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Types of Weight Loss Surgery 

Surgery for weight loss has been around for almost 60 years, beginning in the 1950’s with the jejuno-ileal bypass (intestinal bypass). Since that time, many different types of procedures have been developed and tested. Most have fallen by the wayside, but a few have proven safe and successful. Currently, three different procedures encompass the vast majority of weight loss surgery performed in the world: the Roux-en-y gastric bypass, the laparoscopic adjustable gastric band, and vertical sleeve gastrectomy.

Gastric Bypass
The Roux-en-y gastric bypass is the most popular weight loss surgery procedure in North America, representing the majority of bariatric surgery performed over the last 30 years. It has been around since 1967 and is considered by many to be the “gold standard”. As such, it has been studied, modified, and refined, and now represents a safe, acceptable and effective means of treating morbid obesity. 90% of those who undergo this procedure will achieve successful weight loss (defined as greater than 50% excess weight loss).

On average, weight loss is around 70% within two years. For example, if one weighs 250 pounds with an ideal body weight of 150 pounds, excess weight is 100 pounds. Expected weight loss would be 70 pounds, resulting in a final weight of 180 pounds. This profound and consistent weight loss is achieved by utilizing all four mechanisms described above.

First, restriction is achieved by creating a very small pouch, about the size of a golf ball or egg. This reduces the size of the stomach by over 90%. As such, a feeling of fullness or “satiety” is achieved with only a few bites of food.

In addition, a moderate amount of malabsorption occurs due to the intestinal reconstruction performed when creating the outflow passage of the pouch. A segment of the small intestine is “bypassed”; therefore, after food empties the pouch, it has less time and resources to be broken down and digested by the body, resulting in less nutrient absorption. Over the years, the optimal amount of bypassed intestine has been determined such that the malabsorption effect aids with weight loss but is not so extensive that it causes malnutrition. It has also been noted that this malabsorption effect is most profound within the first 12-18 months following surgery. Most believe that the body adjusts to and accommodates this new anatomy, creating a lesser effect long-term.

The third way this procedure affects weight loss is through hormonal mechanisms. Several gastrointestinal hormones (GLP-1, PYY, Grehlin) are affected when the stomach is divided and the intestine is re-routed. This effect is poorly understood, but results in a profound decrease in hunger. In fact, the vast majority of our patients report that they are “just not hungry” after this procedure. This assists in the ability to maintain the very low caloric intake necessary to affect profound and long lasting weight loss. Many experts believe this to be the most important mechanism by which gastric bypass is effective long-term.

Further, certain foods, particularly sweets and starches, will cause unpleasant side effects, such as cramping, nausea, diarrhea, sweating and light-headedness. This is called dumping syndrome and occurs because food now empties straight into the intestine rather than being diluted and processed in the stomach. The intestine is not designed to handle such a heavy load of carbohydrates and the body reacts by secreting a large amount of fluid into the intestine in an effort to dilute the food. As a result, sweets and junk food hold no attraction for the vast majority of those who undergo this operation. This greatly helps in maintaining disciplined dietary habits.

Results of Gastric Bypass
Together, the above mechanisms produce a powerful tool to achieve profound and lasting weight loss. Studies show that 90% of those undergoing this procedure lose about 70% of their excess weight; this is maintained long-term in approximately 80% of post-operative individuals. Several large studies have shown that over 90% of comorbid conditions associated with morbid obesity are either improved or resolve entirely in those who have undergone gastric bypass. Generally, it is the rule, rather than the exception, to see diseases such as diabetes, hypertension, sleep apnea and hyperlipidemia completely resolve within a few months of surgery. With that said, it is imperative that this procedure be accompanied by a steadfast commitment to adopting healthy habits – like diet in exercise – in order to achieve long-term success.

