What is Gastric Bypass Surgery?

Gastric bypass surgery is a surgical procedure that alters the process of digestion. There are several types of gastric bypass procedures, but they all involve bypassing part of the small intestine by varying degrees. For this reason, procedures of this type are referred to as malabsorptive procedures, because they involve bypassing a portion of the small intestine that absorbs nutrients.

Some of these procedures also involve stapling the stomach to create a small pouch that serves as the “new” stomach, or surgically removing part of the stomach.

Although a gastric bypass procedure is malabsorptive, it can also be restrictive because it reduces the size of the stomach so that the amount of food you can eat is restricted due to the smaller stomach. While malabsorptive procedures are more effective in contributing to weight loss than those that are solely restrictive, they also carry more risk for nutritional deficiencies.

Dr. Morton appears on the Today Show with actor Ron Lester

Today Show Gastric Bypass Video (3:21 min.)

Dr. Morton appears on the Today Show with actor Ron Lester.


Types of Gastric Bypass Procedures

Roux-en-Y Gastric Bypass Surgery (RGB)

Roux-en-Y gastric bypass, the most commonly performed bariatric procedure, is both malabsorptive and restrictive. This surgery can result in two-thirds of extra weight loss within two years. The procedure involves stapling the stomach to create a small pouch that holds less food, and then shaping a portion of the small intestine into a “Y.” The “Y” portion of intestine is then connected to the stomach pouch so that when food is being digested it travels directly into the lower part of the small intestine, bypassing the first part of the small intestine (called the duodenum) and the first part of the second section of the small intestine (called the jejunum). Bypassing these sections of the intestine restricts the amount of calories and nutrients that are absorbed into the body.

The Digestive System and Malabsorptive Surgery

During digestion, food and liquid are broken down into smaller parts so that the body can absorb and use them for nourishment. Digestion starts in the mouth and continues downward into the stomach, where the three mechanical tasks of storing, mixing and emptying of food occur.

The food is then digested in the small intestine and dissolved by the juices from the pancreas, liver and intestine, and the contents of the intestine are mixed and pushed forward to allow further digestion. Malabsorptive procedures alter this process in different ways depending on the type of procedure.

Risks of Gastric Bypass Surgery

With the gastric bypass procedure, malabsorptive symptoms may be more serious, with an increased risk of anemia. Your body may not adequate amounts of iron, calcium and vitamin B12, potentially causing metabolic bone disease and osteoporosis.

Stomal stenosis occurs when there is a stricture (tightening) of the opening between the stomach and intestine after a Roux-en-Y procedure. When this occurs, vomiting after eating and sometimes after drinking may occur. Stomal stenosis can be treated easily but should be treated immediately.

“Dumping syndrome” is also more likely to occur with these procedures because the food in the stomach moves to the intestines quickly. Symptoms include nausea, sweating, fainting, weakness and diarrhea.

There is a risk that you may require additional surgery because of complications.

One of the most serious complications of gastric bypass is a stomach leak that can cause peritonitis to develop. Peritonitis is an inflammation of the peritoneum, the smooth membrane that lines the cavity of the abdomen. There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.

Before GBS

Prior to the procedure, you’ll be going through a significant amount of prep work, both immediately before and in the weeks leading up to your surgery date. Here’s what to expect:

  • Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have.
  • You’ll be asked to sign a consent form that gives your physician permission to perform the procedure. Read the form carefully and ask questions if something is not clear.
  • In addition to a complete medical history, your physician may perform a complete physical examination to ensure you’re in good health before undergoing the procedure. You may undergo blood tests or other diagnostic tests.
  • You’ll be asked to fast for eight hours before the procedure, generally after midnight.
  • If you’re pregnant or suspect that you are pregnant, you should notify your physician immediately.
  • Notify your physician if you’re sensitive to or are allergic to any medications, latex, iodine, tape or anesthetic agents (local and general).
  • Notify your physician of all medications (prescription and over-the-counter) and herbal supplements that you’re taking.
  • Notify your physician if you have a history of bleeding disorders or if you’re taking any anticoagulant (blood-thinning) medications, aspirin or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
  • You may be asked to begin exercising and alter your diet several weeks before surgery.
  • If you’re a woman of child-bearing age, you may receive birth control counseling so that you do not become pregnant in your first year after surgery due to the risk to the fetus from rapid weight loss.
  • You may receive a sedative prior to the procedure to help you relax.
  • The area around the surgical site may be shaved.
  • Based upon your medical condition, your physician may request other specific preparation.
  • You may be asked to use an antiseptic soap during your bath or shower the day prior to your surgery.

