The anatomy and surgical implications of the middle hepatic artery: a systematic review with meta-analysis

The middle hepatic artery (MHA)-the arterial supply to segment 4-is variably defined and frequently under-reported, despite clear implications for transplantation, hepato-pancreato-biliary surgery, and intra-arterial oncologic therapies. We conducted an evidence-based systematic review and meta-analysis to estimate the prevalence and origins of the MHA and to summarize its surgical relevance.

Following evidence-based anatomy principles and the PRISMA 2020 guidelines, we searched PubMed, Scopus, Web of Science, and Google Scholar. Proportion meta-analyses employed random effects and small-study effects were assessed with DOI plot and LFK index.

Fifteen studies (n = 3,819) were included. The pooled prevalence of an identifiable MHA was 81.15% (95% CI 64.70-93.40). The most common origins were the left hepatic artery (LHA) (47.86%, 95% CI 37.09-58.73) and right hepatic artery (RHA) (43.87%, 95% CI 34.85-53.07). Less frequently, the MHA originated from the common hepatic artery (CHA) (8.99%, 95% CI 0.00-32.68), and rarely from a replaced RHA (0.58%), proper hepatic artery (0.28%), or replaced LHA (0.06%). Across studies, the MHA consistently supplied segment 4; rare extensions to segments 2/3 were reported.

An MHA can be identified in most individuals, usually originating from the LHA or RHA. Due to inconsistent terminology across studies, standardized language distinguishing a hilar MHA from intrahepatic A4 branches is necessary. Routine preoperative arterial mapping and the preservation or reconstruction of the MHA should be considered in liver transplantation, pancreatoduodenectomy, and selective intra-arterial therapies to reduce ischemic and biliary complications.