Metabolic Bariatric Surgery: Surgical Treatment of Obesity
Great advances have been made in bariatric surgery in recent years, offering patients safer and more successful treatment options for weight loss. In particular, our surgeons have been at the forefront of developing laparoscopic approaches in bariatric surgery, and virtually all procedures performed at NewYork-Presbyterian/Weill Cornell employ this minimally invasive technique. However, our surgeons are equally skilled in performing traditional, open surgeries that require a larger abdominal incision, when this approach is considered the more appropriate for a patient. The majority of our patients realizes substantial weight loss soon after surgery, and experience a significant improvement in their health and quality of life.
Types of Surgery offered:
• Sleeve Gastrectomy
Pioneered by surgeons at Weill Cornell Medicine, sleeve gastrectomy is the most common weight loss procedure in the United States and in the world. Weight loss is induced by restricting food intake and also by altering gastrointestinal and satiety hormones. With this procedure, the surgeon removes approximately two thirds of the stomach laparoscopically so that the stomach takes the shape of a tube or “sleeve”. This procedure is also unique in that it can be performed on very obese or high-risk patients with the intention of performing another surgery at a later time. The second procedure can either be a gastric bypass or duodenal switch. This combined approach has tremendously decreased the risk of weight loss surgery for specific groups of patients, even when the risk of the two surgeries is added. The timing of the second procedure will vary according to the degree of weight loss, typically 6-18 months.
• Gastric Bypass (Roux-en-Y)
Roux-en-Y gastric bypass is a common form of weight loss surgery in the United States because it results in reliable weight loss with acceptable risks and side effects. In a standard gastric bypass, the surgeon divides the top of the stomach to create a small pouch, which functions as the new stomach. The surgeon then makes a small opening (stoma) in the pouch and attaches that opening to a limb of the small intestine, thus bypassing the majority of the stomach and a small portion of the intestine. Most people who meet criteria for surgery are candidates for laparoscopic gastric bypass, a minimal access approach that uses five to six small incisions in the abdomen, instead of the six-to-eight-inch incision used in traditional “open” gastric bypass surgery. Since the size of the new stomach pouch is limited, the patient feels more satisfied with less food. The altered digestive tract often reduces tolerance for fats and sweets, helping you to avoid these foods.
• Duodenal Switch
Duodenal switch is a procedure that induces weight loss by multiple mechanisms including gastric restriction, intestinal malabsorption and gastrointestinal hormone changes. With this procedure, the surgeon removes approximately 60 percent of the stomach so that the stomach takes the shape of a tube. The lower intestine is then divided further down than it is with gastric bypass, so that more intestine is bypassed. Duodenal switch preserves the outlet muscle (pylorus) that controls emptying of the stomach. This surgery has reliable and long-lasting weight loss but may not be optimal for all patients. You may experience more bowel movements and gas, and your vitamin, mineral and protein levels will need to be closely monitored.
• Adjustable Gastric Bypass (LAP-BAND)
Adjustable gastric banding, also known as LAP-BAND has been performed worldwide since the mid 1990’s and was approved for use in the United States by the FDA in June 2001. It is one of the least invasive obesity surgery procedures, because neither the stomach nor the intestine is cut. Time has shown, however, that weight loss is not as substantial as previously thought and complication rates with the device increase over time. In this procedure, the surgeon places an adjustable silicone band around the upper part of the stomach to create a new small pouch above the band. By adding fluid to the band after recovery from surgery, the surgeon adjusts the size of the opening between the smaller upper pouch and the remaining lower portion of the stomach. The tightness of the banded opening controls passage of food between the two sections of the stomach and helps you to feel satisfied after eating. This satisfied feeling lasts significantly longer than it would without the band.
• Gastric Balloon
A gastric balloon is a soft silicon balloon that is inserted into your stomach. This is a short-term weight loss option that reduces your hunger allowing you to control your portion sizes and can be used as a stepping-stone on the path to weight loss success. Gastric balloon is a popular weight loss option if you cannot lose a large amount of weight and keep it off by dieting, changing your behavior and exercising alone; or if you have serious health problems caused by obesity. One major benefit of the gastric balloon is the avoidance of invasive surgery and the risks associated with surgery. Because the balloon has no lasting effects on the stomach, it is important that you create and maintain a healthy diet and lifestyle. As soon as the balloon has been removed, it will no longer be taking up space in your stomach, and you will again be able to eat larger portions of food. The success of the procedure is dependent on whether the recipient can carry on the same habits after the balloon is removed.
• VBloc Surgery
VBloc Therapy, delivered by a small pacemaker device, is designed to intermittently block the nerves between the brain and stomach to produce earlier feelings of fullness and less hunger, resulting in a decreased food intake and clinically meaningful weight loss. The system is implanted via outpatient surgery and does not restrict or change the inner workings of the body like other bariatric surgical options. This procedure is meant to be a permanent weight loss tool. However, since VBloc therapy does not change the inner workings of the body in any way, the procedure can be reversed with minimal risk.
