Thirty-six Large White male pigs (28.29±5.48 Kg) were used. The ureteral obstruction model was developed by placing a Hem-o-lok ® (Teleflex Medical, North Carolina) in the proximal third of the left ureter. The subjects used in this study were randomly divided into groups, depending on the approach used to create the model: laparoscopic conventional surgery (LAP) or single port (LSP). Both groups were further divided in transperitoneal (+T) or retroperitoneal (+R) approaches.