Laparoscopic Gastric Bypass

The laparoscopic gastric bypass, sometimes referred to as roux-en-y gastric bypass, is the most commonly performed weight loss operation in the United States. This operation first became popular in the 1970's. Because large incisions were used and multidisciplinary teams were not utilized; complication rates were high. Currently, the gastric bypass is performed laparoscopically with a multidisciplinary team caring for patients. As a result, complication rates are low, and weight loss rates are high. The gastric bypass combines a restrictive operation with a malabsorptive procedure. 

The Procedure
Gastric bypass is performed laparoscopically. Six small incisions are made in the abdominal wall. A camera is passed into the abdomen and the surgeon views the operation on a high definition video monitor. The small intestine is divided 40cm below the pancreas. A length of 150 cm, five feet, is measured. The afferent limb (Coming from the pancreas) is connected back to the intestine at this point. This is the creation of the roux limb (Roux-en-y refers to the roux limb resembling a "Y") and is the new point where food will begin to mix with the digestive enzymes. Next, a small hole is made in the bottom of the stomach and a stapling device is placed in the stomach. This hole is closed. A 1 - 2 ounce gastric pouch is then created by dividing the stomach with specialized staplers. The roux limb is then connected to the small gastric pouch using the preplaced stapling device. The new connection between the pouch and the intestine is then tested to identify any leaks. If any further sutures are needed they are placed and the leak test is repeated.

Recovery
Patients undergoing the laparoscopic gastric bypass are followed with a heart monitor for the first 24 hours after surgery. Patients typically stay between two to four days in the hospital. Because this operation is done using laparoscopic techniques, pain is easily controlled with oral pain medicines. On the first day after surgery, patients have an x-ray to check to connection between the stomach and the intestine. Once the x-ray is checked, patients start on a clear liquid diet. By the second day after surgery patients start on a pureed diet which they will remain on for four weeks. The first follow-up appointment is at two weeks. 

How does it work?
The roux-en-y gastric bypass combines a restrictive procedure with malabsorption.

Restrictive: Dividing the stomach to create a small pouch takes the capacity of the stomach from as high as 2 liters to 1 -2 ounces. This small pouch fills very quickly, giving a sense of fullness with only a small amount of food. This drastically limits the amount of calories that can be consumed at one time.

Malabsorption: In order for digestion and absorption to occur, food must mix with bile and the digestive enzymes from the pancreas. The gastric bypass creates a limb of intestine 150 cm long. As a result, ingested food does not mix with the digestive enzymes until further down the intestine. This reduces the amount of calories that are absorbed and results in additional weight loss.

How well does it work?
Gastric bypass results in 60 - 80% loss of excess weight. If you are 200 pound overweight, you can expect to lose between 120 to 160 pounds. The majority of weight loss occurs in the first six to twelve months. Within two to three years the shortened intestine adapts and is able to absorb more calories. Weight loss slows down at this point but the small gastric pouch continues to limit food intake and therefore weight loss is maintained.

Effects on Health:
The goal of any bariatric program is to decrease the health problems associated with obesity. Studies have shown the following effect of gastric banding on obesity related diseases.

Type 2 Diabetes - Resolved in 84% of patients
High Blood Pressure - Resolved in 75% of patients
High Cholesterol - Improved in 95% of patients

Complications:
Complication rates for laparoscopic gastric bypass are lowest when the procedure is performed in a dedicated center with trained staff. The rate of complications is 5%. The complications specific to gastric bypass are:

• Leak at the connection between the gastric pouch and the small intestine
• Narrowing of the gastric pouch outlet
• Bleeding from staple lines
• Blood clots
• Complications related to anesthesia
• Mortality rates for laparoscopic gastric bypass range from 0.3 - 0.5%.