Surgical Treatment – Why Choose Surgery?
The obesity problem has become a national epidemic, now affecting the majority of Americans. The end stage result of this, termed “morbid obesity”, now affects 15 million people, 5% of the US population. It is quickly becoming the number one cause of preventable death in the United States.
All available studies indicate that this condition almost never responds to “medical therapy” (diets, exercise, medications) with “failure” rates upwards of 99%. Conversely bariatric surgery has been shown to successfully treat this problem 80-90% of the time. Indeed, performed correctly, and with recommended change in lifestyle, surgical therapy offers a lifeline for millions of Americans afflicted with this condition. This truth was confirmed by the National Institutes of Health (NIH) in their 1991 consensus conference on obesity. When the world’s data was reviewed, several conclusions were made, and continue to be true today in relation to morbid obesity:
Conclusions About Morbid Obesity
Medical therapy is rarely successful, demonstrating only moderate weight loss (10%), with weight regain in the vast majority (95%) within 24 months. Those who failed medical therapy should undergo surgery, as the long term mortality from obesity far outweighs the risk of surgery.
Criteria for surgery were developed:
- Body Mass Index (BMI) greater than 40
- BMI of 35-40 with “significant medical comorbidities” (hypertension, coronary artery disease, diabetes, myelitis, obstructive sleep apnea, and life-limiting joint disease)
Two surgical procedures are recommended: the gastric bypass and vertical banded gastroplasty (stomach stapling). The NIH concluded that "weight loss surgery for morbid obesity, when combined with behavior modification, is currently the most reliable and only choice for long-term maintenance of excess weight loss".
Since the 1991 consensus conference, bariatric surgery in the US has become a standardized and mainstream treatment for this disease. Once considered a “fringe” specialty, it is now recognized as the only successful treatment for morbid obesity. However, there are still those who “don’t believe” in surgical treatment for morbid obesity. A review of the available data would suggest that this represents an uninformed and biased viewpoint.
Multiple surgical techniques have been proposed over the past 50 years, and have boiled down to four primary procedures offered in the United States:
- Gastric Bypass
- Gastric Banding
- Gastric Sleeve
- Biliopancreatic Diversion with Duodenal Switch
It is very important to understand that not all procedures are equivalent and one does not “fit all”. There is no one perfect procedure, and it is really one’s commitment to disciplined lifestyle changes that will portend their success.
Much progress has been made in our understanding of how surgery works and to produce such significant and long-term weight loss, and in fact, several specific mechanisms have been found to come into play with any given surgical procedure. With that said, not every technique offers these mechanisms.
In general, the more mechanisms of action any given procedure offers, the greater the weight loss is seen and the more successful (percentage of those who achieve greater than 50% excess weight loss) that procedure may be. These mechanisms are as follows:
Restriction. This concept is paramount to all weight loss surgeries. It essentially means that the stomach is somehow made much smaller, often decreasing its capacity up to 80-90%. This can be by way of dividing the stomach with staplers, creating a small pouch (Roux-en-y gastric bypass), or creating a long, slender tube (gastric sleeve), or by putting a band around the top of the stomach, separating it into a pouch above from the remainder of the stomach below.
Malabsorption. This is utilized by the gastric bypass and biliopancreatic diversion. The intestine is re-routed such that food consumed is not sufficiently mixed with pancreatic enzymes, therefore creating a less efficient absorption. This effect is dependent on the amount of intestine that is re-routed and can be of minimal effect (as with the gastric bypass), or can be profound (as with the biliopancreatic diversion). In general, when more intestine is bypassed, weight loss tends to improve, but this is at the expense of increased complications. For the most part, the amount of intestine bypassed for the gastric bypass is less than that which can cause serious consequences. This is why most bariatric surgeons defer performing the BPD (biliopancreatic diversion) in the United States.
Hormonal Changes. This is the most intense area of current research in bariatric surgery and the mechanism by which many believe long term success is attributed. What has been found is when the stomach is divided and/or the intestine is re-routed, the levels of certain gastrointestinal hormones are modified. For reasons that are not fully understood, this has profound effects. Two specific effects occur. First, hunger is markedly reduced, and secondly, certain disease processes are cured within days of the surgery. The most stark example of this is diabetes myelitis, which is resolved in over 85% of patients after gastric bypass and 98% after biliopancreatic diversion, often within days of surgery. The gastric sleeve also will show these changes, but to a lesser degree. The gastric band has not been shown to significantly affect hormonal changes.
Dumping Syndrome. This is often stated as a “side effect” or “complication” of the gastric bypass. This effect is unique to this particular operation and in fact, represents a very effective tool which aids in maintaining a healthy diet. Because the bowel is attached to the gastric pouch, food goes directly into the intestine rather than being held in the stomach. This is important because food that hits the intestine without being diluted or processed. Rich foods, mostly sweets, will therefore irritate the intestine and cause unpleasant side effects such as nausea, cramping, diarrhea and sweating. Essentially, foods high in sugar don’t agree with you after this procedure. As a result, 90% of gastric bypass patients develop an aversion to sweets. Many believe that this, along with the above described hormonal changes, is the reason that weight loss after gastric bypass tends to be more robust and consistent than that seen in purely restrictive procedures, such as gastric banding.
Again, note that one or more of these four mechanisms are utilized by any given weight loss surgery, and every operation does not possess each mechanism. Further, weight loss tends to be greater in those procedures where more than one mechanism is utilized. Detailed discussion concerning each one of these procedures and which mechanisms are utilized can be found elsewhere on this site.