Navigating Complexity in Liver Resection: A Narrative Review of Factors Influencing Intraoperative Difficulty.

Background: Liver resection remains the cornerstone for curative management in primary liver malignancies. Liver surgery ranges from simple wedge resections to complex hepatectomies involving vascular or biliary reconstructions. The anatomical complexity of the liver and these varied surgical approaches create challenges in assessing operative difficulty. This literature review explores the key factors influencing operative difficulty in liver resection for primary liver malignancy across surgical techniques. Methods: A broad literature review was conducted to determine the factors that were associated with increased operative difficulty in liver resection using the Embase, PubMed, and Cochrane databases for studies published between 2000 and 2025. Results: This review identifies several patient, tumor, and surgical factors that influence operative difficulty in liver resection. Numerous difficult scoring systems were identified, yet their applicability across different operative approaches remains uncertain. Across open and minimally invasive techniques, tumor size and location are commonly used to determine complexity. However, debate remains regarding the optimal cutoff for tumor diameter. Other identified factors include the extent of resection, patient-specific variables (e.g., cirrhosis, body mass index, previous surgeries), and surgical technique. In addition, liver resection procedures classified based on the 2000 Brisbane terminology have been stratified into three groups of increasing difficulty. Conclusion: The ability to predict operative difficulty is useful for case selection, surgical planning, and risk stratification for meaningful shared decision-making. Future research should focus on refining predictive models by integrating composite measures, including patient-reported outcomes and long-term survival. A unified, validated scoring system applicable across surgical techniques could enhance consistency in clinical practice and research to improve outcomes.