Conditional cumulative incidence of postoperative complications stratified by complexity classification for laparoscopic liver resection: Optimization of in-hospital observation

Background: The optimal in-hospital observation periods associated with minimal risks of complications and unplanned readmission after laparoscopic liver resection are unknown. The purpose of this study was to assess changes in the risks of postoperative complications over time. Methods: Surgical complexity of laparoscopic liver resection was stratified into grades I (low complexity), II (intermediate), and III (high) using our 3-level complexity classification. The cumulative incidence rate and conditional probability of postoperative complication and risk factors for complication Clavien-Dindo grade ≥II (defined as treatment-requiring complications) were assessed. Results: The cumulative incidence of treatment-requiring complications was higher in patients undergoing grade III resection than in patients undergoing grade I resection (32.3% vs 10.4%, P < .001) and grade II resection (32.3% vs 20.7%, P = .019). The conditional probability of postoperative complication stratified by our complexity classification decreased over time and was <10% for patients undergoing grade I resection on postoperative day 1, grade II resection on postoperative day 4, and grade III resection on postoperative day 10. Conclusion: The conditional cumulative incidence of treatment-requiring complications for patients undergoing laparoscopic liver resection is well stratified based on the 3-level complexity classification. Conditional complication risk analysis stratified by the 3 complexity grades may be useful for optimizing in-hospital observation after laparoscopic liver resection.