This blog provides free general information for anyone who is seeking to understand more about the laparoscopic SADI-S operation, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.

Please note I don’t wish to perform the SADI-S operations in order to avoid long term nutritional and other complications. This blog is for patient information and education purposes only.






In the past there had been many names to describe a similar procedure, as listed below. The SADI-S is probably the preferred term for now.


Single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S)

Stomach intestinal pylorus preserving surgery (SIPS)

One or Single anastomosis loop duodenal switch (OADS, SALDS)

Single anastomosis duodenal switch (SADS)

Single anastomosis duodeno-ileal switch (SADIS)

Single anastomosis duodenal-jejunal bypass with sleeve gastrectomy (SADJB-SG)


Nowadays most people refer to this procedure as SADI-S or the SIPS, which has a single anastomosis and a common channel small intestine length of 300cm.


This is not the same as the bilio-pancreatic diversion or duodenal switch, which has a double anastomosis similar to the Roux Y reconstruction.



Bilio-pancreatic diversion duodenal switch (BPD-DS)


In 1979 Scopinaro described the bilio-pancreatic bypass (BPD) as a surgical treatment of obesity.

In 1987 DeMeester proposed the idea for a duodenal switch.

Traverso and Longmire then reported on the benefits of a pylorus preserving procedure.

In 1989 Hess and Marceau adapted the pylorus preserving procedure to the biliopancreatic diversion procedure.


The BPD-DS has been around for a long time.

  • This procedure have the highest weight loss result (>75% EWL) and superior resolution rate for obesity related medical co-morbidities (especially Type 2 diabetes mellitus) compared to the sleeve gastrectomy and Roux Y gastric bypass.
  • However, this procedure is being performed by a very small number of surgeons in Australia because of the technical difficulties, complexities of the anatomy and physiology disruptions, its nutritional side effects and potential long term complications of the surgery.


The main problem with the BPD-DS was the risk for serious malabsorption.

  • Symptoms include dumping, diarrhoea, steatorrhoea, smelly stools, flatulence, protein calorie malnutrition and vitamin deficiencies.

Nowadays there is a new simplified version of duodenal switch called the stomach intestinal pylorus sparing (SIPS) or the single anastomosis duodeno-ileal anastomosis with sleeve gastrectomy (SADI-S).

There may be slightly more weight loss (not statistically significant) with the older version of the BPD-DS but the patient satisfaction rates may be better with the SADI-S.



SADI was introduced in 2007 by Sánchez-Pernaute and Torres (from Spain).


In brief this is:

  • A sleeve gastrectomy (performed over a 54 French bougie)
  • A duodeno-ileal anastomosis (Billroth 2 omega loop anastomosis instead of a Roux Y anastomosis) with a 200-250 cm common channel.


The single loop anastomosis was done to reduce the risk of internal hernia and small bowel obstruction as a result of the second anastomosis.


Overtime other surgeons have modified this procedure to create a more narrow sleeve gastrectomy (performed over a 40Fr bougie) and a common cannel of at least 300cm.

  • This was done to reduce the risk for malabsorption (which is reported to be less than 1%).


SADI-S may have similar weight loss outcomes similar to the BPD-DS.

  • There may be no statistical significant differences in weight loss between the two procedures.
  • The advantage is that SADI-S is technically easier to do with just one duodenal-jejunal anastomosis (less anatomical complications) and may have less malabsorption side effects (macronutrient and micronutrient deficiencies or physiological complications).



The 3 malabsorption type bariatric procedures:



The common channel is 100-150cm (measured from the ileo-caecal valve).

The sleeve gastrectomy was created with a 40Fr bougie 5cm proximal to the gastric antrum to the angle of His.

Duodenal transection 3cm distal to the antrum.

The Roux limb is 150c and is anastomosed to the duodenal stump.



The common channel is about 300cm.

Some surgeons now perform the sleeve gastrectomy with a 40Fr bougie.



The common channel is 300cm (measured from the ileo-caecal valve).

The remnant stomach is excluded (does not resected, in other words the sleeve gastrectomy is not performed).

(If the SAGI is done as a revision procedure after a sleeve gastrectomy, then obviously there is no remnant stomach or sump syndrome).

Unlike the SADI or SIPS, there is no pylorus preservation proximal to the small bowel anastomosis.


The SAGI or SASI is very similar to the one anastomosis anastomosis or mini gastric bypass (SAGB or MGB).

  • Strictly speaking SAGI is different to the SADI or SIPS because there is no sleeve gastrectomy tube and there is no pylorus sphincter to control the passage of food into the small intestine.
  • The SAGI is more like a one anastomosis gastric bypass with a shorter common channel (300cm proximal from the ileo-caecal junction instead of 150-200cm distal to the duodeno-jejunal flexure).




