The use of bariatric surgery in the management of obesity has developed significantly over the past decade. It is now recognised that for many obese patients who fail to lose weight with lifestyle and drug interventions the risks and expense of long-term obesity outweigh those of surgery.

The NICE guidelines on who should be referred for bariatric surgery and complicated. Essentially NICE recommend that very obese patients (e.g. BMI 40-50 kg/m^2 etc) are referred early for bariatric surgery, particularly if they have other conditions that may be caused by it (e.g. type 2 diabetes mellitus, hypertension), rather than it being a 'last resort'.

Types of bariatric surgery

Primarily restrictive operations

• laparoscopic-adjustable gastric banding (LAGB)
  • it is normally the first-line intervention in patients with a BMI of 30-39kg/m^2
  • produces less weight loss than malabsorptive or mixed procedures but as it has fewer complications
• sleeve gastrectomy
  • stomach is reduced to about 15% of its original size
• intragastric balloon
  • the balloon can be left in the stomach for a maximum of 6 months

Primarily malabsorptive operations

• biliopancreatic diversion with duodenal switch
  • usually reserved for very obese patients (e.g. BMI > 60 kg/m^2)

Mixed operations

• Roux-en-Y gastric bypass surgery
  • is both restrictive and malabsorptive in action