Predictive factors of prolonged warm ischemic time (≥30 minutes) during partial nephrectomy under pneumoperitoneum

PURPOSE: Current clinical data support a safe warm ischemia time (WIT) limit of 30 minutes during laparoscopic partial nephrectomy (LPN) or robot-assisted partial nephrectomy (RPN). We evaluated independent factors predicting prolonged WIT (more than 30 minutes) after LPN or RPN. MATERIALS AND METHODS: A retrospective data review was performed for 317 consecutive patients who underwent LPN or RPN performed by the same surgeon from October 2007 to May 2013. Patients were divided into two groups: group A was defined as prolonged WIT (≥30 minutes) and group B as short WIT (<30 minutes). We compared clinical factors between the two groups to evaluate predictors of prolonged WIT. RESULTS: Among 317 consecutive patients, 80 were in the prolonged WIT group. Baseline characteristics were not significantly different between the groups. In the univariable analysis, PADUA (preoperative aspects and dimensions used for an anatomical) score (p=0.001), approach method (transperitoneal or retroperitoneal approach; p<0.001), and surgeon experience (p<0.001) were significantly associated with prolonged WIT. In the multivariable analysis, PADUA score (p=0.032), tumor size (≥25 mm; odds ratio, 2.98; 95% confidence interval, 1.48-5.96; p=0.002), and surgeon experience (p<0.001) were independent predictors of prolonged WIT. CONCLUSIONS: Surgeon experience, tumor size, and PADUA score predicted prolonged WIT after RPN or LPN. Among these factors, increasing surgical experience with LPN or RPN is the most important factor for preventing prolonged WIT.