Laparoscopic Roux-En y Gastric Bypass
The Roux-en-Y (roo-en-y) gastric bypass is currently the most common surgical procedure used to treat obesity. This surgery reduces the stomach size to less than two ounces (roughly the size of a golf ball) and bypasses the lower stomach and approximately 20% of the upper portion of the small intestine. The combined effects are decreased hunger, smaller food volumes, and reduced ability to absorb calories. On average, our patients lose 75% of their excess body weight within the first year.
Our patients also benefit from the laparoscopic technique used in our Roux-en-Y gastric bypass procedures. Laparoscopy uses very small incisions and special instruments to perform an operation that would traditionally require a much larger incision. These techniques greatly reduce pain and suffering, as well as risks of certain complications such as lung problems, wound infections, and hernias. This results in shorter hospital stays, more rapid recovery, and less scarring. Typically, patients undergoing laparoscopic bariatric surgery leave the hospital in one to two days, resume normal activities in seven to ten days, and are back to work within three weeks.
How the Roux-en-Y Gastric Bypass Procedure Works
All bariatric operations work by altering the digestive functions of the intestinal tract and thereby changing energy balance. To understand this we need to have some basic understanding of what is normal.
Normally, food passes from the mouth to the stomach by way of the esophagus. Digestion begins once the food reaches the stomach. Starches and proteins are broken down by enzymes and acid produced in the stomach. The mechanical churning action of the stomach reduces food to smaller particle sizes before it is released into the small intestine. The normal adult stomach has a capacity of 1 to 1.5 liters (1,500 cc). Most bariatric procedures reduce the size of the stomach pouch, thereby limiting the amount of food that can be eaten. For example, in the Roux-en-Y gastric bypass, the pouch size is reduced to as little as 20 or 30 cc restricting daily caloric intake to well below 1,000 calories.
The first part of the small intestine is called the duodenum. Soon after entering the duodenum, food mixes with bile, which enables fat to be absorbed across the lining of the intestine. The duodenum also plays an important role in the absorption of certain vitamins and minerals. This is a favored site of iron and calcium absorption. This part of the intestinal tract is bypassed with the Roux-en-Y gastric bypass procedure. Because of this, life-long daily mineral and vitamin supplementation is needed.
The duodenum is typically six to ten inches in length. The remainder of the intestine has a length averaging 15 to 22 feet and is the major site of nutrient, mineral and vitamin absorption. In the Roux-en-Y gastric bypass, as well as other bariatric procedures, a portion of the small intestine (usually three to six feet, or 20 to 25% of the length) is placed between a gastric pouch and a site downstream where the intestine is hooked back together to the bypassed stomach and duodenum. This hookup (anastomosis) allows bile, pancreatic secretions and stomach acid to mix with the food entering from above. The “bypassed” limb of intestine is called the alimentary, or “Roux,” limb. Food entering this Roux limb from the gastric pouch has not been effectively broken down by the usual exposure to acid, bile and pancreatic juices. Thus, the efficiency of nutrient absorption is decreased in this bypassed section of the small bowel. Some operations take this principle to the extreme and bypass longer segments of the small intestine resulting in relatively higher rates of malabsorption. While longer bypassed segments generally result in greater and more rapid weight loss, it also has a trade off of higher rates of protein malabsorption and has a greater potential for dangerous consequences related to mineral and vitamin deficiencies. At Surgical Bariatrics Northwest we only perform the proximal gastric bypass which altars digestive efficiency without rsiking the patient’s health.
Once food has been processed by the small intestine, it enters the colon or large bowel. The colon has a larger diameter than the small intestine but is much shorter, averaging five feet in length. The colon does not play a major role in digestion but simply transports waste products of digestion out of the body. As waste is transported from the beginning of the colon to the end, water is removed, converting liquid waste to solids. Colon function is not directly affected by any of the bariatric operations. However, operations that restrict food volume are associated with decreased stool volume and frequency, whereas the opposite effect occurs with procedures that primarily rely on intestinal malabsorption.