Gastric Bypass Surgery – Types, Risk, Procedure, Complications & Results

What is Gastric Bypass Surgery?
The endoscopic intragastric balloon or Gastric Bypass Surgery is a non-surgical procedure in which a gastric balloon is inserted into the stomach. This is a silicone balloon and is non-reactive to the body tissue. This gastric balloon is left inside the stomach for a maximum of six months. Due to the presence of the balloon in the stomach, the patient feels full even after eating a small amount of food.
Types of Gastric Bypass Procedures
Roux-en-Y Gastric Bypass Surgery (RGB)
The Digestive System and Malabsorptive Surgery
Risks of Gastric Bypass Surgery
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 anaemia. 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 diarrhoea.

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 anaesthetic 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 counselling so that you do not become pregnant in your first year after surgery due to the risk to the foetus 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 anaesthesia. Your physician will discuss this with you in advance. Generally, gastric bypass surgery follows this process:

  • You’ll be asked to remove clothing and change into a gown.
  • An intravenous (IV) line will be started in your arm or hand.
  • You’ll be on your back on the operating table.
  • A urinary catheter may be inserted into your bladder.
  • The anaesthesiologist will continuously monitor your heart rate, blood pressure, breathing and blood oxygen level during the surgery.
  • The skin over the surgical site will be cleansed with an antiseptic solution in the rare event you make require an open incision.
  • 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.
  • 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.
  • 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.
  • A drain may be placed in the incision site to remove fluid.
  • The incision will be closed with stitches.
  • 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.

Bariatric Surgery is a significant operation, not just as a procedure, but as a step toward changing the way you live. You should have questions. Here are some of the common ones we receive, and answers that should help. As always, if you’d like more information, feel free to contact us.

1. Is there an age restriction for the surgery?

Surgery is done on patients between the ages of 18-65. If you’re younger than 18, please refer to our Adolescent Bariatric Surgery Program at Lucile Packard Children’s Hospital. If you are older than 65, cases are evaluated on a case by case basis. Please keep in mind your insurance may restrict your options.

2. Is there a weight limit for this operation?

We look at Body Mass Index (BMI), which is the weight over the body surface area squared. Patients who have a BMI of 35-40 and have obesity related co-morbidities are candidates for this surgery. Patients, who have a BMI greater than 40, even if they don’t have co-morbidities, are also candidates for this operation.

3. What are obesity related co-morbidities?

These include diabetes, hypertension, arthritis, degenerative joint disease, sleep apnoea, lower back pain, gastroesophageal reflux disease, stress incontinence, high cholesterol and triglyceride levels and depression.

4. How successful are these operations?

The gastric bypass operation allows you to lose up to 82% of your excess body weight, however it’s almost 100% effective in reversing obesity related co-morbidities including sleep apnoea, hypertension and diabetes. The adjustable gastric banding (lap-band) operation allows you to lose 50% of your excess body weight at two years. It’s also effective in reversing obesity related co-morbidities. The sleeve gastrectomy is between the gastric bypass and gastric banding in terms of weight loss with 60% excess weight loss at 1 year.

5. What are the pre-operative requirements in order to undergo either operation?

You must have a stable relationship with a primary care physician who has been treating you continuously for one year prior to consideration for surgery.
You must have a dietician evaluation.
You must have a psychological evaluation. Patients with bipolar disease are generally excluded from consideration for surgery.
If you have a history of heart disease, if you’ve taken Fen-phen in the past, if you’re over the age of 50, or other cardiac risk factors, you’ll require an echocardiogram.
At some point prior to surgery, you’ll have to undergo a chest x-ray, an EKG and blood tests.

6. What does laparoscopic surgery mean?

Laparoscopic surgery means that instead of making one large incision in your abdomen, we make five small incisions in the middle and to the left side of your abdomen. These smaller incisions allow you to recover faster. You’ll also experience less pain, leave the hospital sooner and will be back to your normal activity sooner. In general, we start all of our cases laparoscopically unless the patient has had previous surgery on their stomach.

7. Why is there a 10% pre-operative weight loss required?

We require patients to begin a diet and exercise program that allows them to lose 10% of their weight pre-operatively for three reasons:

Patients who undergo weight loss before surgery have fewer complications during and after surgery.
This allows patients to truly understand the lifestyle changes that will occur after surgery and therefore make an informed consent about the diet and exercise programs that they will have to be on for the rest of their lives.
This allows us to identify the patients who are truly motivated and therefore who will be most successful following surgery.
Most important, we’ll work with you to develop a weight-loss program to achieve the 10% reduction goal.

8. When will I meet the surgeon?

Your initial workup/consult will be done by a surgeon who will screen you for medical problems. Once the surgeon has determined that you’re a good candidate for this operation and if you’ve met all of our criteria, you’ll then be given a plan for bariatric surgery.

9. When will my surgery be scheduled?

We will work with you to quickly get you started on your new life.

