In Duodenojejunal Bypass, stomach size is reduced according to the patients weight , in addition first part of small intestine (duodenum) along with 200 cm of the jejunum are bypassed in a rerouting operation. In this surgery 1st part of duodenum is joined with the bypassed portion of the jejunum. This operation has the obvious advantages of Roux-en-Y Gastric Bypass and does not cause significant weight loss and dumping.
This operation has similar hormonal mechanism as ileal interposition. After this operation ghrelin levels come down as the fundus of the stomach is removed. GLP 1 and Peptide YY hormones increase as the food rapidly reaches small intestine. These hormonal changes reduce appetite and increase the energy expenditure.
Ghrelin and anti incretins act against insulin. As the levels of these hormones come down, the efficiency of insulin increases. These changes result in resolution/ remission of diabetes.