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updated October 05, 2007

Gastric bypass surgery: What can you expect?

  • Find out what to expect, including the benefits and risks, if you choose to have gastric bypass surgery.
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Filed under: Weightloss (Obesity)

( Weight-loss (bariatric) surgery changes the anatomy of your digestive system to limit the amount of food you can eat and digest. The surgery aids in weight loss and lowers your risk of medical problems associated with obesity.

Gastric bypass is the favored bariatric surgery in the United States. Surgeons prefer this surgery because it's safer and has fewer complications than other available weight-loss surgeries. It can provide long-term, consistent weight loss if accompanied with ongoing behavior changes.

Gastric bypass isn't for everyone with obesity, however. It's a major procedure that poses significant risks and side effects and requires permanent changes in your lifestyle. Before deciding to go forward with the surgery, it's important to understand what's involved and what lifestyle changes you must make. In large part, the success of the surgery is up to you.

How is gastric bypass surgery done?

In gastric bypass (Roux-en-Y gastric bypass) the surgeon creates a small pouch at the top of your stomach and adds a bypass around a segment of your stomach and small intestine.

The surgeon staples your stomach across the top, sealing it off from the rest of your stomach. The resulting pouch is about the size of a walnut and can hold only about an ounce of food. The pouch is physically separated from the rest of the stomach. Then, the surgeon cuts the small intestine and sews part of it directly onto the pouch.

This connection redirects the food, bypassing most of your stomach and the first section of your small intestine, the duodenum (doo-o-DEE-num). Food enters directly into the second section of your small intestine, the jejunum (jay-JOO-num), limiting your ability to absorb calories. Even though food never enters the lower part of your stomach, the stomach stays healthy and continues to secrete digestive juices to mix with food in your small intestine.

Some surgeons perform this operation by using a laparoscope — a small, tubular instrument with a camera attached — through short incisions in the abdomen (laparoscopic gastric bypass). The tiny camera on the tip of the scope allows the surgeon to see inside your abdomen.

Compared with traditional "open" gastric bypass, the laparoscopic technique usually shortens your hospital stay and leads to a quicker recovery. Fewer wound-related problems also occur. Not everyone is a candidate for laparoscopic gastric bypass, however. Talk to your doctor about whether this approach is appropriate for you.

What can you expect during the surgery?

Gastric bypass surgery is performed under general anesthesia. This means you inhale analgesics as a gas or receive the anesthetic agent through an intravenous (IV) line so that you're asleep during the surgery.

During surgery, a tube is passed through your nose into the upper stomach pouch. Occasionally, this tube stays in overnight. The tube is connected to a suction machine after surgery to keep the small stomach pouch empty so that the staple line can heal.

You may have another tube in the bypassed stomach. This tube comes out the side of your abdomen and is removed four to six weeks after surgery. Some skin irritation may develop around this tube.

Gastric bypass surgery takes about four hours. After surgery, you wake up in a recovery room, where medical staff will monitor you for any complications. Your hospital stay may last from three to five days.

What can you expect after gastric bypass surgery?

You won't be allowed to eat for one to three days after the surgery so that your stomach can heal. Then, you'll follow a specific progression of your diet for about 12 weeks. The progression begins with liquids only, proceeds to pureed and soft foods, and finally to regular foods.

With your stomach pouch reduced to the size of a walnut, you'll need to eat very small meals during the day. In the first six months after surgery, eating too much or too fast may cause vomiting or an intense pain under your breastbone. The amount you can eat gradually increases, but you won't be able to return to your old eating habits.

You may experience one or more of the following changes as your body reacts to the rapid weight loss in the first three to six months:

  • Body aches
  • Feeling tired, as if you have the flu
  • Feeling cold
  • Dry skin
  • Hair thinning and hair loss
  • Mood changes
What are the benefits of gastric bypass surgery?

Within the first two years of surgery, you can expect to lose 50 percent to 60 percent of your excess weight. If you closely follow dietary and exercise recommendations, you can keep most of that weight off long term.

