The risks of gastric sleeve surgery explained

Image of consultant bariatric surgeon, Mr Rishi Singhal

Medically reviewed by Prof Rishi Singhal MBBS, MRCS, FRCS, MD

What are the risks of gastric sleeve surgery?

The risks of Gastric sleeve surgery are low but include staple line leakage, stomach narrowing, and bleeding, which may require surgical interventions. Patients should be aware of an elevated risk of reflux disease. While complications are infrequent, acknowledging these risks is essential before proceeding with the procedure.

All patients must understand that these risks are unpredictable. Although we will take all reasonable steps to eradicate the risk of surgical complications, no matter how good the clinical team complications will occur from time to time. All patients must be ready to accept this risk before proceeding with the sleeve gastrectomy procedure. The good news is that the incidence of complications is low. This is because we follow a very comprehensive pre-op process to ensure that patients are screened for obvious risks. Your pre-op blood tests are an example of this.

If you experience a complication it’s important to know what will happen. The 3 complications that are more common among sleeve patients are as follows:

Staple line leakage

These can be identified immediately or a few days/weeks after the surgical procedure. Usually, they will be found within 14 days of surgery. It is preferable to spot them early because they can generally be closed with a return to theatre and by oversewing the site of the leak.

If the leak occurs later after surgery there are several treatment approaches available, but none of them is straightforward. Two of the more common approaches are to convert the procedure to a gastric bypass or to place a stent into the stomach to allow the tissue to recover. If it is possible to convert the procedure to a bypass this is often the preferred option as it allows for a faster recovery. Your surgeon would discuss this option with you. The other treatment for a leak that is commonly used is to put a stent into the stomach. A stent is a manmade tube that sits inside the stomach and allows the tissue around it to heal. The stent would be fitted by taking the patient back to theatre, washing the stomach, fitting the stent and putting a drain in place. The patient would then be put on TPN (fed by a tube) for a period to allow the stomach to rest. The stent would stay in place for a period of months and then be removed.

There are other ways in which to treat leaks and your surgeon will be happy to explain his own approach and preferences to you at consultation. As the leak is a complication that takes a long time to treat and because patients need close observation, they will normally be treated in an NHS bariatric unit, where the necessary skills are available.

Narrowing of the stomach (stricture)

Although this can occur immediately after surgery it is more likely to be revealed when you make the transition from liquids to solid foods. The stomach is always a little tight immediately after surgery due to swelling, and this usually settles, but there are occasions when the narrowing does not ease. This usually requires a return to theatre for the stomach to be stretched a little.

Haemorrhage (bleeding)

This will usually be identified in the 48 hours after surgery, and while you are still in hospital. It will require a return to theatre to identify the source of the bleed and to ‘clip’ it. It’s usually a straightforward procedure and requires a stay of just an extra couple of days in the hospital. On some occasions, the patient will require a blood transfusion.

Although the sleeve is an excellent procedure, patients have to consider that in the event of a complication, those complications are generally harder to fix than for the other procedures. In the case of the staple line leakage, this is because you go from having a large, rather saggy stomach, to having a very tight stomach that is under pressure. The pressure has the effect of making leaks difficult to close as there is pressure pushing them back open.


Several publications show that sleeve patients have a higher risk of reflux disease and hiatus hernia. This means that we would not do a sleeve procedure for a patient who already has reflux disease. A diagnosis of reflux disease would usually be made based on previous endoscopy reports and/or the patient being on long-term PPI medication (e.g. Omeprazole).

Patients proceeding with sleeve must proceed to accept a risk of acid reflux. If this does occur it can usually be treated effectively with PPI medical therapy.

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Image of consultant bariatric surgeon, Mr Rishi Singhal

All content on this page is reviewed by a multi-disciplinary team lead by Prof Rishi Singhal.

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