A complexity-based and stepwise learning curve in 607 laparoscopic liver resections: a single surgeon analysis to define a standard for technical improvement

Abstract

Importance: The standard educational path to complete the learning curve in laparoscopic liver resections (LLR) should be defined taking into account the degree of surgical complexity, to maintain an adequate profile of safety until its completion. Objective: To define a single surgeon learning curve in a series of procedures grouped according to their complexity calculated by difficulty index to define a standard for technical improvement. Design: 607 LLR performed by a single surgeon (2005-2017) were stratified by difficulty scores: Low-Difficulty (LD, n=227); Intermediate-Difficulty (ID, n=197) and High-Difficulty (HD, n=183). The learning curve effect was analyzed in the three Groups using the Cumulative Sum (CUSUM) method taking into consideration the expected risk of conversion. Results: Along with increasing numerosity and complexity of cases, the ratio laparoscopic/total liver resections increased from 5.8% (2005) to 72.8% (2017). The CUSUM analysis per group showed that the average value of the conversion rate was reached at the 50th case in the LD Group and at the 15th in the ID and HD groups. The evolution from LD to ID and HD procedures occurred only when learning curve in LD resections was concluded. Reflecting different degree of complexity, procedures showed significantly different blood loss, morbidity and conversions among groups. Conclusion: A standard educational model - stepwise and progressive - is mandatory to allow surgeons to define the technical and technological background to deal with a specific degree of difficulty, providing an help in the definition of indications to laparoscopic approach in each phase of training.