In addition to dramatic weight loss, gastric bypass surgery may improve or resolve the following conditions associated with obesity:

  • Type 2 (adult-onset) diabetes
  • High blood pressure
  • High blood cholesterol
  • Obstructive sleep apnea
  • Gastroesophageal reflux disease (GERD)

The improvements observed in type 2 diabetes, high blood pressure and high blood triglycerides may significantly decrease the risk of cardiovascular events in people who have undergone gastric bypass surgery compared with those people who did not have surgery. Also, gastric bypass surgery may reduce the risk of dying of diabetes, heart disease and cancer. The surgery has also shown to improve mobility and quality of life for people who are severely overweight.

What are the risks of gastric bypass surgery?

As with any major surgery, gastric bypass carries risks such as bleeding, infection and an adverse reaction to the anesthesia. Possible risks specific to this surgery include:

  • Death. A risk of death has been associated with gastric bypass surgery. It has generally been reported to be one death per 200 to 300 surgeries. Higher risks have been reported amongst Medicare recipients. The risk varies depending on age, general health and other medical conditions. Talk to your doctor about the exact level of risk gastric bypass surgery may pose for you.
  • Blood clots in the legs. Blood clots in the legs are more likely to occur in very overweight people. Blood clots can be dangerous. In some cases, they travel to the lungs and lodge in the lungs' arteries causing a pulmonary embolism — a serious condition that damages lung tissue and can lead to death. Walking and using leg wraps that apply intermittent pressure to the leg can help reduce this risk of blood clots in the legs. Smoking has been shown to increase the risk of clotting in people undergoing gastric bypass surgery. Quitting smoking is strongly recommended.
  • Leaking at one of the staple lines in the stomach. This severe postoperative problem is treated with antibiotics. Many cases heal with time. Often, however, the leak can be serious enough to require emergency surgery.
  • Incision hernia. An incision hernia is a weakness in the incision. This is more likely to occur if you have an open procedure and a large abdominal incision. This usually requires surgical repair, depending on the symptoms and the extent of the hernia.
  • Narrowing of the opening between the stomach and small intestine. This rare complication may require either an outpatient procedure — in which a tube is passed through your mouth to widen (dilate) the narrowed opening — or a corrective surgery.
  • Dumping syndrome. This is a condition where stomach contents move too quickly through the small intestine, causing nausea, vomiting, diarrhea, dizziness and sweating. It's frequently experienced after eating sweets or high-fat foods.

Other potential complications of gastric bypass surgery include:

  • Vitamin and mineral deficiency (iron deficiency anemia, vitamin B-12 deficiency and vitamin D deficiency)
  • Dehydration
  • Gallstones
  • Bleeding stomach ulcer
  • Intolerance to certain foods
  • Kidney stones
  • Low blood sugar (hypoglycemia) related to excessive insulin production
What are other weight-loss surgery options?

Though it's the most commonly used, gastric bypass is just one kind of weight-loss surgery. Other types include:

  • LAP-BAND adjustable gastric banding (LAGB). The surgeon uses an inflatable band to partition the stomach into two parts by wrapping the band around the upper part of your stomach. Pulling it tight like a belt, the surgeon creates a tiny channel between the two pouches. The band keeps the opening from expanding and is designed to stay in place indefinitely. It can be adjusted or surgically removed if necessary. LAGB is gaining popularity because it's a simpler procedure and has a lower complication rate when compared with more-involved procedures. However, LAGB causes less weight loss and a slower rate of weight loss than does the Roux-en-Y gastric bypass. This surgery isn't recommended for people who have certain medical conditions, such as Crohn's disease, large hiatal hernias or a history of gastric ulcers.
  • Vertical banded gastroplasty. This operation, also referred to as stomach stapling, divides the stomach into two parts — limiting space for food and forcing you to eat less. There is no bypass. Using a surgical stapler, the surgeon divides your stomach into upper and lower sections. The upper pouch is small and empties into the lower pouch — the rest of your stomach. Partly because it doesn't lead to adequate long-term weight loss, this weight-loss surgery has fallen out of favor.
  • Biliopancreatic diversion with duodenal switch. In this procedure, the surgeon removes about 80 percent of the stomach. The valve that releases food to the small intestine is left along with a limited portion of the small intestine that normally connects to the stomach (duodenum). The surgery bypasses the majority of the intestine by connecting the end portion of the intestine to the duodenum near the stomach. This weight-loss surgery offers sustained weight loss, but it presents a greater risk of malnutrition and vitamin deficiencies and requires close monitoring. It's generally used for people who have a body mass index greater than 50.
©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

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