Rationale for selecting the SADI-S instead of Roux Y gastric bypass


This procedure is an alternative to the sleeve gastrectomy (LSG) or Roux Y gastric bypass (RYGBP) especially for patients in the super morbid obesity range (BMI>50 or 60 or higher).


The American Society of Metabolic and Bariatric Surgery (ASMBS) have stated (in 2016) that there are not enough randomized trials to confirm the safety, efficacy and durability of the SADI-S compared to the BPD-DS. At this stage this is regarded as an investigational procedure. This may or may not change in the future.


The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) (2018) supports the SADI/SIPS as a recognized bariatric/metabolic surgery but also encourage more research into this area.


In Australia this procedure may not be the first option for most patients but may be an option as a revisional procedure after a sleeve gastrectomy.

  • The LSG provides excellent mid and long term results for weight loss and resolution of co-morbidities for the majority of obese patients. But there may be some with inadequate weight loss or weight regain, who may require an unplanned revision procedure to a RYGBP or SADI-S.


SADI -S offers comparable weight loss result and significantly better resolution for T2DM than the RYGBP. The nutritional side effects may or may not not be worse than the RYGBP.



The advantage of a SADI-S over a RYGBP include:

  • Avoiding the problems usually associated with the second anastomosis, such as internal hernia, small bowel obstruction
  • Avoiding marginal/stomal ulcers
  • Less risk for rapid gastric emptying or early dumping with the pylorus preservation


When a 300cm common channel length is utilized for the SADI-S, less malabsorption complications is noted:

  • Less diarrhoea or steatorrhoea
  • Less smelly/offensive stools
  • Less micronutrient, vitamins/mineral deficiencies
  • Less protein calorie malnutrition (which occurred when <200-250cm of the common channel was created with the DS operations)



SADI versus BPD-DS


SADI-S does not seem to have uncontrolled malnutrition when compared to the BPD-DS (which may have 12% of chronic diarrhoea). The malnutrition fears for the SADI/SIPS may not eventuate.


The T2DM resolution rates may be similar with these two operations as well.


The SADI-S may have a small risk for bile reflux.



SADI after a sleeve gastrectomy


The sleeve was originally described as staged procedure before a DS in 1991 before it became popular as a stand alone procedure.


Logically the SADI-S may be a suitable option as a second stage procedure for inadequate weight loss or weight recidivism after a sleeve gastrectomy, which has less technical issues compared to the BPD-DS and possibly less post op complications.





Weight loss results


SADI-S have up to 95% EWL after 2 years. The resolution rate for T2DM and HPT is around 75 to 95% respectively.


It has comparable weight loss result to that of a RYGBP and is superior to the LSG. At the present time (2018) IFSO supports the SADI-S but there are insufficient trials comparing it to the standard BPD-DS to confirm SADI-S long term safety and efficacy.


Post op complications


Post op complications include staple line leak, bleeding, ileus, internal hernia, small bowel obstruction and micronutrient deficiencies.


Nutritional deficiencies include deficiencies in the fat soluble vitamins (vitamin A, D, E, K), hypocalcemia, secondary hyperparathyroidism, iron, zinc and selenium. Protein deficiencies may occur in up to 30% of patients. Long term follow up of patients are absolutely critical. Some of the older surgeries (BPD_DS) have to be reversed.


Compared to the OAGB and RYGBP, there is much less incidence of anastomotic stricture or marginal ulcers.






Severe protein malnutrition


Severe protein malnutrition is rare after bariatric surgery, accounts for <1% of patients admitted to hospital per year


Protein malnutrition is estimated to occur in:

  • 0-2% after a sleeve gastrectomy
  • <5% after proximal RYGBP
  • <13-15% after distal RYGBP
  • 3-18% after BPD
  • <23-25% after SADI



This may be suspected if the serum albumin is less than 25g/L

  • Albumin 30-35g/L usually indicate mild protein deficiency
  • 25-30g/L is moderate protein deficiency
  • <25g/L is severe hyopoalbuminaemia
    • This may lead to general weakness, oedema, multi-organ failure and death


Apart from aggressive malabsorption type surgery, the risk for protein malnutrition is increased:

  • Reduced protein intake
  • Protein intolerance
  • Gastro-intestinal problems and malabsorption


Treatment sometimes requires re-admission to hospital for proper feeding, which may include:

  • Oral protein rich supplements and pancreatic enzyme supplements
  • Naso-jejunal tube feeding with medium chain triglycerides, enriched amino acids and pancreatic enzyme supplements
  • Parenteral or TPN feeds


The dietician will need to be involved

  • Calorie requirements is calculated using the Harris-Benedict formula
  • Protein requirements is higher than usual, should be around 1/5g/kg ideal body weight (based on a BMI of 25)
  • Obviously vitamin and mineral deficiencies need to be corrected as well