Introduction : In laparoscopic liver resection, judgment of conversion to open surgery is required for ensuring safety. We examined the risk factors of complications after laparoscopic liver resection, to decide indication of conversion to open surgery.

Methods : We analyzed the clinical characteristics of 159 cases of laparoscopic liver resection in our institute from 2007 to 2017.

Results : The median age was 68 years old (29-87 years old). The primary disease was 90 cases of hepatocellular carcinoma (56.6%), and 49 cases of colorectal liver metastasis (30.8%). 114 patients (71.7%) underwent partial resection and 23 patients (14.5%) underwent lateral sectionectomy. 12 patients underwent conversion to open surgery (7.5%). There was a 0% mortality rate in the all cases. In the 12 patients with conversion to open surgery, the amount of bleeding was significantly larger (760 ml vs 404 ml, p = 0.031), the operation time also tended to be long (378 min vs 319 min, p = 0.120), and serious complications of Clavien-Dindo classification grade 3 or higher (16.7% vs 2.0%, p = 0.046) was also increased. Univariate analysis for the risk factors of serious complications revealed the conversion to open surgery and operation time. On the operation time and serious complications, the cut-off value of operation time in the ROC curve using the Youden index was 391 minutes, the sensitivity was 80% and the specificity was 75%.

Conclusions : During laparoscopic hepatectomy, we should always keep in mind the conversion to open surgery, especially if it seemed to take more than 6 hours.