Surgical and Procedural Interventions
What this domain tests
This domain covers the operations themselves: how each anatomy creates a specific complication and nutrition profile, the expected weight loss, and the perioperative bundles that make ambulatory bariatric surgery feasible.
The main procedures
- Sleeve gastrectomy: about 75–80% of the stomach removed along the greater curvature; purely restrictive; staple-line leak classically at the angle of His; roughly 25% total weight loss.
- Roux-en-Y gastric bypass: 15–30 mL pouch with a 75–150 cm Roux limb; restrictive plus malabsorptive; risks include marginal ulcer, internal hernia, dumping, and micronutrient deficiency.
- Adjustable gastric band: purely restrictive, high reoperation rate, no longer first-line.
- BPD/DS and SADI-S: greatest weight loss and greatest malabsorption; require high protein intake and lifelong micronutrient vigilance.
Perioperative bundles
- ERAS: no prolonged fasting, opioid-sparing anesthesia, normothermia, early ambulation, early oral intake.
- Leak testing and drains are selective, not routine.
- VTE prophylaxis combines mechanical and pharmacologic agents.
Worked example
A patient weighs 130 kg at surgery and 100 kg at 6 months; height is 1.65 m. %TWL = (130 − 100) ÷ 130 × 100 = 23.1%. Ideal weight at BMI 25 is 25 × 1.65² = 68 kg, so %EBWL = 30 ÷ (130 − 68) × 100 = 48.4%. Reporting both prevents the common error of calling 23% TWL a failure - it is on track for a sleeve at 6 months.
Traps
- Mixing up %TWL and %EBWL when a question reports one and asks for the other.
- Treating sleeve gastrectomy as nutritionally benign - reflux, iron, and B12 still need surveillance.
- Forgetting that the excluded stomach and duodenum in RYGB are inaccessible to standard endoscopy, which changes how bleeding and ulcer are evaluated.