**2. World statistics and census**

Obesity is a major non-communicable epidemic disease and has been increasing worldwide for both developed and developing countries. It has tripled in number since 1975 according to the World Health Organization (WHO), with the latest data showing more than 1.9 billion adults classified as overweight; 650 million of which are considered as obese. In 2016, obesity accounted for 13% of the world's population (11% of men, 15% of women) [2]. In the Asia-Pacific region, the obesity in Gulf countries is greater than 30%, with T2DM frequency at 8-14.7%. This is in contrast to most of the other Asian countries where diabetes was more frequently seen than obesity [3].

Bariatric surgery is recognized as the most efficacious treatment for morbid obesity and its accompanying co-morbidities [4]. The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) 5th Global Registry Report in 2019 recorded 520,983 bariatric operations performed from 2015 to 2018. The predominating bariatric surgery was SG (58.6%) followed by RYGB (31.6%) [5]. The Asia-Pacific Bariatric and Metabolic Surgery Society 2018 Congress reported 95,125 surgeries in Asia-Pacific countries, with most being performed in Australia and the Gulf countries, reflecting the highest obese populations in Asia. The most commonly performed was SG (68%), followed by the different bypass procedures (19.5%), and other surgeries, including revisional surgery (12.5%). Sleeve gastrectomy is being done at more than 50% of the procedures in most countries. The reported bypass surgeries included RYGB, one-anastomosis gastric bypass, SG with duodenojejunal bypass (SGDJB), and biliopancreatic duodenal switch (BPPDS). The bypass procedures were more than 30% only in Thailand and India. The OAGB was the leading bypass procedure in Taiwan, India and the Gulf countries. The SGDJB was more common in Japan, while RYGB was more common in the other countries [3].

The gold standard in bariatric surgery is still RYGB; but due to its technical difficulty and more severe complications such as marked malnutrition and marginal ulceration, SG has become the more popular bariatric procedure.

#### **3. Brief evolution of bariatric surgery**

Bariatric and metabolic surgery originated in the early 1950s, first performed by Kremen: the jejunoileal bypass. To treat obesity-associated hyperlipidemia, the proximal jejunum was anastomosed to the distal ileum to limit absorption. However, this was associated with post-operative severe malnutrition and liver complications [6]. Taiwan was the first country in Asia recorded to perform the jejunoileal bypass for obesity treatment in 1974 [7]. The initial bariatric surgery was modified to limit malabsorption. In 1960s, Mason developed the first gastric bypass procedure utilizing a transverse gastric pouch remnant anastomosed to a loop of jejunum. Severe bile reflux prompted revision to a Roux-en-Y reconstruction of gastric bypass in the 1970s, which resulted to less diarrhea, kidney stones and gallbladder stones [6]. Taiwan was the first to perform a gastric partition in 1981. Vertical banded gastroplasty then began in Japan in 1982, and then Singapore in 1987 [7].

Biliopancreatic diversion (BPD) by Scopinario and duodenal switch (DS) by Hess were also developed subsequently in 1976 and 1988; but the high incidence of potential metabolic complications and prolonged follow-up made these procedures less common. The RYGB eventually became the gold standard procedure for bariatric surgery [4].

#### *Sleeve-Plus Procedures in Asia: Duodenojejunal Bypass and Proximal Jejunal Bypass DOI: http://dx.doi.org/10.5772/intechopen.96042*

In an attempt to breakdown RYGB and laparoscopic DS to decrease the operative time, SG was initially performed as a first step of a staged procedure [8]. The achievement of weight loss after SG made it an adequate stand-alone procedure.

Laparoscopic bariatric surgeries were first performed in 1994: laparoscopic adjustable gastric banding (LAGB) by Belachaew, and laparoscopic RYGB by Wittgrove and Clark. Asia also started laparoscopic bariatric surgeries during the 1990s [3]. In 1999, laparoscopic BPDDS was initiated by Gagner; and laparoscopic classical BPD by Scopinario. By 2000, McMahon and Gagner performed the first isolated laparoscopic SG, which was the time that majority of bariatric surgeries were already being done laparoscopically [5, 9].

Advancements in minimally invasive surgery lead to the application of single incision laparoscopic surgery (SILS) to bariatric surgery. In 2008, Nguyen reported the first case of bariatric SILS with adjustable gastric banding, [10] while Saber performed SILS SG [11]. Huang documented the first single incision transumbilical (SITU) RYGB in 2009, [12] followed by a series in 2010 comparing surgical outcomes of patients undergoing 5-port LRYGB with the novel SITU RYGB. The SILS has been shown to improve patient satisfaction in terms of cosmesis with comparable weight loss and morbidity rate. However, technical challenges due to the restricted surgical field, longer operative time, and increased post-operative pain have limited its popularity [13]. These procedures are technically feasible and reproducible with proper patient selection, performed by an experienced surgeon.

Restrictive and malabsorptive anatomic conceptualization of bariatric surgical procedures are continually under investigation. Modifications to the accepted standards are being made to further improve the treatment of obesity-related co-morbidities and reduce the impact of surgery.

### **4. Types of sleeve-plus procedures**

The earliest sleeve-plus procedure is the BPDDS which was developed in 1998 by Hess and Marceau [14, 15]. Many of the sleeve-plus procedures were patterned after the BPDDS. The procedure consists of a Roux-en-Y reconstruction of the bowel with a duodeno-ileal anastomosis for the alimentary limb, a lengthy biliopancreatic limb for malabsorption, and a short common limb. Changes in the location of the limb anastomosis and the limb lengths resulted in the different sleeve-plus techniques reported today (**Figure 1**).

In 2007, Sanchez-Pernaute reported a modification of the BPDDS into a loop fashion of limb reconstruction with a longer common channel. He described it as a single anastomosis duodenoileal bypass with sleeve (SADI-S) [16]. Santoro developed the SG with transit bipartition as an ileal anastomosis to the SG antrum with a Roux-en-Y reconstruction. This technique was then revised by Mui into a loop fashion and was called single anastomosis sleeve ileal bypass (SASI) [17, 18].

The sleeve gastrectomy duodenojejunal bypass (SGDJB) was first developed in Asia as an alternative to RYGB to allow the stomach to be screened for gastric cancer in areas with a high-risk population. The procedure may be done in the Roux-en-Y or loop fashion and was developed by Kasama in Japan and Huang in Taiwan, respectively [19, 20].

The ileal interposition with sleeve gastrectomy (IISG) was introduced by Aureo De Paula. The procedure included a segment of the ileum placed between the transected proximal duodenum and to the proximal jejunum, or interposed into the proximal jejunum [21]. The complexity of the procedure limits its widespread application.

**Figure 1.** *Types of sleeve-plus procedures.*

The proximal jejunal bypass (SGPJB) is probably the simplest sleeve-plus procedure to perform. It was developed by Alamo in 2004, where the proximal 20 cm of the jejunum is transected and anastomosed to the distal 300 cm bowel, leaving a blind-ended segment of the jejunum [22].
