Bariatric Surgery

1. Concerning the medical treatment of obesity, which of the following is true?

Very-low-calorie diets primarily restrict either fat intake or carbohydrate intake.

For severely obese patients, medications have shown promising long-term weight loss.

Numerous programs exist to promote weight loss. However, all are encumbered by difficulty in helping patients
sustain long-term weight loss.
The National Institutes of Health (NIH) consensus conference recognized that medical therapy alone had been uniformly unsuccessful in treating the severely obese population. In fact, severely obese patients have a 3% or less chance of losing enough weight by dietary measures alone to achieve a BMI of less than 35 kg/m2.
Surgical treatment of obesity allows a loss of at least 50% of excess body weight in 80% to 90% of eligible individuals with concurrent improvement in comorbid conditions. Nonetheless, it is agreed that patients considering bariatric surgery need to be on a medically supervised diet program before being eligible for an operation.
Diet options include very-low-calorie diets, which primarily restrict either fat intake or carbohydrate intake. Recent pharmacologic therapy focuses on two medications.
Sibutramine blocks the presynaptic uptake of both norepinephrine and serotonin, thereby potentiating their anorexic effect in the central nervous system.
Orlistat inhibits pancreatic lipase and thereby reduces the absorption of up to 30% of ingested dietary fat. For severely obese patients, neither medication has shown promising long-term weight loss.

Explanation

Numerous programs exist to promote weight loss. However, all are encumbered by difficulty in helping patients
sustain long-term weight loss.
The National Institutes of Health (NIH) consensus conference recognized that medical therapy alone had been uniformly unsuccessful in treating the severely obese population. In fact, severely obese patients have a 3% or less chance of losing enough weight by dietary measures alone to achieve a BMI of less than 35 kg/m2.
Surgical treatment of obesity allows a loss of at least 50% of excess body weight in 80% to 90% of eligible individuals with concurrent improvement in comorbid conditions. Nonetheless, it is agreed that patients considering bariatric surgery need to be on a medically supervised diet program before being eligible for an operation.
Diet options include very-low-calorie diets, which primarily restrict either fat intake or carbohydrate intake. Recent pharmacologic therapy focuses on two medications.
Sibutramine blocks the presynaptic uptake of both norepinephrine and serotonin, thereby potentiating their anorexic effect in the central nervous system.
Orlistat inhibits pancreatic lipase and thereby reduces the absorption of up to 30% of ingested dietary fat. For severely obese patients, neither medication has shown promising long-term weight loss.

2. The most common indication for revision surgery after gastric bypass is:

Perforation

Protein deficiency

Failure to lose weight

Dumping syndrome

Anastomotic bleeding

Approximately 10% of gastric bypass patients fail to lose or maintain adequate weight loss and often seek revision
surgery. When assessing these patients, it is important to determine whether there is an anatomic defect (dilated gastric pouch,
enlarged gastrojejunostomy, gastrogastric fistula) that might be the cause of the failure.
Reoperation on a patient who fails to lose weight with an anatomically intact and well-constructed gastric
bypass is likely to be unsuccessful. Revision surgery is associated with an increased rate of infection, organ injury, and leakage.

Explanation

Approximately 10% of gastric bypass patients fail to lose or maintain adequate weight loss and often seek revision
surgery. When assessing these patients, it is important to determine whether there is an anatomic defect (dilated gastric pouch,
enlarged gastrojejunostomy, gastrogastric fistula) that might be the cause of the failure.
Reoperation on a patient who fails to lose weight with an anatomically intact and well-constructed gastric
bypass is likely to be unsuccessful. Revision surgery is associated with an increased rate of infection, organ injury, and leakage.

3. A 37-year-old woman is seen in your office 2 years after placement of an LAGB. She has lost 80 lb and her BMI is down to 28 kg/m2. She states that her port site is tender and red. Her last adjustment took place 3 months earlier. The most likely diagnosis is:

Trocar site hernia

Wound infection from poor sterile technique during her lastband adjustment

Band erosion

Leakage of the access port tubing

Band slippage

The mortality associated with laparoscopic adjustable gastric banding ranges from 0.02% to 0.1%, which is
significantly lower than that associated with bypass (0.3% to 0.5%) or the malabsorptive operations (0.9% to 1.1%). The rate of perioperative complications with LAGB is 1.5%, with late complications occurring in up to 15% of patients: band slippage or prolapse (13.9%), erosion (3%), and port access problems (5.4%).
Band slippage occurs when the fundus of the stomach herniates up through the band and causes obstruction; preferential use of the pars flaccida technique over the perigastric technique has resulted in a decrease in band slippage rates from 15% in early studies to 4% in recent studies.
Port access site problems are the most common complication after LAGB and include leakage of the access tubing, kinking of the tubing as it passes through the fascia, or port flip. Most port site problems can be repaired with the patient under local anesthesia.
Port site infection is rare ( involves removal of the band and repair of the stomach

