Postoperative collections after liver surgery: Risk factors and impact on long-term outcomes.

Introduction: Postoperative collection (PC) can occur after liver surgery, but little is known on their impact on short and long-term outcomes. The aim of this study was to analyse factors predicting the occurrence of PC, the need of drainage and their impact on oncologic outcomes.

Methods: This single-center, cohort-study included adult patients undergoing liver surgery between 2008 and 2017. The primary objective was to determine variables associated with PC occurrence defined by fluid collection on postoperative day-7 CT scan. Secondary objectives were factors predicting drainage requirement, and predictors of overall survival.

Results: During the study period 395 patients were included: 53.6% of them (n=210) developed a PC with 12% (n=49) requiring drainage. Variables associated to the occurrence of PC were body mass index>35kg/m (OR 8.09, 95%CI (1.50,43.60) P=0.015) and extension of liver surgery (major vs. minor, OR 1.96, 95% CI (1.05,3.64) P<0.034) while laparoscopic approach was associated to a protective role (OR 0.35, 95%CI (0.18,0.67) P=0.001) in the multivariate analysis. The presence of a PC requiring treatment was associated to long-term mortality (OR:1.85, 95% CI (1.15, 2.97) P<0.01) in patients with malignant disease.

Conclusions: Patients undergoing to major open liver surgery with BMI>35kg/m have an increased risk to develop a PC: this target population need a systematic imaging in the postoperative period, even if the indication for drainage should be guided by clinical symptoms. Last, the presence of PC requiring treatment has a negative impact on overall survival among patients treated for malignant disease.