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USC Metabolic & Bariatric Surgery Program

Gastric bypass illustrationProcedure Information

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Comparison of Surgical Procedures (PDF file, 2,2MB)

Defining Bariatric Surgery

Bariatric surgery is a treatment option for people living with morbid obesity—especially for those who have not experienced long-term weight loss success through other means. Often referred to as weight loss surgery, bariatric surgery has transformed the health and lives of more than 800,000 people in the past six years.

How Does Bariatric Surgery Work?

Bariatric surgery is the clinical term for several different procedures. The procedures use one or both of two approaches to help patients lose weight and improve or resolve co-morbid conditions.

Restrictive Procedures

During these procedures, the surgeon creates a small stomach pouch, that limits the amount of food patients can eat. The smaller stomach pouch fills quickly, which helps patients feel satisfied with less food.

Examples of restrictive procedures:

  • Gastric banding
  • Sleeve gastrectomy

Malabsorptive Procedures

During these procedures, the surgeon reroutes the small intestine so that food skips a portion of it. The small intestine absorbs calories and nutrients from food, and avoiding part of it means that many calories and nutrients are not absorbed.

Surgeons rarely perform strictly malabsorptive procedures. Most procedures that use malabsorption also use restriction.

Combination Procedures

Certain procedures use both restriction and malabsorption. For example, Roux-en-Y gastric bypass surgery uses a combination of restriction and malabsorption. During the procedure, the surgeon creates a small pouch. The surgeon then attaches a Y-shaped section of the small intestine directly to the stomach pouch. This allows food to bypass a large portion of the small intestine, which absorbs calories and nutrients. The smaller stomach pouch causes patients to feel fuller sooner and eat less food; bypassing a portion of the small intestine means the patient’s body absorbs fewer calories.

Examples of combination procedures:

  • Gastric bypass
  • Biliopancreatic diversion with duodenal switch

These different methods work to help patients lose excess weight, lower their BMI, and transform their health by resolving or improving co-morbid conditions. Bariatric surgery has many benefits that can lead to a healthier, higher quality of life. It also has certain risks.

 

Gastric Bypass

Roux-en-Y gastric bypass surgery uses a combination of restriction and malabsorption. During the procedure, the surgeon creates a smaller stomach pouch. The surgeon then attaches a Y-shaped section of the small intestine directly to the pouch. This allows food to bypass a large portion of the small intestine, which absorbs calories and nutrients. Having the smaller stomach pouch causes patients to feel fuller sooner and eat less food; bypassing a portion of the small intestine means the patient’s body absorbs fewer calories.

Life After Gastric Bypass

Excess Weight Loss

Gastric bypass patients typically lost 61.6 percent of their excess weight.

Health Benefits

Studies found that gastric bypass:

  • Resolved type 2 diabetes in 83.8% of patients and often resolved the disease within days of surgery
  • Resolved high blood pressure in 75.4% of patients
  • Improved high cholesterol in 95% of patients

For more information about the effect of gastric bypass on weight-related co-morbid conditions, visit Health Benefits.

Quality of Life

One meta-analysis stated that for bariatric surgery patients who experienced significant weight loss:

  • Overall quality of life improved greatly.
  • They experienced improved physical functioning and appearance.
  • They experienced improved social and economic opportunities.

Recovery

One study found that gastric bypass patients were able to:

  • Leave the hospital after two days
  • Return to work after 21 days

Potential Concerns of Gastric Bypass

  • A condition known as dumping syndrome can occur from eating high-fat, high-sugar foods. While it isn’t considered a health risk, the results can be very unpleasant and may include vomiting, nausea, weakness, sweating, faintness, and diarrhea.
  • Patients must supplement their diet with a daily multivitamin and calcium. Some patients must take vitamin B12 and/or iron.
  • The stomach, duodenum, and parts of the small intestine cannot be seen easily using X-ray or endoscopy if there are problems after surgery such as ulcers, bleeding, or malignancy.

Visit Health Benefits and Risks of Surgery for full descriptions of the benefits and risks of gastric bypass.

