Cumulative summation analysis of learning curve for robot-assisted gastrectomy in gastric cancer

Background: The purpose of this study was to determine the learning curve for robot-assisted gastrectomy using the Cumulative Summation (CUSUM) technique.

Methods: Two series of consecutive robotic gastrectomy were retrospective analyzed. Patient demographics, surgical performance, and short-term outcomes were examined and data of operation time were abstracted for the learning curve analysis.

Results: Similar processes occurred in the two surgeons. Each of their learning curves of robotic gastrectomy was best modeled as a third-order polynomial, with equation CUSUMOT in minutes equal to 0.0495 case number (3) - 4.217 case number(2) + 91.206 case number 100.11(R(2) = .8731) for surgeon A and 0.0314 case number (3) - 2.4106 case number(2) + 33.682 case number + 315.28(R(2) = 0.8816) for surgeon B. They both included three unique phases: an initial phase, a well-developed phase, and a mastery phase after the accumulation of additional experience.

Conclusion: The CUSUM method is a useful tool for objective evaluation of practical skills for surgeons during the learning phase of robotic surgery training. The robotic gastrectomy is found to have a short learning curve for experienced laparoscopic surgeons and the popularity of this new technology won't reduce because of its difficulty to learn.