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Mini Gastric Bypass

Laparoscopic mini-gastric bypass, sleeve gastric bypass

Min-ee Gas-trick Bi-pass
En Español (Spanish Version)

Definition | Reasons for Procedure | Possible Complications | What to Expect | Call Your Doctor


A mini gastric bypass (MGB) is a procedure done on the stomach and intestines to help people lose weight. It is a type of bariatric surgery.

Abdominal Organs

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Reasons for Procedure

A mini-gastric bypass is a treatment for obesity. The procedure will help limit overeating and decrease how many calories you absorb.

A mini gastric bypass may be recommended for people with a:

  • Body mass index (BMI) greater than 40
  • BMI greater than 35 with cardiovascular disease, sleep apnea or uncontrolled type 2 diabetes
  • BMI greater than 35 with severe physical limitations that affect employment, mobility, and family life

This procedure may be done after a person has failed to lose weight by other ways such was healthful eating and exercise.

Benefits of bariatric surgery will depend on lifestyle changes that are also adopted. Benefits may include:

  • Long-term weight loss
  • Improvement in many obesity-related conditions, such as diabetes, sleep apnea, high blood pressure, and high cholesterol
  • Improved mobility and increased energy
  • Improved mood, self-esteem, and quality of life
  • Reduced risk of dying from cardiovascular disease

Possible Complications

If you are planning to have a mini gastric bypass, your doctor will review a list of other complications such as:

  • Adverse reaction to anesthesia, especially in patients who also have sleep apnea
  • Infection
  • Blood clot formation in the veins of the legs or lungs
  • Excess bleeding
  • Leaking of stomach contents into the abdominal cavity
  • Hernia formation
  • Death (rare)

Conditions that may develop after surgery may include:

  • Gallstones
  • Dyspepsia or ulcers
  • Scar tissue formation creating a bowel obstruction
  • Low blood sugar called hypoglycemia
  • Nutritional deficiencies particularly low levels of protein or vitamins
  • Body image distortion—patients have difficulty adjusting to their new appearance
  • Inability to lose weight after surgery
  • Excess weight loss (rare)

Factors that may increase the risk of problems include:

  • Smoking
  • Recent or chronic illness, such as kidney disease
  • Diabetes
  • Increased age
  • Heart or lung disease
  • Bleeding or clotting disorders

Talk to your doctor about these risks before the procedure.

What to Expect

Each bariatric surgery program has specific requirements. Your program will likely include:

  • A physical exam and review of your medical history
  • Attempts to lose weight through medically approved dietary means
  • Ongoing consultations with a registered dietician
  • Mental health evaluation and counseling

Before your procedure:

  • Talk to your doctor about your medicines, herbs, and dietary supplements. You may be asked to stop taking some medicines up to one week before the procedure. These may include:
    • Anti-inflammatory drugs
    • Blood thinners
    • Anti-platelet drugs
  • Do not start taking any new medicines, herbs, or supplements without talking to your doctor.
  • Arrange for a ride to and from the hospital.
  • Arrange for help at home as you recover.
  • You may be asked to take laxatives or give yourself an enema to clear your intestines.
  • The night before your surgery, eat a light meal. Do not eat or drink anything after midnight unless told otherwise by your doctor.
  • Shower or bathe the morning of your surgery.

General anesthesia will be used to. You will be asleep during the surgery.

An IV line will be placed in your arm. Fluids and medication will be delivered through this line during the procedure.

A breathing tube will be placed through your mouth and into your throat. It will help you breathe during surgery.

Small incisions will be made in the abdominal wall. A camera and surgical instruments will be passed through these incisions.

The stomach will be divided into two parts. One part will be reconstructed to resemble a tube. This tube will be attached to the small intestine 6-7 feet after its beginning.

The small incisions will be closed. The doctor may place bandages over the incision sites.

After the operation, you will be taken to the recovery room for observation.

About 1 ½ to 2 ½ hours

Anesthesia prevents pain during surgery. As you recover, you may have some pain. Your doctor will give you pain medicine.

