Gastric sleeve surgery, also known as sleeve gastrectomy, is one of the most commonly performed metabolic and bariatric procedures worldwide and has been the most frequently performed primary bariatric procedure reported in recent Australian bariatric surgery registry data.
The procedure involves removing approximately 75-80% of the stomach, leaving behind a smaller, tube-shaped stomach known as a “sleeve”. By reducing stomach capacity and changing appetite-regulating hormones, sleeve gastrectomy helps patients achieve significant and sustained weight loss.
Unlike gastric bypass procedures, sleeve gastrectomy does not involve bypassing the small intestine. Food continues to follow the normal digestive pathway.
At Metabolic & Bariatric Surgery Australia (MBSA), Dr Mani Niazi provides personalised assessment to determine whether sleeve gastrectomy is the most appropriate treatment option for each patient. The recommended procedure depends on individual factors including medical history, obesity-related conditions, lifestyle, nutritional considerations and long-term health goals.
What Happens During Gastric Sleeve Surgery?
Sleeve gastrectomy is performed under general anaesthesia, usually using laparoscopic (keyhole) surgical techniques.
During the operation:
- Approximately 75-80% of the stomach is removed.
- The remaining stomach is reshaped into a narrow tube or sleeve.
- The removed portion of the stomach is permanently removed and is not reattached.
The procedure does not involve changing the connection between the stomach and intestine. After surgery, food continues to pass through the digestive system in the usual way.
The operation typically takes approximately 60 minutes, although the exact duration may vary depending on individual patient factors.
How Does Gastric Sleeve Surgery Help With Weight Loss?
Sleeve gastrectomy works through several mechanisms.
1. Reduced stomach capacity
The smaller stomach limits the amount of food that can be eaten at one time. Patients generally feel satisfied with smaller meals and are encouraged to develop long-term healthy eating habits.
2. Changes in hunger hormones
The upper part of the stomach (the fundus) produces a significant amount of ghrelin, a hormone involved in hunger regulation.
By removing the fundus, sleeve gastrectomy reduces ghrelin production, which may contribute to:
- reduced hunger
- improved appetite control
- better ability to maintain smaller portion sizes
3. Metabolic effects
Sleeve gastrectomy also affects gut hormones involved in appetite regulation and glucose metabolism. These changes can contribute to improvement in obesity-related conditions such as type 2 diabetes.
What Happens After Gastric Sleeve Surgery?
Following surgery, patients gradually progress through different dietary stages under the guidance of the bariatric team.
The usual progression includes:
- clear fluids initially
- liquid diet
- pureed foods
- soft foods
- gradual return to healthy solid foods
Most patients remain in hospital for approximately one to two nights, depending on their recovery and clinical progress.
Long-term follow-up is an essential part of bariatric surgery care. This includes:
- regular surgical reviews
- nutritional monitoring
- blood tests to assess vitamin and mineral levels
- vitamin and mineral supplementation as required
- dietary and lifestyle support
Although sleeve gastrectomy does not bypass the intestine, nutritional deficiencies can still occur. Lifelong monitoring and appropriate supplementation are important to maintain long-term health.
What Are the Risks of Gastric Sleeve Surgery?
Like all surgical procedures, sleeve gastrectomy carries potential risks.
Possible risks and complications include:
- bleeding
- staple-line leak
- infection
- blood clots
- narrowing or twisting of the sleeve
- gastro-oesophageal reflux disease (GERD)
- nutritional deficiencies
- weight regain over time
The Australian Bariatric Surgery Registry collects outcome data from bariatric procedures performed across Australia and provides important information regarding safety and quality outcomes.
Although serious complications following sleeve gastrectomy are uncommon, individual risks vary depending on factors including:
- age
- BMI
- medical conditions
- smoking status
- previous surgery
- overall health
During your consultation, Dr Niazi will discuss your individual risk profile and the strategies used to optimise safety.
Who Is Suitable for Gastric Sleeve Surgery?
Gastric sleeve surgery may be considered for adults living with clinically significant obesity when appropriate non-surgical treatments have not achieved sufficient or sustainable weight loss.
The decision to proceed with surgery is based on a comprehensive assessment rather than BMI alone.
Factors considered include:
- overall health
- obesity-related medical conditions
- previous weight management attempts
- eating behaviours
- nutritional status
- psychological readiness
- ability to participate in long-term follow-up care
Evidence-Based Eligibility Recommendations
The Australian and New Zealand Metabolic and Obesity Surgery Society (ANZMOSS) supports evidence-based metabolic and bariatric surgery practice in Australia and New Zealand.
