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Morbid Obesity

Morbid Obesity/Severe Obesity

  • BMI > 40
  • Body weight is twice the ideal weight
  • 100 lbs above the ideal weight
  • Super Obese: BMI > 60
  • Edward Mason: Father of bariatric surgery

Ghrelin

  • Only known orexigenic agent (hunger-stimulating hormone)
  • Increases Neuropeptide Y and Growth Hormone in the hypothalamus
  • Ghrelin levels increase after fasting
  • 80% reduction in ghrelin levels after Roux-en-Y gastric bypass (RYGB)

MCQ: Ghrelin Stimulates

Question:

Ghrelin stimulates:

  1. ACTH
  2. GH
  3. Cortisol
  4. Prolactin

Answer:

2) GH (Growth Hormone)

Also stimulates Neuropeptide Y

Explanation:

  • Ghrelin is a potent stimulator of Growth Hormone (GH) secretion and Neuropeptide Y, which plays a role in increasing appetite.
  • It does not primarily stimulate ACTH, cortisol, or prolactin.

**Indications for Bariatric Surgery

[Box 47-2: Sabiston]**

  • BMI > 40 kg/m² or BMI > 35 kg/m² with an associated medical comorbidity worsened by obesity
  • Failed dietary therapy
  • Psychiatrically stable without alcohol dependence or illegal drug use
  • Knowledgeable about the operation and its sequelae
  • Motivated individual
  • Medical problems not precluding probable survival from surgery

MCQ: Indications for Bariatric Surgery

Question:

All of the following are indications for bariatric surgery except:

A) BMI >40 kg/m² with no associated comorbidity

B) Failure of medical management

C) Cosmesis

D) BMI >35 kg/m² with an associated medical comorbidity worsened by obesity

Answer:

C) Cosmesis

Explanation:

  • Cosmesis (surgery for cosmetic reasons) is not an indication for bariatric surgery. Bariatric surgery is indicated for severe obesity (BMI >40 kg/m² or BMI >35 kg/m² with associated comorbidities) and for individuals who have failed medical management or have obesity-related medical conditions. The goal is to improve health, not for cosmetic purposes.

Bariatric Operations: Mechanism of Action

Restrictive Procedures:

  • Vertical banded gastroplasty (historic purposes only)
  • Laparoscopic adjustable gastric banding (LAGB)
  • Laparoscopic sleeve gastrectomy (LSG)

Largely Restrictive, Moderately Malabsorptive:

  • Roux-en-Y gastric bypass (RYGB)

Largely Malabsorptive, Mildly Restrictive:

  • Biliopancreatic diversion (BPD)
  • Duodenal switch (DS)

MCQ: Primarily Malabsorptive Bariatric Operation

Question:

Which of the following is primarily a malabsorptive bariatric operation?

a) LAGB

b) LSG

c) RYGB

d) BPD

Answer:

d) BPD

Explanation:

  • Biliopancreatic diversion (BPD) is a largely malabsorptive procedure with mild restrictive properties, making it the correct answer.
  • LAGB and LSG are purely restrictive procedures, while RYGB is a combination of both restrictive and malabsorptive mechanisms but is primarily restrictive.

Roux-en-Y Gastric Bypass (RYGB)

  • Weight Loss:
    • Results in a 60-70% loss of excess weight.
  • Pre-operative Preparation:
    • Patients are placed on a liquid diet for 2 weeks before surgery.
    • This helps in shrinking the fatty liver and thinning the abdominal wall, making the surgery safer.
  • Surgical Details:
    • The left gastric artery trunk is preserved during the procedure.
  • Health Benefits:
    • Improves GERD (Gastroesophageal Reflux Disease).
    • Improves insulin-dependent Type 2 Diabetes Mellitus.

