What is the recommended procedure for gastric bypass in adults with a high body mass index (BMI) and weight-related health issues?

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

The standard gastric bypass procedure is the Roux-en-Y gastric bypass (RYGB), which involves creating a small gastric pouch (approximately one ounce or 20 mL) and anastomosing it to a segment of jejunum in a Roux-en-Y configuration, bypassing the duodenum and proximal jejunum. 1

Technical Description of RYGB

The procedure consists of two key components:

• Gastric pouch creation: The stomach is transected to create a small proximal gastric pouch of approximately 20 mL (roughly walnut-sized), which dramatically restricts food intake 1

• Roux-en-Y anastomosis: The jejunum is divided and the distal end is anastomosed to the small gastric pouch (gastrojejunostomy), while the proximal biliopancreatic limb is anastomosed to the jejunum downstream (jejunojejunostomy), creating the characteristic "Y" configuration 1, 2

• Mechanism of action: RYGB achieves weight loss through both restrictive effects (small pouch) and malabsorptive effects (bypassing duodenum and proximal jejunum), plus neurohormonal changes 1

Current Prevalence and Alternatives

• RYGB historically accounted for 70% of bariatric operations in the United States, though vertical sleeve gastrectomy (VSG) has recently overtaken it as the most commonly performed procedure worldwide 1

• Alternative procedures include vertical sleeve gastrectomy (VSG), adjustable gastric band (AGB), biliopancreatic diversion with duodenal switch (BPD-DS), and one-anastomosis gastric bypass (OAGB) 1

Weight Loss and Metabolic Outcomes

RYGB produces superior outcomes compared to most other procedures:

• Expected weight loss: 25-30% of initial body weight, or 50-65% of excess weight loss, with approximately 30% total body weight loss at 12 months 1, 3

• Diabetes remission: 66.7% remission rate for type 2 diabetes, with 29% achieving A1C ≤6.0% at 5 years in the STAMPEDE trial 1, 3

• Hypertension and dyslipidemia: More frequent resolution compared to restrictive procedures like gastric banding 3

Complication Profile

Early complications (perioperative period):

• Mortality: 0.2% 3
• Anastomotic leak: 0.6-4.4% 3
• Venous thromboembolism: 0.4% 3
• Reoperation rate: 3-5% 3

Late complications (long-term):

• Stenosis: 8-19% (higher than VSG) 3
• Internal hernia: 2.5-5% (specific to RYGB) 3, 2
• Marginal ulceration: 2.5-5% (specific to RYGB) 3
• Small bowel obstruction: Can occur from adhesions or internal hernias 2, 4
• Nutritional deficiencies: Requires lifelong supplementation of thiamin, B12, folate, iron, vitamin D, calcium, vitamins A/E/K, zinc, and copper 3

Indications for RYGB Selection

Choose RYGB when:

• Maximum weight loss is the priority, with expected 30% total body weight loss at 12 months 3
• Severe type 2 diabetes requiring superior metabolic outcomes 3
• Severe dyslipidemia requiring more aggressive lipid improvement 3
• Patient can tolerate higher perioperative risk and longer operative time 3

Choose VSG instead when:

• Lower perioperative risk is needed 3
• Shorter operative time and hospital stay are priorities 3
• Contraindications to RYGB exist (e.g., need for endoscopic access to bypassed stomach) 3

Critical Pitfalls to Avoid

• Do not delay imaging when complications are suspected—anastomotic leaks, staple-line disruption, and internal hernias can be life-threatening, and clinical symptoms are often inconclusive 2

• Ensure patency of both anastomoses (gastrojejunostomy and jejunojejunostomy) with contrast studies before discharge, preferably 24-72 hours post-surgery 2

• Refer to high-volume centers with experienced bariatric surgeons to optimize outcomes and minimize mortality 3

• Counsel patients that 20-30% may experience suboptimal response or weight regain despite surgery, requiring continued lifestyle modifications 3, 5

• Arrange lifelong nutritional monitoring with protein intake of 60-80 g/day and comprehensive micronutrient supplementation 3