Basics of Bariatric Surgery

Sleeve Gastrectomy: The Procedure

Sleeve GastronomyThe Laparoscopic Sleeve Gastrectomy – often called the sleeve – is performed by removing approximately 80 percent of the stomach.The remaining stomach is a tubular pouch that resembles a banana. This procedure works by several mechanisms. First, the new stomach pouch holds a considerably smaller volume than the normal stomach and helps to significantly reduce the amount of food (and thus calories) that can be consumed. The greater impact, however, seems to be the effect the surgery has on gut hormones that impact a number of factors including hunger, satiety, and blood sugar control. Short term studies show that the sleeve is as effective as the roux-en-Y gastric bypass in terms of weight loss and improvement or remission of diabetes. There is also evidence that suggest the sleeve, similar to the gastric bypass, is effective in improving type 2 diabetes independent of the weight loss. The complication rates of the sleeve fall between those of the adjustable gastric band and the roux-en-y gastric bypass. 

Sleeve Gastrectomy: Advantages

1) Restricts the amount of food the stomach can hold

2) Induces rapid and significant weight loss that comparative studies find similar to that of the Roux-en-Y gastric bypass. Weight loss of >50% for 3-5+ year data, and weight loss comparable to that of the bypass with maintenance of >50%

3) Requires no foreign objects (AGB), and no bypass or re-routing of the food stream (RYGB)

4) Involves a relatively short hospital stay of approximately 2 days

5) Causes favorable changes in gut hormones that suppress hunger, reduce appetite and improve satiety 

Sleeve Gastrectomy: Disadvantages

1) Is a non-reversible procedure

2) Has the potential for long-term vitamin deficiencies

3) Has a higher early complication rate than the AGB

Gastric Bypass: The Procedure

Gastric BypassThe Roux-en-Y Gastric Bypass – often called gastric bypass – is considered the ‘gold standard’ of weight loss surgery and is the most commonly performed bariatric procedure worldwide. There are two components to the procedure. First, a small stomach pouch, approximately one ounce or 30 milliliters in volume, is created by dividing the top of the stomach from the rest of the stomach. Next, the first portion of the small intestine is divided, and the bottom end of the divided small intestine is brought up and connected to the newly created small stomach pouch. The procedure is completed by connecting the top portion of the divided small intestine to the small intestine further down so that the stomach acids and digestive enzymes from the bypassed stomach and first portion of small intestine will eventually mix with the food.

The gastric bypass works by several mechanisms. First, similar to most bariatric procedures, the newly created stomach pouch is considerably smaller and facilitates significantly smaller meals, which translates into less calories consumed. Additionally, because there is less digestion of food by the smaller stomach pouch, and there is a segment of small intestine that would normally absorb calories as well as nutrients that no longer has food going through it, there is probably to some degree less absorption of calories and nutrients. Most importantly, the rerouting of the food stream produces changes in gut hormones that promote satiety, suppress hunger, and reverse one of the primary mechanisms by which obesity induces type 2 diabetes.

Gastric Bypass: Advantages

1)  Produces significant long-term weight loss (60 to 80 percent excess weight loss)

2) Restricts the amount of food that can be consumed

3) May lead to conditions that increase energy expenditure

4) Produces favorable changes in gut hormones that reduce appetite and enhance satiety

5) Typical maintenance of >50% excess weight loss

Gastric Bypass: Disadvantages

1) Is technically a more complex operation than the AGB or LSG and potentially could result in greater complication rates

2) Can lead to long-term vitamin/mineral deficiencies particularly deficits in vitamin B12, iron, calcium, and folate

3) Generally has a longer hospital stay than the AGB

4) Requires adherence to dietary recommendations, life-long vitamin/mineral supplementation, and follow-up compliance