The most common mechanism of gallstone ileus formation is migration of a gallstone through the cholecystoduodenal fistula
to remain impacted in the distal ileum lumen and causing an intestinal obstruction (3,4).
The passage of a large gallstone through a cholecystoduodenal fistula and the subsequent impaction in the duodenum causing gastric outlet obstruction are a rare occurrence and this is known as Bouveret syndrome.
All the previous reported cases describe Bouveret syndrome mostly secondary to cholecystoduodenal fistula. Most of the bilioenteric fistulas are associated with cholelithiasis but choledochoduodenal fistulas are unique as they are predominantly attributed to duodenal peptic ulcers (75-80%) and are a rare occurrence [1-3].
There have been three reports of gallbladder pulse granulomas, one in association with a cholecystoduodenal fistula
related to cholecystitis and cholelithiasis  and one with a cholecystogastric fistula with chronic cholecystitis .
Reasons for conversion to open surgery reported in literature include injury to bowel and major blood vessels, bleeding, avulsion of cystic duct, duodenal injury, cholecystoduodenal fistula
, respiratory acidosis, dense adhesions at Calot's triangle, difficult and obscure anatomy, severe inflammation, injury to bile ducts, abnormal intraoperative cholangiogram, unsuspected pathology and equipment failure10.
A cholecystoduodenal fistula
was left intact because the chances of recurrence are very low and the patient did not have residual gallstones.
A case of gallstone ileus displaying spontaneous closure of cholecystoduodenal fistula
In about 50% there is a history of jaundice, either in the past or at presentation, and loose bowel motions may be associated with a cholecystocolonic fistula (7) Severe haemorrhage complicating cholecystoduodenal fistula
has also been reported (7).
Upon relieving the obstruction, a cholecystoduodenal fistula
was palpated and also visualized via the endoscope.
In one patient (2.5%) the procedure was converted to open cholecystectomy (OC) due to finding of cholecystoduodenal fistula
During the operation, the presence of a cholecystoduodenal fistula
was confirmed, and signs of bile duct ischemia were found.
In 2.5% to 14% of cases conversion of LC to OC is needed8-10due to massive bleeding bile duct injuries obscure anatomy bowel injuries and cholecystoduodenal fistula
although surgeons do not consider it a complication.