Roux-en-Y Gastric Bypass

Roux-en-Y gastric bypass (RYGB) is performed by bariatric surgeons at the Massachusetts General Hospital Weight Center to reduce the size of the stomach and encourage weight loss in patients who are obese.
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Call to refer a patient or request a new patient appointment: 617-726-0373

About This Procedure

What is Roux-en-Y Gastric Bypass and Why is it Performed?

Roux-en-Y gastric bypass (RYGB) is a weight loss surgery that reduces the size of the stomach and is the most common type of gastric bypass surgery in the United States. Bariatric surgeons at the Massachusetts General Hospital Weight Center perform gastric bypass as a minimally invasive procedure or a standard procedure, depending on the needs of the patient.

RYGB is recommended for patients based on the following benefits:

To qualify for this procedure, patients must have a Body Mass Index (BMI) of 40 or greater, or a BMI of 35 or greater plus a medical condition such as type 2 diabetes, high blood pressure or sleep apnea. Patients must also have tried other weight loss approaches that did not lead to significant and sustainable weight loss.

How is Roux-en-Y Gastric Bypass Performed?

roux-en-y gastric bypass
Roux-en-Y gastric bypass

During gastric bypass surgery, a surgeon creates a small gastric pouch from the top of the stomach. This pouch is approximately two tablespoons in volume, therefore limiting the patient’s food intake.

During the procedure, the small intestine is divided into two “limbs”: the biliopancreatic limb and the Roux limb. The biliopancreatic limb, also known as the duodenum, is located at the beginning of the small intestine. This limb contains digestive juices from the stomach, bile and pancreas. The Roux limb, the middle portion of the small intestine also known as the jejunum, is connected to the pouch. Food flows directly from the pouch into the Roux limb, bypassing most of the stomach. The remaining stomach continues to produce digestive juices that flow into the biliopancreatic limb, which is re-attached below the Roux limb. The intersection of these limbs forms a "Y."

At Mass General, gastric bypass surgery is usually performed laparoscopically with a few small incisions. Surgeons use narrow cylindrical tubes called trocars to access the abdominal cavity through small incisions in the upper abdominal wall. The duration of this procedure varies between an hour and half to four hours.

After the procedure, you will stay at the hospital for one or two nights. We recommend taking off three to four weeks from work.

What Preparation is Required Before Roux-en-Y?

You may be required to enroll in the Mass General Weight Center's pre-surgery nutrition program before you can undergo this procedure. All patients scheduled for weight loss surgery are required to lose some weight prior to surgery. Weight loss before bariatric surgery results in a decrease of the size of the liver, commonly known as “shrink the liver” diet. This size decrease in the liver makes the surgery less difficult and faster, reducing postoperative complications. Your Mass General dietitian will create a meal plan specifically tailored to your weight loss goals.

Learn more about preparation for bariatric and metabolic surgery

What Happens After Roux-en-Y is Performed?

At the Mass General Weight Center, your care team develops an individualized postoperative program to monitor, guide and support you after the procedure. The program is divided into two phases—Postoperative Adjustment and Lifestyle Modification— each lasting three months.

Learn more about postop treatment for bariatric and metabolic surgery

How Safe is the Procedure?

Your Mass General Weight Center care team will discuss the benefits (see above) and risks of this procedure, including complications such as:

  • Bleeding
  • Dehydration
  • Dumping, where food and digestive juices from your stomach move to your small intestine in an uncontrolled, abnormally fast manner. Symptoms include dehydration, sweating and rapid heartbeat. Foods high in carbohydrates lead to this complication
  • Internal hernias, which occur in 2% to 4% of patients, could lead to obstruction, where the intestines malfunction, preventing the normal digestive process  
  • Revisional surgery, if perforation of the pouch occurs
  • Ulcers in the pouch, occurs in 2% to 7% of patients

Why Mass General?

Mass General is consistently ranked among the best hospitals in the country by U.S. News & World Report. As part of the Mass General Digestive Healthcare Center, the Mass General Weight Center is unique for its expert, multidisciplinary approach to Roux-en-Y gastric bypass surgery. Our surgeons, among the most experienced in the region, are accustomed to seeing both local and international patients with multiple medical conditions.

At the Mass General Weight Center, your care team comprises a surgeon, dietitian and psychologist, who meet weekly to coordinate your care. Before and after your surgery, your care team designs an individualized treatment plan for you that promotes long-term weight loss. Mass General experts are available for counseling on nutrition, exercise and behavior modification along with medical management of related diseases.

Learn more about our approach to bariatric and metabolic surgery

Conditions & Diseases

  • Barrett's Esophagus

    Barrett's esophagus is a condition in which normal cells that line the esophagus turn into cells not usually found in humans called “specialized columnar cells.”

  • Coronary Heart Disease

    Coronary heart disease occurs when cholesterol builds up within the walls of the heart’s arteries (coronary arteries), forming what is called plaque.

  • Diabetes

    Type 1 diabetes may also be known by a variety of other names, including the following: insulin-dependent diabetes mellitus (IDDM), juvenile diabetes, brittle diabetes, or sugar diabetes.

  • Gallstones

    Gallstones form when bile stored in the gallbladder hardens into stone-like material.

  • Gastroesophageal Reflux Disease (GERD) / Heartburn

    Gastroesophageal reflux disease (GERD) is a digestive disorder that is caused by gastric acid flowing from the stomach into the esophagus.

  • Heart Attack

    A heart attack occurs when one or more regions of the heart muscle experience a severe or prolonged lack of oxygen caused by blocked blood flow to the heart muscle.

  • High Blood Pressure / Hypertension

    Blood pressure, measured with a blood pressure cuff and stethoscope by a nurse or other health care provider, is the force of the blood pushing against the artery walls.

  • Metabolic Syndrome

    Metabolic syndrome is a condition that includes the presence of a cluster of risk factors specific for cardiovascular disease. Metabolic syndrome significantly raises the risk of developing diabetes, heart disease, and/or stroke.

  • Obesity

    Obesity increases the risk for many diseases, especially heart disease, stroke, cancer, and diabetes.

  • Sleep Apnea

    Sleep apnea is a serious breathing disorder that causes brief interruptions of breathing during sleep.



Learn more about the Weight Center Request an appointment

Call to refer a patient or request a new patient appointment: 617-726-0373

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