Department of Urology, Cancer Precision Diagnosis and Treatment and Translational Medicine, Hubei Engineering Research Center, Zhongnan Hospital of Wuhan University, 169 Donghu Road, Wuhan, 430071, China.
Urolithiasis. 2024 May 27;52(1):78. doi: 10.1007/s00240-024-01585-0.
This study aims to identify optimal parameters for using Thulium fiber lasers (TFL) in ureteral stone lithotripsy to ensure laser safety and maximize efficacy. Our goal is to improve the outcomes of single-use semi-rigid ureteroscopy for treating stones located in the proximal ureter. A clinically relevant thermal testing device was designed to investigate heating effects during TFL stone fragmentation. The device was utilized to identify safe power thresholds for TFL at various irrigation rates. Three other devices were used to assess varying pulse energy effects on stone fragmentation efficiency, dusting, retropulsion, and depth of tissue vaporization. Comparative experiments in fresh porcine renal units were performed to validate the efficacy and safety of optimal TFL parameters for semi-rigid ureteroscopy in proximal ureteral stone procedures. Our study found that the improved device generated a higher thermal effect. Furthermore, the safe power threshold for laser lithotripsy increased as the irrigation rate was raised. At an irrigation rate of 40 ml/min, it is safe to use an average power of less than 30 watts. Although increasing pulse energy has a progressively lower effect on fragmentation and dust removal efficiency, it did lead to a linear increase in stone displacement and tissue vaporization depth. Thermal testing showed 20 W (53.87 ± 2.67 °C) indicating potential urothelial damage. In our study of laser lithotripsy for proximal ureteral stones, the group treated with 0.3 J pulses had several advantages compared to the 0.8 J group: Fewer large fragments (> 4 mm): 0 vs. 1.67 fragments (1-2.25), p = 0.002, a lower number of collateral tissue injuries: 0.50 (0-1.25) vs. 2.67 (2-4), p = 0.011, and lower stone retropulsion grading: 0.83 (0.75-1) vs. 1.67 (1-2), p = 0.046. There was no significant difference in operating time between the groups (443.33 ± 78.30 s vs. 463.17 ± 75.15 s, p = 0.664). These findings suggest that TFL irradiation generates a greater thermal effect compared to non-irradiated stones. Furthermore, the thermal effect during laser lithotripsy is influenced by both power and irrigation flow rate. Our study suggests that using a power below 15 W with an irrigation flow rate of 20 ml/min is safe. Moreover, a pulse energy of 0.3 J appears to be optimal for achieving the best overall stone fragmentation effect.
本研究旨在确定钬光纤激光（TFL）在输尿管结石碎石术中的最佳参数，以确保激光安全并最大限度地提高疗效。我们的目标是改善单次使用半刚性输尿管镜治疗近端输尿管结石的效果。设计了一种临床相关的热测试设备，以研究 TFL 碎石过程中的加热效应。该设备用于确定在不同冲洗速率下 TFL 的安全功率阈值。还使用了另外三个设备来评估不同脉冲能量对碎石效率、粉尘化、后向推进和组织汽化深度的影响。在新鲜猪肾单位中进行了对比实验，以验证优化后的 TFL 参数对半刚性输尿管镜治疗近端输尿管结石的疗效和安全性。我们的研究发现，改进后的设备产生了更高的热效应。此外，随着冲洗率的增加，激光碎石的安全功率阈值也随之增加。在冲洗率为 40ml/min 时，使用平均功率小于 30 瓦是安全的。虽然增加脉冲能量对碎石和粉尘去除效率的影响逐渐降低，但确实导致结石位移和组织汽化深度的线性增加。热测试显示 20W（53.87±2.67°C）表明潜在的尿路上皮损伤。在我们对近端输尿管结石的激光碎石研究中，与 0.8J 组相比，0.3J 脉冲组具有以下几个优点：
较大碎片数量减少（>4mm）：0 个（1-2.25）与 1.67 个（1-2.25）碎片，p=0.002。
组织损伤减少：0.50（0-1.25）与 2.67（2-4）个，p=0.011。
结石后向推进分级降低：0.83（0.75-1）与 1.67（1-2）级，p=0.046。
两组之间的操作时间无显著差异（443.33±78.30s 与 463.17±75.15s，p=0.664）。这表明与非照射结石相比，TFL 照射会产生更大的热效应。此外，激光碎石过程中的热效应受功率和冲洗流速的影响。我们的研究表明，使用 15W 以下的功率和 20ml/min 的冲洗流速是安全的。此外，0.3J 的脉冲能量似乎是实现最佳整体碎石效果的最佳选择。