Eating too much will cause discomfort. Work with a dietitian to create a meal plan that will provide enough nutrition without causing discomfort.

This is done in a hospital. The usual length of stay is 2 days. If you have any problems, you may need to stay longer.

While you are recovering at the hospital, you may receive the following care:

  • Pain medicine will be given as needed.
  • On the day after surgery—you will have an x-ray to check for leaks from the stomach.

Your stomach will not only be smaller but will also be swollen after surgery. This will limit the types and amount of food you can eat. You will be started on liquids only. Medications or vitamins may also need to be crushed up or taken as liquid.

While in the hospital, you may be asked to do the following:

  • Use an incentive spirometer to help you take deep breaths. This helps prevent lung problems.
  • Wear elastic surgical stockings or boots to promote blood flow in your legs.
  • Get up and walk in the hall daily.

For best success, you will need to practice lifelong healthy eating and exercising habits. Walk as soon as possible. Make a goal to exercise daily.

You will meet regularly with your healthcare team for monitoring and support. Be sure to follow your doctor’s instructions.

You may have emotional ups and downs after this surgery. Ask your doctor about support groups or counseling that may help.

Your new stomach is samll and slow to empty, causing you to feel full quickly. Therefore, you need to eat very small amounts and eat every slowly. Some basic steps may include:

  • You will begin with 4-6 meals per day. A meal is two ounces of food. For the first 4-6 weeks after surgery, all food must be pureed.
  • Once you move to solid foods, you will need to consume enough protein. Follow your dietitian’s meal plans.
  • Avoid sweets and fatty foods.
  • Eating too much or too quickly can cause vomiting or intense pain under your breastbone. Most people quickly learn how much food they can eat.
  • If you are taking medications or supplements:
    • Crush any non-chewable pills
    • Opt for chewable pills or liquid when possible

Call Your Doctor

After you leave the hospital, call your doctor if any of the following occurs:

  • Signs of infection, including fever and chills
  • Redness, swelling, increasing pain, excessive bleeding, or discharge from the incision site
  • Cough, shortness of breath, chest pain, or severe nausea or vomiting
  • Worsening abdominal pain
  • Blood in the stool
  • Pain, burning, urgency or frequency of urination, or persistent bleeding in the urine
  • Persistent nausea and/or vomiting
  • Pain and/or swelling in your feet, calves, or legs
  • Sudden shortness of breath or chest pain
  • Any other worrisome symptoms

In case of an emergency, call for medical help right away.


American Society for Metabolic and Bariatric Surgery


Weight Control Information Network



Canadian Laparoscopic Weight Loss Surgery



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Bariatric surgery: day of surgery and hospital stay. West Penn Allegheny Healthy System website. Available at: http://www.wpahs.org/specialties/bariatric-surgery/day-surgery-and-hospital-stay. Accessed January 15, 2013.

Bariatric surgery Risks and Complications. West Penn Allegheny Healthy System website. Available at: http://www.wpahs.org/specialties/bariatric-surgery/risks-and-complications-bariatric-surgery. Accessed January 15, 2013.

Gastrointestinal surgery for severe obesity. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: http://win.niddk.nih.gov/publications/gastric.htm. Accessed January 15, 2013.

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Maciejewski ML, Livingston EH, Smith VA, et al. Survival among high-risk patients after bariatric surgery. JAMA. 2011;305(23):2419-2426.

Mini-gastric bypass. Sutter Pacific Medical Foundation website. Available at: http://www.sutterpacific.org/bariatrics/weightloss/mini-gastric-bypass.html. Accessed January 15, 2013.

Rationale for the surgical treatment of morbid obesity. American Society for Bariatric Surgery website. Available at: http://asmbs.org/rationale-for-surgical-treatment. Accessed January 15, 2013.

Weight loss surgery. Boston Medical Center website. Available at: http://www.bmc.org/weight-loss-surgery/choosingsurgery/surgeryoptions.htm#Gastric_Bypass. Accessed January 15, 2013.

Last reviewed November 2013 by Michael Woods, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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