Advances in bariatric and metabolic surgery.

1Department of Vascular Surgery, Singapore General Hospital, Singapore 2Department of Upper GI and Bariatric Surgery, Singapore General Hospital, Singapore Address for Correspondence: Dr Shanker Pasupathy, Department of Upper GI and Bariatric Surgery, Singapore General Hospital, Outram Road, Singapore 169608. Email: [email protected] Bariatric surgery is the euphemistic name for the surgical treatment of severe or morbid obesity.1 Weight loss is induced by 2 main mechanisms. The fi rst mechanism is restriction of the stomach, effected either by placement of a band to narrow the gastric inlet (think of a choker necklace) or by removing part of the stomach to limit its capacity. The second mechanism is reduced nutrient absorption; a gastrointestinal bypass is created such that there is less surface area and contact time between food and intestine. These mechanisms are represented today in the 3 most widely accepted procedures—laparoscopic adjustable gastric banding (LAGB), laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB). Emerging in the post-world war II economic boom, bariatric surgery was largely unregulated and very much a fringe discipline in the early years. However, recognition of truncal obesity as a contributor to a conglomeration of risk factors leading to increased cardiovascular risk (now called the metabolic syndrome) put obesity on the radar of health authorities.2 The availability of standardised operative procedures which produced signifi cant and long-term weight loss led the National Institutes of Health (NIH) to publish guidelines on the indications for bariatric surgery in 1991.3 Several events soon converged to allow bariatric surgery to grow into an independent specialty. The fi rst was the advent of laparoscopy. In 1993, the fi rst laparoscopic gastric bypass was performed by Alan Wittgrove in the USA.4 At the same time, the fi rst gastric bands were placed by laparoscopy in both Europe and Australia.5,6 The laparoscopic approach was shown to be safer than open surgery.7 Hospital length of stay and major complication rates were consistently lower after laparoscopic surgery. However, there was an important caveat. Surgeons needed training in this new type of surgery to be good at it. The concept of the “learning curve” was born.8 It was important to acquire good skills, and spend enough time to gain adequate experience before one could operate independently with consistently good results. The second was the recognition that obesity-related medical conditions improved dramatically after bariatric surgery. In particular, type 2 diabetes mellitus (T2DM) appeared to be “cured” after gastric bypass up to 80% of the time.9 Improvement was also noted in the control of blood pressure and cholesterol. These results were momentous and provided real medical (and survival) benefi t to many obese patients who otherwise had a dismal future and limited treatment options. In the USA, the national society eventually changed its name to the American Society of Metabolic and Bariatric Surgery (ASMBS) to fully describe the new spectrum of weight loss surgery. The third was the change in obesity patterns worldwide: no more is obesity a problem of the Western world. With developing countries registering rapidly rising obesity rates, over-nutrition overtook under-nutrition in terms of health impact.10 Obesity is today well and truly a pandemic. In tandem with the rise in obesity comes the demand for its treatment. However as with all diseases, there is a wide variation in patterns of obesity and the medical implications thereof in different ethnic groups and different environments. For example, for each kilogramme of body weight, Asians have more body fat—and visceral fat in particular—compared to Caucasians.11 The last but most signifi cant transformation of recent times is that both society at large and medical professionals, who in general are rather conservative, acknowledge that obesity requires serious attention. Much debate has sprung up in the past year after the American Medical Association declared obesity to be a disease.12 Whether the ‘disease’ label is appropriate or not, there is little doubt that leaving obesity untreated in individuals with serious obesity-related conditions such as T2DM, is tantamount to disregarding the ‘elephant in the room’. Perhaps the perceived reluctance on the part of endocrinologists and internists to address this obvious target has emboldened bariatric surgeons to enter the war on diabetes.13