Learning curve for robotic bedside assistance for rectal cancer: application of the cumulative sum method

Background This investigation assesses the learning curve for dedicated bedside assistance at a facility that recently adopted robot-assisted rectal resection. Methods Data from patients with rectal cancer who underwent robotic rectal resections from September 2019 through April 2020 were retrospectively analyzed. Before starting robotic surgery, we set the rule that a console surgeon would not enter the sterile field and all of those maneuvers would be left to a dedicated physician. Docking time was analyzed using the cumulative sum (CUSUM) method to evaluate the learning curve. Different phases in the learning curve were identified according to CUSUM plot configuration. A comparison was made of phases 1 and 2 combined, and phase 3. Result The procedures were performed in 30 patients. Median docking time, console time was 13 min. A total of nine patients had histories of abdominal surgery. CUSUM analysis of docking time demonstrated 3 phases. Each docking time was longer in Phase 1 (the first 3 cases) than the average docking time over the all cases. The docking time in Phase 2 (the 9 middle cases) approximated the average time over the all cases. Phase 3 (the remaining 18 cases) showed further improvement of the docking procedure and time was reduced. A comparison of Phases 1 and 2 combined, and Phase 3, revealed that Phase 3 had a significantly higher rate of history of abdominal surgery. Conclusion Docking manipulation proficiency was achieved in approximately 10 cases without the influence of surgical difficulty.