Often, those who are very overweight have tried dieting for years before giving up in frustration. But more obese people are turning to bariatric surgery to jump-start their weight-loss programs.
The surgery is low-risk but isn't for everyone. It requires a commitment to other lifestyle changes. But it can have many health benefits, according to Dr. Cynthia Long, advanced laparoscopic and bariatric surgeon at Sinai Hospital.
Can you describe the different types of bariatric surgery?
In general, there are three main categories of bariatric procedures. They include restrictive, malabsorptive and combination procedures. In restrictive procedures, the functional size of the stomach is markedly reduced. In malabsorptive procedures, ingested food bypasses segments of the intestine so that there is reduction in caloric intake. Finally, there are combination procedures, which employ both restrictive and malabsorptive methods to achieve weight loss. The adjustable gastric band is a purely restrictive procedure in which a device reduces the gastric capacity, thus achieving satiety with much smaller portions of food. Another example of a restrictive procedure is the vertical sleeve gastrectomy in which the gastric capacity is reduced by removing about 80 percent of the stomach. The biliopancreatic diversion is a malabsorptive procedure. The Roux-en-y gastric bypass employs both restriction and malabsorption to bring about weight loss on the order of 75-80 percent in the first 18 months.
The number of bariatric procedures has rapidly increased, from 6,868 in 1996 to 45,473 in 2001, and up to 220,000 per year were performed in the United States by 2008.
Who is the best candidate for each type of surgery?
There are basic clinical guidelines for patients based on their BMI, or body mass index, and the presence of obesity-related medical issues. All patients are prescreened by a mental health specialist to ensure that they do not have untreated major depressive symptoms and major eating disorders, which would sabotage their attempts at weight loss. The National Institutes of Health criteria view the following categories of patient as appropriate surgical candidates. Individuals who have a BMI from 35-39.9 and are medically treated for one or more major obesity-related co-morbidities, like type 2 diabetes mellitus, obstructive sleep apnea, heart disease, and hypertension. The second category of candidates are those who have a BMI of 40 or greater, with or without associated co-morbidities. Within the aforementioned groups, the best patients are those who recognize that surgery is just a tool and have committed to making the necessary lifestyle changes to support long-term weight management.
Why do these procedures work when diet and exercise have failed?
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The reasons are multifactorial. We know that there are certainly methods and degrees of weight loss that are within one's control, i.e. diet and exercise. Weight-loss efforts can often be stymied, though, by one's own physiological system that regulates weight similar to a thermostat controlling temperature. One's weight "set point" is genetically influenced, such that a decrease in body fat stores can cause a compensatory change in appetite and metabolism that counteracts weight loss. Furthermore, there is strong evidence that the satiety-regulating mechanisms in morbidly obese individuals are disturbed. With bariatric surgery, there is physical restriction of the stomach, which minimizes intake. In some procedures, there is rerouting of the intestines, which reduces absorption of the calories that are consumed. There can also be an alteration in the body's hormonal environment, which affects hunger. Finally, when patients experience the extensive weight loss, they are energized and further motivated to continue in their weight-loss efforts.
Can the surgery help with diabetes, high blood pressure and other illnesses linked to obesity?
The salutary effects of this surgery on different medical conditions are truly impressive. There is improvement and resolution of many disease processes like type II diabetes, hypertension, obstructive sleep apnea, polycystic ovary syndrome and infertility, hypercholesterolemia, and osteoarthritis, just to name a few. Observational studies have shown between 55-95 percent remissions of type 2 diabetes mellitus with bariatric surgeries. These benefits are slightly more pronounced in the Roux-en-y gastric bypass procedure, which induces long-term control of type 2 diabetes by weight reduction, but also with alteration of gastrointestinal hormone secretion. About 79 percent of bariatric patients have improvement or resolution of high blood pressure and about 98 percent improve their hyperlipidemias.
What are the challenges or complications that could result?
Like any other abdominal surgeries, bariatric surgery is not without risk. In general, the risks associated with these procedures are less than the risks of obesity and obesity-associated co-morbidities. The loss of life expectancy due to obesity is profound in comparison with a normal-weight individual, a 25-year-old morbidly obese man has a 22 percent reduction in expected remaining life span, representing an approximate loss of 12 years of life. Certainly with the advent of minimally invasive techniques and designated centers of excellence, there are far fewer complications than has been seen in the past. The adjustable gastric band, a device approved by the Food and Drug Administration in 2001, has gained popularity because of its very low risk profile and slow, gradual weight loss. The average short-term mortality rate is 0.05 percent. The Roux-en-y gastric bypass, which has been performed since the 1960s, has an average mortality rate of 0.1 percent. These mortality rates are comparable to what one would expect with a laparoscopic gallbladder removal. Because of the relatively low complication profiles of these surgeries now, the greatest challenge that most patients face after bariatric surgery is making permanent dietary and lifestyle changes.