Predictors of warm ischemia time and perioperative complications in a multicenter, international series of robot-assisted partial nephrectomy

Abstract

Background: Warm ischemia time (WIT) and complication rates are two important parameters for evaluating the perioperative results of robot-assisted partial nephrectomy (RAPN). Few data are available about the clinical predictors of WIT and overall complications.

Objective: To identify clinical predictors of WIT and perioperative complications.

Design, setting, and participants: This is a retrospective study including 347 patients who underwent RAPN for suspicious renal cell carcinoma (RCC) at four referral centers from September 2008 to September 2010.

Intervention: All patients underwent RAPN using the da Vinci S Surgical System with hilar clamping.

Measurements: WIT >20 min and overall complication rates were the main outcomes. Postoperative complications were classified according to the Clavien/Dindo system. Moreover, the following perioperative variables were considered: clinical tumor size, anatomical tumor characteristics according to Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) classification score, surgeon experience, console time, blood loss, and upper collecting system (UCS) repair.

Results and limitations: WIT >20 min was reported in 125 (36%) cases. Intraoperative and postoperative complications were observed in 10 (2.9%) and 41 (11.8%) cases, respectively. Surgeon experience (odds ratio [OR]: 6.381; 95% confidence interval [CI], 3.687-11.042; p<0.001), clinical tumor size (OR: 1.022; 95% CI, 1.002-1.044; p=0.03), the other anatomic characteristics determined by the PADUA classification score (OR: 1.294; 95% CI, 1.080-1.549; p=0.005), and the UCS repair (OR: 2.987; 95% CI, 1.728-5.165; p<0.001) turned out to be independent predictors of WIT >20 min. Similarly, surgeon experience (OR: 3.937; 95% CI, 2.011-7.705; p<0.001), clinical tumor size (OR: 1.033; 95% CI, 1.009-1.058; p=0.007), and the other anatomical characteristics determined by the PADUA classification score (OR: 1.427; 95% CI, 1.149-1.773; p<0.001) turned out to be independent predictors of overall complication rates. The retrospective design is the main limitation of this multicenter, international study. Therefore, some patient characteristics and comorbidities were not recorded.

Conclusions: Anatomic tumor characteristics as determined by the PADUA classification score were independent predictors of WIT and overall complications, once adjusted for the effects of surgeon experience and clinical tumor size.