An International Expert Delphi Consensus on Defining Textbook Outcome in Liver Surgery (TOLS)

Objective: to reach global expert consensus on the definition of TOLS in minimally invasive and open liver resection among renowned international expert liver surgeons using a modified Delphi method.Summary background data: textbook outcome is a novel composite measure combining the most desirable postoperative outcomes into one single measure and representing the ideal postoperative course. Despite a recently developed international definition of Textbook Outcome in Liver Surgery (TOLS), a standardized and expert consensus-based definition is lacking.Methods: this international, consensus-based, qualitative study used a Delphi process to achieve consensus on the definition of TOLS. The survey comprised 6 surgical domains with a total of 26 questions on individual surgical outcome variables. The process included 4 rounds of online questionnaires. Consensus was achieved when a threshold of at least 80% agreement was reached. Results from the Delphi rounds were used to establish an international definition of TOLS.Results: in total, 44 expert liver surgeons from 22 countries and all three major international hepato-pancreato-biliary associations completed round 1. Forty-two (96%), 41 (98%) and 41 (98%) of the experts participated in round 2, 3 and 4, respectively. The TOLS definition derived from the consensus process included the absence of intraoperative grade ≥2 incidents, postoperative bile leakage grade B/C, postoperative liver failure grade B/C, 90-day major postoperative complications, 90-day readmission due to surgery-related major complications, 90-day/in-hospital mortality and the presence of R0 resection margin.Conclusions: this is the first study providing an international expert consensus-based definition of TOLS for minimally invasive and open liver resections by use of a formal Delphi consensus approach. TOLS may be useful in assessing patient-level hospital performance and carrying out international comparisons between centers with different clinical practices to further improve patient outcomes.