Partial nephrectomy is the standard treatment for small renal masses. The evolution of minimally invasive partial nephrectomy led to widespread utilization of laparoscopic (LPN) and robotic partial nephrectomy (RPN). Both LPN and RPN can be performed through transperitoneal (TP) or retroperitoneal (RP) approach. RP approach is less utilized than TP approach because of technical difficulties when using rigid laparoscopic instruments in the small space of retroperitoneum cavity. However, with advanced surgical skills and thoughtful patient selection, RP approach may be associated with shorter OT, less EBL, shorter LOS compared with TP approach.~Therefore, the investigators performed randomized control trial to compare the outcomes of the two approaches (TP-LPN or RPN vs RP-LPN or RPN).~The purpose of this study To compare the treatment outcomes of the transperitoneal and retroperitoneal approach during LPN or RPN in treatment of small renal masses.~Inclusion criteria During the study period, a small renal mass (less than 4cm, T1a stage) patients are going to underwent LPN or RPN.~Exclusion criteria~Patients who underwent radical nephrectomy~Patients with bilateral renal masses~Patients with a solitary kidney~Patients reject a written informed consent~Pregnancy~The number of target subjects More than 106 patients who meet the inclusion criteria
Both laparoscopic partial nephrectomy (LPN) and robotic partial nephrectomy (RPN) can be performed through transperitoneal (TP) or retroperitoneal (RP) approach. RP approach is less utilized than TP approach because of technical difficulties when using rigid laparoscopic instruments in the small space of retroperitoneum cavity. However, with advanced surgical skills and thoughtful patient selection, RP approach may be associated with shorter operative time (OT), less estimated blood loss (EBL), shorter length of hospital stay (LOS) compared with TP approach.~Therefore, the investigators performed randomized control trial to compare the outcomes of the two approaches (TP-LPN or RPN vs RP-LPN or RPN).