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Stomach Weight Loss Surgeries: Types, Mechanisms, and Selection Guide

Bariatric Surgery Options: Restrictive, Malabsorptive, and Combined

Bariatric procedures alter gastrointestinal anatomy to promote weight loss and metabolic improvement. Selection depends on BMI, comorbidities, anatomy, patient preference, and surgeon expertise.

Primary Procedures

ProcedureMechanismTypical %EWL*Key Features
Sleeve Gastrectomy (SG)Restrictive: ~80% stomach removed → tubular sleeve50–60%Most common (60% US); no rerouting; preserves pylorus; low malnutrition risk; irreversible.
Roux-en-Y Gastric Bypass (RYGB)Restrictive + malabsorptive: small pouch + biliopancreatic limb bypass60–70%Gold standard for reflux, diabetes; higher nutrient monitoring; dumping syndrome risk.
Adjustable Gastric Band (AGB)Restrictive: silicone band around proximal stomach40–50%Declining use; adjustable/reversible; high reoperation rate (band slip, erosion); frequent visits.
Biliopancreatic Diversion / Duodenal Switch (BPD/DS)Sleeve + extensive intestinal bypass70–80%Highest weight loss/metabolic effect; highest malnutrition risk; complex; for BMI ≥50 or failed SG/RYGB.
Single Anastomosis Duodenal Switch (SADI-S)Sleeve + single loop duodeno-ileal anastomosis65–75%Simpler than BPD/DS; emerging; good metabolic outcomes.
Endoscopic Sleeve Gastroplasty (ESG)Endoscopic full-thickness suturing → sleeve15–20% TBWL**Non-surgical; outpatient; reversible; lower weight loss; BMI 30–40; bridge or primary.

*%EWL = % Excess Weight Loss at 1–2 yrs. **TBWL = Total Body Weight Loss.

Revision Surgery

For inadequate weight loss, weight regain, or complications (stricture, fistula, severe reflux). Options: band → sleeve/RYGB; sleeve → RYGB/SADI-S; RYGB → distalization/revision. Higher risk than primary.

Selection Criteria

  • BMI ≥40, or ≥35 with comorbidity (T2DM, HTN, OSA, etc.)
  • Failed nonsurgical attempts
  • Psychological readiness, no active substance misuse
  • Commitment to lifelong follow-up, supplementation, lifestyle change

Multidisciplinary Evaluation Required

Bariatric surgeon, dietitian, psychologist, medical specialist (cardiology, pulmonology, endocrinology as needed). Insurance often mandates 3–6 months supervised weight loss pre-approval.

Surgery is a tool—not a cure. Long-term success requires sustained behavioral change.

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