BACKGROUND: While commonly used to describe liver resections at risk for post-operative complications, no standard definition of 'major hepatectomy' exists. The objective of the present retrospective study is to specify the extent of hepatic resection that should describe a major hepatectomy. METHODS: Demographics, diagnoses, surgical treatments and outcomes from patients who underwent a liver resection at two high-volume centres were reviewed. RESULTS: From 2002 to 2009, 1670 patients underwent a hepatic resection. Post-operative mortality and severe, overall and hepatic-related morbidity occurred in 4.4%, 29.7%, 41.6% and 19.3% of all patients. Mortality (7.4% vs. 2.7% vs. 2.6%) and severe (36.7% vs. 24.7% vs. 24.1%), overall (49.3% vs. 40.6% vs. 35.9%) and hepatic-related (25.6% vs. 16.4% vs. 15.2%) morbidity were more common after resection of four or more liver segments compared with after three or after two or fewer segments (all P < 0.001). There were no significant differences in any post-operative outcome after resection of three and two or fewer segments (all P > 0.05). On multivariable analysis, resection of four or more liver segments was independently associated with post-operative mortality and severe, overall, and hepatic-related morbidity (all P < 0.01). CONCLUSIONS: A major hepatectomy should be defined as resection of four or more liver segments.
