1 3 World J Urol DOI 10.1007/s00345-016-1798-2 ORIGINAL ARTICLE Impact of parenchymal loss on renal function after laparoscopic partial nephrectomy under warm ischemia Fariborz Bagheri 1,2 · Csaba Pusztai 2 · László Farkas 2 · Panagiotis Kallidonis 3 · István Buzogány 4 · Zsuzsanna Szabó 5 · János Lantos 6 · Marianna Imre 7 · Nelli Farkas 8 · Árpád Szántó 2 Received: 6 January 2016 / Accepted: 16 February 2016 © Springer-Verlag Berlin Heidelberg 2016 P-DRF of the operated kidney was attributed to the RI. Subtraction of the P-DRF decline from the T-DRF decline was attributed to the parenchymal loss caused by the resec- tion of the tumor and suturing of the normal parenchyma. Results The mean WI time was 22 min, and the mean weight of resected specimen was 18 g. The mean postoper- ative eGFR declined to 87 ml/min/1.73 m 2 from its baseline mean value of 97 ml/min/1.73 m 2 (p value = 0.075). Mean postoperative T-DRF and P-DRF of the operated kidney declined by 7 and 3 %, respectively. Conclusions After LPN of small renal mass, decline in renal function is primarily attributed to parenchymal loss caused by tumor resection and suturing of the normal parenchyma rather than the RI. Keywords Laparoscopy · Parenchymal loss · Partial nephrectomy · Renal function · Warm ischemia Introduction Partial nephrectomy (PN) has become a standard of care for treatment of small renal masses. Hilar occlusion is com- monly performed for a precise tumor resection and renal reconstruction. The above surgical maneuver results in warm ischemia (WI) of the remaining renal tissue and has been associated with ischemic reperfusion injury (RI) to the organ. Current evidence showed that the length of the warm ischemia time (WIT) and the subsequent RI may result in permanent renal damage [1, 2]. Moreover, the resection of the renal tumor and the suturing of the parenchyma resulted in additional reduction in the functional renal tissue [3, 4]. Thus, two mechanisms of renal function damage dur- ing PN could be proposed. Nevertheless, the importance of the mechanisms for the decline of the postoperative renal Abstract Purpose To elucidate the impact of renal parenchymal loss and the ischemic reperfusion injury (RI) on the renal function after laparoscopic partial nephrectomy (LPN) under warm ischemia (WI). Methods Thirty-five patients with a single polar renal mass ≤4 cm and normal contralateral kidney underwent LPN. Transperitoneal LPN with WI using en bloc hilar occlusion was performed. The total differential renal func- tion (T-DRF) using 99m Tc-dimercaptosuccinic acid was evaluated preoperatively and postoperatively over a period of 1 year. A special region of interest (ROI) was selected on the non-tumorous pole of the involved kidney, and was compared with the same ROI in the contralateral kidney. The latter comparison was defined as partial differential renal function (P-DRF). Any postoperative decline in the * Panagiotis Kallidonis pkallidonis@yahoo.com 1 Department of Urology, Dubai Hospital, Dubai Health Authority, Dubai, UAE 2 Department of Urology, University of Pécs Medical School, Pécs, Hungary 3 Department of Urology, University of Hospital of Patras, 26504 Rion, Patras, Greece 4 Department of Urology, PéterfySándor Street Hospital, Budapest, Hungary 5 Department of Nuclear Medicine, University of Pécs Medical School, Pécs, Hungary 6 Department of Research and Techniques, University of Pécs Medical School, Pécs, Hungary 7 Diagnostic Center of Pécs, Pécs, Hungary 8 Institute of Bioanalysis, University of Pécs Medical School, Pécs, Hungary