No, RYGB is Not the Same as Partial Gastrectomy
Roux-en-Y gastric bypass (RYGB) and partial gastrectomy are fundamentally different procedures with distinct anatomical alterations and mechanisms of action. While both involve modification of the stomach, they differ substantially in their surgical technique, extent of gastric resection, and physiological effects.
Key Anatomical Differences
RYGB creates a small gastric pouch (approximately one ounce or "walnut-sized") that is then connected to the distal small intestine, bypassing the duodenum and proximal jejunum entirely. 1 This procedure involves:
- Transection of the stomach to create a tiny pouch 1
- Creation of a Roux-en-Y gastrojejunostomy 1
- Diversion of ingested nutrients away from the gastric remnant, duodenum, and proximal jejunum 1
- Two anastomoses (connections between bowel segments) 2
In contrast, a partial gastrectomy involves surgical removal of a portion of the stomach without the intestinal bypass component. The remaining stomach is reconnected to the duodenum or jejunum, but the normal flow of food through the gastrointestinal tract is largely preserved 1.
Mechanism of Weight Loss
RYGB achieves weight loss through a combination of restrictive and malabsorptive mechanisms, plus significant enteroendocrine hormone changes. 1 The procedure:
- Restricts food intake through the small gastric pouch 1
- Creates malabsorption by bypassing absorptive intestinal segments 1
- Induces robust changes in gut hormones including GLP-1 and PYY 1
Sleeve gastrectomy (which involves 80% gastric resection) is closer to a partial gastrectomy conceptually, but even this differs from traditional partial gastrectomy by removing the ghrelin-producing greater curvature and creating a tubular stomach based on the lesser curvature. 1
Clinical Implications
The distinction matters clinically because:
- RYGB carries different nutritional risks than simple gastric resection, requiring lifelong vitamin and micronutrient supplementation due to the malabsorptive component 1
- RYGB patients face unique complications including internal hernias through mesenteric defects, dumping syndrome, and postbariatric hypoglycemia that don't occur with simple partial gastrectomy 1
- Endoscopic access differs significantly - RYGB creates altered anatomy that makes reaching the papilla and managing bile duct stones substantially more challenging than after partial gastrectomy 1
Common Pitfall to Avoid
Do not confuse RYGB with sleeve gastrectomy or any form of partial gastrectomy. While sleeve gastrectomy involves substantial gastric resection (80%), it remains a primarily restrictive procedure without the intestinal bypass and malabsorptive component that defines RYGB. 1 RYGB's defining feature is the bypass of the duodenum and proximal jejunum, not simply the size of the gastric pouch.