Guidelines for Bariatric Surgery
After a careful and thorough evaluation and assessment, our team may recommend bariatric surgery as the optimal method of treatment. It is important to note that weight is only one of several criteria when considering bariatric surgery. Candidates may include those who:
• are 100 pounds or more overweight or have a body mass index (BMI) of 40 or above
• are 80 pounds or more over ideal weight or have a BMI of 35 or above, with related health problems such as diabetes, high blood pressure or sleep apnea
• have had multiple weight-loss attempts with no long-term success
Obesity is usually classified by body mass index (BMI). A person with a BMI of 30 or more is generally considered obese. A person with a BMI equal to or more than 25 is considered overweight. These thresholds are usually lowered by 2.5 points for individuals of Asian descent. Clinically severe or 'morbid' obesity is considered to be either class III obesity (BMI >40 kg/m2) or class II obesity (BMI >35kg/m2) with significant obesity-related illness and health problems (co-morbidity), including type 2 diabetes.
Being overweight and obesity are major risk factors for a number of chronic diseases, including diabetes, cardiovascular diseases and cancer. It is believed that the increased risk for these conditions is due to excessive or abnormal fat accumulation, which may occur, however, even in individuals with lower BMI. Hence, a simple measure of weight such as BMI may not entirely reflect actual risk in individual patients.
Diet and lifestyle modification remain the best approach to prevent obesity. When severe obesity has fully developed, however, lifestyle modification alone may not be enough to achieve sufficient and/or durable weight loss. Morbid obesity represents an indication for metabolic/bariatric surgery to attain adequate weight loss and prevent long-term risks associated with obesity.
WHAT IS BARIATRIC SURGERY?
Bariatric surgery indicates a set of surgical procedures on the gastrointestinal tract originally designed to reduce intake and/or absorption of nutrients by reducing the stomach's size or bypassing a part of the small intestine, or by a combination of the above.
Over several decades of clinical use and research studies, it has become clear that the reduction of food intake after bariatric surgery is not just the result of mechanical reduction of the capacity of the stomach but the consequence of modulation of hormones and neural signals that regulate the feelings of hunger and satiety.
WHY IT IS IMPORTANT TO TREAT OBESITY AND WHAT ARE THE BARRIERS TO EFFECTIVE SURGERY?
Negative societal attitudes about obesity are unfortunately a barrier to bariatric surgery and more in general to the provision of effective health care for obese individuals. In spite of the many benefits to bariatric surgery, in the U.S., less than 2% of patients that eligible by medical and insurance criteria have access to surgery. The figure is even lower in other countries.
Lack of awareness, concerns about risks of surgery may play a role for this low utilization of bariatric surgery. The most important barrier, however, may be a cultural one.
In fact, there are widely held views that the majority of obese people are responsible for their current weight, and severe obesity is too often believed to be a 'cosmetic' problem resulting from lack of self-control or motivation. In reality, severe obesity is not a cosmetic problem, but a condition that can reduce life expectancy in certain cases as well as expose to the risk of severe metabolic cardiovascular disease.
There is also a common perception among public at large (and even part of the medical community) that obesity is merely a behavioral issue and that weight reduction can be achieved by just the decision to eat less and exercise more.
Such assumptions ignore the very strong evidence that body- weight is controlled by powerful physiological mechanisms that make it difficult for people to maintain weight loss in the long term. In fact, weight loss is usually followed by compensatory mechanisms that increase hunger and decrease energy expenditure, ultimately promoting weight regain.
Bariatric surgery can effectively contrast such physiologic, compensatory changes and therefore results in greater and more durable weight loss than any other weight reduction therapy.
BARIATRIC SURGERY: BENEFITS BEYOND WEIGHT LOSS
Although originally developed merely for weight reduction, bariatric surgery results in benefits beyond just weight loss. In fact, surgery can prevent or dramatically improve a number of conditions and diseases including diabetes, elevated blood pressure, high cholesterol and triglycerides, sleep apnea, cardiovascular disease and others.
A recent scientific paper looking at over 2000 morbidly obese patients who underwent bariatric surgery compared to matched individuals treated by usual care as participants of the ongoing Swedish Obese Subject (SOS) study, found that surgery reduces the incidence of heart attacks and stroke. Surprisingly, however, these benefits were not related to the initial BMI, nor to the degree of weight loss after surgery, which brings into question the current use of strict BMI cut-offs for surgical indications. There is increasing agreement now that other parameters in addition to BMI should be considered to determine appropriate candidates who would benefit from the surgery. However, currently, most insurers still use the following criteria to define eligibility:
1. BMI above 40 kg/m2
2. BMI > 35 kg/m2 if associated with co-morbidities such as diabetes, hypertension, dyslipidemia, sleep apnea and significant arthritis
As with any other form of surgery, efficacy of bariatric/metabolic surgery varies, depending on the individual characteristics of a patient's disease. In cases where surgery cannot achieve the desired weight loss effect or when weight regain becomes an issue, pharmacotherapy may be a valuable complement to further weight loss. At the NYP/Weill Cornell Metabolic and Diabetes Surgery Center, surgeons, physicians, nutritionists and other specialists work as a multidisciplinary team to ensure each patient is provided with the most appropriate plan of care for his/her condition.
REVISIONAL BARIATRIC SURGERY
In some cases, such as substantial weight regain or side effects of an initial bariatric procedure, revisional bariatric surgery may become necessary to convert one procedure into another as appropriate to improve efficacy or resolve side effects. To further weight loss or metabolic control, sometimes restrictive procedures (i.e. gastric banding, or vertical banded gastroplasty, an older and now uncommon operation) are converted in gastric bypass or sleeve gastrectomy. On the other one hand, rare but possible side effects of gastric bypass or biliopancreatic-diversion duodenal switch may require surgical revision. Our team is able to perform such revisional surgery by laparoscopic approach (minimally invasive surgery).