Gastric bypass is a surgical technique that alters the pathway of food from the stomach to the small bowel. The new pathway creates a smaller pouch of stomach, and diverts food from the first part of the small bowel. It is both a restrictive and malabsorptive form of bariatric surgery. The smaller stomach size restricts the amount of food that can be consumed. This aids satiety (the sensation of being full) and alters the release of gut hormones that control appetite. Through bypassing the first section of small bowel, the procedure also reduces absorption of nutrients and calories.
There are two forms of gastric bypass surgery – Roux-en-Y gastric bypass surgery (RYGB) and single anastomosis gastric bypass, which is also known as Omega-Loop or ‘Mini’ gastric bypass (MGB) surgery. Both procedures are performed through laparoscopic (keyhole) surgery, but there are advantages and disadvantages to each technique that make each suitable for different people.
It’s important for your surgeon to select the weight loss procedure that is most suitable for your individual needs.
What is the difference between a Roux-en-Y Gastric Bypass and a ‘Mini’ Gastric Bypass?
MGB is a newer form of gastric bypass surgery. A long, narrow stomach pouch is formed through surgical stapling and attached to the small bowel. This anastomosis (surgical join) bypasses approximately two metres of small bowel. In comparison, RYGB requires two anastomoses and is a more complicated procedure.
The advantages of a Roux-en-Y Gastric Bypass include:
- Effectiveness: It is one of the most effective weight loss procedures, with patients losing more weight after a gastric bypass than after a gastric band, and equal weight loss to that of sleeve gastrectomy.
- Good results with health complications: Gastric bypass effectively resolves obesity-related health problems including rapid resolution of type 2 diabetes in 80 per cent of patients by the time they are discharged from hospital, long before significant weight loss occurs.
- Good results with reflux: It is the best weight loss option for people with severe pre-existing gastro-oesophageal reflux disease, especially those with Barrett’s oesophagus.
- Long term data: Gastric bypass has a proven track record. It has been the most commonly performed weight loss operation in the United States for last 20 years and long-term results are available.
The disadvantages of a Roux-en-Y Gastric Bypass include:
- Technical complexity: The RYGB is more invasive and complex than a MGB, gastric band or sleeve gastrectomy. It carries a higher risk of post-operative complications and long-term nutritional deficiencies and therefore requires more frequent monitoring to identify and manage complications early.
- Potential for serious side effects: A RYGB carries the risk of developing complications down the track (such as dumping syndrome, peptic ulcers and internal herniation of the bowel), which do not occur after a gastric band or sleeve.
The advantages of a ‘Mini’ Gastric Bypass include:
- Less technical complexity: This theoretically reduces the risk of an anastomosis leak.
- Theoretically reduced risk of internal hernias: As there is a single anastomosis, there is only one potential site for abnormal protrusion (herniation) of bowel.
- Shorter operative time: The single anastomosis technique is faster to perform, and is theoretically easier to reverse or revise if required.
- Safe and effective alternative: Studies comparing MGB to RYGB report that it is an appropriate alternative, and has similar results with weight loss and recovery.
- Good results with type 2 diabetes: Studies have reported that MGB is an effective form of treatment for type 2 diabetes.
The disadvantages of a ‘Mini’ Gastric Bypass include:
- The potential for more serious side effects: The surgical pathway created in MGB permits reflux of bile (digestive juice). This persistent bile reflux can cause ulceration, which leads to concerns about the long term risk of stomach or oesophageal cancer, however long term studies have not yet been performed. Patients with symptomatic bile reflux may also require reversal of their bypass, or to have their MGB converted to a standard RYGB.
- Vitamin and mineral deficiencies: As a larger portion of small bowel is bypassed in MGB, individuals are at greater risk for nutritional deficiencies following surgery.
- Long term data is not available for MGB: as a newer procedure, MGB lacks the breadth of research regarding long term outcomes that RYGB possesses.
Which type of gastric bypass is best for me?
We believe that RYGB surgery is usually the preferred form of bypass surgery for the majority of our patients. RYGB and MGB surgery each result in excellent weight loss, and both procedures are performed at the Surgical Weight Loss Centre. Greater resolution of associated conditions (such as gastro-oesophageal reflux), and a solid track record of long term outcomes support the role of RYGB as our preferred form of gastric bypass. However, MGB is a suitable form of surgery for a certain subset of individuals, such as those who have a higher BMI or Type 2 Diabetes, where gastric sleeve is not as effective.
Dr Jordaan will discuss the advantages and disadvantages of each procedure during his consultation with you, to ensure that the most appropriate form of gastric bypass is performed for your individual needs.