Severe obesity is associated with multiple comorbidities and is refractory to dietary management with or without behavioral or
drug therapies. There are a number of
surgical procedures for the treatment of
morbid obesity, including purely gastric restrictive, a combination of malabsorption and gastric restriction or primary malabsorption. The purely gastric restrictive procedures, including
vertical banded gastroplasty and laparoscopic adjustable
silicone gastric banding, do not provide adequate
weight loss. African-American patients do especially poorly after the banding procedure with the loss of only 11% of excess weight in one study.
Gastric bypass (GBP) is associated with the loss of 66% of excess weight at 1 to 2 years after surgery, 60% at 5 years and 50%
at 10 years. For unknown reasons, African-American patients lose significantly less weight than Caucasians after GBP. There is a risk of
micronutrient deficiencies after GBP, including
iron deficiency anemia in menstruating women,
vitamin B12, and
calcium deficiencies. Prophylactic supplementation of these nutrients is necessary. Recurrent
vomiting after
bariatric surgery may be associated with a severe
polyneuropathy and must be aggressively treated with endoscopic dilatation before this complication is allowed to develop. The malabsorptive procedures include the partial
biliopancreatic bypass (BPD) and BPD with duodenal switch (BPD/DS). The BPD appears to cause severe
protein-calorie malnutrition in American patients; the BPD/DS may be associated with less
malnutrition.
Weight loss failure after GBP does not respond to tightening a dilated gastrojejunal stoma or reducing the size of the gastric pouch. These patients may require conversion to a malabsorptive distal GBP, similar to the BPD. However, because of the risk of severe
protein-calorie malnutrition and
calcium deficiency BPD should be reserved for patients with
severe obesity comorbidity. The risk of death following
bariatric surgery is between 1% and 2% in most series but is significantly higher in patients with
respiratory insufficiency of
obesity. In most patients, surgically induced
weight loss will correct
hypertension, type II
diabetes mellitus,
sleep apnea,
obesity hypoventilation syndrome,
gastroesophageal reflux, venous stasis disease,
urinary incontinence, female sexual
hormone dysfunction,
pseudotumor cerebri, degenerative
joint disease pains, as well as improved self-image and employability.