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MCQ: Mechanism of Weight Loss in Bariatric Surgery

Question:

All of the following are true regarding the mechanism of weight loss in bariatric surgery except:

A) Alterations in the gut microbiome induced by the bypass of the duodenum may play a significant role in the long-lasting metabolic changes after surgery

B) RYGB increases nutrient exposure to the small intestine, which decreases GLP-1 secretion, thereby improving glucose metabolism

C) Small gastric pouch and early satiety induced by the gastric stretch fibers and the vagal feedback to the satiety center play a role in weight loss after RYGB

D) Patients undergoing RYGB and LSG have suppressed postoperative levels of ghrelin

Answer:

B) RYGB increases nutrient exposure to the small intestine, which decreases GLP-1 secretion, thereby improving glucose metabolism

Explanation:

  • RYGB actually increases GLP-1 secretion due to rapid nutrient delivery to the small intestine, which improves glucose metabolism. The statement that it decreases GLP-1 secretion is incorrect.
  • Alterations in the gut microbiome, small gastric pouch, and suppressed ghrelin levels are all valid mechanisms for weight loss after bariatric surgery, including RYGB and LSG.

Incretins and RYGB Mechanism [ RYGB Contd.]

  • Incretins:
    • Family of peptides essential for insulin synthesis and regulation
    • Produced in the small and large intestine
    • Secreted in response to various nutrients
    • RYGB increases nutrient exposure to incretin-secreting cells in the intestines, stimulating:
      • Villus hyperplasia
      • Increased GLP-1 secretion
      • Improved glucose metabolism
  • Beta Cell Function and Glycemic Control:
    • Improvement may also be due to altered bile acid levels post-RYGB.

RYGB Mechanism

  • Foregut Hypothesis:
    • Bypass of proximal duodenum and jejunum reduces anti-incretin factors.
  • Hindgut Hypothesis:
    • Rapid delivery of intestinal content to the distal jejunum and ileum increases secretion of incretins such as:
      • Glucagon-like peptide-1 (GLP-1)
      • Peptide-YY (PYY)

Antecolic vs. Retrocolic RYGB

  • Antecolic Roux Limb:
    • Easier to construct
    • Mesocolon is not disturbed
    • No twisting of the Roux limb
    • Less risk of internal hernia
    • However, requires a greater length of alimentary limb to reach the gastric pouch

Stenosis of Gastrojejunostomy (GJ) After RYGB

  • Incidence:
    • Occurs in 2% to 14% of cases.
    • More common with circular stapler (10%) compared to sutured anastomosis.
  • Timeline:
    • Typically develops 4 to 6 weeks postoperatively.
  • Symptoms:
    • Progressive intolerance to solids, followed by liquids.
  • Treatment:
    • Successfully treated with endoscopic balloon dilation.

Internal Hernia After Roux-en-Y Gastric Bypass (RYGB)

Potential Mesenteric Openings Leading to Internal Hernia:

  • A) Stammer’s Hernia [Transverse Mesocolon Defect]:
    • Hernia can occur through a defect created in the transverse mesocolon during the creation of the Roux limb.
  • B) Petersen Hernia:
    • Occurs in the space between the mesentery of the Roux limb and the transverse mesocolon.
  • C) Jejunojejunostomy [Brolin Space] Mesenteric Defect:
    • A defect created near the site of jejunojejunostomy (the anastomosis between the Roux limb and the biliopancreatic limb) can lead to internal herniation.

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Complications of Roux-en-Y Gastric Bypass (RYGB)

Nutritional Deficiencies:

  • Most Common Deficiency:
    • Iron deficiency with an incidence of 15-40%.
  • Iron Deficiency Anemia:
    • Occurs in 20% of patients.
    • Treatment:
      • Oral iron supplementation in the form of iron gluconate, which is well absorbed even in a non-acidic environment.
  • Next Common Deficiency:
    • Vitamin B12 deficiency.
    • Caused by delayed mixing with intrinsic factor (IF).
    • Despite this deficiency, megaloblastic anemia is rare.

