Roux-en-Y Gastric Bypass
What the Examiner Expects
A combined restrictive and malabsorptive bariatric procedure creating a small (15–30 mL) gastric pouch with a Roux-en-Y gastrojejunal anastomosis. The examiner expects you to know the indications (BMI ≥ 40, or BMI ≥ 35 with comorbidities such as type 2 diabetes, OSA, hypertension), the preoperative workup (nutritional counseling, psych evaluation, sleep study, EGD for H. pylori screening), and key technical elements: the pouch is created along the lesser curvature, the Roux limb is typically 75–150 cm, and the biliopancreatic limb is approximately 50 cm. Mesenteric defects at Petersen's space and the jejunojejunostomy must be closed to prevent internal hernias.
Key Examiner Focus Points
- Indications: BMI ≥ 40 or BMI ≥ 35 with obesity-related comorbidities
- Small gastric pouch (15–30 mL), 75–150 cm Roux limb, 50 cm biliopancreatic limb
- Internal hernia sites: Petersen's space and jejunojejunostomy mesenteric defect
- Marginal ulcer at the gastrojejunostomy is most common late complication
- Must supplement B12, iron, calcium, fat-soluble vitamins lifelong
Common Curveballs
POD 1 patient has tachycardia > 120, is anxious, and has a normal CT scan
Tachycardia after bariatric surgery is an anastomotic leak until proven otherwise — even with a negative CT. The classic teaching is that tachycardia is the most reliable early sign of a leak. Obtain an upper GI series with water-soluble contrast, or take the patient back to the OR for diagnostic laparoscopy. Do not dismiss this.
Patient presents 2 years postop with acute crampy abdominal pain and bilious emesis with no prior surgical history between operations
Internal hernia — the most common cause of SBO after Roux-en-Y. CT may show the swirl sign (mesenteric rotation). Take to the OR for laparoscopic exploration. Close the mesenteric defect. Do not dismiss as adhesive SBO.
Patient develops a marginal ulcer at the gastrojejunostomy
Test for H. pylori, ensure the patient is on PPI therapy, check for NSAID use, smoking, and confirm the gastric pouch is not too large (retained parietal cells). Treat medically first. Refractory cases may need revision surgery with truncal vagotomy.
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