Obesity & Weight Loss Surgery / Bariatric Surgery

What types of bariatric surgery can be performed?

There are three bariatric procedures commonly performed in Australia: the adjustable gastric band (AGB), the roux-en-Y gastric bypass (RYGBP), and the sleeve gastrectomy (SG).  These procedures are generally performed laparoscopically, although open surgery is sometimes used in the revisional setting.  All three operations act primarily by restricting the volume that can be eaten.  Primarily malabsorptive operations, such as the bilio-pancreatic diversion, have been associated with significant morbidity and mortality and are not routinely performed in this country.  The vertical banded gastroplasty (“stomach stapling”) is now obsolete.

Laparoscopic SG is a relatively new procedure.  It originated as the first stage of a two stage procedure in the super-obese, but is now increasingly performed as a definitive bariatric operation.  It is the only non-reversible bariatric operation: it involves removal of the greater curvature of the stomach leaving a narrow gastric tube.  The fundus of the stomach is the primary site for ghrelin secretion.  Ghrelin is the only identified orexigenic hormone (“hunger hormone”) and SG has been shown to lead to sustained reduction in ghrelin levels and reduced hunger compared to other bariatric operations.  Karamanakos et al enlisted 32 patients in a double blind RCT comparing SG with RYGBP and found better weight loss in the SG group at one year (70% vs 60%).  Himpens et al compared SG with AGB (80 patients) and found better weight loss at three years (66% vs 48%).  The long term results of the SG are yet to be published: gastric reflux and dilatation of the sleeve have been reported, and the incidence of weight regain is not yet known.  The SG sits between the AGB and RYGBP in terms of operative morbidity: anastomotic leak from the long gastric staple line has been reported in up to 1% of cases, however there is no potential for procedure-related complications once convalescence is complete (cf. RYGBP where there is up to a 5% lifetime incidence of internal hernia requiring re-operation).  This may make the SG an appropriate choice for people living remotely.

The RYGBP is the most established bariatric procedure; gastric bypass for weight loss has been performed since the 1960s.  Predicted weight loss averages 65% EBW, mostly by 18 months post-op and there is a sustained reduction of 30% of total body-weight at 10 years. This sophisticated procedure combines two powerful weight loss mechanisms: restriction and malabsorption. During the surgery, your surgeon creates a small stomach pouch about the size of an egg, which dramatically limits the amount of food you can eat at one time. The small intestine is then rearranged in a distinctive Y-shaped configuration, bypassing the lower portion of your stomach and the first section of your small intestine (duodenum). This rerouting means that food travels directly from your new small stomach pouch into the middle section of your small intestine, reducing the absorption of calories and nutrients.

While the primary effect of surgery is to restrict the volume of food eaten, undigested food entering the roux limb can lead to a dumping syndrome which acts as a deterrent to over-eating calorie rich foods. Bypass of the proximal small bowel leads to a reduction in putative diabetogenic factors which leads to rapid resolution of type two diabetes, even before significant weight-loss occurs.  Remission of diabetes is seen in 75-95% of patients.

The complications of surgery (anastomotic leak, stomal ulceration, internal hernia) are potentially life threatening.  Nutritional sequelae such as iron deficiency, vitamin B12 deficiency, osteoporosis and gallstone formation occur with greater frequency than with the AGB, and mandate careful follow-up.

The Mini Gastric Bypass (MGB), also known as One Anastomosis Gastric Bypass (OAGB), is a modern bariatric procedure that offers the benefits of traditional gastric bypass surgery through a simplified, streamlined approach. This innovative technique combines both restrictive and malabsorptive mechanisms to achieve significant weight loss, but does so with fewer surgical connections than the traditional Roux en Y procedure.

During MGB surgery, your surgeon creates a long, narrow stomach pouch by dividing the stomach lengthwise, leaving you with a tube-shaped stomach approximately the size of a banana. This new stomach pouch is then connected directly to the small intestine approximately 150-200 centimeters (about 6 feet) from its beginning, bypassing a significant portion of the small intestine where calories and nutrients are normally absorbed.

The "mini" designation comes from the procedure's simplified design, requiring only one surgical connection (anastomosis) compared to the two connections needed in traditional Roux en Y surgery. This streamlined approach often results in shorter operative times and potentially fewer complications, while still delivering excellent weight loss results. The procedure has gained significant popularity worldwide and is now recognized as a safe and effective alternative to more complex bariatric surgeries.

Single Anastomosis Duodenal-Ileal Interposition (SADI) is an innovative and powerful bariatric procedure that represents the newest advancement in weight loss surgery. This sophisticated technique combines the restrictive benefits of a sleeve gastrectomy with the malabsorptive advantages of intestinal bypass, creating one of the most effective surgical options available for patients with severe obesity or complex metabolic conditions.

The SADI procedure is performed in two distinct components. First, your surgeon performs a sleeve gastrectomy, removing approximately 80% of your stomach to create a narrow, banana-shaped stomach sleeve that restricts food intake. Second, the surgeon creates a single connection (anastomosis) between the first part of your small intestine (duodenum) and the final portion of your small intestine (ileum), bypassing the majority of the small intestine where nutrient absorption typically occurs.