Trifecta Outcomes to Assess Learning Curve of Robotic Partial Nephrectomy

The learning curve for achieving desirable perioperative outcomes in robot-assisted partial nephrectomy (RAPN) has not been well studied. Information is available regarding "trifecta" outcomes of no complications, no positive margins, warm ischemia time (WIT) of ≤25 minutes, and a ≤15% decrease in postoperative glomerular filtration rate (GFR). This study was conducted to assess the impact of the learning curve on surgical outcomes in patients undergoing RAPN.

We reviewed 131 consecutive patients who underwent RAPN by a single, fellowship-trained surgeon from October 2007 through June 2015. Patients were divided into 4 subgroups, and mean perioperative values were compared. The learning curve was evaluated as the time it took the surgeon to attain a trifecta outcome.

Means for the RENAL Nephrometry Score, procedure length, WIT, and estimated blood loss (EBL) were 5.3 ± 1.2, 172.1 ± 43.5 minutes, 22.7 ± 7.0 minutes, and 267.2 ± 341.8 mL, respectively. Significance was noted for differences in WIT (P = .50), postoperative creatinine (P = .006), postoperative estimated (e)GFR (P = .40), and percentage change in creatinine (P = .023). The learning curve for achieving positive outcomes was noted in >61-90 cases after 66-80 months of performing minimally invasive partial nephrectomy surgeries at a rate of 20 cases per year.

RAPN is a safe, feasible procedure with slightly better surgical outcomes than laparoscopic partial nephrectomy (LPN). In the hands of an experienced surgeon, the learning curve for achieving trifecta outcomes can involve a significant number of cases over several years.