Validation of a difficulty scoring system for laparoscopic liver resection in hepatolithiasis

Background A difficulty scoring system (DSS) based on the extent of liver resection, tumor location, liver function, tumor size, and tumor proximity to major vessels was previously developed to assess the difficulty of laparoscopic liver resection (LLR). Recently, we proposed a modified DSS for patients who undergo LLR for intrahepatic duct (IHD) stones. In this study, we validated the modified DSS for LLR for IHD stones. Methods We reviewed the clinical data of 121 patients who underwent LLR for IHD stones between July 2003 and November 2015 and validated the modified DSS in patients who underwent LLR according to their surgical outcomes. We divided the patients into subgroups according to their scores and compared the surgical outcomes, including hospital stay, operation time, blood loss, transfusion rate, and the postoperative complication rate and grade, among the subgroups of patients. Results The DSS score ranged from 3 to 12 in LLR for IHD stones. The operation time (P < 0.001) significantly increased according to the DSS score. The median hospital stay after surgery (P = 0.024) and transfusion rate (P = 0.001) were significantly different among subgroups of patients divided by their difficulty scores. When we divided the patients into two groups based on the side of liver of resected, the operation time (P < 0.001), mean difficulty score (P < 0.001), and blood loss (P = 0.041) were greater in patients who underwent right liver resection. Conclusions The surgical difficulty varies among patients undergoing the same LLR procedure for IHD stones. The modified DSS for IHD stones can effectively predict the surgery outcomes and complications of LLR.