Weight loss Surgery

Long-term weight loss can be achieved through a combination of diet, increased physical activity, behavioral modification and pharmacological treatment. However, weight regain is very common. Wing and Phelan (2005) estimate that only about 20% of overweight and obese individuals are able to maintain a 10% reduction in body weight for one year.

"Weight loss surgery is an option for weight reduction in patients with clinically severe obesity, i.e., a BMI ≥40, or a BMI ≥ 35 with comorbid conditions. Weight loss surgery should be reserved for patients in whom other methods of treatment have failed and who have clinically severe obesity". "Weight loss surgery provides medically significant sustained weight loss for more than 5 years in most patients." *

Picot and Jones et al. (2009) evaluated 3 randomized controlled trials and three cohort studies for the effectiveness of weight loss surgery versus non-surgical intervention. They found that weight loss "surgery is a more effective intervention for weight loss than non-surgical options. Surgery led to a greater reduction in weight in all six studies and the difference was statistically significant in five studies reporting a statistical comparison". One of the studies reported "a statistically significant reduction in the incidence of three out of six comorbidities assessed at 10 years follow-up after surgery compared with conventional therapy".

Picot and Jones et al. (2009) also investigated the efficacy of various surgical options. They found that gastric bypass (GBP) is more effective for long term weight loss than either vertical banded gastroplasty (VBG) or adjustable gastric banding (AGB).

There are three basic categories of weight loss surgery (WLS): restrictive, malabsorptive and combinations of restrictive and malabsorptive surgeries. Restrictive procedures limit the intake of food by reducing the size of the stomach and therefore the amount of food that it can accept at each feeding. Malabsorptive surgeries limit the absorption of nutrients by changing the path of food through the alimentary tract.

Common Types of Weight Loss Surgeries (WLS)
Procedure Restrictive vs Malabsorptive Expected Excess Body Weight Loss
Surgical Changes

Perioperative complications and adverse events by procedure type*

Laparoscopic Gastric Bypass


Restrictive and Malabsorptive 70%
  • 30 ml gastric pouch (restrictive),
  • 1 cm outlet stoma
  • 70 cm Roux limb (standard), 150 cm Roux limb (for super obese)
  • 90% of stomach is bypassed; the lower compartment still produces necessary digestive juices and drains into small intestines which receives food from the gastric pouch.
  • Any complication 10.3%
  • Non-Life-threatening 6.7%
  • Potentially life-threatening 3.1%
  • Permanently disabling .33%
  • Fatal .14%
Gastric Banding “Lap-Band” (Laparoscopic) Restrictive 25-50%
  • Adjustable silicone band placed completely around upper stomach
  • Band stricture diameter is controlled through access port
  • Access port placed under the skin, just below the rib (50 cm kink resistant tube).
  • Any complication 2.3%
  • Non-Life-threatening 1.5%
  • Potentially life-threatening 0.78%
  • Permanently disabling 0.04%
  • Fatal 0.04%
Vertical Sleeve Gastrectomy (Laparoscopic) Restrictive 50-80%
  • Surgical staples and nonreversible resection reduce the stomach volume to 60-80 cc.
  • Eliminates stomach tissue that produces ghrelin, a hunger inducing hormone.
  • The pylorus is preserved which eliminates "dumping syndrome".
  • Eliminates malabsorption because the food does not bypass the duodenum or portions of the jejunum.
  • Any complication 5.9%
  • Non-Life-threatening 3.6%
  • Potentially life-threatening 2.2%
  • Permanently disabling 0.0%
  • Fatal 0.0%

The National Institutes of Health (NIH) published safety guidelines for the selection of patients for weight loss surgery in 1991. The NIH patient criteria for weight loss surgery included:

Since then, improved anesthetic and laparoscopic techniques have allowed the benefits of weight loss surgery to be extended to:

Each health care institutions will set it's own patient selection criteria. Medical professionals need to familiarize themselves with the policies and procedures that govern their practice in order to provide safe and effective care.

Some common perioperative considerations include: