The Digestive Process
To better understand how weight loss surgery works, it is helpful to know how the normal digestive process works. As food moves along the digestive tract, special digestive juices and enzymes arrive at the right place at the right time to digest food and absorb calories and nutrients. After we chew and swallow our food, it moves down the esophagus to the stomach, where a strong acid and powerful enzymes continue the digestive process. The stomach can hold about three pints of food at one time. Food is slowly released into the small intestine where absorption of the nutrients, vitamins and minerals takes place. The rate at which foods and fluids are released into the small intestines is controlled by a sphincter on the outlet of the stomach. Empty time can be over several hours.
Normal Stomach
Gastric Bypass Operations
Gastric bypass surgery is an operation that creates a small pouch to restrict food intake and bypasses a segment of the small intestine. In the gastric bypass procedure, a surgeon makes a direct connection from the stomach pouch to a lower segment of the small intestine, bypassing the duodenum (the first part of the small intestine) and some of the jejunum (the second part of the small intestine), delaying the mixing of ingested food and the digestive enzymes.
Roux-en-Y Gastric Bypass Surgery (RYGB)
RYGB is the most common type of bariatric surgery. The surgeon begins by creating a small pouch by dividing the upper end of the stomach. This restricts the food intake. Next, a section of the small intestine is attached to the pouch to allow food to bypass the duodenum, as well as the first portion of the jejunum. The small intestine is re-connected 150 centimeters from the pouch to allow ingested food and digestive enzymes to mix.
The advantages of Roux-en-Y gastric bypass include superior weight loss when compared to vertical banded gastroplasty, with excellent long-term weight reduction and resolution or elimination of co-morbidities (80 percent resolution of Type II diabetes after surgery). Early and late complication rates are reasonably low, and operative mortality ranges from 0.2 percent to 1 percent.
Disadvantages of Roux-en-Y gastric bypass include the potential for anastomotic leaks and strictures, severe dumping syndrome symptoms and procedure-specific complications, including distension of the excluded stomach and internal hernias. Roux-en-Y gastric bypass is technically more challenging to perform than the restrictive procedures, particularly when using the laparoscopic approach. In experienced hands, the conversion rate of laparoscopic Roux-en-Y gastric bypass to open is 5 percent.
Restrictive Operations
Alternatives to gastric bypass procedures are restrictive operations such as vertical-banded gastroplasty (not offered at the Cleveland Clinic) or adjustable gastric banding. Restrictive surgery results in weight loss when the surgeon creates a small pouch at the top of the stomach where the food enters from the esophagus. The pouch's lower outlet usually has a diameter of about 1/4-inch. The small outlet delays the emptying of food from the pouch creating a feeling of fullness. Following surgery, patients can usually eat only one-half to 1 cup of food without discomfort or nausea. Most people who have a restrictive operation lose the ability to eat a large amount of food at one time. Some patients do return to eating modest amounts of food, without feeling overly hungry. Both operations serve only to restrict food intake and do not alter the normal digestive and absorptive process.
Vertical Banded Gastroplasty
The surgeon uses staples and a plastic band to create a smaller stomach pouch. Patients are unable to eat large quantities of food and do notice a feeling of fullness. Long-term complications such as weight regain and sever acid reflux or difficulty swallowing solids occur in up to one-half of patients who underwent VBG. This procedure is not offered at the Clinic. We do manage patients with complications of VBG and these often require conversion to a gastric bypass.
Laparoscopic Adjustable Gastric Banding (LAGB)
During the procedure, surgeons typically use laparoscopic techniques and instruments to implant an inflatable silicone band around the upper portion of the stomach. The band creates a new, tiny pouch that limits and controls the amount of food consumed. The band also creates a small outlet that slows the emptying process into the stomach and the intestines allowing the patient to experience an earlier sensation if fullness and increased satisfied with smaller amounts of food. This ultimately results in weight loss.
The LAGB patient can expect a reduced hospital stay of one to two days; in some instances there may be an increased stay if the surgery required an abdominal incision or complications occurred. Patients may resume normal activities in one to two weeks; again, expect a delay if there is an abdominal incision or complications occur.
The LAGB procedure requires no cutting or stapling of the stomach and bowel and is considered the least invasive weight loss surgery available. The band is also adjustable and can be modified by inflating or deflating the inner surface with saline solution. The surgeon can control the amount of saline in the band using a fine needle through the skin. The adherence to monthly appointments for band adjustments the first 6-12 months after surgery is very important to achieve optimal results. Once the band is adjusted properly, the duration between visits can be lengthened. The adjustments are made in the surgeon's exam room and patients have minimal discomfort. Finally, should the band need to be removed, the stomach will return to its original form and function.
Laparoscopic Sleeve Gastrectomy
The Laparoscopic Sleeve Gastrectomy (also known as Vertical Gastrectomy) includes removing about 75% of the stomach leaving a narrow gastric tube or "sleeve" through which food passes. No intestines are removed or bypassed during sleeve gastrectomy.
The sleeve gastrectomy is used for selected patients who are not candidates for the band or gastric bypass due to severe medical conditions, extremely high BMI, or prior bowel surgery. In some patients, the sleeve is used as a first stage procedure to improve their medical condition prior to a second stage gastric bypass.
Laparoscopic technique helps reduce pain, shorten recovery
Traditional or "open" gastric bypass surgery requires a 6-to 8-inch incision and approximately four weeks of recuperation. Cleveland Clinic surgeons can offer most gastric bypass patients the laparoscopic band surgery approach.
This procedure involves making five to six small openings (approximately 1/1-1 inch in size) in the abdomen. These openings allow the bariatric surgeon to pass a light, camera and surgical instruments into the abdomen. The abdomen is inflated with gas (carbon dioxide) to allow the surgeon to get a better view of the stomach and internal structures. Surgical instruments about the width of a pencil are placed into the abdomen to complete the laparoscopic band surgery.
In a Roux-en-Y gastric bypass surgery, most of the stomach is "bypassed" and a small portion (about the size of an egg) remains functional. In some cases, the bariatric surgeon may find it necessary to convert from laparoscopic to open surgery. The surgeon bases this decision on various factors, including the patient’s safety and the opportunity to achieve the best possible outcome.
The minimally invasive approach achieves results identical to those associated with open surgery, but with less post-operative pain and swifter recovery. Patients who undergo laparoscopic bypass surgery can return to work after two to four weeks. Laparoscopic band surgery also reduces the risk of developing hernias, which are more common after traditional abdominal surgery.
