Southern Surgical Associates

How Does Bariatric Surgery Work?
There are two basic ways that bariatric surgery works to help patients lose weight and improve or resolve co-morbidities: One way is malabsorption and the other is restriction. The most common bariatric surgery performed today, Roux-en-Y gastric bypass surgery, uses both.

1. Restrictive procedures limit food intake:
Procedures that use restriction limit the amount of food patients can eat. This is accomplished surgically by creating a small stomach pouch. When eating, the pouch fills quickly and gives a feeling of fullness much sooner. Because patients feel satisfied and full sooner, they eat less.

2. Malabsorptive procedures alter digestion:
Procedures that use malabsorption change the body’s ability to absorb calories and nutrients from food. The surgeon changes the way food travels through the patient’s system. By rerouting food past a large part of the stomach and a portion of the small intestine, much of the calories and nutrients pass through without being absorbed.

Both methods work to help patients lose excess weight, lower their BMI, and transform their health by resolving or improving co-morbidities. Bariatric surgery has many benefits that can lead to a healthier, higher quality of life, but also has certain risks. Read on to learn more about the different types of bariatric surgery.

According to two organizations, the American Society for Bariatric Surgery and the National Institutes of Health, Roux-en-Y (pronounced ROO-en-why) gastric bypass surgery is the most popular bariatric surgery in the United States.

In this procedure, the surgeon creates a small stomach pouch and then constructs a “bypass” for food. The bypass allows food to skip parts of the small intestine. By skipping a large part of the small intestine, the body cannot absorb as many calories or nutrients.

Advantages
A 2004 meta-analysis of more than 22,000 patients showed that those who underwent a bariatric surgical procedure experienced complete resolution or improvement of their co-morbid conditions including diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea.16
83.7 percent of type 2 diabetes cases were resolved.3
In the studies analyzed, the control group that didn’t have bariatric surgery was at a higher risk for type 2 diabetes: 3.7 times higher.3
Resolution of type 2 diabetes often occurred within days of the surgery.3
96.9 percent of hyperlipidemia cases were resolved.3
75.4 percent of hypertension cases were resolved; 87.1 percent were resolved or improved.3
Substantial weight reduction occurred; 61.6 percent of excess weight was lost.3
In 2000, a study of 500 patients showed that 96 percent of co-morbidities (the study looked specifically at back pain, sleep apnea, high blood pressure, type 2 diabetes, and depression) were improved or resolved.8
A great deal of excess weight was lost, and patients experienced resolution of co-morbidities, and improved appearance, social opportunities, and economic opportunities.3

Risks and Disadvantages

Because the duodenum and other sections of the small intestine are bypassed, poor absorption of iron and calcium can cause low total body iron and a greater chance of having iron-deficiency anemia. Patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids should be aware of the chance of iron-deficiency anemia. Women, already at risk for osteoporosis that can occur after menopause, should be aware of the possibility of increased bone calcium loss. By taking a multivitamin and calcium supplements, patients can maintain a healthy level of minerals and vitamins.
Bypassing the duodenum can cause metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back, and fractures of the ribs and hipbones. Eating foods rich in nutrients and taking vitamins can help patients avoid this.
Chronic anemia due to vitamin B12 deficiency may occur. The problem usually can be managed with vitamin B12 pills or injections.
A condition known as dumping syndrome can occur from eating too much sugar or large amounts of food. While it isn’t considered a serious health risk, the results can be very unpleasant. Symptoms can include vomiting, nausea, weakness, sweating, faintness, and, on occasion, diarrhea. Some patients are unable to eat sugary foods after surgery.
The bypassed portion of the stomach, duodenum, and parts of the small intestine cannot be seen easily using X-ray or endoscopy if there are problems such as ulcers, bleeding, or malignancy.
It is a permanent, nonreversible procedure.
The procedure could result in death.

The Laparoscopic Adjustable Gastric Banding procedure is a purely restrictive surgical procedure in which a band is placed around the uppermost part of the stomach. This band divides the stomach into two portions: one small and one larger portion. Since the stomach is divided into smaller parts, most patients feel full faster. As the name indicates, the band is adjustable. So if the rate of weight loss is not acceptable, the band can be adjusted. Food digestion happens through normal digestion.

Advantages
A 2004 meta-analysis of more than 22,000 patients showed that those who underwent a bariatric surgical procedure experienced complete resolution or improvement of their co-morbid conditions including diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea.16
47.9 percent of type 2 diabetes cases were resolved.3
Significant improvements in overall cholesterol occurred, including a boost in HDL levels.3
70.8 percent of hypertension cases were resolved or improved.3
Patients lost roughly 47 percent of their excess weight.3
The amount of food that could be consumed at a meal was restricted.
Food passed through the digestive tract in the usual order, allowing it to be absorbed fully by the body.
In studies involving more than 3,000 patients, excess weight loss ranged from 28 to 87 percent, with a minimum of two-year postoperative follow-up.3
Band can be adjusted to increase or decrease restriction via an access port.
Surgery can be reversed.

