Gastric bypass surgery alters the process of digestion by either limiting the amount of food that can be taken in or by limiting the absorption of that food. There are some surgeries that do both. Weight loss surgery is the only option today that effectively treats morbid obesity for people who have had no success with more conservative measures such as diet, exercise, or medication.
Bariatric surgery works in one of three ways:
- Combination of both restriction and malabsorption
Restrictive weight loss surgery is when the size of the stomach is reduced with staples or bands. The smaller stomach becomes full rapidly, preventing overeating. The purely restrictive bariatric surgeries are called gastric banding or gastric sleeves.
Malabsorptive weight loss surgery helps patients lose weight by significantly decreasing the calories and fats the body can absorb from food. This is normally accomplished by cutting out or bypassing parts of the small intestine so it cannot digest food, greatly reducing the number of calories that can be absorbed. There is only one true malabsorptive surgery and it is the biliopancreatic diversion.
There are several procedures that combine both malabsorptive and restrictive procedures. The best examples of combined malabsorptive and restrictive types of bariatric surgery are the Roux-en-Y(this is the one that I had) and the biliopancreatic diversion with duodenal switch. Surgeries that are a combination of both restriction and malabsorption are called gastric bypass.
RESTRICTIVE WEIGHT LOSS SURGERY
Restrictive procedures affect the capacity of the stomach without making any changes to other portions of the digestive tract. The three main restrictive weight loss surgery procedures are:
- Sleeve Gastrectomy
- Laparoscopic Adjustable Gastric Banding
- Vertical Banded Gastroplasty
The sleeve gastrectomy is one of the restrictive irreversible types of bariatric surgery, but it’s also one of the most effective. During the sleeve gastrectomy, about 80% of the stomach is permanently removed. The remaining part of the stomach is roughly the same shape and size as a banana. This smaller stomach can’t hold as much food. It also produces less of the appetite-regulating hormone called ghrelin, which may lessen your desire to eat.
The sleeve gastrectomy was invented as a modification to a similar weight loss surgery called the duodenal switch. Many surgeons began performing this procedure instead of the duodenal switch because of the lower risk of complications. Out of all the types of bariatric surgery, sleeve gastrectomy has become one of the most popular due to its effectiveness and lack of long-term side effects. The sleeve gastrectomy is even used to help obese teenagers and some children.
Laparoscopic Adjustable Gastric Banding
This procedure is also known as the lap band procedure and does not require the stomach to be permanently altered. Instead, an adjustable silicone band is placed around the upper portion of the stomach. This band forms a very small pouch that holds food until it has been digested. Laparoscopic adjustable gastric banding limits the ability to eat a large amount of food in one sitting, significantly reducing overall caloric intake. With the lap band surgery, your doctor can easily adjust the band to change the rate at which food moves throughout the digestive tract. If the irreversible types of bariatric surgery concern you, laparoscopic adjustable gastric banding might be just what you need to start your weight loss journey.
Vertical Banded Gastroplasty
Vertical banded gastroplasty used to be one of the most common options for patients who wanted a restrictive surgery. Now that there are many other types of bariatric surgery, vertical banded gastroplasty is rarely used. Even though it can be easily reversed and does not result in nutritional deficiencies, it is not used often because of the strict diet that is needed due to the vertical band. Patients who do not follow strict diets can become extremely sick after this procedure. If your doctor thinks you will comply with the diet plan associated with vertical banded gastroplasty, you may be eligible for this procedure.
MALABSORPTIVE WEIGHT LOSS SURGERY
Malabsorptive procedures alter the structure of the digestive tract, without changing the capacity of the stomach. This allows food to bypass portions of the small intestine, resulting in calories not being absorbed by the body. Malabsorptive procedures generally incorporate restrictive methods by also reducing the capacity of the stomach for enhanced weight loss. The only strictly malabsorptive weight loss surgery is:
- Biliopancreatic diversion
Biliopancreatic diversion is not commonly performed. It is a strictly malabsorptive surgery where the capacity of the stomach is left intact but is connected directly to the last part of the small intestine. As the food is digested it completely bypasses the larger section of the small intestine resulting in less absorption of food. This procedure does not reduce the amount of food that is able to be consumed but does reduce the amount of food that is absorbed. This is not helpful for people who have problems with overeating.