 

Gastric Banding

Gastric banding is a restrictive surgical procedure. During this procedure, two medical devices are implanted in the patient: a silicone band and an injection port. The silicone band is placed around the upper part of the stomach and molds the stomach into two connected chambers. The injection port is attached to the abdominal wall, underneath the skin. The port is connected to the band with soft, thin tubing.

The band is adjustable. Adjustments are made by your healthcare professional using a needle to inject saline solution into your band through the port. Adding saline increases the amount of restriction provided by the band, helping patients feel fuller sooner and with less food.

Life After Gastric Banding

Excess Weight Loss

Gastric banding patients typically lost 47% of their excess weight.4

Health Benefits

Studies found that gastric banding:

  • Resolved type 2 diabetes in 47.8 percent of patients and often resolved the disease within days of surgery
  • Resolved high blood pressure in 38.4% of patients
  • Improved high cholesterol in 78.3% of patients

For more information about the effect of gastric banding on weight-related co-morbid conditions, visit Health Benefits.

Quality of Life

One meta-analysis stated that for bariatric surgery patients who experienced significant weight loss:

  • Overall quality of life improved greatly
  • They experienced improved physical functioning and appearance
  • They experienced improved social and economic opportunities

Recovery

Your healthcare team will advise you when to return to work and when you are able to resume normal activities.

Potential Concerns of Gastric Banding

  • Gastric banding can help you feel satisfied sooner and with less food, but it won’t eliminate the desire to eat. You will need to follow your specific diet and exercise guidelines provided by your surgeon to achieve success.
  • Gastric banding requires more intensive follow-up care than most other bariatric surgeries. This is mostly because the band is adjustable. Keep in mind that even after reaching and maintaining your success weight, you may still need to see your healthcare professional for further adjustments.

Visit Health Benefits and Risks of Surgery for full descriptions of the benefits and risks of gastric banding.

 

Sleeve Gastrectomy

Sleeve gastrectomy is a restrictive bariatric surgery. During this procedure, the surgeon creates a small, sleeve-shaped stomach. It is larger than the stomach pouch created during Roux-en-Y bypass—and is about the size of a banana.

Sleeve gastrectomy is typically considered as a treatment option for bariatric surgery patients with a BMI of 60 or higher. It is often performed as the first procedure in a two-part treatment. The second part of the treatment can be gastric bypass.

Co-morbid condition resolution 12 to 24 months after sleeve gastrectomy has been reported in 345 patients. Sleeve gastrectomy patients experienced resolution rates for type 2 diabetes, high blood pressure, high cholesterol, and obstructive sleep apnea that were similar to resolution rates for other restrictive procedures such as gastric banding.

To learn more about sleeve gastrectomy, visit the website of the American Society for Metabolic and Bariatric Surgery (ASMBS) and review the ASMBS Position Statement on Sleeve Gastrectomy As a Bariatric Procedure.

Visit Health Benefits and Risks of Surgery for full descriptions of the benefits and risks of sleeve gastrectomy.

 

Open Versus Minimally Invasive Surgery

Surgery Techniques

Bariatric surgery has been performed for decades. For most of those years, surgeons performed bariatric surgery using an open technique, which required a long incision and traditional medical instruments. 

As medical technology evolved, the laparoscopic or minimally invasive technique was introduced and widely adopted. Using the minimally invasive technique, a surgeon performs the same operation, but creates several ¼ to ½ inch incisions and uses long-handled instruments. This technique is associated with faster recovery, less pain, and less scarring.

Both approaches have similar success rates in reducing excess weight and improving or resolving co-morbid conditions.

Considerations

Not all patients are candidates for the laparoscopic approach, just as not all bariatric surgeons are trained to perform this less-invasive method.

In some patients, the laparoscopic, or minimally invasive, technique cannot be used. Here are reasons why you may have an open procedure, or that may lead your surgeon to switch from laparoscopic to open:

  • Prior abdominal surgery that has caused dense scar tissue
  • Inability to see organs
  • Bleeding problems during the procedure

The American Society for Metabolic and 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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