Risk-adjusted cumulative sum (RA-CUSUM) method for real time monitoring of surgical units performance.

BACKGROUND

This cross-sectional study evaluated risk-adjusted cumulative sum (RA-CUSUM), a tool for real-time monitoring of perioperative outcomes, in liver surgery across an international multicenter cohort.

METHODS

Patients undergoing curative-intent hepatectomy for hepatocellular carcinoma (31%), intrahepatic cholangiocarcinoma (29.7%), or colorectal liver metastases (39.3%) across 25 centers (2000-2023) were analyzed. RA-CUSUM curves were generated for operative time, intraoperative blood loss, major complications (Clavien-Dindo ≥ III), and length of stay (LOS). Mixed-effects models were used for overall curves and center-specific regressions for institutional analyses. Secondary outcomes included R1 resection and 1-year recurrence comparing the first 50 and subsequent cases at each center.

RESULTS

Among 5880 cases 38.2% were major hepatectomies, while 15.1% were minimally invasive. Median operative time was 240 min (IQR 150-356), median blood loss 300 mL (IQR 100-600), and median LOS 9 days (IQR 6-14). Major complications occurred in 35.1% of patients. RA-CUSUM curves demonstrated a biphasic pattern, with deterioration coinciding with the spread of minimally invasive surgery, and subsequent improvement. Center-level curves revealed marked heterogeneity. Secondary outcomes demonstrated no uniform early-period disadvantage.

CONCLUSIONS

RA-CUSUM offers a real-time visualization of surgical performance and can guide quality review and support targeted quality-improvement initiatives in liver surgery units.