Gastric Sleeve

Sleeve gastrectomy, also known as laparoscopic gastric sleeve surgery, is a weight-loss procedure that involves reducing the size of the stomach by approximately 75-85%.

During the surgery, the lateral two-thirds of the stomach are removed using a stapling device, resulting in the remaining stomach taking the shape of a tube or "sleeve." This modification limits the amount of food you can consume.

The surgery is performed laparoscopically, which is a minimally invasive procedure. Under general anesthesia you will be asleep while the operation is carried out. Typically, the surgery takes one to two hours to complete.

Sleeve gastrectomy has been proven to be effective in helping patients achieve weight loss. On average, patients tend to lose around 50-60% of their excess body weight after undergoing this procedure.

About the operation

The laparoscopic sleeve gastrectomy is a relatively recent surgical procedure that can be performed as a standalone operation or as part of a two-stage approach for very large patients with a BMI over 60.

In these cases, the second operation, a roux-en-Y gastric bypass, is conducted several months later when the patient has shed a significant amount of weight, reducing the risks associated with further surgery.

During the procedure, the stomach is divided vertically from top to bottom using a stapling device, creating a slender pouch that resembles a 'banana-shaped' stomach along its inner curve. The lower part of the stomach, where the pyloric valve regulates the passage of food into the small intestine, remains intact. The excess portion of the stomach is then removed.

As a result, the operation restricts the amount of food that can be consumed at any given time, making it a restrictive operation. However, it does not affect the normal absorption of vitamins and minerals, preserving their absorption in the digestive process.

What are the alternatives? 

Additional surgical alternatives include laparoscopic gastric banding as well as laparoscopic gastric bypass surgery.

Typically, surgery is advised solely when non-surgical interventions like dietary changes, physical activity, and medication have proven ineffective.

What are the advantages of having sleeve gastrectomy?

In the laparoscopic sleeve gastrectomy procedure, the nerves within the stomach and pylorus remain untouched, thereby maintaining the stomach's functionality.

The remaining structure of the gastrointestinal tract remains unaltered, allowing ingested food to progress along its usual path. Consequently, there is a reduced likelihood of experiencing deficiencies in vitamins and minerals, as well as a lower risk of encountering dumping syndrome.

This surgery notably reduced hunger through the removal of the stomach segment responsible for producing key appetite-stimulating hormones.

Compared to laparoscopic gastric banding, this method necessitates fewer clinical follow-ups since adjustments to band size are unnecessary.

What are the risks?

Sleeve gastrectomy is typically considered a safe surgical procedure.

Nevertheless, to ensure you can make an informed decision and provide consent for the surgery, it's important that you are informed about potential side effects and the associated risks and complications of this treatment. 

Side effects

These are the mostly temporary, undesired outcomes of a successful intervention.

It's probable that you will experience bruising, discomfort, and skin swelling around the healing incisions.

After eating, you might encounter feelings of nausea or vomiting, particularly if you consume excessive amounts of food. 

Over time, your limited diet might result in deficiencies of nutrients such as iron, calcium, and vitamins. Consequently, you might need to indefinitely incorporate multivitamin/mineral supplements into your routine. 


Complications can arise during or following the surgical procedure.

Most people will not encounter any severe complications due to this type of surgery.

As with any surgical operation, undergoing general anesthesia carries its own set of risks. Possible complications include unexpected reactions to the anesthesia, excessive bleeding, or the development of blood clots, typically in leg veins (deep vein thrombosis, DVT) or in the lungs (pulmonary emboli, PE). These risks are heightened for individuals with pre-existing medical conditions such as heart disease or high blood pressure.

Some of the potential complications that could arise after undergoing a sleeve gastrectomy are listed below:

  • Infection: Antibiotics are usually administered during surgery to prevent infection.
  • Organ Damage in Abdomen: Injury to other abdominal organs might necessitate subsequent surgical repair.
  • Staple Line Leakage: The staple line along the stomach may leak within the first few days to a week, potentially requiring corrective surgery.
  • Sleeve Stricture or Ulceration: The gastric 'sleeve' could narrow or develop ulcers post-surgery, requiring endoscopy with or without dilatation or additional surgery to address the issue.
  • Heartburn / Reflux: There's a possibility of exacerbating pre-existing symptoms or developing new heartburn / reflux symptoms after surgery. These are usually manageable with medication, but some patients might require additional surgery for control.
  • Gallstones: Rapid weight loss can elevate the risk of gallstone formation, which might require surgical removal due to the associated pain.
  • Inadequate Weight Loss: It's conceivable that weight loss might not meet expectations, or previously lost weight might be regained after the surgery.
  • Conversion to Open Surgery: In some instances, your surgeon might need to switch from a keyhole procedure to open surgery if safety cannot be ensured via the minimally invasive technique.

The precise risks are individualized and divergent for each person. Overall, there is a 5% risk of encountering adverse effects (as outlined above) and a 1 in 500 (0.2%) likelihood of death attributed to this operation. 

How long does it take to get better from surgery?

Typically, you can anticipate a hospital stay of approximately two to three days following the procedure. A complete recuperation from a sleeve gastrectomy usually spans a period of two to three weeks.

Is the sleeve gastrectomy operation reversible?

Sleeve gastrectomy is classified as a lasting weight-loss technique.

This factsheet is intended for individuals contemplating or seeking information about sleeve gastrectomy. While we strive to provide comprehensive information, certain details might not be covered here. Additionally, your care will be customized to suit your unique requirements, potentially differing from the details outlined in this document.

Further information 

Association for the Study of Obesity (ASO) 020 8503 2042

British Obesity Surgery Patients Association (BOSPA) 0845 602 0446