Cumulative Sum Analysis of the Learning Curve for Uniportal Video-Assisted Thoracoscopic Lobectomy and Lymphadenectomy

Abstract

Purpose: The study was performed to analyze the learning curve of performing uniportal video-assisted thoracoscopic surgery (uVATS) for lobectomy and lymphadenectomy, and to evaluate the possible disadvantages in outcomes during the course of learning. Materials and Methods: This is a prospective study of 52 consecutive patients undergoing uVATS lobectomy by a single surgeon from January 2016 to December 2017. Operation time (OPT) and the number of harvested lymph nodes (LNs) were evaluated by means of cumulative sum control chart by assessing efficiency (refinement in procedure to reach decreasing OPT and increasing number of harvested LNs) and mastery (absence of outliers). Failure rate, blood loss, and complications were retrospectively compared with the last 52 patients undergoing "classical" VATS lobectomy in the period before this study from January 2014 to December 2015. Results: Efficiency in OPT for uVATS was reached after 27 cases and mastery after 39 procedures (M_1st = 172 ± 39 minutes; M_2nd = 138 ± 34 minutes; p_{1-2 =} 0.022; M_3rd = 120 ± 25 minutes; p_{1-3 =} 0.00; p_{2-3 =} 0.65). Efficacy in the number of harvested LNs was reached after 26 cases and mastery after the 42nd procedure (MED_1st = 17, IQR 12-19; M_2nd = 21, IQR 16.25-29.75; p_{1-2 =} 0.018; M_3rd = 18, IQR 16-22; p_{1-3 =} 0.004; p_{2-3 =} 0.8). There were no significant differences in the failure rate (uVATS = 7.7%, VATS = 5.8%; P = .7), blood loss (MED_uVATS = 250 mL, IQR 200-387.5; MED_VATS = 225 mL, IQR 200-300; P = .77), and complications between the groups (uVATS = 13; 25%; VATS = 11; 21.2%; P = .41). Finally no significant differences could be found in OPT (uVATS = 151.36 ± 41.55; VATS = 156.69 ± 40.08; P = .52) or LNs (uVATS = 18, IQR 16-22; VATS = 19, IQR 14.25-20; P = .71) between the groups. Conclusions: Assuming a surgeon is skilled in "classic" VATS lung resections, achieving efficiency and mastery in uVATS is possible after sufficient experience even without dedicated education in this procedure, without measurable disadvantages throughout the course of learning. This study created a benchmark for already experienced VATS surgeons who are novices in uVATS, elucidating the number of operations required to reach both efficiency and mastery.

Keywords: CUSUM; learning curve; lobectomy; uniportal VATS.