Additionally, as a result of the changes to the GI tract, the body may not absorb certain nutrients, like iron, calcium and vitamin B12, as efficiently as it once did. Therefore, part of the newly adopted regimen must include regularly taking vitamins and supplements to make up the difference. Over the years, it is possible to develop problems secondary to nutrient deficiencies, such as anemia and osteoporosis, but these issues are relatively easily avoided by sticking with recommended vitamin and calcium replacement therapy. Annual follow-up appointments to check these levels are recommended for anyone undergoing gastric bypass.

Adjustable Gastric Banding
Although gastric banding has been around since the 1970s, it has gained popularity in the United States only in the last ten years. It was first evaluated primarily in Europe and Scandinavia almost 40 years ago. At that time, the results were not as good as gastric bypass or vertical banded gastroplasty (VBG), so it fell out of favor.

Interest rose again in the early 1990s when an inflatable variant was developed, and in 1993 the first laparoscopic adjustable gastric band (LAGB) placement was performed. This was evaluated in Europe and Australia throughout the 1990s and popularity grew. In 2001, the FDA approved laparoscopic adjustable banding in the United States. Currently, there are two laparoscopic LAGB devices available: the LAP-BAND® system and the Realize® band.

The band is placed just below the junction of the stomach and esophagus, thus creating a small pouch (similar in size to the pouch created with the gastric bypass). The inside of the band is lined with balloons, or inflatable mechanisms, which are attached to a catheter that leads to an infusion port. The infusion port is safely implanted underneath the skin of the abdominal wall and is used to inflate the balloons by injecting saline into the device. As the balloons fill, the band tightens around the stomach, decreasing the size of the outflow (or stoma) between the pouch and the rest of the stomach.

In essence, by placing a band we create a small gastric pouch with an adjustable outflow. If the band is fully inflated, it will likely be too tight to allow any food to pass. Likewise, if the band is completely deflated, food passes without any difficulty whatsoever. The band utilizes restriction as the singular mechanism for weight loss. Generally, there is neither decreased hunger, nor will there be any dumping or malabsorption effect: once food passes the band, it progresses normally through the GI tract.

Multiple adjustments (or “fills”) are made throughout the process, starting about six weeks after surgery. These are performed at regular intervals, usually every three to four weeks, injecting a little more saline each time until the band is filled to the right volume. This process is customized to each patient and the final volume may vary significantly between individuals. Usually four to six adjustments are made in the first twelve months, with regular maintenance required long-term. For this reason, diligent, long-term follow up is essential to success with the laparoscopic adjustable band.

Adjustable Gastric Banding Results
The weight loss experience with the LAGB has generally been found to be less robust and more variable than that compared to gastric bypass. On average, weight loss is approximately 40-60% and this is only experienced in about half of individuals. In other words, 50% of people that undergo the surgery lose 50% of their excess weight. The majority of the remainder will lose 20-30% of their excess weight and approximately 2-5% will lose no weight at all or actually gain weight. On the other hand, however, up to 10% may lose over 60% of their excess weight.

Resolution of medical problems associated with obesity is blunted. Diseases like diabetes are cured in about 50% of cases compared to the 85% achieved with gastric bypass. It has also been shown that those undergoing a LAGB will have a higher rate of repeat operations: up to 15-25% of bands placed may be removed secondary to problems or complications.

With that said, gastric banding does offer several advantages. It is a less invasive operation on the GI tract, recovery time is a little shorter and it is “sort of” reversible (if necessary). It can also be adjusted at any time and there is less chance of certain nutritional problems, such as mineral (iron and calcium) and vitamin (B12) deficiency. The lack of dumping, malabsorption and hormonal changes, however, make it easier to “cheat”. Most believe this is why the previously mentioned results vary so much, reinforcing the fact that – in order to meet and maintain weight loss surgery goals – it is imperative that one pursues a disciplined strategy for success. With all weight loss surgeries, and especially LAGB, be sure to make a plan that includes specific dietary guidelines and focuses on maintaining a healthy, active lifestyle. Make a commitment to follow up with your bariatric surgeon as well.

