Congenital anomaly of low insertion of cystic duct: endoscopic retrograde cholangiopancreatography findings and clinical significance.

Background/aim: Low insertion of cystic duct (LICD) may be problematic during cholecystectomy. This study was performed retrospectively to assess the prevalence of LICD and identify the risk factors of stone recurrence between LICD and non-LICD (NLICD) after removal of stones.

Methods: Between January 1999 and November 2005, 3546 patients received endoscopic retrograde cholangiopancreatography examination for suspicion of biliary tract diseases. The age and sex-matched group with NLICD was enrolled to compare the clinical differences with LICD group. LICD was defined as "the orifice level of the cystic duct being below the low third of the extrahepatic duct." Recurrence was defined as "patients suffering from cholangitis or biliary stones 1 year later after the first intervention."

Results: Of the enrolled 3546 patients (male/female=1821/1725), 191 (5.4%) had LICD. Excluding cases of malignancy, nonbiliary stones, and incomplete data, 122 LICD patients were available. Periampullary diverticula and positive bacterial culture from bile were less common in the LICD group than the NLICD group (P=0.045; P<0.001, respectively). Lower recurrent rate of common bile duct (CBD) stones in the recurrent cases were found in the LICD group compared with the NLICD group (P=0.024; P=0.039, respectively). Univariate analysis revealed that LICD [odds ratio (OR)=0.284; P=0.032] and CBD stones (OR=4.496; P=0.006) were significantly correlated to stone recurrence.

Conclusions: Our study clearly demonstrated the prevalence (5.4%) of LICD in cases with suspicion of biliary tract disease based on endoscopic retrograde cholangiopancreatography. Notably, the strongest predictors, NLICD and CBD stones, appeared to result in the higher stone recurrence.