**3. Short description of the main bariatric surgery procedures used in diabetic patients**

Currently accepted bariatric procedures for the treatment of type 2 diabetic patients are Rouxen-Y gastric by-pass (RYGB), laparoscopic adjusted gastric banding (LAGB), bilio-pancreatic diversion (BPD) and duodenal switch variant (BPD-SD), and sleeve gastrectomy (SG) [18]

**The Roux-en-Y gastric bypass** (Figure 1) is one of the most commonly performed bariatric procedures worldwide. It developed in the late 60's from the observation that patients with partial gastrectomy suffer a significant and persistent weight loss. After successive changes and optimizations, it is now considered the gold-standard in bariatric surgery. The interven‐ tion has several components: in the first step, a 30 milliliters stomach pouch is created by dividing the top of the stomach from the rest of it. Next, the first portion of the small intestine is divided, and the bottom end of the divided small intestine is connected to the newly created stomach pouch. In the final step, the top portion of the divided small intestine is connected to the small intestine further down so that the stomach acids and digestive enzymes from the bypassed stomach and first portion of small intestine will eventually mix with the food [19].

**Figure 1.** Roux-en-Y gastric bypass

**Laparoscopic adjusted gastric banding** (Figure 2) involves surgical insertion of an adjustable inflatable band that is placed around the upper part of the stomach to create a smaller stomach pouch. This slows and limits the amount of food that can be consumed at one time, but it does not decrease gastric emptying time. The size of the stomach opening can be adjusted by filling the band with sterile saline, which is injected through a port placed under the skin.

**Figure 2.** Laparoscopic adjusted gastric banding

**Sleeve Gastrectomy (SG**) is a procedure that involves removing the lateral part of the great gastric curvature, with stomach resection along the little curvature, from Hiss angle to the antrum [20] – Figure 3. The intervention was initially used as the first part of a two-stage procedure for super-obese patients (BMI > 60kg/m2 ), who were considered poor surgical candidates and who would not tolerate a prolonged or more involved procedure. The aim of the procedure was to allow the patients an opportunity to achieve some weight loss before being converted to the more complex gastric bypass or biliopancreatic diversion with duodenal switch (BPD-DS) [21]. It was, however, rapidly proved that weight loss and metabolic benefits were significant and nowadays it is used as a definitive weight loss procedure, with the advantage of the technical simplicity and the lower risk for complications [22]. The most recent guideline of the American Society for Metabolic and Bariatric Surgery also endorsed by the American Association of Clinical Endocrinology does not include this procedure among the investigational ones but considers it consecrated [23]

**Figure 3.** Sleeve gastrectomy

**Figure 1.** Roux-en-Y gastric bypass

198 Treatment of Type 2 Diabetes

**Figure 2.** Laparoscopic adjusted gastric banding

**Laparoscopic adjusted gastric banding** (Figure 2) involves surgical insertion of an adjustable inflatable band that is placed around the upper part of the stomach to create a smaller stomach pouch. This slows and limits the amount of food that can be consumed at one time, but it does not decrease gastric emptying time. The size of the stomach opening can be adjusted by filling

the band with sterile saline, which is injected through a port placed under the skin.

**Biliopancreatic diversion with duodenal switch (**Figure 4) is a weight loss surgery interven‐ tion that is composed of two procedures: in the first one, a smaller, tubular stomach pouch is created by removing a portion of the stomach, and afterwards, a large portion of the small intestine is bypassed. After dividing duodenum just past the outlet of the stomach, a segment of the distal small intestine is then brought up and connected to the outlet of the newly created stomach; in this way, approximately three-fourth of the small intestine in by-passes by food. The bypassed small intestine, which carries the bile and pancreatic enzymes, is reconnected to the last portion of the small intestine [19]

**Figure 4.** Biliopancreatic diversion with duodenal switch
