Department of Urology, The First Affiliated Hospital of Nanchang University, 17 YongWai Street Surgery Building, 17th Floor, Nanchang, 330006, Jiangxi, China.
Urolithiasis. 2023 Aug 17;51(1):106. doi: 10.1007/s00240-023-01469-9.
This study aims to explore the optimal location of flexible ureteral access sheath (f-UAS) in retrograde intrarenal lithotripsy (RIRS). RIRS model was built by AutoCAD 2011 software, and imported COMSOL 5.6 software to computer simulation. An RIRS model was constructed in vitro to analyze the distribution pattern of stone fragments and compare the weight of stone fragments carried out by the irrigation fluid when the f-UAS is in different positions. Computer simulation showed that the highest flow of irrigation fluid was in the channel of flexible ureteroscopy (f-URS) and in the lumen of f-UAS. From the f-URS to the renal collection system and then to the f-UAS, the velocity of irrigation fluid changes gradually from high-flow to low-flow and then to high-flow. When the f-URS and the f-UAS are at the same level, the irrigation fluid is always at a state of high flow during the process from f-URS to f-UAS. When the f-URS and the f-UAS are at the same level, it can increase the local intrarenal pressure (IRP) at the front of f-URS. The stone fragments are mainly sediment in the low-flow region of irrigation fluid. More stone fragments could follow the irrigation fluid out of the body when the tip of f-URS and the tip of f-UAS are at the same level (P < 0.001). The f-UAS should be brought closer to the stone in RIRS. And more stone fragments can be taken out of the body by the effect of irrigation fluid.
本研究旨在探讨逆行性肾内碎石术（RIRS）中柔性输尿管镜鞘（f-UAS）的最佳位置。使用 AutoCAD 2011 软件建立 RIRS 模型，并将其导入 COMSOL 5.6 软件进行计算机模拟。建立体外 RIRS 模型，分析结石碎片的分布模式，并比较 f-UAS 处于不同位置时冲洗液携带结石碎片的重量。计算机模拟显示，冲洗液的最高流速位于柔性输尿管镜（f-URS）的通道和 f-UAS 的管腔中。从 f-URS 到肾集合系统，再到 f-UAS，冲洗液的流速逐渐从高流变为低流，然后再变为高流。当 f-URS 和 f-UAS 处于同一水平时，冲洗液在从 f-URS 到 f-UAS 的过程中始终处于高流速状态。当 f-URS 和 f-UAS 处于同一水平时，它可以增加 f-URS 前端的局部肾内压（IRP）。结石碎片主要沉积在冲洗液的低流速区域。当 f-URS 尖端和 f-UAS 尖端处于同一水平时，更多的结石碎片可以随冲洗液排出体外（P < 0.001）。在 RIRS 中，f-UAS 应更靠近结石。并且冲洗液的作用可以带出更多的结石碎片。
