Gastric sleeve surgery, also known as sleeve gastrectomy, is a type of bariatric (weight-loss) surgery offered to certain patients to treat obesity. This surgical procedure alters the size of a person’s stomach to promote weight loss.

Doctors surgically remove a significant portion of a person’s stomach during the procedure, which reduces the volume that the stomach can hold by 80%. As a result, the stomach looks more like a tube that food travels through rather than a pouch that can hold and help digest food. Sleeve gastrectomy is not reversible.

Sleeve gastrectomy is the most commonly performed weight-loss surgery in the United States, accounting for about 58% of all bariatric surgical procedures. It’s also a safe, resulting in few serious short- or long-term complications (more on that below).

Doctors may recommend sleeve gastrectomy or other types of weight-loss surgery to certain people with obesity who have been unable to lose weight through diet, exercise, and other nonsurgical interventions. (Patients do not need to specifically try or fail anti-obesity medications to be eligible for bariatric surgery, including sleeve gastrectomy.) Patients must also be evaluated by a psychiatrist, who will assess whether they are mentally prepared to undergo surgery requiring them to alter their eating habits for the rest of their lives.

Patients who undergo sleeve gastrectomy are expected to gradually lose about 60% of their excess body weight. The weight loss associated with sleeve gastrectomy may reverse and/or reduce the future risk of chronic health conditions associated with obesity, including type 2 diabetes, high blood pressure, and/or sleep apnea, enabling them to live longer, healthier lives.

Gastric sleeve surgery, or sleeve gastrectomy, is a surgical procedure that can help an individual with obesity lose excess weight over time. During the procedure, 50%-75% of a patient’s stomach is surgically removed. Because the remaining stomach is much smaller and less likely to stretch to accommodate large meals, patients feel fuller when they consume smaller amounts of food. This influences patients’ eating habits, encouraging weight loss over time.

Removing a portion of the stomach also reduces the amount of the “hunger” hormone, ghrelin, produced by the stomach. Patients also experience increases in glucagon-like peptide 1 (GLP-1) and peptide YY (PYY), hormones that decrease appetite and make patients feel satiated. With less ghrelin and more GLP-1 and PYY, patients feel less hungry and more satisfied with what they’ve eaten, leading to less food intake.

However, weight gain after the procedure is possible, so it’s important for patients to maintain a healthy diet and to exercise, as well as avoid certain behaviors, such as binge-eating, eating continuously throughout the day, and eating when full.

Gastric sleeve surgery is performed as minimally invasive laparoscopic surgery in most instances; surgeons insert tools and a camera into the body through tiny incisions they make in the abdomen. In rare cases, however, the procedure may be performed as an open surgery through one large incision in the abdomen. In either type of procedure, patients receive general anesthesia.

During the procedure, a surgeon cuts off the blood supply to the portion of the stomach that will be removed to prevent bleeding. If a patient has a hiatal hernia—a section of stomach that has pushed upwards through the diaphragm—it will be corrected before proceeding.

To create a sleeve-like structure out of stomach tissue, the surgeon inserts a thin, cylindrical tube through the mouth and esophagus until it reaches the stomach. This helps them visualize where to form the new one. The surgeon then cuts across the stomach to remove unnecessary tissue and staple the remaining tissue together to make a cylindrical stomach. (The staples may be reinforced to avoid bleeding or fluid leakage.) Once the stapling is completed, the surgeon removes the cylindrical tube through the mouth and excess stomach tissue through one of the small surgical incisions.

For two weeks after the procedure, patients consume a clear liquid diet. Gradually, they reintroduce solid foods to their diet. They should receive specific recommendations from a nutritionist or physician about how much to consume, which foods to include and avoid in the diet, as well as exercise recommendations.

Patients who follow their doctor’s advice are expected to lose up to 60% of their excess body weight in the first two years after surgery.

Gastric sleeve surgery is an effective treatment for obesity. To determine whether or not a person has obesity, doctors use their height and weight to calculate their body mass index (BMI). People with a body mass index (BMI) of 30 or higher have obesity.

Doctors may recommend sleeve gastrectomy to certain patients with obesity who have been unable to lose weight—and/or keep it off—through diet and exercise, including:

• Patients with obesity who have a BMI of 40 or higher
• Patients with obesity who have a BMI of 35 or higher and a chronic health condition related to obesity, such as type 2 diabetes, high blood pressure, or sleep apnea
• Patients with obesity who have a BMI in the 30 to 35 range and uncontrollable diabetes or metabolic syndrome

Bariatric surgery procedures, including sleeve gastrectomy, have been shown to be the most effective way for people with obesity to lose weight in the long term, meaning about 10 years after surgery.

Sleeve gastrectomy can significantly benefit a person’s overall health. The weight loss that occurs after the procedure reduces the risk of certain cancers and non-alcoholic fatty liver disease (a condition in which excess fat builds up in your liver). It also increases a patient’s life expectancy.

In fact, type 2 diabetes resolves in about two-thirds of patients with obesity who undergo sleeve gastrectomy, and the condition improves in about one-quarter of people who have the procedure, reducing their need for insulin or medication.

Gastric sleeve surgery is simpler than other types of bariatric surgery. It causes fewer changes to the patient’s overall anatomy than gastric bypass surgery, and it doesn’t introduce a foreign object into the abdominal cavity, as does gastric banding, which uses an inflatable silicone device placed around the top portion of the stomach.

Sleeve gastrectomy is nearly as effective as gastric bypass surgery in helping patients lose weight and helping to manage their diabetes or metabolic syndrome. However, patients tend to lose more of their excess body weight with gastric bypass surgery.

Patients who undergo sleeve gastrectomy are more likely to experience gastroesophageal reflux disease (GERD), or chronic acid reflux, than those who undergo other types of bariatric surgery.

The following risks are associated with gastric sleeve surgery:

• Infection or bleeding. Patients may experience a post-surgical infection or bleeding after sleeve gastrectomy, which may occur after any surgical procedure.
• GERD. Sleeve gastrectomy decreases the volume that a patient’s stomach can hold, increasing the pressure placed on the patient’s esophagus. The additional pressure increases the risk of GERD and the chance of liquid leaking from the stomach, resulting in severe infection.
• Blood clots. Sleeve gastrectomy increases the risk of blood clots, including portomesenteric vein thrombosis, a condition in which blood clots develop in veins that carry blood away from the intestines. It may be life-threatening in some cases.
• Weight gain. A risk for patients who undergo any type of weight-loss surgery, including sleeve gastrectomy, is weight gain, which is more likely to occur when patients don’t follow their doctor’s recommendations regarding diet and exercise.
• Increased risk of gallbladder problems. Patients can develop gallstones as they lose weight.

“Yale Bariatrics exemplifies clinical excellence,” says Neil Floch, MD, a Yale Medicine bariatric surgeon and director of Bariatric Surgery at Greenwich Hospital. “The program is composed of surgeons who are technically gifted and academically oriented. The integrated health team of registered dieticians, mental health experts, and exercise physiologists work together to ensure that patients are best prepared to be successful after their gastric sleeve surgery. There is compassion, understanding, and emotional support for our patients in need."