BackgroundThe main surgical procedure for Bismuth‒Corlette III–IV hilar cholangiocarcinoma (HCCA) is hemihepatectomy/extended hemihepatectomy. However, many patients have no opportunity for surgery due to having an insufficient remnant liver volume. Preservation of more liver volume on the premise of ensuring R0 resection is the goal. Mesohepatectomy with caudate lobectomy may be a new method to meet these requirements.MethodsThe clinical data of 41 patients with Bismuth‒Corlette III–IV HCCA, including 18 patients who underwent mesohepatectomy with caudate lobectomy (the mesohepatectomy group) and 23 patients who underwent hemihepatectomy or extended hemihepatectomy (the hemihepatectomy group), were analyzed retrospectively. The perioperative indicators and prognostic survival time between the two groups were analyzed.ResultsThe mesohepatectomy group was compared with the hemihepatectomy group, and the operation time was 7.95 ± 1.2 vs. 7.15 ± 1.5 h (P> 0.05); the intraoperative blood loss was 600.0 ± 153.4 vs. 846.1 ± 366.8 mL (P< 0.05); the postoperative hospital stay was 9.9 ± 2.2 vs. 13.8 ± 3.0 days (P< 0.05); and the R0 resection rate was 100% vs. 87.0% (P> 0.05). The postoperative complications of the two groups included bile leakage (22.2% vs. 21.7%), pleural effusion (11.1% vs. 8.7%), and fever (16.7% vs. 8.7%), with no significant differences in the incidences (P> 0.05). The 1-, 3-, and 5-year survival rates of the two groups were 87.5%, 55.7%, 27.8% and 83.5%, 56.1%, 24.5%, respectively, with no significant differences (P> 0.05).ConclusionsMesohepatectomy with caudate lobectomy can preserve more functional liver volume while ensuring the bile duct margin. It can be applied as the surgical treatment of Bismuth‒Corlette III–IV HCCA.