Evaluation of the Impact of Ureteroscope, Access Sheath, and Irrigation System Selection on Intrarenal Pressures in a Porcine Kidney Model

Introduction: Elevated intrarenal pressure (IRP) during flexible ureterorenoscopy (FURS) is a predictor of postoperative complications. The aim of this study is to evaluate IRP during FURS in a porcine kidney model to determine the safest combination of irrigation device, ureteral access sheath (UAS), and ureteroscope. Methods: Urinary tracts were harvested from Landrace pigs slaughtered for the food chain. Two flexible ureteroscopes, 8.7F and 9.5F, were evaluated. Irrigation systems evaluated included the following: TraxerFlow (TM) (Rocamed, France), SAPS (TM) single action pumping system (Boston Scientific), Pathfinder Plus (TM) (Utah Medical), and a manual "bag squeeze." This experiment was conducted with no UAS, followed by an 11/13F UAS and then a 12/14F UAS. IRPs were measured in the prepared porcine kidney during all possible combinations of scope, UAS, and irrigation system. Results: Pressures were significantly reduced when using 12/14F UAS compared with 11/13F UAS (16.45 +/- 5.3 cmH(2)O vs 32.73 +/- 35.66 cmH(2)O, p = 0.006), and when using 11/13F UAS compared with no UAS (32.73 +/- 35.66 cmH(2)O vs 49.5 +/- 29.36 cmH(2)O, p = 0.02). Pressures were significantly reduced with the 8.7F scope compared with the 9.5F scope (24.1 +/- 21.24 cmH(2)O vs 41.68 +/- 34.5 cmH(2)O, p = 0.001). SAPS generates significantly greater IRP than TraxerFlow, Pathfinder Plus, and a "bag squeeze" (p < 0.05). The most dangerous combination was using the SAPS, no UAS, and larger ureteroscope leading to an IRP of 100.6 +/- 16.1 cmH(2)O. The safest combination was using Pathfinder Plus with a 12/14F UAS and smaller ureteroscope giving an IRP of 11.6 +/- 3.65 cmH(2)O. Conclusion: IRPs are reduced by selecting larger UAS and a small ureteroscope. The SAPS generates significantly higher IRPs than other irrigation systems. To maintain safe IRPs during FURS, urologists should use large UAS, narrow ureteroscopes, and be cautious in the selection of an irrigation device.