ANZMOSS aligns with contemporary international recommendations, including the joint guidelines published by the American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO).
Based on these evidence-based recommendations, metabolic and bariatric surgery may be considered in appropriately selected patients with:
BMI 35 kg/m2 or higher
Metabolic and bariatric surgery is recommended to be considered for individuals with BMI 35 kg/m2 or higher, regardless of whether obesity-related medical conditions are present.
BMI 30-34.9 kg/m2
Surgery may be considered in selected patients, particularly those with metabolic disease such as type 2 diabetes or other obesity-related conditions that have not improved adequately with non-surgical treatment.
BMI thresholds should not be considered in isolation. BMI does not fully account for differences in body composition, fat distribution, ethnicity or individual metabolic risk.
In Australia, eligibility for Medicare-funded surgery may involve additional requirements under the Medicare Benefits Schedule (MBS). Clinical suitability for surgery and Medicare funding eligibility are separate considerations.
How Is Gastric Sleeve Surgery Different From Gastric Bypass?
Both sleeve gastrectomy and gastric bypass are effective metabolic and bariatric procedures, but they work differently.
Sleeve Gastrectomy
Sleeve gastrectomy:
- removes approximately 75-80% of the stomach
- reduces stomach capacity
- changes appetite-regulating hormones
- does not alter intestinal anatomy
Gastric Bypass
Gastric bypass procedures include:
- Roux-en-Y Gastric Bypass (RYGB)
- One Anastomosis Gastric Bypass (OAGB), also known as Mini Gastric Bypass
They:
- create a smaller stomach pouch
- change the pathway food takes through the digestive system
- produce additional hormonal and metabolic effects
The choice between sleeve gastrectomy and gastric bypass depends on individual factors, including:
- gastro-oesophageal reflux symptoms
- type 2 diabetes
- weight loss goals
- nutritional considerations
- previous abdominal surgery
- long-term follow-up requirements
There is no single procedure that is best for every patient.
Does Gastric Sleeve Surgery Require Preparation?
Preparation before surgery helps improve safety and optimise outcomes.
Before surgery, patients usually undergo:
- bariatric surgeon consultation
- nutritional assessment
- medical review
- blood tests
- anaesthetic assessment
- medication review
A pre-operative diet is commonly recommended before surgery. This helps reduce liver size and can make the operation safer.
Patients who smoke are strongly advised to stop smoking before surgery because smoking increases the risk of complications and can impair healing.
Summary
Gastric sleeve surgery is a well-established metabolic and bariatric procedure that permanently reduces stomach size and produces hormonal changes affecting hunger, appetite and metabolism.
The operation is performed laparoscopically under general anaesthesia and usually takes approximately 60 minutes.
For appropriately selected patients, sleeve gastrectomy can result in significant long-term weight loss and improvement in obesity-related medical conditions.
Choosing the most appropriate bariatric procedure requires careful assessment of each patient’s individual circumstances.
At MBSA, Dr Mani Niazi provides evidence-based bariatric care and personalised treatment planning to help patients understand their options and make informed decisions about their health journey.
Frequently Asked Questions
Is gastric sleeve surgery reversible?
No. Sleeve gastrectomy is considered a permanent procedure because the removed portion of the stomach cannot be restored. In selected circumstances, revision surgery or conversion to another bariatric procedure may be considered.
Will I need vitamins after gastric sleeve surgery?
Patients require ongoing nutritional monitoring after surgery. Vitamin and mineral supplementation is commonly recommended, with requirements determined according to individual blood tests and clinical review.
Who qualifies for gastric sleeve surgery in Australia?
Suitability depends on clinical assessment, current evidence-based recommendations, and where applicable, Medicare funding criteria.
Does gastric sleeve surgery cure obesity?
Obesity is a chronic disease. Bariatric surgery is part of a long-term treatment approach and works best when combined with healthy lifestyle changes, medical support and ongoing follow-up.
Do I need a referral to see a bariatric surgeon?
Referral requirements depend on the healthcare pathway and funding arrangements. Patients should discuss this with their GP or bariatric team.
Disclaimer: This article is intended for general informational purposes only. It does not constitute medical advice. Individual outcomes vary. Patients should consult a qualified medical professional before making decisions about surgical or medical treatment.