Robot-assisted partial nephrectomy: analysis of the first 100 cases from a single institution

Robot-assisted partial nephrectomy (RAPN) is an alternative to open and laparoscopic partial nephrectomy for small renal tumors. Our objectives were to report our experience and short-term outcomes from the first 100 cases of robot-assisted partial nephrectomy (RAPN) performed at a single institution, as well as to evaluate the effect of the learning curve and identify any factors associated with adverse perioperative outcomes. Patient records of the first 100 RAPN cases performed by three surgeons between October 2007 and March 2010 were retrospectively reviewed. The cases were divided into two groups to analyze a possible learning curve effect. Group 1 consisted of the first half (chronologically) of the cases performed by each surgeon, and Group 2 consisted of the second half. For the entire series, the median warm ischemia time was 24 min (range 11-49), mean length of follow-up was 13.4 months, and the median postoperative change in glomerular filtration rate (GFR) was -6.6 mL/min/1.73 m(2). Three patients had microscopically positive margins on final pathology, three intraoperative complications occurred, and 13 postoperative complications were recorded (10 Clavien grade IIIa or less). Median operative time was significantly longer in Group 1 (193 min) than in Group 2 (165 min, P = 0.003). Multivariate analysis identified male gender and cases done in Group 1 to be associated with increased operative time, while male gender and higher nephrometry scores were associated with increased blood loss. Tumor characteristics associated with greater reductions in GFR included higher nephrometry scores, endophytic tumors, and hilar tumors. In conclusion, RAPN appears to be safe and the major effect of the learning curve appears to be on operative time. Warm ischemia times are sufficiently low to prevent significant renal impairment, while male gender and higher nephrometry scores may be predictors of longer operative times and more intraoperative blood loss. Overall operative time decreased with increasing case volume, although this was not uniform among the three surgeons in the study. Further longitudinal study is necessary to establish oncologic outcomes.