Sleeve Gastrectomy — Procedure Guide, Recovery & Risks | MyMedicPlus

Sleeve gastrectomy (laparoscopic sleeve gastrectomy, LSG) is a bariatric surgical procedure in which approximately 75–80% of the stomach is permanently removed along the greater curvature, creating a narrow tubular 'sleeve' with a capacity of 60–150 mL — compared to the normal gastric capacity of 1,000–1,500 mL. The pylorus (gastric outlet valve) is preserved, maintaining natural food passage to the small intestine without the malabsorptive complications of gastric bypass.

Weight loss after sleeve gastrectomy is achieved through two complementary mechanisms: restriction (reduced gastric capacity causing earlier satiety after smaller meals) and hormonal change (resection of the gastric fundus eliminates the majority of ghrelin-producing cells, significantly reducing hunger — the most important and distinguishing mechanism compared to adjustable gastric band). Ghrelin, the 'hunger hormone,' normally rises before meals and falls after eating; post-sleeve patients have substantially lower ghrelin levels, explaining reduced appetite as a primary weight-loss mechanism.

Sleeve gastrectomy has become the most commonly performed bariatric procedure globally, surpassing Roux-en-Y gastric bypass in many countries, due to its relative technical simplicity, shorter operative time, absence of an intestinal anastomosis, and comparable short- to medium-term weight loss outcomes. It is also used as the first stage of a planned two-stage approach for extremely high-risk, super-obese patients (BMI greater than 60) before definitive bypass or duodenal switch.

Sleeve gastrectomy is indicated for adults with a body mass index (BMI) of 40 kg/m² or above (Class III obesity, previously termed morbid obesity), or a BMI of 35–39.9 kg/m² (Class II obesity) with at least one significant obesity-related comorbidity. These comorbidities include type 2 diabetes mellitus, obstructive sleep apnoea, hypertension, hyperlipidaemia, non-alcoholic fatty liver disease (NAFLD/NASH), osteoarthritis of weight-bearing joints, polycystic ovary syndrome (PCOS), gastro-oesophageal reflux disease (GORD), and obesity-related cardiomyopathy.

Since 2022, international guidelines (IFSO, ASMBS) have expanded eligibility to patients with BMI 30–34.9 with poorly controlled type 2 diabetes, metabolic syndrome, or other significant metabolic comorbidities, reflecting growing evidence of metabolic benefit at lower BMI thresholds.

Candidates must have documented failure of supervised non-surgical weight management (diet, exercise, pharmacotherapy) for a minimum of 6 months, be willing to undergo comprehensive pre-operative psychological assessment, commit to long-term dietary and lifestyle changes, and be fit for general anaesthesia. Relative contraindications include severe gastro-oesophageal reflux disease (as sleeve can worsen GORD — gastric bypass preferred in such cases), Barrett's oesophagus, and large hiatus hernia not amenable to concomitant repair. Sleeve is generally preferred over bypass for patients concerned about malabsorption, those on multiple medications requiring reliable absorption, and those preferring a simpler reversible-in-principle anatomy.

Preoperative preparation includes a 2–4 week very low calorie diet (VLCD) to reduce liver size (hepatomegaly from fatty infiltration obstructs the operating field), medication review (anticoagulants, diabetic medications), and nutritional assessment.

Under general anaesthesia, 4–5 laparoscopic trocars (5 mm and 12 mm) are placed in the upper abdomen. A 36–40 French (12–13 mm) bougie (calibration tube) is passed orally into the stomach, positioned along the lesser curvature to standardise the width of the sleeve. The greater omentum and gastrocolic ligament are divided, devascularising the greater curvature of the stomach.

A series of linear staple fires — using a laparoscopic linear stapler (60–80 mm loads) loaded with the appropriate staple height (blue 3.5 mm loads for most of the stomach, green 4.8 mm loads for the thick antrum) — divides the stomach parallel to the bougie from the antrum (4–5 cm from the pylorus) to the angle of His, completing the sleeve. The staple line is tested by methylene blue or air insufflation to confirm integrity. The staple line may be oversewn or reinforced with buttressing material to reduce leak risk. The resected stomach specimen is extracted through the largest port site. Total operative time: 45–90 minutes. The bougie is withdrawn after stapling is complete. The staple line integrity is tested with methylene blue dye injected via an oro-gastric tube while ports are occluded.

