Surgical procedures for weight loss

Before any extremely obese person is considered for surgery, failure of a comprehensive program that includes calorie restriction, exercise, lifestyle modification, psychological counseling, and family involvement should be demonstrated. Failure is defined as an inability of the patient to reduce body weight by one third and body fat by one half and an inability to maintain any weight loss achieved. Such patients have intractable morbid obesity and should be considered for surgery. Before surgery the patient should be evaluated extensively with respect to physiologic and medical complications, psychological problems such as depression and poor self-esteem, and the extent of motivation.

Some surgical procedures are restrictive because they decrease the amount of food entering the GI tract, others cause malabsorption, because they prevent food from being absorbed from the GI tract.

Bariatric surgery is an accepted form of treatment for extreme or class III obesity with a BMI of 40 and greater, or a BMI of 35 or greater with comorbidities.

Gastroplasty reduces the size of the stomach by applying rows of stainless-steel staples to partition the stomach and create a small gastric pouch, leaving only a small opening into the distal stomach.

Gastric bypass involves reducing the size of the stomach with the stapling procedure but then connecting a small opening in the upper portion of the stomach to the small intestine by means of an intestinal loop.

Both these procedures have the effect of reducing the amount of food that can be eaten at one time and producing early satiety. The new stomach capacity may be as small as 20-30 ml/1 oz/2 tbsp.

The most frequent complications of gastric surgery are bloating of the pouch, nausea and vomiting. A postsurgical food record noting the tolerance for specific foods in particular amounts helps in devising a program to avoid these episodes. Attention to vitamin and mineral supplementation, particularly calcium, folate, iron and vitamin B12 is advised. Iron deficiency anemia is the likely cause and should be corrected. Later patient monitoring should include an assessment of body-fat loss, deficiencies of potassium, magnesium. Usually multivitamin-mineral supplementation is necessary. Patients with higher presurgical BMI are at greater risk for postsurgical complications.

The gastric bypass patients may also have dumping syndrome – as food empties quickly into the duodenum. The symptoms of tachycardia, sweating, and abdominal pain are so negative that they motivate the patients to make the appropriate behavioral changes and refrain from overeating. 

Weight-loss surgery can improve several of the obesity-related diseases or comorbidities, including hypertension, Type II diabetes, osteoarthritis, back pain, dyslipidemia, cardiomyopathy, nonalcoholic steatohepatitis, sleep apnea and may improve kidney function. 

Liposuction involves aspiration of fat deposits by means of a 1-2 cm incision through which a tube is fanned out into the adipose tissue. The most successful operations are performed on younger persons with only small amounts of fat to be removed, where the elastic properties of the skin are able to allow tightening over the aspirated areas. It is not usually a weight-reduction technique but rather a cosmetic surgery because usually only about 5 lb of fat are removed at a time. Sometimes liposuction is done more aggressively – as much as 50 lb of fat are removed using an incision and removal of the fat on the abdomen followed with a tummy tuck and removal of excess skin.

Complications of this procedure are infection, cellulitis, and hemorrhage.

Unless it is aggressive, abdominal liposuction does not significantly improve obesity-associated metabolic abnormalities. Decreasing adipose tissue mass alone will not achieve the metabolic benefits of weight loss. By itself, abdominal liposuction is not a clinical therapy for obesity.