**2.3 Laparoscopic adjustable gastric banding (LAGB)**

One of the most secure surgical methods used to treat obesity is LAGB [24]. Firstly, in 1993, laparoscopic adjustable gastric banding was described by Belachew. Since then, the LAGB has undergone many changes, revisions, and corrections to become the way it is now defined. These changes influenced both surgical and technological techniques, but most importantly, the management of pre-and postoperative [25].

In LAGB, a silicone ring is placed around the gastric to create a little upper stomach pouch under the esophagus. Within the 1970s, this method was introduced and remains secure, well endured, and effective with a relatively low risk of complications. Increasing the effect of weight loss without compromising safety by adjusting the band is another benefit of this method. An option that makes LAGB attractive to most patients is that it is a reversible form of laparoscopic surgery, although it is not touted as a temporary method due to the considerable risk of regaining weight after removal [24]. LAGB at first accounted for most methods and affected weight loss by a restrictive mechanism [26]. And indeed even though its popularity has been diminishing over time, it remains a choice for a specific group of patients, creating significant weight loss and improving obesity-associated comorbidities [24]. Due to the lack of any resection or anastomosis, reversibility, low life-threatening complications, and a minimally invasive intervention, LAGB surgical procedure seems to be useful [27]. Obesity to a lower degree, at a younger age, and at the time of surgery, the lesser severity of comorbidities for successful weight loss can be an important indicator, making these patients the perfect candidate for LAGB [24]. LAGB is the simplest form of minimally invasive or surgical method performed for obesity, but it is less commonly used due to the high rate of secondary revision to complications and late weight gain. Weight loss was promising in the initial results but in the long-term, the result is less encouraging [28]. LAGB has some minor complications, such as port slippage, port tube separation, and port infection, and major complications, such as band intolerance, band erosion, band migration, pouch enlargement, band slippage, and band opening [27]. One of the less common late-onset complications is digestive lumen band erosion/migration, which occurs after LAGB. Late complications after LAGB are more than the initial complications and include band slippage, device-related complications, band erosion, and pouch dilation. Major life-threatening complications, manifesting as severe gastrointestinal hemorrhage, perforation, or obstruction are rare and require immediate surgical intervention [28].

### **2.4 Biliopancreatic diversion (BPD)**

One of the most effective surgical methods for obesity is BPD, which generally loses more than 72% of excess body weight in 5 years. Firstly, Scopinaro described BPD, done over the past 25 years, and lead to sustainable and effective long-term weight loss [29]. Among the existing bariatric methods, biliopancreatic diversion (BPD) was common in prior decades. It is a combination of a Roux-en-Y construction with a distal gastrectomy [30]. Biliary and pancreatic juices are transported by the biliopancreatic limb to the common limb, while ingested food is transferred to the common limb by the alimentary limb [30]. One of the most effective methods in decreasing comorbidities of obesity and weight loss with minimal long-term weight regain is biliopancreatic diversion (BPD) [30, 31]. Patients lose weight because of the reduction in the area of absorption by bypassing most of the intestines with nutrients, also because of reduced absorption and digestion by the attachment of nutrients to the biliopancreatic enzymes and secretions distally [32]. BPD leads to many metabolic syndrome complications remission [29]. BPD has a positive effect on T2DM and other complications of metabolic syndrome in the short-term and long-term. After surgery, triglycerides, total cholesterol, and LDL decrease, while HDL levels increase. HTN improvement or resolution is observed. Before surgery, the HTN incidence was 56.7%. After surgery, approximately 50% of hypertensive patients improved or recovered after a one-year follow-up [31]. Signaling of bile acid, increased secretion of intestinal

#### *Do All Bariatric Surgery Methods Have the Same Effects on the Gut Microbiota? DOI: http://dx.doi.org/10.5772/intechopen.107176*

hormones (oxyntomodulin, PYY, and GLP-1), Gut microbiota changing and intestinal glucose transport reduction through circulating branched-chain amino acids and SGLT1, improved initial sensitivity and secretion of insulin, and increased satiety, is thought to cause these effects [29]. However, BPD is not widespread due to it is associated with long-term side effects, such as vitamin deficiency and protein malnutrition due to malabsorption [29, 31]. BPD anatomical late complications were reported to a less frequent [29]. Protein malnutrition is a common and frightening aspect of bariatric surgery [31]. In 7.7–11.9% of patients with BPD, protein malnutrition can occur; when the gastric pouch is less than 200 MLS, this reaches even in 17.8%. To minimize this risk, the common limb's length and the gastric pouch's size can be adapted (increase from 50 cm to 100 cm). In 60% of BPD patients, iron deficiency anemia will occur due to exclusion of the proximal jejunum and duodenum and decreased gastric acid secretion [29]. Especially, according to the fat-soluble vitamins in malabsorptive bariatric methods, multiple vitamin supplements will be required. Calcium metabolism changes significantly, usually due to vitamin D deficiency. Weight loss, even before surgery, reduces bone density because of mechanical disorders of load on bones and usually, secondary hyperparathyroidism is established. Vitamin D and calcium deficiency occur more often after malabsorptive methods than in restrictive methods [31]. BPD, which is surgically challenging, is rarely performed today due to the high risk of lifelong needs and nutritional complications for follow-up [29]. Presently, late complications are frequently observed in elderly patients [30].
