First described by Rutledge in 1997, this new combined procedure also known as One Anastomosis Gastric Bypass (OAGB) or Single Anastomosis Gastric Bypass (SAGB) or Loop Gastric Bypass (LGB) is based on reducing the size of the stomach and connecting the small gastric pouch to the small bowel at the level of the jejunum approximately 2 meters after the end of the stomach.
In this case a single anastomosis is done between a small long gastric tube (also calibrated on an orogastric tube inserted by the anesthesiologist) and the jejunal part of the small bowel. This will necessitate food consumption in very small quantities. Along with the restrictive part, the ingested amount of food will be diverted from the digestive fluid secretions. This bypass of the food will cause an important reduction of the absorption of nutrients and induce weight loss.
This intervention will achieve an almost similar to slightly better results than the classic RYGB, in term of long term weight loss and resolution of co-morbidities. The post-operative morbidity is less than the RYGB.
The main concern remains in the severity of Dumping syndrome in certain cases and the more important mal-absorptive component can be managed by multiple oral supplementations (especially for Iron). To note that it is the only technique that can be amenable to reversibility in case of excessive weight loss or severe malabsorption.
Single Anastomosis Duodeno-Ileal Bypass (SADI) :
Andrés Sánchez-Pernaute was the first to develop this new procedure in 2007. It is a combined procedure that will join the duodenum to the distal small bowel (SADI). It can be associated to a Sleeve Gastrectomy (SADI-S). The first step of the procedure is a restrictive part, by creating a sleeved stomach (Same technique as the LSG). In a second step a major malabsorptive component is added after dividing the stomach pouch at the level of the duodenum to reconnect it to the distal small bowel at a distance between 2.5 to 3 meters from the ileo-caecal valve. In this case, a single anastomosis is done between a small long gastric tube with the pylorus kept in place and the distal part of the small bowel. This will necessitate food consumption in very small quantities.
Along with the restrictive part, the ingested amount of food will be diverted from the digestive fluid secretions. This bypass of the food will cause an important reduction of the absorption of nutrients and induce weight loss.
Initial reports suggest that the excess weight loss 5 years after a SADI procedure remains comparable to the DS at 90% (compared with 50-70% for the sleeve or bypass).
To note that this procedure can be performed as a single stage procedure for initial morbid obesity or as a Redo procedure for weight recidivism. Long term results in term of weight loss and late complications are still lacking.