Photo Credit: Pikovit44

The following is a summary of “Comparison of the safety of flexible ureteroscopy with the different irrigation methods in a 3D print kidney model,” published in the November 2024 issue of Urology by Bai et al. 

Researchers conducted a retrospective study to analyze intrarenal pressure (IRP) and irrigation flow by adjusting water height and manual pressure during flexible ureteroscopy (fURS ) in a 3D-printed kidney model. 

A 3D-printed silicone model simulated the kidney, with a ureteral access sheath (UAS) connected at the ureteropelvic junction. Central venous pressure tubing monitored renal pelvis pressure under varying conditions. Sheath sizes of 12Fr and 14Fr were tested with fURS sizes of 7.5, 8.5, and 9.5Fr, respectively. Gravity-based irrigation was applied, with water heights set at 60, 90, 120, 150, and 180 cm, while manual pumping measured maximum IRP. 

The results showed that with a 12Fr sheath and 9.5Fr fURS, IRP was 8.4–17.5 cmH2O, exceeding 60 cmH2O with manual pumping. Adding a 200-um laser fiber lowered IRP to 6.4–10.5 cmH2O, and a stone basket reduced it to 4.0–5.0 cmH2O. Using a 14Fr sheath with 9.5Fr fURS reduced IRP to 2.5–6.0 cmH2O (17 cmH2O with manual pumping). With a 12Fr sheath and 7.5Fr fURS, IRP was 5.4–8.2 cmH2O, increasing to 25.5 cmH2O with manual pumping. Using a 14Fr sheath and 7.5Fr fURS, IRP was 1.5–4.3 cmH2O, reaching 9.0 cmH2O with manual pumping. 

The study concluded that IRP remained within a safe range using different fURS/UAS combinations with suspended water heights below 180 cm. However, they found that manual pumping with specific fURS/UAS (9.5Fr/12Fr) combos exceeded safe IRP limits. 

Source: bmcurol.biomedcentral.com/articles/10.1186/s12894-024-01638-x