Risks and Disadvantages
The access port may leak or twist, which can require an operation to correct the problem.
Surgery may not provide the necessary feeling of satisfaction that one has had enough to eat.
Dumping syndrome, which may provide important warning signs, does not occur.
Band may erode into the stomach wall.
Band may move or slip.
Weight loss is slower than that following Roux-en-Y gastric bypass surgery.
The procedure could result in death.

Malabsorptive procedures reduce the size of the stomach. However, the pouch is a bit larger than with other procedures. The pouch is connected to the lower part of the small intestine. Connecting to the lower part of the small intestine means that absorption of calories and nutrients is reduced greatly. There are three malabsorptive procedures: Biliopancreatic Diversion with Duodenal Switch, Biliopancreatic Diversion, and Extended Roux-en-Y gastric bypass surgery.

Biliopancreatic Diversion with Duodenal Switch
In this version of BPD, stomach removal is limited to the outer margin, creating a sleeve of stomach. The duodenum, the first portion of the small intestine, is divided so that pancreatic and bile drainage are bypassed.

Advantages
A 2004 meta-analysis of more than 22,000 patients showed that those who underwent a bariatric surgical procedure experienced complete resolution or improvement of their co-morbid conditions including diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea.16
BPD had the highest rate of type 2 diabetes resolution of all the different bariatric surgery procedures: 98.9 percent.3
BPD had the highest rate of hyperlipidemia resolution: 99.1 percent.3
75.1 percent of hypertension cases were resolved or improved.3
91.9 percent of sleep apnea cases were resolved.3
Excess weight loss was roughly 70.1 percent.3
These operations often resulted in a high degree of patient satisfaction because patients were able to eat larger meals than with a purely restrictive or standard Roux-en-Y gastric bypass procedure.
These procedures could produce the greatest weight loss because they have the highest rates of malabsorption.
Long-term maintenance of excess body weight loss could be successful if the patient adjusts to and maintains an easy-to-follow dietary, supplement, exercise, and behavioral routine.
As with every type of bariatric surgery, the overall quality of life for patients improved greatly. A great deal of excess weight was lost, and patients experienced resolution of co-morbidities, and improved appearance, social opportunities, and economic opportunities.3

Risks and Disadvantages
There is a period when the intestines adjust and bowel movements can be very liquid and frequent. This condition may lessen over time, but may be a lifelong condition.
Abdominal bloating and foul-smelling stool or gas may occur.
Patients and their primary care physicians should monitor for protein malnutrition, anemia, and bone disease throughout the patient’s life. Patients also need to take vitamin supplements for the rest of their lives. Not taking either of these precautions can lead to health issues that require treatment. In fact, it’s been found that if patients do not follow eating and vitamin supplement instructions closely, at least 25 percent will develop problems that require treatment.
Changes to the intestinal structure can increase the risk of forming gallstones and the need for removal of the gallbladder.
Patients should be aware of the possibilities of intestinal irritation and ulcers.
The procedure could result in death.

Bariatric surgery has been performed for many decades. For many of those years, the surgery was performed as an open procedure. An open procedure means a surgeon creates a long incision, or cut, opening up the patient. As medical technology evolved, laparoscopic or minimally invasive surgery became a possibility. With laparoscopic surgery, the surgeon creates small incisions. Both approaches have similar success rates in reducing excess weight and improving or resolving co-morbidities.24,25
Most surgeons will perform bariatric surgery using the laparoscopic method. However, this is a decision that the doctor and patient must make together. An important question for patients to ask is: How many minimally invasive versus open procedures has the surgeon performed? Read below to learn more about both procedures.

Open Surgery
Open surgery involves the surgeon creating a long incision line to open the abdomen and operating with "traditional” medical instruments. Because of the incision, the patient’s stay in the hospital will be several days longer than with minimally invasive surgery. The recovery time is also longer. Patients generally will need to heal for several weeks before returning to work and regular physical activities. With a longer wound, there is more of a chance of wound complications such as infections and hernias. A long incision leads to a long scar. In some cases, the open method is necessary due to some patient-specific risks.

Laparoscopic or Minimally Invasive Surgery
A laparoscopic operation involves making several small incisions for different medical devices to be used. There are, on average, four to six ports created. The devices, including a small video camera, are inserted through the ports. The surgeon uses a monitor to perform the procedure. Most laparoscopic surgeons believe this gives them a good view and access to key body parts. Many patients are able to recover from the surgery in a shorter time than open procedures require. In fact, some return to work in little more than a week, and many are able to quickly return to physical activity. Patients generally have very small scars. There is also a lower chance of wound complications such as infection and hernia.

Your Next Step
Laparoscopic and open procedures for bariatric surgery both produce similar weight loss. However, not all patients are candidates for the laparoscopic approach, just as all bariatric surgeons are not trained to perform this less-invasive method. The American Society for Bariatric Surgery recommends that laparoscopic bariatric surgery should be performed only by surgeons who are experienced in both laparoscopic and open bariatric procedures.

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