Primary paper: pmc.ncbi.nlm.nih.gov/articles/PMC1360123/ . Daniel Dindo, Nicolas Demartines and Pierre-Alain Clavien, Annals of Surgery 240(2), 205–213 (2004); DOI doi.org/10.1097/01.sla.0000133083.54934.ae . Methods and Definitions distinguish deviation from normal postoperative course, failure to cure and inherent sequelae. Table 1 states the revised classification. Evaluation used a 6,336-patient cohort and an international surgeon survey.
Patients and Methods, Validation of the Modified Classification: patients with more than one complication were represented by their most severe complication. The international survey used clinical case descriptions; the abstract reports 144 surgeon respondents from 10 centers. These reporting choices distinguish patient-level severity summaries from total event counts and raw agreement from clinical validity.