Abstract
BACKGROUND: Postoperative pancreatic fistula (POPF) is a major complication after left pancreatectomy. The current International Study Group of Pancreatic Surgery classification has limitations, including heterogeneity in morbidity and high interobserver variability. This study aimed to assess POPF-related morbidity after left pancreatectomy and propose a refined classification system. METHODS: Patients undergoing left pancreatectomy at nine high-volume centres between January 2010 and April 2023 were included. All postoperative treatments and interventions related to POPF were collected. The Comprehensive Complication Index (CCI) was used to assess total cumulative morbidity. The International Study Group of Pancreatic Surgery B POPF was subclassified (B1 = prolonged drainage, B2 = pharmacological intervention, B3 = percutaneous intervention, B4 = endoscopic or angiographic intervention). A new POPF grading system was developed by combining subclasses with similar morbidity. RESULTS: Among 2284 patients, 497 (21.8%) had B (B1: 48 (2.1%), B2: 135 (5.9%), B3: 175 (7.7%), B4: 99 (4.3%)) or C (40 (1.8%)) POPF. Median (interquartile range) POPF-related CCI was 33.5 (22.6-39.7). A significant overlap existed between B and C POPF in terms of CCI. Median CCI (i.q.r.) increased with the B POPF subclasses (B1-B4), 8.7 (8.7-8.7) - 22.6 (20.9-22.6) - 33.5 (33.5-34.6) - 47.4 (39.7-52.1) (P < 0.001), but no difference between B4 POPF and C POPF was observed (median CCI 47.4 versus 50.2; P = 0.265). The refined POPF grading system consists of grades 0 (including biochemical leak and B1), A (including B2), B (including B3), and C (including B4 and C) reflecting worsening morbidity. CONCLUSION: The current International Study Group of Pancreatic Surgery classification includes highly heterogeneous grade B POPF cases, ranging from minimal to severe morbidity. The refined grading system improves classification and clinical relevance by aligning POPF severity with morbidity and short-term outcomes.