What is Roux-en-Y (RNY) Gastric Bypass?

What is Roux-en-Y (RNY) Gastric Bypass?

Doctor Answers 3

What is Roux-en-y Gastric Bypass Surgery?

Laparoscopic Roux-en-Y Gastric Bypass

With the Surgical Obesity Service, the Roux-en-Y gastric bypass procedure is usually performed laparoscopically (i.e. keyhole surgery with a telescope); however in some cases it may be necessary to perform an open procedure. This type of bypass operation has proven to be an effective, consistent way of losing weight and keeping it off.

In this gastric bypass operation, the stomach is completely divided with a stapler to leave a pouch that initially measures only 25mls. The small bowel is divided and the divided end brought up and joined to the small stomach pouch. The other small bowel end is joined back on to the small bowel about a metre down from the stomach. Thus the whole stomach is bypassed apart from a tiny pouch. This operation works in two ways:


Effective weight loss operation in most patients (although where patients end up is always dependent on how they use the tool they are given)

  • More rapid weight loss than banding
  • Dumping offers a useful deterrent to eating high
  • calorie food and drinks
  • Long track record- the operation has been around in various forms for 30 years
  • There is nothing to break or erode
  • This procedure has a slightly higher serious complication rate than some of the other operations (i.e. gastric banding) because of the bowel joins. There is a need to take oral supplements of iron, vitamins and calcium for life, and some patients also need Vitamin B12 injections. Recovery time slightly longer than after banding.
  • Residual stomach capacity: 30-50mls
  • Estimated weight loss: 60-70% EWL over 2 years.

Long Island Bariatric Surgeon
5.0 out of 5 stars 3 reviews

Roux-en-Y Gastric Bypass

Roux-en-Y Gastric Bypass Surgery is the most common and successful combined procedure in the United States. It is considered the ‘gold standard’ of bariatric surgery. First, we create a small stomach pouch to restrict food intake. Next, a Y-shaped section of the small intestine is attached to the pouch to allow food to bypass the lower stomach, the duodenum (the first segment of the small intestine), and the first portion of the jejunum (the second segment of the small intestine). This reduces the amount of calories and nutrients the body absorbs. Most patients lose weight quickly and continue to lose for 18 to 24 months after the procedure. With the Roux-en-Y gastric bypass, many patients maintain a weight loss of 75 to 85 percent of their excess weight for 10 years or more. Because combined operations result in greater weight loss than restrictive operations, they are also more effective in improving the health problems associated with severe obesity, such as hypertension (high blood pressure), sleep apnea, type 2 diabetes, and osteoarthritis.

David Buchin, MD, FACS

David Buchin, MD
Long Island Bariatric Surgeon
5.0 out of 5 stars 5 reviews

Roux en Y Gastric Bypass explanation

When weight cannot be lost by diet and exercise there are various surgical procedures that can help. They are classically divided into RESTRICTIVE (making the stomach much smaller thereby making eating large quantities impossible) or MALABSORPTIVE (making the absorption of food and calories harder).

Cesar Roux was a noted Swiss surgeon who described the bowel connection configuration named after him when he performed the fist complete stomach removal and connection of small bowel to the food tube. The Y limb created an internal sump which prevented food backing up.

The Bariatric gastric Bypass involves making the stomach smaller creating a pouch about the size of a small egg. Then, the first section of the small intestine (the duodenum) is cut  loose from the second distal or Roux section. The Roux bowel loop is pulled up and joined (anastomosed) to the new very small stomach pouch. The internal sump is then created by joining the near bowel segment, the  to the small intestine.

The overall result is a new smaller stomach with some malabsorption of nutrients that leads to rapid weight loss.

Dr. Aldea

Peter A. Aldea, MD
Memphis Plastic Surgeon
4.9 out of 5 stars 109 reviews

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.