Robotic partial nephrectomy outcomes at a single institution and experience with R.E.N.A.L. nephrometry score

Partial nephrectomy is the current gold-standard treatment of small renal masses. The articulated instruments of the surgical robot have made the laparoscopic approach more feasible. We present our experience with 50 robot-assisted laparoscopic partial nephrectomy (RALPN) surgeries and attempt to validate a recently reported nephrometry score. From July 2008 to July 2010, 50 (53 planned) elective RALPNs were performed utilizing the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA). All patients had an enhancing renal mass on CT scan pre-operatively. Clinicopathologic, surgical, and renal functional (Cockcroft-Gault formula) outcomes were recorded prospectively and analyzed. Mean tumor size, length of surgery (LS), warm ischemia time (WIT), and nephrometry scores were 3.6 cm (1-8), 303 min (133-610), 29.1 min (11-42), and 6.8 (4-11) respectively. Renal cell carcinoma was found in 39 (78%) patients. When evaluating the nephrometry score, comparison of low, medium, and high complexity tumors for length of surgery, WIT, and estimated blood loss (EBL) showed no difference (p > 0.05). Nearness to the collecting system (N score 1 vs. N score 3) showed increased EBL (195 ml vs. 510 mL, p = 0.005), and location relative to polar lines (L score 1 and L score 2) increased mean LS (265 vs. 359 min, p = 0.02). RALPN is safe and effective. Nephrometry scores are a method of standardizing tumor complexity and can be utilized in comparing tumor cohorts but may not be predictive of intra-operative outcomes.