Definitions and surgical technique
Definitions were adopted from the Brisbane 2000 Guidelines for liver anatomy[16]. Resection of ≥3 segments was defined as major resection. The Clavien–Dindo classification was used to grade postoperative complications[17]. Major complications were defined as ≥class 3 complications. The definition of bile leakage and post-hepatectomy liver failure was adopted from the International Study Group of Liver Surgery[18, 19]. The favorable tumor locations were defined as segments S2, S3, S4b, S5, and S6 and the unfavorable tumor locations were defined as segments S1, S4a, S7, and S8. The surgical technique of OH and LH was mentioned in our previous study[9].