Proper bile duct flow, rather than radical excision, is the most critical factor determining treatment outcomes of bile duct cysts

BACKGROUND: The purpose of this study was to compare the impact of the extent of excision and the patent bile duct flow on treatment outcomes of bile duct cysts (BDCs). METHODS: We retrospectively analyzed the records of 382 patients who received surgery for BDCs from January 2005 to December 2014. RESULTS: For Type Ia cysts, proper bile flow was associated with good long-term treatment outcomes with a greater level of significance (p < 0.001) than complete excision (p = 0.012). For Type IVa cysts, proper bile flow, but not complete excision, was associated with good long-term outcomes (p < 0.00001). In addition, 96.3% (104/108) of Type IVa patients with proper bile flow had no late complications and good biliary function, while no patient without patent bile flow had a good clinical outcome. For Type Ic cysts, 92 patients who received partial excisions had good outcomes when proper bile flow was restored. Regression analysis revealed that the absence of proper bile flow, in comparison to incomplete excision, is a greater risk factor for poor long-term treatment effects for Type Ia and Type IVa cysts. CONCLUSIONS: Compared to complete excision, the establishment of proper bile flow exerted a greater impact on improving long-term clinical outcomes after BDC surgery. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12876-018-0862-3) contains supplementary material, which is available to authorized users.