Modern laparoscopic theatres
Mini gastric bypass surgery, also known as one-anastomosis gastric bypass (OAGB), is a type of bariatric surgery that reduces the size of the stomach and reroutes part of the small intestine using a single surgical connection. Compared with a traditional Roux-en-Y gastric bypass, the procedure involves a single anastomosis rather than two.
At OptiWeight, mini gastric bypass surgery is considered as part of a multidisciplinary approach to weight management. Specialist general surgeon Dr Ashok Gunawardene will assess your medical history, overall health and treatment goals to determine whether the procedure may be appropriate for your circumstances. He will also explain how mini gastric bypass compares with other bariatric procedures, including gastric sleeve surgery and Roux-en-Y gastric bypass, to support informed decision-making.
A mini gastric bypass changes the digestive system in two ways. First, a long, narrow stomach pouch is created to reduce the amount of food the stomach can hold. The pouch is then joined directly to a loop of the small intestine using a single connection (anastomosis), allowing food to bypass part of the stomach and a section of the small intestine.
Unlike a traditional Roux-en-Y gastric bypass, which involves two surgical connections, a mini gastric bypass uses one. The procedure is typically performed using keyhole (laparoscopic) surgery.
By reducing stomach capacity and changing the digestive pathway, a mini gastric bypass may affect how much food a person can comfortably eat, influence appetite-related signals and alter the absorption of some nutrients.
Mini gastric bypass involves significant and generally permanent changes to the digestive system. Whether it is appropriate depends on an individual assessment of your health, weight management history, treatment goals and clinical needs. It should be considered as part of a broader, medically supervised weight management plan.
When clinically appropriate and combined with ongoing lifestyle changes and follow-up care, mini gastric bypass surgery may offer benefits for some people. Depending on your individual health and circumstances, these may include:
Outcomes vary between individuals and depend on factors such as your overall health, starting weight, and long-term adherence to dietary, lifestyle, and follow-up recommendations. During your consultation, Dr Ashok will discuss the potential benefits, risks and limitations of the procedure based on your individual circumstances.
Mini gastric bypass surgery is not suitable for everyone. Suitability is determined through an individual clinical assessment. As a general guide, the procedure may be considered for adults who:
Mini gastric bypass may not be appropriate for everyone. Factors such as reflux symptoms, previous abdominal surgery, medical history and overall health are considered when assessing suitability. A consultation with Dr Ashok will determine whether the procedure may be appropriate for your individual circumstances.
The cost of mini gastric bypass surgery varies depending on your individual circumstances and whether you have private health insurance. For self-funded patients, an all-inclusive laparoscopic mini gastric bypass typically starts from approximately $25,000 and may include hospital, theatre, accommodation, consumables, surgeon, assistant surgeon and anaesthetist fees.
If you have appropriate private health insurance, some hospital and theatre costs may be covered by your health fund, which may reduce your out-of-pocket expenses. Medicare and private health fund rebates may also be available for eligible patients.
Following your consultation, the OptiWeight team will provide a personalised, itemised estimate outlining the expected costs of your treatment. If you have any questions about consultation fees, procedure costs, rebates or payment options, our team will be happy to discuss these with you.
Your care begins with a comprehensive consultation with Dr Ashok. He will assess your medical history, weight management history, overall health and weight-related conditions to determine whether mini gastric bypass surgery may be appropriate for your circumstances.
The consultation will also cover the potential benefits, risks, limitations and recovery considerations, along with how mini gastric bypass compares with other bariatric procedures, including gastric sleeve surgery and Roux-en-Y gastric bypass.
Before surgery, further investigations may be recommended to help assess your suitability and plan your care. Depending on your medical history and symptoms, these may include a gastroscopy, a sleep study, an echocardiogram, or oesophageal manometry. Reflux symptoms are also carefully assessed when considering a mini gastric bypass.
You will also meet with an OptiWeight bariatric dietitian, who will provide guidance on nutrition, eating behaviours and the pre-operative liver-reducing diet.