Explanation

The mortality associated with laparoscopic adjustable gastric banding ranges from 0.02% to 0.1%, which is
significantly lower than that associated with bypass (0.3% to 0.5%) or the malabsorptive operations (0.9% to 1.1%). The rate of perioperative complications with LAGB is 1.5%, with late complications occurring in up to 15% of patients: band slippage or prolapse (13.9%), erosion (3%), and port access problems (5.4%).
Band slippage occurs when the fundus of the stomach herniates up through the band and causes obstruction; preferential use of the pars flaccida technique over the perigastric technique has resulted in a decrease in band slippage rates from 15% in early studies to 4% in recent studies.
Port access site problems are the most common complication after LAGB and include leakage of the access tubing, kinking of the tubing as it passes through the fascia, or port flip. Most port site problems can be repaired with the patient under local anesthesia.
Port site infection is rare ( involves removal of the band and repair of the stomach

4. Which of the following statements concerning the hormone ghrelin is true?

It is produced mainly by the arcuate nucleus of the hypothalamus.

Plasma levels increase after meals.

Plasma levels are increased after gastric bypass.

Plasma levels are increased in individuals following a low calorie diet.

Plasma levels are unchanged after sleeve gastrectomy.

Ghrelin is a 28–amino acid peptide predominantly secreted by the oxyntic glands of the proximal part of the stomach with lesser amounts produced by the bowel, pancreas, and hypothalamus. Ghrelin is a potent orexigenic circulating hormone that causes release of growth hormone and influences the insulin signaling mechanism. Ghrelin secretion is increased by weight loss and by caloric restriction. Ghrelin levels are decreased after gastric bypass and sleeve gastrectomy.

Explanation

Ghrelin is a 28–amino acid peptide predominantly secreted by the oxyntic glands of the proximal part of the stomach with lesser amounts produced by the bowel, pancreas, and hypothalamus. Ghrelin is a potent orexigenic circulating hormone that causes release of growth hormone and influences the insulin signaling mechanism. Ghrelin secretion is increased by weight loss and by caloric restriction. Ghrelin levels are decreased after gastric bypass and sleeve gastrectomy.

5. At her 3-month postoperative clinic visit, which of the following observations would require further investigation?

After an initial weight loss of 50 lb, she has not lost any weight in a week.

She is tolerating a general diet but because of the operation has vomited three times after eating steak.

She reports two to three loose bowel movements per day.

Her neck and trunk appear thinner but her lower extremities are unchanged.

She complains of fatigue.

Weight loss after gastric bypass is nonlinear, and short periods without weight loss are expected.
Change in appearance of the head, neck, and upper part of the body as a result of weight loss are more pronounced than of the lower extremities.
Nausea and vomiting are not unusual in isolated circumstances after gastric bypass, especially in relation to the patient’s adaptation to food restrictions.
Persistent vomiting may lead to Wernicke encephalopathy. This neurologic deficit may be preventable with parenteral thiamine. Loose bowel movements are common after all malabsorptive procedures and vary in severity. Iron is preferentially absorbed in the duodenum and proximal jejunum. The incidence of iron deficiency anemia after gastric bypass is approximately 20%, and it will often be manifested clinically as fatigue.

Explanation

Weight loss after gastric bypass is nonlinear, and short periods without weight loss are expected.
Change in appearance of the head, neck, and upper part of the body as a result of weight loss are more pronounced than of the lower extremities.
Nausea and vomiting are not unusual in isolated circumstances after gastric bypass, especially in relation to the patient’s adaptation to food restrictions.
Persistent vomiting may lead to Wernicke encephalopathy. This neurologic deficit may be preventable with parenteral thiamine. Loose bowel movements are common after all malabsorptive procedures and vary in severity. Iron is preferentially absorbed in the duodenum and proximal jejunum. The incidence of iron deficiency anemia after gastric bypass is approximately 20%, and it will often be manifested clinically as fatigue.