Felix Krenzien

Background Adherence to enhanced recovery after surgery (ERAS) protocols is crucial for successful liver surgery. The aim of this study was to assess the impact of minimally invasive liver surgery complexity on adherence after implementing an ERAS protocol. Methods Between July 2018 and August 2021, a prospective observational study involving minimally invasive liver surgery patients was conducted. Perioperative treatment followed ERAS guidelines and was recorded in the ERAS interactive audit system. Kruskal–Wallis and ANOVA tests were used for analysis, and pairwise comparisons utilized Wilcoxon rank sum and Welch's t-tests, adjusted using Bonferroni correction. Results A total of 243 patients were enrolled and categorized into four groups based on the Iwate criteria: low (n = 17), intermediate (n = 81), advanced (n = 74) and expert difficulty (n = 71). Complexity correlated with increased overall and major morbidity rate, as well as longer length of stay (all P < 0.001; standardized mean difference = 0.036, 0.451, 0.543 respectively). Adherence to ERAS measures decreased with higher complexity (P < 0.001). Overall adherence was 65.4%. Medical staff-centred adherence was 79.9%, while patient-centred adherence was 38.9% (P < 0.001). Complexity significantly affected patient-centred adherence (P < 0.001; standardized mean difference (SMD) = 0.420), but not medical staff-centred adherence (P = 0.098; SMD = 0.315). Postoperative phase adherence showed major differences among complexity groups (P < 0.001, SMD = 0.376), with mobilization measures adhered to less in higher complexity cases. Conclusion The complexity of minimally invasive liver surgery procedures impacts ERAS protocol adherence for each patient. This can be addressed using complexity-adjusted cut-offs and ‘gradual adherence’ based on the relative proportion of cut-off values achieved.