Assessment of Quality Outcomes and Learning Curve for Robot-Assisted Minimally Invasive McKeown Esophagectomy

Background: This study aimed to identify the results of the quality assessment and the learning curve of robot-assisted minimally invasive McKeown esophagectomy (RAMIE-MK). Methods: The study retrospectively reviewed the data of 400 consecutive patients with esophageal cancer who underwent RAMIE-MK by a single surgeon from November 2015 to March 2019. Cumulative summation analysis of the learning curve was performed. The patients were divided into decile cohorts of 40 cases to minimize demographic deviations and to maximize the power of detecting statistically significant changes in performance. Results: The 90-day mortality rate for all the patients was 0.5% (2 cases). The authors’ experience was divided into the ascending phase (40 cases), the plateau phase (175 cases), and the descending phase (185 cases). After 40 cases, significant improvements in operative time (328 vs. 251 min; P = 0.019), estimated blood loss (350 vs. 200 ml; P = 0.031), and conversion rates (12.5% vs. 2.5%; P < 0.001) were observed. After 80 cases, a decrease in the rates of anastomotic leakage (22.5% vs. 8.1%; P = 0.001) and vocal cord palsy (31.3% vs. 18.4%; P = 0.024) was observed. The number of harvested lymph nodes increased after 40 cases (13 vs. 23; P < 0.001), especially for lymph nodes along the recurrent laryngeal nerve (3.0 vs. 6.0; P < 0.001). Conclusions: The learning phase of RAMIE-MK consists of 40 cases, and quality outcomes can be improved after 80 procedures. Several turning points related to the optimization of surgical outcomes can be used as benchmarks for surgeons performing RAMIE-MK.