473 Background: The word heminephrectomy originally referred to the removal of half of a kidney with a duplicated collecting system. In the era of partial nephrectomies, heminephrectomy is sometimes used to describe the removal for tumor of >30% of the parenchyma of a non-duplicated kidney. We herein propose a new definition of heminephrectomy: excision of the upper or lower pole of the kidney, removing at least 30% of the parenchymal mass, cutting to hilar fat, and transecting the collecting system. Methods: Our institutional database of robotic and laparoscopic partial nephrectomies was queried for patients who underwent a partial nephrectomy for tumor between 2002 and 2011. Patients who had a heminephrectomy for obstruction in a duplicated collecting system were excluded. The patients who had a heminephrectomy by our strict definition were compared to the remainder of patients who had a partial nephrectomy. Logistic regression was used to compare outcomes between the two groups. Results: 61 patients met our strict definition of heminephrectomy out of 643 patients who underwent a partial nephrectomy for tumor. Heminephrectomy and non-heminephrectomy patients were similar in age, gender, BMI, ASA score, proportion of left- versus right-sided tumors, solitary kidney status, preoperative creatinine and GFR. (all p>0.1). The tumors in the heminephrectomy group were larger (5.1 vs. 2.8 cm, p<0.001) and had a higher R.E.N.A.L nephrometry score (8.5 vs. 6.5, p<0.001). Operative outcomes reflected the high complexity of performing a heminephrectomy. Estimated blood loss was greater (373 vs. 267 ml, p=0.04), operative time was longer (214 vs. 185 minutes, p<0.001), warm ischemia time was longer (25 vs. 20 minutes, p=0.002), and the rate of intra-operative complications was greater (11% vs. 4%, p=0.02) in the heminephrectomy group. On multivariable analysis adjusted for age, preoperative GFR, R.E.N.A.L. score, and warm ischemia time, heminephrectomy was a significant predictor of lower post-operative GFR (p<0.001). Conclusions: Our strict definition of heminephrectomy performed for tumor in a non-duplicated system will allow precise clinical and research communication about heminephrectomy patients and may aid in the prediction of outcomes after partial nephrectomy.
Anatomic Complexity Quantitated by Nephrometry Score Is Associated With Prolonged Warm Ischemia Time During Robotic Partial Nephrectomy