Evaluating the learning curve for laparoscopic liver resection: a comparative study between standard and learning curve CUSUM

Background: Laparoscopic liver resection (LLR) requires training in both hepatobiliary surgery and advanced laparoscopy. Available data on LLR learning curves are derived from pioneer surgeons. The aims of this study were to evaluate the LLR learning curve for second generation surgeons, and to compare different CUSUM methodology with and without risk adjustment. Methods: Retrospective analysis of a prospective database of 111 consecutive patients who underwent LLR by two surgeons at a single centre between 2011 and 2016. The LLR learning curve for minor hepatectomy (MH) was evaluated for each surgeon using standard CUSUM before and after risk-adjusting for operative difficulty using the Iwate index, and compared with Learning Curve (LC) CUSUM. The end points were operative time and conversion rate. Results: Standard CUSUM analysis identified a learning curve of 50-60 MH procedures. The corresponding learning curve reduced to 25-30 after risk-adjusting for operative difficulty, whilst LC-CUSUM identified a learning curve of 17-25 procedures. Conclusions: The learning curve for laparoscopic minor liver resection by second generation surgeons is shorter than that for pioneer surgeons. Laparoscopic HPB fellowship programmes may further shorten the learning curve, facilitating safe expansion of LLR. The LC-CUSUM method is an alternative technique that warrants further study.