Post-Pancreatectomy Chyle Leak: Annals of Surgery | June 2026

• This study evaluated 1,063 patients undergoing pancreatic surgery; 11% developed conventionally defined chyle leak.
• Most clinically relevant cases were grade B, while no grade C leaks were reported.
• A minimally invasive surgical approach was independently associated with a higher likelihood of chyle leak.
• Maximum daily drain output was also strongly associated with clinically relevant leakage.
• The key finding was that triglyceride-rich drainage was frequently not milky.
• More than one-third of patients had drain triglycerides ≥1.2 mmol/L despite the absence of classic milky-colored fluid.
• Patients with high-volume drainage ≥300 mL/day and elevated triglycerides had prolonged hospitalisation, even when the drainage appeared clear or non-milky.
• Their length of stay was comparable to that of patients with high-volume, triglyceride-rich, visibly milky drainage.
• In contrast, low-volume triglyceride-rich drainage had less clinical impact.
• These findings challenge reliance on drain appearance when diagnosing post-pancreatectomy chyle leak.
• Measuring both drain triglyceride concentration and daily output volume may identify clinically important lymphatic leakage more accurately.
• The current International Study Group for Pancreatic Surgery definition may therefore underestimate clinically relevant cases that lack a milky appearance.
• As this was an observational single-centre study, external validation is needed before formal diagnostic criteria are changed.

Bottom line: After pancreatic surgery, high-volume triglyceride-rich drainage should be managed as a clinically relevant chyle leak even when it is not milky.