In 1881, Dr. Theodore Billroth performed the first successful gastrectomy for pyloric tumor. He removed the distal part of the stomach and tumor of the pyloric region and reconnected the distal end of the transected stomach directly to the segment of the duodenum. This was later renamed as Billroth I procedure. In Billroth I the anastomosis allows the food pathway to stay in the same directional flow with the exception of pyloric valve having been removed. There is, however, increased incidence of bile reflux with the pyloric value removal.

There are incidences where the resected segment is so large that the proximal stomach and the distal duodenal can not be mobilized and brought close to each other to be able to create the Billroth-I anastomosis. Larger resection, where the Billroth I could not be completed Dr. Billroth in 1885 created a procedure call the Billroth II. The Billroth II was performed when the tumor was very large and the continuity of the GI track was created by a loop gastrojejunostomy. This procedure was named Billroth II.

In the Billroth II the bile flow from the small bowel flows toward the stomach, and this results in a much higher incidence of Bile reflux and its associated complication.

The lesson learned from Billroth I and Billroth II was that bile reflux can be a significant problem when creating the continuity of the proximal GI track with exclusion of the pyloric valve. In Bilroth II, there is the additional burden of the bile flowing toward the stomach unlike the Billroth I.

The SADI or SIPS, Loop procedures that are incorrectly promoted as “duodenal switch” employ a loop anastomosis, which results in a biliary flow toward the post pyloric duodenum significantly increasing the chance and the possible incidence of Bile reflux.

All these unknowns about the SIPS, SADI Loop are yet to be investigated.