If mini gastric bypass surgery is appropriate and you decide to proceed, the procedure will be performed by Dr Ashok at Northern Private Hospital in Epping or St Vincent’s Private Hospital in Werribee. Surgery is performed under general anaesthesia using laparoscopic (keyhole) techniques where clinically appropriate.
During the procedure, a long, narrow stomach pouch is created and joined to the small intestine using a single surgical connection (anastomosis). Most patients stay in the hospital for approximately 2 to 3 nights, though this may vary. Before surgery, you will receive information about the procedure, including the potential risks, expected recovery and follow-up care.
Recovery includes a staged return to eating, beginning with liquids, progressing to soft foods, and then to a more regular diet, as guided by your care team.
As a mini gastric bypass changes how your body absorbs nutrients, lifelong vitamin and mineral supplementation, regular blood tests and ongoing clinical follow-up are required to help maintain your nutritional health. Dr Ashok typically reviews patients at 2 weeks, 6 weeks, 12 weeks, 6 months, and 12 months after surgery, followed by ongoing reviews as clinically appropriate.
Mini gastric bypass is a major surgical procedure and, like all surgery, carries potential risks and complications. These may include:
This is not a complete list of potential risks and complications. Dr Ashok will discuss the risks, expected benefits and alternative treatment options relevant to your individual circumstances before you decide whether to proceed with surgery.
FRACS
MBChB Hons
GESA
PhD
ANZMOSS
Dr Ashok Gunawardene is a registered specialist general surgeon with subspecialist training in upper gastrointestinal and weight loss surgery. With over 15 years of clinical experience across the United Kingdom, New Zealand and Australia, he brings a considered, evidence-informed approach to weight management care.
As Director of OptiWeight, Dr Ashok supports patients through both surgical and non-surgical treatment pathways, helping them understand their options and make informed decisions about their health. His approach focuses on ensuring patients feel supported, informed and respected throughout their care.
“My approach is simple: I want every patient to feel safe, supported, and never rushed. Surgery is a tool – your long-term health is the goal.”
Considering mini gastric bypass surgery is a significant decision. A private consultation with Dr Ashok Gunawardene allows you to ask questions, discuss your health history and understand whether a mini gastric bypass may be appropriate for your circumstances. Dr Ashok will explain the potential benefits, risks, alternatives and follow-up requirements before any treatment pathway is planned.
A mini gastric bypass surgery is a major surgical procedure and, like all surgeries, carries potential risks and complications. These may include bleeding, infection, blood clots, reactions to anaesthesia, leakage, bile reflux, bowel obstruction, vitamin and mineral deficiencies, and the need for further treatment or surgery. During your consultation, Dr Ashok will discuss the potential risks and whether the procedure may be appropriate for your individual circumstances.
Gastric sleeve surgery reduces the size of the stomach, while a mini gastric bypass surgery also alters the digestive pathway by connecting the stomach pouch to the small intestine. Both procedures are used in bariatric surgery, but they differ in how they work, their potential benefits and risks, and their long-term nutritional considerations. The most appropriate procedure depends on your medical history, weight-related health conditions and treatment goals.
Yes, as mini gastric bypass surgery changes how some nutrients are absorbed, long-term vitamin and mineral supplementation is generally recommended. Regular follow-up appointments and blood tests are also important for monitoring your nutritional status and identifying any deficiencies that may require treatment.
A mini gastric bypass surgery is generally considered a permanent procedure. In some circumstances, it may be revised or converted to another bariatric procedure if clinically indicated, though this may involve further surgery. Your surgeon can discuss whether this is appropriate for your individual circumstances.
For some people, mini gastric bypass surgery may contribute to improvement in type 2 diabetes and other weight-related health conditions associated with excess weight. Outcomes vary between individuals and depend on a range of factors. During your consultation, Dr Ashok will discuss the potential benefits, risks and limitations based on your individual health.
This page is general information only and is not a substitute for personalised medical advice. Weight loss surgery is a significant decision with benefits and risks that differ for each person. Outcomes vary and cannot be guaranteed. Please consult Dr Ashok Gunawardene or your GP to discuss whether a procedure is appropriate for your individual circumstances.
