What are the risks of obesity surgery?

We have highlighted the benefits but there are risks with this type of surgery which you need to be aware of. These fall into two camps – ‘operative’ (related to the actual procedure itself) and ‘long term’ (happen after the procedure).

Complications can happen although they are uncommon: however, it’s as well to take these into account before making a decision.

Obesity surgery is usually performed under a general anaesthesia and this can be risky especially if you are carrying a fair degree of weight. However, these risks are quite small and your anaesthetist is a highly qualified doctor who will be able to deal with any complications if they do arise.

There are risks which apply to any surgery and these include: internal bleeding, infection, deep vein thrombosis (blood clots), leakage, reflux, vomiting and diarrhoea and nutritional deficiencies.

There are some which are specific to a particular procedure. For example, if you have undergone gastric banding then one of the risks is ‘band slippage’. If however, you have opted for a gastric bypass then there is the risk of ‘stenosis’ (narrowing of the intestinal loop).

Mortality rates are very low for obesity surgery. Death, during or after surgery can occur but fortunately it is a rarity. On average, mortality rates are 0.1% for gastric banding and 0.5% for gastric bypass.

Comparison of the benefits and risks of obesity surgery



Dramatic weight loss.
Gastric band: 50-60%
Gastric bypass: 60-70%
Biliopancreatic diversion: 70-80%
Sleeve gastrectomy
(with duodenal switch): 70-80%

Weight loss slows down or is not as great as originally planned. In some cases there may be very little which can be due to complications (band slippage etc).

Weight loss slows down in the second year after surgery.

Improved or resolved obesity-related conditions. These are as follows:

  • Hypertension (high blood pressure)
  • Stroke
  • Heart Disease
  • Cancer
  • Infertility
  • Skin Conditions
  • Stress Incontinence
  • Reflux
  • Osteoarthritis
  • Type II Diabetes
  • Sleep Apnoea
  • Liver Disease
  • Respiratory Illnesses
  • Kidney Failure

Risks (operative and long term) associated with obesity surgery:

  • Adverse reaction to anaesthesia
  • Adverse reaction to medication
  • Leakage
  • Bleeding
  • Stomach stretches over time
  • Infection
  • DVT (Deep Vein Thrombosis)
  • Pulmonary Embolus (blood clots in the lungs)
  • Reflux
  • Procedure specific complications
  • Nutritional Deficiencies
  • Death

Improved quality of life.

Cosmetic surgery may be needed (to correct loose folds of skin after dramatic weight loss).

Failure to follow aftercare plan can lead to weight gain and subsequent health problems.

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