Bariatric surgical procedures are an option for treating severe obesity, by reducing intake or absorption of calories. There are various options, all of which have potential complications. Bariatric surgery should always be performed in a specialist centre and long-term follow-up of patients is necessary.
Bariatric surgery is an option in severely obese patients, where lifestyle and medication have been evaluated but found not to be effective. Surgery can be combined with other treatments.
BMI ≥40 kg/m2 OR BMI 35-40 kg/m2 with other significant disease (eg, type 2 diabetes, hypertension) that could be improved by weight loss and:
- All appropriate non-surgical measures have failed to achieve or maintain adequate clinically beneficial weight loss.
- They are receiving or will receive intensive specialist management.
- They are generally fit for anaesthesia and surgery.
- They commit to the need for long-term follow-up.
Surgery is not generally recommended, as it is fraught with ethical issues and the potential long-term benefits and complications are not yet known. NICE suggests that it may be considered in exceptional circumstances, if:
- They have achieved or nearly achieved physiological maturity.
- They are receiving or will receive intensive specialist management. This will include
- Full information on procedures available and risks and benefits.
- Management of comorbidities.
- Psychological support before and after surgery.
- Regular postoperative assessment, including specialist dietetic and surgical follow-up
- Information about access to plastic surgery, such as apronectomy, where appropriate.
- Access to suitable equipment for obese young people.
- Assessment of fitness for anaesthesia and surgery.
- They have had a comprehensive psychological, educational, family and social assessment before undergoing bariatric surgery.
- They have had a full medical evaluation, including genetic screening or assessment before surgery to exclude rare, treatable causes of obesity. They should also have had a specialist assessment to exclude eating disorders
Contra-indications and cautions:
- Unfit for surgery.
- Uncontrolled alcohol or drug dependency.
- Uncontrolled emotional disorders.
- Lack of ability to understand surgery, consequences, need for follow-up.
- Some centres advise pre-operative psychiatric and nutritionist assessment.
Bariatric surgery procedures currently used:
- Laparoscopic adjustable gastric banding.
- Vertical sleeve gastrectomy.
- Biliopancreatic diversion with/without duodenal switch.
Both restrictive and malabsorptive:
- Roux-en-Y gastric bypass (RYGB).
- Other types of gastric bypass.
- Gastric stimulation.
- Intragastric balloon.
Laparoscopic adjustable gastric banding:
Places a constricting ring around the stomach, below the gastro-oesphageal junction. The bands incorporate an inflatable balloon which can adjust the size of the ring, to regulate food intake.
Most of the stomach is removed, leaving a sleeve-shaped cylinder of stomach with reduced capacity. This procedure is irreversible.
Creates a small gastric pouch (restrictive) joined to the jejunum, bypassing the duodenum and proximal jejunum (malabsorptive). The RYGB is the usual procedure at the current time.
This is a more extensive form of the gastric bypass, with the gastric pouch joined to the ileum, totally bypassing the duodenum and jejunum. It produces more extreme malabsorption.
Biliopancreatic diversion is sometimes performed with a duodenal switch. This produces a short distal length of small intestine, severely limiting caloric absorption. This is a complex operation which takes some hours to complete.
This uses an implanted pacemaker-type device to produce electrical gastric stimulation, thought to cause a feeling of satiety.
This is an endoscopic rather than surgical procedure, placing a silicone balloon inflated in the stomach to promote a feeling of satiety. There is insufficient evidence to assess its effectiveness and there have been complications such as gastric erosions and ulcers. It is therefore usually removed after six months.
It is apart from balloon insertion, various other endoscopic procedures are being developed but are not currently in common NHS use. These are collectively known as primary obesity surgery endolumenal (POSE)
Complications and disadvantages of surgery:
Pre-operative discussion is important; patients may have unrealistic ideas about the amount of weight they are likely to lose, the need for follow-up and the potential complications. Peri-operative mortality is low at less than 0.3%, and is declining.
The incidence of complications within the first six months varies from 4-25%, and depends on procedure used, duration of follow-up and individual patient characteristics. Complications to consider include:
- Peri-operative complications as for any abdominal surgery include venous thromboembolism. The use of prophylaxis has reduced the incidence of deep vein thrombosis and pulmonary embolism considerably
- Possible complications of banding are band slippage, leakage, infection or migration.
- Surgical complications of bypass surgery include leakage or stenosis of the stoma, gastrointestinal ulcers or bleeding, small bowel obstruction and hernias.
- Nausea and vomiting may occur due to overeating or to stenosis at the surgery site.
- Dumping syndrome: symptoms are flushing, light-headedness, palpitations, fatigue and diarrhoea, typically triggered by sugar after a RYGB. It is a neurohormonal reaction. It may help to discourage overeating.
Micronutrient deficiencies are a recognised problem, especially with malabsorptive procedures. Iron-deficiency anaemia is the most common complication. Calcium, zinc, folate and vitamin D deficiencies can occur. Thiamine, B12 and copper deficiencies may cause neurological symptoms and should be remembered. Protein-calorie malnutrition can also occur. Long-term follow-up is important.