Postoperative acute pancreatitis affects recovery after pancreatoduodenectomy—understanding its definitions can optimize patient management.

• Incidence of postoperative acute pancreatitis: 11.9% (ISGPS), 41.2% (Atlanta-adapted), and 17.6% (Connor’s definition).
• The Atlanta-adapted framework showed the best ability to predict severe complications (AUC 0.68).
• A new graded Atlanta-Helsinki classification correlates with complication rates: 12.3% (none), up to 56.3% (both criteria).

Adopting this classification can refine decision-making and improve patient outcomes post-surgery.