Initial learning curve for robot-assisted partial nephrectomy performed by a single experienced robotic surgeon

The objective of this study was to evaluate the initial learning curve for robot-assisted partial nephrectomy (RAPN) using the da Vinci Xi Surgical System (Intuitive Surgical, Sunnyvale, California).

This study included the initial 65 consecutive patients with small renal tumors who had undergone RAPN at our institution. A single trained surgeon with extensive experience in robot-assisted radical prostatectomy, but not in laparoscopic partial nephrectomy, performed RAPN for all patients using the da Vinci Xi. The learning curve was analyzed by examining the perioperative outcomes among five groups each consisting of 13 consecutive patients.

In this series, the median tumor size and R.E.N.A.L. nephrometry score were 23 mm and 7, respectively, and the median console time and warm ischemia time (WIT) were 116 and 15 minutes, respectively. Fifty-eight patients (89.2%) achieved trifecta outcomes, meaning that the ischemic time was ≤25 minutes, there was a negative surgical margin, and no major postoperative complications occurred. Although there were no significant changes in R.E.N.A.L. nephrometry scores over time, increased surgeon experience was significantly associated with a shorter console time and WIT. Drawing logarithmic approximation curves enabled the achievement of a console time ≤150 minutes and WIT ≤20 minutes at the sixth and fourth procedures, respectively. Furthermore, multivariate analysis identified an independent correlation between surgeon experience with WIT, but not with console time.

These findings suggest that regardless of a surgeon's prior experience in laparoscopic partial nephrectomy, an experienced robotic surgeon can perform RAPN using the da Vinci Xi with acceptable perioperative outcomes after a small number of procedures.