Biliopancreatic Diversion (BPD) - Scopinaro, Duodenal Switch (DS) - Marceau/Demeester

  • Weight Loss:
    • 70-80% sustained loss of excess body weight is typical after these procedures.
  • Duodenal Switch (DS):
    • Reduces stomal ulceration compared to other procedures.
  • Length of Common Channel:
    • The length of the common channel is a key factor in determining the degree of weight loss.
    • A shorter common channel leads to more malabsorption and greater weight loss but may also increase the risk of nutritional deficiencies.

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Laparoscopic Sleeve Gastrectomy (LSG)

  • Advantages:
    • Simplicity of the procedure
    • Preservation of the pylorus, which helps avoid dumping syndrome
    • Metabolic reduction of ghrelin levels, reducing appetite
    • No need for serial adjustments, unlike the Laparoscopic Adjustable Gastric Banding (LAGB)
    • Reduction in internal hernias compared to other procedures
    • Reduction in malabsorption seen with laparoscopic Roux-en-Y Gastric Bypass (RYGB)
  • Flexibility:
    • Can later be modified to either a laparoscopic RYGB or Duodenal Switch (DS) configuration if needed.
  • Weight Loss:
    • Achieves 55% loss of excess body weight, which is generally lower than RYGB or BPD/DS.

Surgical Details:

  • Resection of 80% of the stomach along the greater curvature.
  • First stapling is done 5-7 cm from the pylorus.
  • Shorter sleeve length results in greater weight loss but also increases nausea and reduces the functionality of the antral pump.
  • 36 F Bougie is used as a guide for sleeve creation.
  • Smaller bougie sizes provide greater weight loss, but also increase the risk of leaks.

Complications:

  • Leak:
    • Most dreaded complication of LSG.
    • Typically occurs in the proximal third of the stomach.
    • Early leaks (≤2 days post-op) result from stapler misfires or tissue trauma.
    • Late leaks are often due to ischemia and high intragastric pressure, especially when there's distal stenosis (commonly at the incisura angularis).
    • Diagnostic tools: Best identified using an oral contrast-enhanced CT scan or diagnostic laparoscopy (D Lap).
  • GERD and Contraindications:
    • 50% incidence of GERD post-LSG.
    • Contraindicated in patients with severe reflux.
  • Metabolic Complications:
    • BPD and DS have the highest metabolic complications compared to other bariatric procedures.

Mini Gastric Bypass (MGB)

  • Pouch along the lesser curvature with low distensibility.
  • Increased pouch length decreases bile reflux.
  • Gastrojejunostomy (GJ) is performed 200 cm from the DJ flexure.
  • Optimizes control of diabetes and hypercholesterolemia.

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One-Anastomosis Duodenal Switch (OADS)

  • Duodenoileostomy performed 200 cm from the ileocecal (IC) valve.
  • Results in intense weight loss (up to 90% excess body weight loss at 5 years).
  • Provides excellent control of diabetes.

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Endoscopic Methods for Bariatric Surgery

  • Suitable for patients with BMI 30-40.
  • Balloons approved by the FDA for temporary weight loss.
  • Must be removed after 6 months.

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MCQ 1: Most Common Bariatric Surgery Done at Present

Question:

Which is the most commonly performed bariatric surgery currently?

  1. LAGB
  2. RYGB
  3. LSG
  4. LDS

Answer:

3) LSG (Laparoscopic Sleeve Gastrectomy)

Explanation:

  • LSG is the most commonly performed bariatric procedure due to its simplicity, lower complication rate, and effectiveness in weight loss.

MCQ 2: Most Common Malabsorptive Procedure

Question:

Which is the most common malabsorptive procedure?

  1. BPD
  2. LDS
  3. MGB
  4. RYGB

Answer:

2) LDS (Laparoscopic Duodenal Switch)

Explanation:

  • LDS is primarily a malabsorptive procedure with a long common channel, leading to substantial malabsorption compared to other surgeries.

