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Bariatric Surgery: What is it? Who can get it? What are the risks?

Reasons to choose Wilson Browne

Obesity rates in the UK have being increasing significantly over the last few years.

It is often considered that in order to become obese a person needs to consume a significant amount of calories on a daily basis. The reality is that cumulative effect seems to be the real issue: it has been suggested that a person only needs to consume a two finger Kit-Kat (104 calories) on a daily basis, in addition to their normal daily caloric intake, for a period of 5 years before they will become obese.

What is Bariatric Surgery?

Bariatric surgery (weight loss surgery) includes a variety of procedures performed on people who are obese. Weight loss is achieved by reducing the size of the stomach either with a gastric band or through removal of a portion of the stomach (sleeve gastrectomy) or by resecting and re-routing the small intestine to a small stomach pouch (gastric bypass surgery).

What is BMI and who is eligible for Bariatric Surgery? 

For an answer to the first part of the question, look here

In the UK, one in four adults and approximately one in five children are now obese, with a BMI of 30 or more.

Bariatric surgery is recommended for individuals with Class III obesity (body mass index or BMI greater than 40) or Class II obesity (a BMI of between 35 and 40) but also suffer from one or more obesity-related diseases such as diabetes or high blood pressure and who have failed conservative weight control management for a period of 12 to 24 months.

Patients who are eligible for bariatric surgery should be managed by a multidisciplinary team with input from physicians, psychologists, dieticians and specialist surgeons. The screening process typically includes a thorough medical evaluation as well as a psychological evaluation, nutritional consultation and education about the surgery and what to expect afterwards.

Less than 1% eligible population in the UK go on to have Bariatric Surgery. 

Types of Bariatric Surgery

As mentioned above, the most common procedures carried out in bariatric surgery are gastric band, gastric bypass and sleeve gastrectomy. Each of the procedures has their own advantages and disadvantages.

Gastric Bands are recommended to patients who are large portion eaters. It is a very safe procedure which can be reversed. However, there is a requirement for band maintenance and follow ups following the procedure and there have been incidences of the need for revision surgery when complications have arisen.

Gastric sleeve is a permanent restrictive procedure which gives a good weight loss profile and is effective at diabetic resolution. However, there is a higher operative risk than gastric band, it is irreversible and the complications, whilst rare, are serious with long recovery times.

Gastric bypass, this type of procedure is good for patients who like to snack and have severe morbid obesity. Again like the gastric sleeve, it has an excellent weight loss profile and is extremely effective at diabetic resolution but there is a higher operative risk and the need for vitamin supplementation for life.

Benefits of Bariatric Surgery

Bariatric surgery is associated not only with substantial weight loss but also with improvement in or resolution of health problems such as hypercholesterolemia, high blood pressure, sleep apnoea, type II diabetes and a reduction in mortality of 23% to 40%. The aforementioned health benefits have to be weighed up against the immediate and longer-term complications and risks with major abdominal surgery, including a small possibility (less than 0.5%) of death.

Adverse effects of Bariatric Surgery

Complications from bariatric surgery are frequent. A study of insurance claims of 2522 people who had undergone bariatric surgery, showed 21.9% complications during the initial hospital stay and a total of 40% risk of complications in the subsequent six months. Common problems were gastric dumping syndrome (20%), leaks at the surgical site (6%), incisional hernia (7%) infections (6%) and pneumonia (4%), where mortality was 0.2%. Data shows the rate of complications appear to be reduced when the procedure is performed by an experience surgeon and so guidelines recommend that surgery be performed in dedicated or experienced units where it has been observed that the rate of leaks in high volume centres were a lot less.

The National Bariatric Surgery Registry suggest serious complications occur in only 2.4% of cases, however, an authoritive British Study found that the primary bariatric procedures carried out by the NHS between 2009 and 2016 put the risks much higher and found one in ten weight loss operations resulted in significant problems and that at least 29 deaths in-hospital deaths and 32 deaths after 30 days of discharge from hospital had occurred from Bariatric surgery.

It should be noted, therefore, that bariatric surgery is not without significant risk and cannot be deemed to be an “easy fix” for obese patients wanting to lose weight.


Louise Tyler


Louise Tyler


Louise is the Head of the Medical Negligence Team working in this area of law for 25 years. She is a member of the Law Society Clinical Negligence Panel, the AvMA (Action for Victims of Medical Accidents) Panel and been appointed to the Executive Committee…