Chapter 13: Bariatric Surgery

Introduction

Over 15 million adult Americans (6.6% of the population) had a BMI > 40 kg/m² in 2013, and the rate of obesity continues to rise.¹ Obesity is associated with increased morbidity and mortality.² Approximately 179,000 weight loss procedures were performed in the United States in 2013, and strong data now demonstrate that bariatric surgery decreases morbidity and mortality in obese patients.³

The first published bariatric case series was performed in the early 1960s by Payne and colleagues.⁴ The authors described the jejunocolic bypass, an operation aimed purely at malabsorption, that consisted of dividing the proximal jejunum 35–50 cm from the ligament of Treitz and anastomosing it to the proximal transverse colon.⁴ Although this resulted in successful weight loss, virtually all the patients suffered from diarrhea, dehydration, and severe electrolyte imbalances.⁵ In an attempt to avoid these complications, jejunoileal bypass replaced the jejunocolic, with an anastomosis performed 10 cm proximal to the ileocecal valve, and with the bypassed small intestine anastomosed to the transverse or sigmoid colon. This operation, however, was also fraught with complications, including diarrhea, dehydration, vitamin and mineral deficiencies, protein depletion, polyarthralgia, hepatic insufficiency, and ultimately, weight regain.^6,7

The high morbidity rate of these procedures led to the exploration of weight loss operations that combined malabsorption with restriction. Biliopancreatic diversion with partial distal gastrectomy and Roux-en-Y reconstruction became popular in the 1970s. Subsequently, the biliopancreatic diversion with duodenal switch, where a sleeve gastrectomy maintained the integrity of the pylorus and proximal duodenum, became popular in the late 1990s. These procedures led not only to significant excess weight loss, but also to very high rates of remission of diabetes mellitus, hypertension, and hyperlipidemia.^8,9,10 The Roux-en-Y gastric bypass configuration (RYGB) also appeared in the 1970s, proving to be superior to jejunoileal bypass with regard to its complication rates.^11,12 Unfortunately these operations still carried significant malabsorptive side effects, leading some surgeons to favor purely restrictive procedures, such as nonadjustable vertical banded gastroplasty (VBG), and later, adjustable gastric banding (AGB). These are less successful than the RYGB in weight loss and reduction of obesity-related comorbidities such as diabetes mellitus. They also have their own procedure-related complications, including staple line dehiscence or stoma stenosis after VBG, and band slippage or erosion with the AGB.^6,13,14

The final bariatric procedure that was initially conceived as a solely restrictive solution, but which has since been shown to induce concurrent metabolic changes, is the standalone sleeve gastrectomy, in which the fundus and the lateral 80% of the body of the stomach is resected. It was initially used in superobese patients with BMI > 50 as a first stage before proceeding with duodenal switch or gastric bypass. However, over the last 10 years the laparoscopic version of this operation [laparoscopic sleeve gastrectomy (LSG)] has become the most prevalent surgical ...