MCQ 3: True Statement

Question:

The following statement is true:

  1. Laparoscopic sleeve gastrectomy is suitable for BMI > 50
  2. RYGB has three potential sites of herniation
  3. The common ileum channel in LBPD-DS is 50 cm
  4. Cholecystectomy should be performed in all cases of RYGB

Answer:

2) RYGB has three potential sites of herniation

Explanation:

  • RYGB is associated with three potential herniation sites: transverse mesocolon defect, Petersen’s space, and jejunojejunostomy mesenteric defect.

MCQ 4: RYGB - False Statement

Question:

Which of the following is false regarding RYGB?

  1. DM controls before weight loss
  2. GLP-1 decreases
  3. Ghrelin decreases
  4. CRP decreases after surgery

Answer:

2) GLP-1 decreases

Explanation:

  • GLP-1 actually increases after RYGB due to rapid nutrient delivery to the small intestine, improving glucose metabolism. The other options are true.

MCQ 5: Duodenal Switch - False Statement

Question:

Which of the following is false regarding the Duodenal Switch?

a. Sleeve gastrectomy

b. Incidence of anastomotic ulcer more compared to BPD

c. Common channel 100 cm

d. Duodeno-ileostomy end-to-side anticolic loop

Answer:

b) Incidence of anastomotic ulcer more compared to BPD

Explanation:

  • The incidence of anastomotic ulcers is actually lower in the Duodenal Switch compared to Biliopancreatic Diversion (BPD). The other statements are accurate.

MCQ 6: All Are True Except

Question:

All are true except:

  1. Iron deficiency anemia – RYGB, BPD contraindicated
  2. Severe GERD – LSG contraindicated
  3. Immunosuppression drugs and CCF taking drugs – drugs poorly absorbed in RYGB, BPD, DS
  4. Steroid medication contraindicated in LAGB
  5. DS and LSG contraindicated if NSAID cannot be discontinued

Answer:

5) DS and LSG contraindicated if NSAID cannot be discontinued

Explanation:

  • RYGB is contraindicated if NSAIDs cannot be discontinued due to the risk of marginal ulcers, not DS and LSG.

MCQ 7: Most Common Bougie Size Used in LSG

Question:

What is the most common size of bougie used in LSG?

  1. 34F
  2. 36F
  3. 32F
  4. 38F

Answer:

2) 36F

Explanation:

  • The 36F bougie is the most commonly used guide during LSG to maintain a balance between weight loss and minimizing complications.

MCQ 8: 50-Year-Old Male with Vomiting 4 Weeks After RYGB

Question:

A 50-year-old male develops vomiting to solid food 4 weeks after RYGB, followed by progressive intolerance to liquids. What is the most likely diagnosis?

  1. Small bowel obstruction
  2. Anastomotic stricture
  3. Internal herniation
  4. Too small pouch

Answer:

2) Anastomotic stricture

Explanation:

  • Anastomotic stricture typically develops 4-6 weeks postoperatively, causing progressive intolerance to solids and eventually liquids. Treatment is with endoscopic balloon dilation.

MCQ 9: Marginal Ulcer After RYGB

Question:

Which of the following is true regarding marginal ulcers after RYGB?

  1. Incidence 2-10%
  2. Epigastric pain
  3. Prevented by anti-H. pylori testing before surgery
  4. No role for surgery

Answer:

4) No role for surgery

Explanation:

  • Surgery may be required if complications like a fistula to the distal stomach develop. Otherwise, conservative management is preferred, and anti-H. pylori testing can be useful but does not prevent all ulcers.

Not Yet Standardized Procedures:

  • Single Anastomosis Gastric Bypass
  • Single Anastomosis Duodenal Switch
  • Endoscopic methods:

    • Balloon, Endoscopic Sleeve Gastrectomy, Endocinch, Aspire Assist

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