10. What are the risks of the operation?

Weight loss surgery is major abdominal surgery with significant risks. However, we know experience counts and high-volume centres like Stanford Hospital & Clinics have an extremely low complications rate. The following potential complications include, but are not limited to:

  • risk from general anaesthesia
  • bleeding
  • infection
  • pneumonia
  • blood clot in the legs or lungs
  • hernias (internally or externally)
  • blockage or obstruction
  • narrowing where surgeons suture the pouch to the intestine, which can require another endoscopy and dilation
  • leakage from the stomach or the intestines
  • injury to liver and/or spleen
  • pulmonary and/or cardiac and/or renal failure
  • With the adjustable gastric band (lap-band), there’s a risk that the band can either slip or erode. There’s a risk that you will not lose weight if you don’t follow the diet and exercise program.
  • There’s a risk of needing another operation or conversion to an open operation with a long incision.
  • While there’s a risk of death with each procedure: 1-in-200 with the gastric bypass, 1-in-500 with sleeve gastrectomy, and 1-in-10,000 with the lap band.

11. What is the conversion rate?

Conversion to open surgery is required in less than 1% of patients. The risk of conversion is higher in patients who have had previous upper abdominal surgery.

12. How do I know which operation is for me?

Deciding which procedure is best for you is largely a personal one best achieved in discussion with your surgeon.

13. Is there anything else I need to know?

It’s very important that you understand this surgery won’t remove your sense of hunger. It won’t cause you to lose your desire to eat and it won’t remove any of the psychological cravings that you may have for food. If you eat when you’re stressed, you’ll still feel like eating when you’re stressed. Therefore, it’ll be very important that you understand the stresses that make you feel like eating and identify other ways of resolving these issues. Part of your Bariatric Surgery team can include a psychologist to help you understand your eating triggers and how to cope with them.

14. What will happen when I’m in the hospital?

In general, you’ll be in the hospital for two nights. We’ll expect you to get up and walk while you’re in the hospital – this is your best defence against blood clots. You’ll meet with the dietician before going home and while you’re here, you’ll have a clear liquid diet that will be limited to a medicine cup every 15 minutes.

Laparoscopic Gastric Bypass [Surgery for overweight / obese diabetics]

Gastric Bypass [Surgery for overweight / obese diabetics] involves reduction in stomach size leading to early satiety/satisfaction with small quantity of food. Additionally a large part of stomach & small intestine is bypassed, so that food & digestive juices mix with each other distally. This results in delayed & reduced absorption of nutrients & calories.

  • Surgical Time*: 2 – 3 hours
  • Hospitalization Period*: 4 – 5 days
  • Recuperation Period*: 7 – 15 days

Performed by key-hole route or laparoscopically, gastric bypass is considered the gold standard procedure for weight loss. This leads to early, rapid & sustained weight loss in most of the patients.

Mechanisms of Diabetes Resolution – The proposed mechanisms for blood sugar control are:

The range of procedures that can be performed at the time of standard knee arthroscopy include:-

  • Restriction in Calorie Intake.
  • Bypass of Small Intestine – Early small intestine (duodenum) is probable site of secretion of as yet unidentified factor (Rubino factor) which may be responsible for insulin resistance in T2DM.
  • Early delivery of undigested food products to distal intestine (ileum), the site for secretion of GLP-1 hormone which helps in blood sugar control through increased insulin secretion from pancreas.
Special Dietary Requirement
Daily mandatory intake of protein with a multivitamin & mineral intake will prevent any possible nutritional deficiency. Iron & Calcium supplements are required as well. Special dietary advice is provided to post-op patients & regular follow up is essential.
The reported incidence of complications is at par with other major surgeries performed on obese. These include: Operative Mortality – 0.5% after gastric bypass procedures.
Intra-operative Complications

1.4% including bleeding, injury & stapler malfunctioning etc.

Early Complications

This includes wound infections (1-3%), pulmonary embolism (1%-2%), intestinal leaks (1%-2%), rarely bleeding, bowel obstructions & rarely cardio-pulmonary complications etc.

Late Complications

These includes gall stone formation, incisional hernia, rarely intractable vomiting, ulcer, intestinal obstruction, weight regain, metabolic sequelae including iron deficiency, B12, Folate deficiencies etc.

Weight Loss

The average excess weight loss is > 60% after gastric bypass surgery.

Co-morbidity improvement – The reported improvement in associated illnesses provides the most compelling reason for RyGBP surgery.

  • Diabetes: Resolution in > 80% & Resolution/Improvement in > 90%
  • Hyperlipidaemia: Resolution in > 90%
  • Hypertension: Resolution is noticed in > 75% patients
  • Sleep Apnoea: Resolved in > 85% patients
Over 90% of obese diabetic patients after gastric bypass have diabetes resolution.

Gastric Bypass is performed by expert surgeons at the following Apollo Spectra Hospitals Centres. Click on the location to make an appointment.