This is when problems occur during or after the operation. Most people are not affected. The possible complications of any operation include an unexpected reaction to the anaesthetic, excessive bleeding or developing a blood clot, usually in a vein in the leg (DVT).
Complications specific to a gastric band operation are listed here.

• Infection – antibiotics are usually given during surgery to prevent infection. If an infection doesn’t respond to antibiotics your band may need to be removed.
• Damage to other organs in your abdomen – you may need further surgery to repair any damage.
• Band problems – your band may slip out of place, leak, or work its way through the stomach wall. If this happens, your band may need to be repositioned, removed or replaced.
• Gallstones – there is a risk you may develop gallstones if you lose weight quickly. These can be painful and you may need surgery to remove them. Your surgeon may advise removing your gallbladder when you have your operation.

There is a chance your surgeon may need to convert your keyhole procedure to open surgery. This means making a bigger cut on your abdomen. This is only done if it’s impossible to complete the operation safely using the keyhole technique.

Around one in 10 people with a gastric band may need another gastric band operation in the future. It’s also possible you may fail to lose sufficient weight or regain weight you have lost. The chances of this happening are reduced if you choose an aftercare clinic that is NIOPPS registered, as you will be able to see the weight loss results of that clinic.  NIOPPS ensures all registered clinics publish their own weight loss results not those of other clinics,. Or those quoted in research papers for gastric band surgery.
The exact risks are specific to you and will differ for every person, so we have not included statistics here. Ask your surgeon to explain how these risks apply to you.