Risk factors for conversion of laparoscopic cholecystectomy to open surgery associated with the severity characteristics according to the Tokyo guidelines

The aim of this retrospective study was to identify the risk factors associated with the severity characteristics in the Tokyo guidelines for conversion to open surgery in patients with acute cholecystitis (AC) who underwent laparoscopic cholecystectomy. A total of 225 patients were enrolled in the study. The patients were classified into two groups: a conversion group and a no-conversion group. The preoperative characteristics and therapeutic strategy were analyzed as risk factors for conversion to open surgery. The postoperative outcomes were also analyzed. Conversion to open surgery occurred in 29 patients (12.9 %), including seven patients (6.7 %) with mild AC and 22 patients (18.5 %) with moderate AC. A univariate analysis showed that the risk factors for conversion to open surgery included a duration of symptoms longer than 72 h, an elevated C-reactive protein (CRP) value and the Tokyo guidelines 2013 (TG 13) severity classification. The multivariate analysis showed that the risk factors for conversion to open surgery included a duration of symptoms longer than 72 h and a CRP value > 11.5 mg/dl. A duration of symptoms longer than 72 h, which is included in the criterion for moderate AC severity in the TG 13, was an independent risk factor for conversion to open surgery. In addition, adoption of a high CRP value as an additional criterion for moderate AC may increase the utility of the TG 13.