Society for Metabolic and Bariatric Surgery (ASMBS) and the American College of Surgeons (ACS). In 2011, it occupied over 25 % of bariatric procedures worldwide, which became the second most commonly performed bariatric procedure after RYGB. While the mechanism of action seen after SG is mainly regarded as restriction of calorie intake, the hormonal changes related to gastric resection and expedited food transport to distal small bowel might be involved as well. Ghrelin is a hunger-regulating peptide hormone mainly produced from the fundus of the stomach. Besides its well-known function in modulating appetite, ghrelin may directly regulate glucose homeostasis. Although the effect of ghrelin to incretins remains unclear, it has been suggested that the low levels of ghrelin after surgery are attributable to the secretion of endogenous gastrointestinal hormones such as GLP-1 and PYY that stimulate pancreatic beta cells. The pattern of rapid gastric emptying could be another factor that influences diabetes resolution. Rapid meal emptying into small intestine could contribute to shorter contact time of food with proximal gut and rapid arrival of food to terminal ileum. As a consequence, the hormonal environment of diabetes patients could be ameliorating (hindgut theory). It also has advantages including relatively simple surgical technique, no intestinal anastomosis thus excluding the risk of internal herniation and marginal ulcer, no foreign body, normal intestinal absorption, prevention of the dumping syndrome by pylorus preservation, fewer metabolic and nutritional complications, and preservation of endoscopic access to the upper gastrointestinal tract. The drawback of LSG has been the lack of data based on the well-designed prospective randomized study and long-term results. However, recently several prospective randomized controlled trials and 5 years or more of midterm results about laparoscopic sleeve gastrectomy proved this procedure is safe, effective, and durable.