Predicting cholecystocholedochal fistulas in patients with Mirizzi syndrome undergoing endoscopic retrograde cholangiopancreatography

BACKGROUND: Mirizzi syndrome (MS) is defined as an extrinsic compression of the extrahepatic biliary system by an impacted stone in the gallbladder or the cystic duct leading to obstructive jaundice. Endoscopic retrograde cholangiopancreatography (ERCP) could serve diagnostic and therapeutic purposes in patients with MS in addition to revealing the relationships between the cystic duct, the gallbladder, and the common bile duct (CBD). Cholecystectomy is a challenging procedure for a laparoscopic surgeon in patients with MS, and the presence of a cholecystocholedochal fistula renders preoperative diagnosis important during ERCP. AIM: To evaluate cholecystocholedochal fistulas in patients with MS during ERCP before cholecystectomy. METHODS: From 2004 to 2018, all patients diagnosed with MS during ERCP were enrolled in this study. Patients with associated malignancy or those who had already undergone cholecystectomy before ERCP were excluded. In total, 117 patients with MS diagnosed by ERCP were enrolled in this study. Among them, 21 patients with MS had cholecystocholedochal fistulas. MS was further confirmed during cholecystectomy to check if cholecystocholedochal fistulas were present. The clinical data, cholangiography, and endoscopic findings during ERCP were recorded and analyzed. RESULTS: Gallbladder opacification on cholangiography is more frequent in patients with MS complicated by cholecystocholedochal fistulas (P < 0.001). Pus in the CBD and stricture length of the CBD longer than 2 cm were two additional independent factors associated with MS, as demonstrated by multivariate analysis (odds ratio 5.82, P = 0.002; 0.12, P = 0.008, respectively). CONCLUSION: Gall bladder opacification is commonly seen in patients with MS with cholecystocholedochal fistulas during pre-operative ERCP. Additional findings such as pus in the CBD and stricture length of the CBD longer than 2 cm may aid the diagnosis of MS with cholecystocholedochal fistulas.