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

Overview

• Gastric restriction (small pouch limits food intake)
• Mild malabsorption (bypassing the duodenum and proximal jejunum)
• Profound gut hormone changes that increase satiety and suppress hunger (GLP-1, PYY)

Antecolic-antegastric Roux-en-Y gastric bypass. Gastric pouch at top, Roux (alimentary) limb, and jejunojejunostomy below. (Johns Hopkins University)

Indications (Box I - Current Surgical Therapy 14e)

Surgical Technique (Step-by-Step)

Step 1: Jejunojejunostomy (Roux Limb Creation)

1. Identify the ligament of Treitz
2. Transect the jejunum 40-75 cm distal to the ligament of Treitz using a 60-mm white stapler
3. Divide the mesentery with a gray stapler or ultrasonic shears
4. Create a side-to-side jejunojejunostomy 75-100 cm distal from the transection point using a 60-mm white laparoscopic stapler - this forms the "Y" connection
5. Close the mesenteric defect with running suture to prevent internal hernia

Step 2: Gastric Pouch Creation

1. Retract the left lateral liver segment with a Nathanson retractor
2. Dissect peritoneal attachments at the angle of His, expose the left crus
3. Open the gastrohepatic ligament (lesser sac access)
4. Divide the neurovascular bundle on the lesser curve just distal to the left gastric artery
5. Use multiple 60-mm blue staple cartridges to transect the stomach superiorly, creating a vertically oriented ~20 mL proximal gastric pouch
6. A 40Fr bougie guides the staple line along the lesser curve up to the angle of His

Step 3: Gastrojejunostomy

1. Bring the Roux limb antecolic-antegastric to the gastric pouch (preferred over retrocolic - reduces internal hernia risk)
2. Suture the side of the Roux limb to the gastric pouch staple line
3. Create a small enterotomy and gastrotomy, then fire a 60-mm blue stapler (using only 40 mm) to form the gastrojejunostomy
4. A 32Fr bougie calibrates the anastomosis to prevent stricture
5. Close the common enterotomy with a 60-mm blue stapler
6. Leak test the anastomosis

Step 4: Closure

• Close trocar sites and skin
• Routine DVT prophylaxis (subcutaneous LMWH, SCDs) and antibiotics are given pre/perioperatively

Outcomes

Complications

Early (< 30 days)

• Anastomotic leak (< 1% with laparoscopic technique) - presents with tachycardia, tachypnea, abdominal pain; treated with sepsis control, often operative management
• Hemorrhage (~1-1.6%) - from staple lines
• Pulmonary embolism/DVT (~0.23% with modern prophylaxis) - accounts for 17% of deaths
• Wound infection (~0.8-0.9%)

Late (> 30 days)

• Anastomotic stenosis (2-7%) - progressive food intolerance at 4-6 weeks; treated with endoscopic balloon dilation
• Marginal ulcer (2-14%) - epigastric pain; treated with PPIs; related to larger pouch, H. pylori, NSAIDs, smoking
• Internal hernia (0.9-4.5%) - can cause small bowel obstruction and requires urgent reoperation; mesenteric defect closure at time of surgery reduces incidence by ~70%
• Dumping syndrome - early (osmotic) or late (reactive hypoglycemia); requires dietary modification
• Wernicke's encephalopathy - from thiamine deficiency with persistent vomiting; treat with IV thiamine

Nutritional Deficiencies (Long-term)

• Iron deficiency (15-40%) - duodenum/proximal jejunum are bypassed; treat with oral iron gluconate
• Vitamin B12 deficiency (15-20%) - intrinsic factor loss and bypass of ileal absorption; supplement with B12
• Also: Vitamin D, calcium, folate, zinc deficiencies require lifelong supplementation

Key Anatomy of RYGB (3 limbs)

• Biliopancreatic (hepatobiliary) limb - from duodenum to jejunojejunostomy; carries bile and pancreatic enzymes; NOT connected to food
• Alimentary (Roux) limb - from gastric pouch to jejunojejunostomy; 75-100 cm; carries food
• Common limb - distal to the "Y" junction; both food and digestive juices mix here