“The Critical 18” of postoperative white blood cell count and C-reactive protein level predicts postoperative pancreatic fistula after distal pancreatectomy

Background Distal pancreatectomy (DP) carries high risk for postoperative pancreatic fistula. This study evaluates white blood cell count (WBC), C-reactive protein (CRP) and interleukin-6 (IL-6) as serum-based predictors, offering potential alternatives to drain amylase for early pancreatic fistula diagnosis. Methods This retrospective cohort study included adult patients who underwent elective distal pancreatectomy between 01/2014 and 12/2023. Inclusion criteria required the availability of WBC count and CRP levels during the first three postoperative days. Exclusions were prior pancreatic surgery, combined DP/enucleation, or missing data. Data collected included demographics, comorbidities, intraoperative details, and postoperative serum markers (WBC, CRP, IL-6) from postoperative day 1 to postoperative day 3. Results This study included 210 patients who underwent distal pancreatectomy and met all inclusion criteria. Median WBC counts were significantly higher in patients with pancreatic fistula, especially on postoperative day 2 (18.5 × 10⁹/L vs. 16.0 × 10⁹/L, p < 0,01). CRP levels peaked higher in the pancreatic fistula group on postoperative day 3 (19.8 mg/dL vs. 15.3 mg/dL, p < 0.001). IL-6 levels showed no significant difference. Receiver Operating Characteristic (ROC) analysis identified WBC on postoperative day 2 (AUC = 0.62) and CRP on postoperative day 3 (AUC = 0.65) as relevant predictors, with optimal cut-off values of 17.9 × 10⁹/L and 17.2 mg/dL, respectively, which were rounded to 18. The combined elevation of both markers, defined as the “Critical 18” was associated with a markedly higher pancreatic fistula rate (59% vs. 18% in patients without elevation of either marker). Conclusions In light of these findings, we propose the “The Critical 18” as a simple yet powerful tool for early risk stratification of pancreatic fistula following distal pancreatectomy. By using WBC > 18 × 10 × 9/L on postoperative day 2 and CRP > 18 mg/dl on postoperative day 3, clinicians can easily identify patients at escalating risk, offering a clear framework for guiding postoperative management and interventions. Clinical trial number Not applicable.