Learning Curve of Single-Port Robotic-Assisted Extraperitoneal Radical Prostatectomy: A CUSUM-Based Analysis

Background: Single-port robotic-assisted radical prostatectomy (SP-RARP) has been demonstrated to be a feasible and safe procedure. Nonetheless, the challenges of SP surgery could limit the transferability of skills from multi-port (MP) console. The aim of our study was to assess the learning curve of SP-RARP. Methods: SP-RARPs performed by a single experienced surgeon were reviewed. The surgical learning curve was assessed using risk-adjusted cumulative summation (CUSUM) methodology in terms of operative time, separately for SP-RARPs with pelvic lymphadenectomy (PLND) and without PLND. Results: 119 extraperitoneal SP-RARPs were evaluated, 83 with PLND and 36 without PLND. After CUSUM calculation, a cubic polynomial regression was performed to plot the learning curves. The inflection points, representing the number of cases required to achieve proficiency, corresponded to the 42^nd and 20^th procedure, respectively, for SP-RARP with and without PLND. The learning curves were subsequently divided into a learning phase and a proficiency phase to compare perioperative and postoperative outcomes of the two phases. In both groups, cases in the proficiency phase demonstrated significantly lower median operative times (P = .01 and P < .001) and hospital stays (P = .015 and P = .04). In the SP-RARP without the PLND group, patients in the proficiency phase demonstrated significantly lower postoperative pain scores (P = .04). No differences were found in terms of estimated blood loss, complication rates, and positive surgical margin rates (P > .05). Conclusion: Results from our analysis suggest that the learning curve of extraperitoneal SP-RARP is not longer than that reported for MP-RARP. Moreover, when cautiously approached, the learning process can be undertaken without compromising safety and oncological outcomes.