Malabsorptive Methods – Roux-En-Y Gastric Bypass Surgery

Schematic of gastric bypass using a Roux-en-Y procedure

There are two basic types of bariatric surgery. These are restrictive and malabsorptive. Laparoscopic adjustable gastric banding (LAGB) is a form of restrictive surgery. The presence of a band restricts the amount of food entering and leaving the stomach. This process differs from that of roux-en-Y (RYGB) – another form of popular weight loss surgery.

What is Roux-en-Y Gastric Bypass Surgery?

RYGB is the most common type of gastric bypass surgery. It derives its name from the Swiss surgeon, César Roux (1857-1918) who was instrumental in coming up with the technique. The name is based on the y-shaped tissue connection he made. The first instance on record occurred in 1892. The actual process is officially called RYGB anastamosis or the narrowing of the tissue where it connects the stomach pouch to the intestine. Since its origins in the late 19th century, it has been refined and adapted to address modern needs and concerns.

When you ask for your medical doctor to perform RYGB, you are considering an interesting hybrid. It is true that this type of surgery is a specific form of malabsorptive bariatric surgery. This particularly refers to the role the small intestine plays in digestion – specifically absorption of nutrients.  The reference to RYGB as being malabsorptive surgery indicates the nutrition provided by food is not completely absorbed into the body through the digestive system. In this type of surgery, the surgeon may partially or completely bypass all or a large portion of the small intestine.

Yet, RYGB is also considered restrictive surgery. It accomplishes this by preventing the food ingested from reaching it normal goal – the stomach. In fact, RYGB melds the two forms together. Its focus is on preventing the digestive system from absorbing many of the nutrients, yet it approaches the issue in a fashion similar to that employed by adjustable gastric banding (AGB).

The performance of an RYGB surgery results in the creation of a small stomach. This is similar to restrictive AGB surgery. Yet, the process goes one step further. It creates a small outlet from the pouch. To this is connected what is called a roux limb. This lengthy tube is the portion of the small intestine that is connected directly to the small pouch. This aspect of surgery is the malabsorptive component.

The pouch restricts the amount of food entering into the digestive system. The pouch also restricts how the food is actually absorbed. RGYB, by its bypassing of other components of the digestive system – specifically the stomach, duodenum and upper intestine, has a major affect upon how the actual food is handled within the small intestine.

How RYGB Works

This bariatric technique works simply. The creation of a new and smaller stomach makes the body feel fuller faster and with less food. As a result, someone who undergoes RYGB will end up eating less. In addition, the bypassing of the stomach and pancreas results in less food absorption. This is because the enzymes at work in these parts of the body are not allowed to work upon food until they meet it further along the digestive tract. This provides them with less time to break down the nutrients for rapid absorption by the body.

Types of RYGB Techniques

As is the case with many types of bariatric surgery, the technique may be open or laparoscopic. Recently research has indicated the laparoscopic method to be as safe and effective as that of open RYGB1. In fact several advantages are found. They consist of:

  • Lesser intra-operative blood loss
  • Shorter period for hospitalization
  • Pain following the operation is significantly reduced
  • Fewer pulmonary complications
  • Speedier recovery
  • Less scarring or marring of the flesh and body
  • Fewer complications as a result of the incisions such as hernias and infections

Currently, both methods are being utilized by bariatric surgeons. The effects vary depending upon such factors as age and, more significantly, overall body mass index.


There are advantages to RYGB. Among them are:

  • Safe means of weight loss
  • It is potentially reversible
  • It controls the intake of food easily
  • The weight loss is often significant and rapid (50-60% loss of excess fat in 9 months)


Unfortunately, RYGB has several possible and potentially serious complications. It demands more internal recovery time before a patient may drink fluids. Overall, the main disadvantages of RYGB are:

  • Dumping syndrome is the primary complaint of those who undergo RYGB. Essentially, this is an unpleasant reaction that occurs when the individual eats certain items of food.
  • Nausea and palpitations are present for as long as 10 years following the operation
  • Overnight stay in the hospital or medical facilities
  • Possible failure of the staple line
  • Ulcers
  • The narrowing or blockage of the stomach
  • Vomiting
  • Decreased vitamin absorbtion

Is it a Successful Means of Weight Loss?

Weight loss as a result of RYGB is acceptable. It is perceived in most research as being more effective than LAGB as a weight loss procedure2. Overall, however, studies do indicate the short-term scores for weight loss remain similar to those of other popular restrictive and malabsorptive methods of bariatric surgery3.

Yet research indicates that it is less effective when the body mass of the individual is greater than or equal to 50 kg/m. The failure rate when an individual reaches the level of super-obesity decreases to 40%4. This is particularly true when the technique is laparoscopic.


RYGB is the most common form of what is best described as a blend of restrictive and malabsorptive types of bariatric surgery. Surgeons can perform it using either open or laparoscopic techniques. It is considered safe and efficient with fewer serious side effects than other forms of surgery. The major drawback is the dumping syndrome as well as its reduced effectiveness for the super-obese.


1 ASMBS (2005). Story of Obesity Surgery Retrieved from asmbs.org/story-of-obesity-surgery/

2 Franco, JVA; Ruiz, PA; Palermo, M; and Gagner, M (2011). A Review of Studies Comparing Three Laparoscopic Procedures in Bariatric Surgery: Sleeve Gastrectomy, Roux-en-Y Gastric Bypass and Adjustable Gastric Banding. Obesity Surgery 21(9): 1458-1468.

3 Schweiger, C; Weiss, R; and Keidar, A. (2010). Effect of Different Bariatric Operations on Food Tolerance and Quality of Eating. Obesity Surgery 20 (10):1393-1399.

4 Prachand, VN; Davee, RT; and Alverdy, JC. (2006). Duodenal Switch provides Superior Weight Loss in the Super-Obese (BMI > Or =50 Kg/M2) Compared with Gastric Bypass. Annals of Surgery 244(4):611-619.

Image source: en.wikipedia.org/wiki/Roux-en-Y_anastomosis


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