Types of weight-loss surgery: sleeve, bypass, SADI-⁠S, ESG and revisions

Weight-loss surgery, also called bariatric or metabolic surgery, is not one operation. Each procedure changes the stomach, the intestine or both in a different way. Canadian and international guidelines describe several accepted options. Here are the ones you are most likely to hear about.

Gastric sleeve

How it works. About 80% of the stomach is removed through small incisions, leaving a narrow tube. You feel full with much less food. The removed part makes most of the hunger hormone ghrelin, and studies found lower ghrelin levels after a sleeve.

Often discussed for adults with a BMI of 35 or more, or 30 or more with metabolic disease, according to international guidelines.

The years after. In the SLEEVEPASS trial, people had kept off on average about 49% of their excess weight five years after a sleeve. Reflux can start or get worse after a sleeve, so your surgeon asks about it beforehand. Daily vitamins and yearly bloodwork are needed for life. More about the gastric sleeve

Gastric bypass

How it works. In a Roux-en-Y gastric bypass, the surgeon makes a small pouch at the top of the stomach, about the size of an egg, and joins it to a lower loop of the small intestine. Food skips most of the stomach and the first part of the intestine.

Often discussed for people who already have reflux, people living with type 2 diabetes, or a higher BMI.

The years after. In two long-term trials that compared it with a sleeve, weight loss at five years was similar or somewhat greater after a bypass, and reflux was less common. A bypass calls for lifelong vitamins, and smoking and anti-inflammatory pain medicines need to be avoided. Gastric bypass vs gastric sleeve

SADI-⁠S

How it works. SADI-⁠S starts with a sleeve. The first part of the intestine is then divided just past the stomach and joined to a lower loop of intestine with one single connection. Food and digestive juices meet only for the last stretch.

Often discussed for a higher BMI, type 2 diabetes, or as a second step after a sleeve.

The years after. The American Society for Metabolic and Bariatric Surgery recognizes SADI-⁠S as an appropriate procedure and calls for more long-term data. Absorption of some nutrients, including vitamins A, D, E and K, is reduced, so vitamins and bloodwork are checked more closely. Some people have more frequent or loose bowel movements. More about SADI-⁠S

Endoscopic sleeve gastroplasty (ESG)

How it works. A flexible endoscope passes through the mouth into the stomach. Stitches placed from the inside fold the stomach into a narrower shape. There are no incisions and nothing is removed, and most people go home the same day.

Often discussed for people with a BMI of about 30 to 40 who want a less invasive option, or who are not ready for surgery.

The years after. In the MERIT trial, people with a BMI of 30 to 40 lost on average 13.6% of their weight one year after ESG, compared with 0.8% with lifestyle changes alone. Most of those who had a good result at one year kept it at two years. More about ESG

Revisions

Sometimes an earlier procedure needs support: a gastric band that causes problems, reflux after a sleeve, or weight regain. Common options include:

• Gastric band to sleeve. The band is removed and a sleeve is made, in one step or two. Band to sleeve
• Sleeve to SADI-⁠S or to a bypass. A sleeve can sometimes be converted as a second step, for example for reflux or weight regain.
• TORe after a bypass. A stretched outlet of a gastric bypass is made smaller with stitches placed through the mouth. About TORe

A revision starts with a review of what was done and how it looks today. Revision and TORe

How the choice is made

There is no single right procedure for everyone. At a consultation, your surgeon looks at:

1. Your BMI and your weight history.
2. Health conditions such as type 2 diabetes, reflux, sleep apnea and high blood pressure.
3. Any earlier stomach or weight-loss surgery.
4. The medicines you take, and whether you smoke.
5. How you feel about daily vitamins, bloodwork and follow-ups for life.

Your surgeon then explains which options may suit you, with the benefits and risks of each, so you can decide together.