If greasy food is often consumed in large quantities this procedure can result in “dumping syndrome” which can result in vomiting or diarrhea. Long-term follow-up and tight dietary control are required to prevent protein malnutrition, anemia, and secondary hyperparathyroidism. Lifelong prevention of deficiencies through multivitamins and minerals is necessary. Biliopancreatic diversion is most commonly combined with Duodenal Switch to create a combination weight loss procedure.
COMBINATION WEIGHT LOSS SURGERY
Combination weight loss surgery works by combining both restrictive and malabsorptive elements. The two main combination surgeries are:
- Biliopancreatic Diversion with Duodenal Switch
Roux-en-Y Gastric Bypass
Roux-en-Y gastric bypass is the most commonly performed bariatric procedure. It is the one that I had. It works by combining both elements of restrictive and malabsorptive surgeries. This surgery is normally not reversible. It works by decreasing the amount of food you can eat at one sitting and reducing the absorption of nutrients.
The restrictive element is achieved by stapling the stomach into two sections. The top section becomes a small pouch that is the new stomach. The resulting pouch is about the size of an egg and can hold only about an ounce of food. Normally, your stomach can hold about 3 pints of food. The small size of this newly formed stomach “restricts” or limits the amount of food intake. It also provides a feeling of fullness with smaller portions of food. The lower section of the stomach continues to secrete digestive juices but no longer interacts with food.
The malabsorptive part of gastric bypass is done by surgically dividing the small intestine in a certain area. Once divided, the lower part of the intestine is pulled up to connect with the new stomach. The other end of this divided intestine is attached further down the small intestine. Now, when food is eaten, it enters the new stomach, then travels into the newly attached lower intestine “bypassing” the upper part of the intestine. The effect of bypassing the upper portion of the intestine decreases the number of calories that are absorbed. Because of the malabsorption, this increases the risk of nutritional deficiencies. After surgery, it is important to take nutritional supplements.
The Roux-en-Y procedure may be performed with a laparoscope rather than through an open incision in most patients. This procedure uses several small incisions and three or more laparoscopes, small thin tubes with cameras attached, during the operation. The surgeon performs the surgery while looking at a TV monitor. People with a Body Mass Index (BMI) of 60 or more, like I was, or those who have had some type of abdominal surgery are usually not eligible for laparoscopic surgery. Laparoscopic gastric bypass usually reduces the length of hospital stay, the amount of scarring, and results in quicker recovery than an open procedure.
Biliopancreatic Diversion with Duodenal Switch
Like the Roux-en-Y, the Biliopancreatic Diversion with Duodenal Switch is an option that also permanently alters the shape of the stomach. A biliopancreatic diversion with Duodenal Switch is primarily malabsorptive and is a more complicated procedure to perform than the Roux-en-Y.
This is a two-part surgery. The first step involves performing a procedure similar to a sleeve gastrectomy. During this procedure, a part of the lower stomach is removed.
The second part involves connecting the end portion of the intestine, bypassing the majority of the intestine. The part of the stomach that is left is connected directly to the last part of the small intestine. This part is called the jejunum. As the food is digested, it completely bypasses a larger section of the small intestine than in the Roux-en-Y gastric bypass. This procedure significantly reduces the body’s absorption of fat and cuts back on the amount of time it has to absorb calories from meals, resulting in extreme weight loss. This surgery can result in more malabsorption than the Roux-en-Y, which can result in greater nutritional deficiencies. It is not as commonly performed.
Gastric bypass surgery is one of the most effective ways to achieve lasting weight loss but does carry a few surgical risks. Long term, these surgeries can restrict the amount of food you can eat, and also limit the calories your body can absorb. Both restrictive and malabsorptive procedures offer certain benefits. Each procedure can be performed with minimally invasive surgical techniques and offers its own guidelines pertaining to post-surgical lifestyle changes. Talking to your doctor is the first step in deciding which surgery would be the best option for you.