During the Procedure

Gastric bypass surgery requires a stay in the hospital. The procedure will be performed while you’re asleep under general anesthesia. Your physician will discuss this with you in advance. Generally, gastric bypass surgery follows this process:

  1. You’ll be asked to remove clothing and change into a gown.
  2. An intravenous (IV) line will be started in your arm or hand. 
  3. You’ll be on your back on the operating table.
  4. A urinary catheter may be inserted into your bladder.
  5. The anesthesiologist will continuously monitor your heart rate, blood pressure, breathing and blood oxygen level during the surgery.
  6. The skin over the surgical site will be cleansed with an antiseptic solution in the rare event you make require an open incision.
  7. For an open procedure, the physician will make a single large incision in the abdominal area. For a laparoscopic procedure, the surgeon will make a series of small incisions in the abdomen. Then carbon dioxide gas will be introduced into the abdomen to inflate the abdominal cavity so that the appendix and other structures can easily be visualized with the laparoscope.
  8. For an open procedure, the abdominal muscles will be separated and the surgeon will open the abdominal cavity. For a laparoscopic procedure, the physician will insert the laparoscope and other small instruments.
  9. For a Roux-en-Y gastric bypass, the physician will staple the stomach across the top to create a new small pouch for a stomach. The rest of the stomach will be separated from the new pouch and closed off by the staples; however, the remaining stomach will continue to produce digestive juices that will be used in digestion. A portion of the small intestine will be shaped like a “Y” and connected to the pouch.
  10. A drain may be placed in the incision site to remove fluid.
  11. The incision will be closed with stitches.
  12. A sterile bandage/dressing will be applied.

After the Procedure

After the procedure, you’ll be taken to the recovery room for observation. Once your blood pressure, pulse and breathing are stable and you’re alert, you’ll be taken to your hospital room.

You may receive pain medication as needed, either by a nurse or by administering it yourself through a device connected to your intravenous line. You’ll also be encouraged to move around as much as you can while you are in bed, and then to get out of bed and walk around as your strength improves.

At first you’ll receive fluids through an IV. After a day or two you’ll be given liquids, such as broth or clear juice, to drink.

Your physician will instruct you about how long to eat pureed foods after surgery. By one month after your procedure, you may be eating solid foods.

A nutritionist will instruct you about taking nutritional supplements to replace the nutrients lost due to the reconstruction of the digestive tract. Before you’re discharged from the hospital, we’ll schedule an appointment for a follow-up visit with your physician.

At Home

Once you’re home, it’ll be important to keep the surgical area clean and dry. Your physician will give you specific bathing instructions.

The incision and abdominal muscles may ache, especially with deep breathing, coughing and exertion. Take a pain reliever for soreness as recommended by your physician. Because aspirin or certain other pain medications can increase the chance of bleeding, be sure to take only recommended medications.

Continue the breathing exercises you began using in the hospital, and gradually increase your physical activity as tolerated. It may take several weeks to return to your previous levels of stamina. You may be instructed to avoid lifting heavy items for several months in order to prevent strain on your abdominal muscles and surgical incision.

Weight loss surgery can be emotionally difficult because you’ll be adjusting to new dietary habits and a body in the process of change. You may feel especially tired during the first month following surgery. But once your body adjusts, you’ll start to feel better. Also, exercise and attending a support group can be helpful at this time.

Notify your physician to report any of the following:

  • fever and/or chills
  • redness, swelling, or bleeding or other drainage from the incision site
  • increased pain around the incision site

Following gastric bypass surgery, your physician may give you additional or alternate instructions, depending on your particular situation.


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