Patients begin sipping clear fluids (water, diluted juice) on the day of surgery, progressing to 30–60 mL per hour in the immediate post-operative period to prevent dehydration. Hospital stay is typically 1–2 days for uncomplicated laparoscopic sleeve gastrectomy in ERAS (Enhanced Recovery After Surgery) pathways.

Diet is advanced in four stages over 4–8 weeks: liquid (weeks 1–2), pureed (weeks 3–4), soft (weeks 5–6), and regular diet from week 7 onward. Portions remain very small (60–120 mL initially, increasing to 240–350 mL at 12 months). Protein intake targets of 60–80 g per day must be met to prevent muscle loss. Hydration of at least 1.5 litres per day is essential, sipped steadily throughout the day.

Nutritional supplementation is mandatory lifelong: complete bariatric multivitamin, calcium citrate 1,200–1,500 mg daily, vitamin D 3,000 IU daily, vitamin B12, and iron (particularly in menstruating women). Return to non-strenuous work occurs at 1–2 weeks; exercise is encouraged from week 3. Follow-up at 2 weeks, 1 month, 3 months, 6 months, and 12 months, then annually, monitors weight loss, nutritional parameters, and comorbidity management.

Staple-line leak is the most serious complication (1–3%) and occurs most commonly at the gastro-oesophageal junction where tissue is thinnest. Leak presents at 3–7 days with fever, tachycardia, and left shoulder tip pain; confirmed by CT with oral contrast. Management involves nil by mouth, IV antibiotics, endoscopic stenting in early leaks, and CT-guided or surgical drainage. Prolonged leaks (greater than 6 weeks) require endoscopic intervention or reoperation.

Gastro-oesophageal reflux disease (GORD) develops or worsens in 20–30% of sleeve patients, attributed to disruption of the angle of His and reduced lower oesophageal sphincter competence; proton pump inhibitors are taken for at least 6 months post-operatively. De novo Barrett's oesophagus has been reported at increased rates after sleeve, raising long-term cancer concern.

Inadequate weight loss (less than 25% excess weight loss at 2 years) occurs in 10–15%, and weight regain (greater than 50% of initial weight loss by 5 years) in 20–30%, often attributable to sleeve dilation and resumption of high-calorie liquid calorie intake. Nutritional deficiencies (iron, vitamin B12, vitamin D) affect up to 30% who are non-compliant with supplementation. Stricture (narrowing) of the sleeve requiring endoscopic dilation occurs in 1–2%.

Sleeve gastrectomy produces an average excess weight loss (EWL) of 60–70% at 12–18 months in controlled studies, with total body weight loss of 25–30%. At 5-year follow-up, EWL of 50–60% is maintained in the majority of compliant patients. Type 2 diabetes remission occurs in 60–70% of patients (defined as HbA1c below 48 mmol/mol off medications), often before significant weight loss has occurred — reflecting improved insulin sensitivity from ghrelin reduction and changes in incretin hormone profiles.

Hypertension resolves or improves in 50–75% of patients, hyperlipidaemia in 50–60%, and obstructive sleep apnoea resolves or significantly improves in 70–80%. PCOS symptoms including menstrual irregularity and hirsutism improve markedly with weight reduction. Knee and hip pain from osteoarthritis is substantially reduced, often delaying the need for joint replacement.

The Swedish Obese Subjects study (SOS) — the landmark long-term bariatric study — demonstrated 25–30% reduction in all-cause mortality in bariatric surgery patients versus matched controls at 20 years. Quality of life, mental health, employment status, and sexual function all show significant improvement. Compared to gastric bypass, sleeve offers equivalent weight loss at 5 years with a simpler procedure and no risk of dumping syndrome or malabsorptive deficiencies from intestinal bypass.