Sleeve Gastrectomy
Vertical sleeve gastrectomy (VSG) is a relatively new procedure, first developed in 1993. Its popularity increased in 2001 when it was proposed the procedure be used as the first stage of a much more complex and complicate surgical technique. It was found, however, that a certain segment of individuals lost adequate weight with the sleeve alone and didn’t require the second stage and so on.

In 2005, studies on laparoscopic VSG performed as a standalone procedure were conducted. By 2010, data on over 2,500 patients had been compiled, showing a weight loss of 33-85%, with an average of 60% excess weight loss at five years. Based on this, several societies and insurance companies agreed that this was an acceptable surgical procedure for weight loss. It is therefore a covered benefit for some companies, but may still be considered investigational by others.

The VSG is an operation that involves limiting the amount of food taken in by removing about 75%-85% of the stomach. This is done by cutting away a large portion of the stomach and thus creating a thin tube or sleeve that is about the size of a banana. There are no changes made to the remainder of the gastrointestinal tract.

It affects weight loss by utilizing two of the four mechanisms for surgical weight loss.
• Restriction
• Restriction occurs as the stomach volume is severely reduced. The sleeve is approximately three times the size of the gastric pouch created with the band or gastric bypass, but still remains markedly smaller than the natural stomach. The part of the stomach removed is critical for two reasons. First, this portion, called the fundus, is the part of the stomach that functions to expand with a meal. The sleeve, which remains, is thicker and more muscular and therefore not only smaller, but less compliant. It creates an earlier feeling of “satiety” or satisfaction with eating smaller meals.
• Secondly, the removed portion is the part of the stomach that is responsible for creating ghrelin, a hormone that triggers the hunger center in the brain. As a result, about 75% of patients have a significantly reduced sensation of hunger.
• Because the gastrointestinal tract is not disturbed, there is no malabsorption nor will most experience the effects of dumping syndrome.

Sleeve Gastrectomy Results
As stated above, the VSG is a relatively new procedure and thus far, minimal data exists as to its effectiveness beyond five years. However, the results so far reveal weight loss ranging from 35-85%, with an average of 60% in excess weight loss at this juncture.

It is important to understand that the long-term results are unclear. The minimal preliminary data reveals weight loss at 7-8 years averaging about 55%. Just as the amount of weight loss is seen to be somewhere between that of gastric bypass (70%) and gastric band (50%), the same is true of the reduction in medical problems. Take diabetes for example: an average of 60% resolution is experienced with VSG whereas an average of 85% resolution experienced with gastric bypass (GBP) and 50% with LAGB.

The potential for vitamin and mineral deficiency is significantly less than that associated with gastric bypass, as the normal flow of food remains intact.

Again, it is important to know several facts when considering this procedure for weight loss:
• As stated, the long-term results are not known.
• The procedure was conceived as the first of two stages and some patients will lose inadequate weight and therefore could be considered for (or need) a second stage procedure to achieve desired results. At the current time, the recommended second stage procedure is conversion to a gastric bypass.
• The sleeve gastrectomy is the only truly irreversible weight loss surgery.
• Although considered by many to be a “safer” operation than the gastric bypass, complications such as leaking or bleeding are actually higher after a sleeve gastrectomy. Overall, surgical mortality rates are identical to gastric bypass at .2%.

With the above aspects understood, we believe that VSG is an excellent operation for surgical weight loss. As data continues to become available, our knowledge and understanding of long-term outcomes will continue to grow.

Note: How to Calculate Percent of Excess Weight Loss
When describing the results of efforts at weight loss, we use the term “percent excess weight loss” (% EWL). This is calculated by dividing the actual weight loss by the amount of excess body weight for that individual. As a result, we can calculate a percentage that will be comparable between people with different body weights.

% EWL = Weight Loss / Excess Body Weight x 100
For example, suppose an individual is 5’6” and 250 pounds. At this height, the ideal body weight is 150 pounds; therefore they have 100 pounds excess body weight. If they lose 50 pounds, then % EWL is 50/100 x 100 or 50%.